WorldWideScience

Sample records for analysis load

  1. Umbilical cable recovery load analysis

    Science.gov (United States)

    Yan, Shu-wang; Jia, Zhao-lin; Feng, Xiao-wei; Li, Shi-tao

    2013-06-01

    Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field. The severe ocean environment makes great challenges to umbilical maintenance and repair work. Damaged umbilical is usually recovered for the regular operation of the offshore production system. Analysis on cables in essence is a two-point boundary problem. The tension load at the mudline must be known first, and then the recovery load and recovery angle on the vessel can be solved by use of catenary equation. The recovery analysis also involves umbilical-soil interaction and becomes more complicated. Calculation methods for recovery load of the exposed and buried umbilical are established and the relationship between the position of touch down point and the recovery load as well as the recovery angle and recovery load are analyzed. The analysis results provide a theoretical reference for offshore on-deck operation.

  2. Umbilical Cable Recovery Load Analysis

    Institute of Scientific and Technical Information of China (English)

    YAN Shu-wang; JIA Zhao-lin; FENG Xiao-wei; LI Shi-tao

    2013-01-01

    Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field.The severe ocean environment makes great challenges to umbilical maintenance and repair work.Damaged umbilical is usually recovered for the regular operation of the offshore production system.Analysis on cables in essence is a two-point boundary problem.The tension load at the mudline must be known first,and then the recovery load and recovery angle on the vessel can be solved by use of catenary equation.The recovery analysis also involves umbilicalsoil interaction and becomes more complicated.Calculation methods for recovery load of the exposed and buried umbilical are established and the relationship between the position of touch down point and the recovery load as well as the recovery angle and recovery load are analyzed.The analysis results provide a theoretical reference for offshore on-deck operation.

  3. Automated Loads Analysis System (ATLAS)

    Science.gov (United States)

    Gardner, Stephen; Frere, Scot; O’Reilly, Patrick

    2013-01-01

    ATLAS is a generalized solution that can be used for launch vehicles. ATLAS is used to produce modal transient analysis and quasi-static analysis results (i.e., accelerations, displacements, and forces) for the payload math models on a specific Shuttle Transport System (STS) flight using the shuttle math model and associated forcing functions. This innovation solves the problem of coupling of payload math models into a shuttle math model. It performs a transient loads analysis simulating liftoff, landing, and all flight events between liftoff and landing. ATLAS utilizes efficient and numerically stable algorithms available in MSC/NASTRAN.

  4. Load Characteristics Analysis of State Grid

    Institute of Scientific and Technical Information of China (English)

    Chen Wei; Zhou Feng; Han Xinyang; Shan Baoguo; Zhu Li

    2009-01-01

    @@ Introduction Analysis and forecast of load characteristics are important aspects in power market analysis and prediction.Correctly mastering grid load characteristics and its development trend is not only the vital basis for power planning,generation and operation,but also the important references for formulating the relevant policies.It is usually very hard to grasp the load characteristics of power grid.

  5. PLASTIC LIMIT LOAD ANALYSIS OF DEFECTIVE PIPELINES

    Institute of Scientific and Technical Information of China (English)

    ChenGang; LiuYinghua; XuBingye

    2003-01-01

    The integrity assessment of defective pipelines represents a practically important task of structural analysis and design in various technological areas, such as oil and gas industry, power plant engineering and chemical factories. An iterative algorithm is presented for the kinematic limit analysis of 3-D rigid-perfectly plastic bodies. A numerical path scheme for radial loading is adopted to deal with complex multi-loading systems. The numerical procedure has been applied to carry out the plastic collapse analysis of pipelines with part-through slot under internal pressure, bending moment and axial force. The effects of various shapes and sizes of part-through slots on the collapse loads of pipelines are systematically investigated and evaluated. Some typical failure modes corresponding to different configurations of slots and loading forms are studied.

  6. Lateral load pattern in pushover analysis

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The seismic capacity curves of three types of buildings including frame, frame-shear wall and shear wall obtained by pushover analysis under different lateral load patterns are compared with those from nonlinear time history analysis. Based on the numerical results obtained a two-phase load pattern: an inverted triangle(first mode)load pattern until the base shear force reaches β times its maximum value,Vmax, followed by a(x/H)α form, here β and α being some coefficients depending on the type of the structures considered, is proposed in the paper, which can provide excellent approximation of the seismic capacity curve for low-to-mid-rise shear type buildings. Furthermore, it is shown both the two-phase load pattern proposed and the invariant uniform pattern can be used for low-to-mid-rise shear-bending type and low-rise bending type of buildings. No suitable load patterns have been found for high-rise buildings.

  7. Transient loads analysis for space flight applications

    Science.gov (United States)

    Thampi, S. K.; Vidyasagar, N. S.; Ganesan, N.

    1992-01-01

    A significant part of the flight readiness verification process involves transient analysis of the coupled Shuttle-payload system to determine the low frequency transient loads. This paper describes a methodology for transient loads analysis and its implementation for the Spacelab Life Sciences Mission. The analysis is carried out using two major software tools - NASTRAN and an external FORTRAN code called EZTRAN. This approach is adopted to overcome some of the limitations of NASTRAN's standard transient analysis capabilities. The method uses Data Recovery Matrices (DRM) to improve computational efficiency. The mode acceleration method is fully implemented in the DRM formulation to recover accurate displacements, stresses, and forces. The advantages of the method are demonstrated through a numerical example.

  8. Pressure Hull Analysis under Shock Loading

    Directory of Open Access Journals (Sweden)

    Ya-Jung Lee

    2008-01-01

    Full Text Available The hull of high performance submarines must resist underwater shock loading due to exploding torpedoes or depth bombs. An underwater shock involving an initial shock wave and successive bubble pulsating waves is so complex that a theoretical technique for deriving shock pressure distribution is required for improving simulation efficiency. Complete shock loading is obtained theoretically in this work, and responses of a submarine pressure hull are calculated using ABAQUS USA (Underwater Shock Analysis codes. In the long run, this deflection and stress data will assist in examining the structural arrangement of the submarine pressure hull.

  9. Contact analysis and load distribution of double-envelop hourglassworm gearing affected by errors and load

    Institute of Scientific and Technical Information of China (English)

    XU Wujiao; QIN Datong; SHI Wankai

    2003-01-01

    An approach for the contact analysis and load distribution of double-envelop hourglass worm gearing is presented,which is based on a 3-D elastic contact finite element method (FEM) model that 3ccommodates the influence of errors and load.As compared with existing tooth contact analysis model that assumes rigidity for the contacting surfaces, the proposed model provides a more realistic analysis on the contact patterns, the distribution of contact load and transmission errors. It is also capable of exploring the influence of different errors on meshing performances, the contact deformation, the shift of the contact zone and load share among the meshing tooth-pairs under different load.

  10. An Analysis on Limit Load for Corroded Submarine Pipelines

    Institute of Scientific and Technical Information of China (English)

    TAN Kai-ren; XIAO Xi

    2006-01-01

    By means of elastic-plastic finite element analysis, a systematic nonlinear analysis of material and geometry has been carried out for submarine pipelines. A criterion for deriving limit load is studied. Based on this criterion, the limit load for corroded submarine pipelines is calculated. The corrosion length, corrosion depth and corrosion width affect the limit load. A solution to limit load is proposed and proved valid through comparison of the solution with burst test results and ASME B31G solutions.

  11. Structural Analysis Of Offshore Structures Exposed To Blast Loads

    DEFF Research Database (Denmark)

    Hansen, Hans Jakup; Thygesen, Ulf; Kristensen, Anders;

    2002-01-01

    Numerical methods for simulations of blast loads and resulting structural response are investigated and compared to results obtained from tests. The CFD code EXSIM is used for the simulation of the blast load. This code provides a load profile wich is entered in the FEM analysis model....

  12. Distributional Analysis for Model Predictive Deferrable Load Control

    OpenAIRE

    Chen, Niangjun; Gan, Lingwen; Low, Steven H.; Wierman, Adam

    2014-01-01

    Deferrable load control is essential for handling the uncertainties associated with the increasing penetration of renewable generation. Model predictive control has emerged as an effective approach for deferrable load control, and has received considerable attention. In particular, previous work has analyzed the average-case performance of model predictive deferrable load control. However, to this point, distributional analysis of model predictive deferrable load control has been elusive. In ...

  13. Pressure Hull Analysis under Shock Loading

    OpenAIRE

    Ya-Jung Lee; Chia-Hao Hsu; Chien-Hua Huang

    2008-01-01

    The hull of high performance submarines must resist underwater shock loading due to exploding torpedoes or depth bombs. An underwater shock involving an initial shock wave and successive bubble pulsating waves is so complex that a theoretical technique for deriving shock pressure distribution is required for improving simulation efficiency. Complete shock loading is obtained theoretically in this work, and responses of a submarine pressure hull are calculated using ABAQUS USA (Underwater Shoc...

  14. Analysis of aeroelastic loads and their contributions to fatigue damage

    DEFF Research Database (Denmark)

    Bergami, Leonardo; Gaunaa, Mac

    2014-01-01

    The paper presents an analysis of the aeroelastic loads on a wind turbine in normal operation. The characteristic of the loads causing the highest fatigue damage are identified, so to provide indications to the development of active load alleviation systems for smart-rotor applications. Fatigue...... analysis is performed using rain-flow counting and Palmgren-Miner linear damage assumption; the contribution to life-time fatigue damage from deterministic load variations is quantified, as well as the contributions from operation at different mean wind speeds. A method is proposed to retrieve...... an estimation of the load frequencies yielding the highest fatigue contributions from the bending moment spectra. The results are in good agreement with rain-flow counting analysis on filtered time series, and, for the blade loads, show dominant contributions from frequencies close to the rotational one...

  15. Phloem loading through plasmodesmata: a biophysical analysis

    CERN Document Server

    Comtet, Jean; Stroock, Abraham D

    2016-01-01

    In many species, sucrose en route out of the leaf migrates from photosynthetically active mesophyll cells into the phloem down its concentration gradient via plasmodesmata, i.e., symplastically. In some of these plants the process is entirely passive, but in others phloem sucrose is actively converted into larger sugars, raffinose and stachyose, and segregated (trapped), thus raising total phloem sugar concentration to a level higher than in the mesophyll. Questions remain regarding the mechanisms and selective advantages conferred by both of these symplastic loading processes. Here we present an integrated model - including local and global transport and the kinetics of oligomerization - for passive and active symplastic loading. We also propose a physical model of transport through the plasmodesmata. With these models, we predict that: 1) relative to passive loading, oligomerization of sucrose in the phloem, even in the absence of segregation, lowers the sugar content in the leaf required to achieve a given...

  16. Load Response Analysis of Asphalt Pavement

    Directory of Open Access Journals (Sweden)

    Xiao Zhijun

    2016-01-01

    Full Text Available Based on the filed data of Fuzhou test road, load response regulation of nonlinear pavement structure was analyzed in this paper; Mechanics software was adopted to analyze linear elastic and nonlinear of the pavement structure, analyzed results and road filed data were compared, and determine the correlation between them and the field data.

  17. Dynamic Gust Load Analysis for Rotors

    Directory of Open Access Journals (Sweden)

    Yuting Dai

    2016-01-01

    Full Text Available Dynamic load of helicopter rotors due to gust directly affects the structural stress and flight performance for helicopters. Based on a large deflection beam theory, an aeroelastic model for isolated helicopter rotors in the time domain is constructed. The dynamic response and structural load for a rotor under the impulse gust and slope-shape gust are calculated, respectively. First, a nonlinear Euler beam model with 36 degrees-of-freedoms per element is applied to depict the structural dynamics for an isolated rotor. The generalized dynamic wake model and Leishman-Beddoes dynamic stall model are applied to calculate the nonlinear unsteady aerodynamic forces on rotors. Then, we transformed the differential aeroelastic governing equation to an algebraic one. Hence, the widely used Newton-Raphson iteration algorithm is employed to simulate the dynamic gust load. An isolated helicopter rotor with four blades is studied to validate the structural model and the aeroelastic model. The modal frequencies based on the Euler beam model agree well with published ones by CAMRAD. The flap deflection due to impulse gust with the speed of 2m/s increases twice to the one without gust. In this numerical example, results indicate that the bending moment at the blade root is alleviated due to elastic effect.

  18. Dynamic Analysis of Structural Columns Subjected to Impulsive Loading

    Institute of Scientific and Technical Information of China (English)

    GONG Shunfeng; LU Yong; GAO Feng; JIN Weiliang

    2006-01-01

    For a building structure subjected to impulsive loading,particularly shock and impact loading,the response of the critical columns is crucial to the behaviour of the entire system during and after the blast loading phase.Therefore,an appropriate evaluation of the column response and damage under short-duration impulsive loading is important in a comprehensive assessment of the performance of a building system.This paper reports a dynamic analysis approach for the response of RC columns subjected to impulsive loading.Considering that the dynamic response of a column in a frame structure can also be affected by the floor movement which relates to the global vibration of the frame system,a generic column-mass model is used,in which a concentrated mass is attached to the column top to simulate the effect of a global vibration.To take into account the high shear effect under impulsive load,the model is formulated using Timoshenko beam theory,and three main nonlinear mechanisms are considered.Two typical scenarios,one under a direct air blast loading,and another under a blast-induced ground excitation,are analyzed and the primary response features are highlighted.

  19. AN FE ANALYSIS OF REINFORCED SUBGRADE UNDER AUTOMOBILE LOADING

    Institute of Scientific and Technical Information of China (English)

    YAN Shuwang; ZHANG Xinqiang; LIU Run

    2004-01-01

    An FE analysis procedure was presented to predict the behavior of soil-geogrid interaction under automobile loading. The dynamic interactions between the transverse bars, the longitudinal ribs and the soil were simulated by a system consisting of nonlinear springs, dashpots and masses, to study the deformation properties of the reinforced soil. The equivalent stiffness and damping ratios could be determined with the shaking table. The dynamic responses of a reinforced subgrade were analyzed with the 3D finite element approach. This approach is programmed and applied to analyze the soil-geogrid interaction under dynamic loading. The comparative analysis of the response of the reinforced subgrade and that of the subgrade without reinforcement shows that the geogrid placed at the bottom of the base layer may effectively reduce the accumulative plastic deformation due to the cyclic automobile loading.

  20. Earth slope reliability analysis under seismic loadings using neural network

    Institute of Scientific and Technical Information of China (English)

    PENG Huai-sheng; DENG Jian; GU De-sheng

    2005-01-01

    A new method was proposed to cope with the earth slope reliability problem under seismic loadings. The algorithm integrates the concepts of artificial neural network, the first order second moment reliability method and the deterministic stability analysis method of earth slope. The performance function and its derivatives in slope stability analysis under seismic loadings were approximated by a trained multi-layer feed-forward neural network with differentiable transfer functions. The statistical moments calculated from the performance function values and the corresponding gradients using neural network were then used in the first order second moment method for the calculation of the reliability index in slope safety analysis. Two earth slope examples were presented for illustrating the applicability of the proposed approach. The new method is effective in slope reliability analysis. And it has potential application to other reliability problems of complicated engineering structure with a considerably large number of random variables.

  1. Influence Of Lateral Load Distributions On Pushover Analysis Effectiveness

    Science.gov (United States)

    Colajanni, P.; Potenzone, B.

    2008-07-01

    The effectiveness of two simple load distributions for pushover analysis recently proposed by the authors is investigated through a comparative study, involving static and dynamic analyses of seismic response of eccentrically braced frames. It is shown that in the upper floors only multimodal pushover procedures provide results close to the dynamic profile, while the proposed load patterns are always conservative in the lower floors. They over-estimate the seismic response less than the uniform distribution, representing a reliable alternative to the uniform or more sophisticated adaptive procedures proposed by seismic codes.

  2. Numerical Analysis of Vibrations of Structures under Moving Inertial Load

    CERN Document Server

    Bajer, Czeslaw I

    2012-01-01

    Moving inertial loads are applied to structures in civil engineering, robotics, and mechanical engineering. Some fundamental books exist, as well as thousands of research papers. Well known is the book by L. Frýba, Vibrations of Solids and Structures Under Moving Loads, which describes almost all problems concerning non-inertial loads. This book presents broad description of numerical tools successfully applied to structural dynamic analysis. Physically we deal with non-conservative systems. The discrete approach formulated with the use of the classical finite element method results in elemental matrices, which can be directly added to global structure matrices. A more general approach is carried out with the space-time finite element method. In such a case, a trajectory of the moving concentrated parameter in space and time can be simply defined. We consider structures described by pure hyperbolic differential equations such as strings and structures described by hyperbolic-parabolic differential equations ...

  3. Simulation of probabilistic wind loads and building analysis

    Science.gov (United States)

    Shah, Ashwin R.; Chamis, Christos C.

    1991-01-01

    Probabilistic wind loads likely to occur on a structure during its design life are predicted. Described here is a suitable multifactor interactive equation (MFIE) model and its use in the Composite Load Spectra (CLS) computer program to simulate the wind pressure cumulative distribution functions on four sides of a building. The simulated probabilistic wind pressure load was applied to a building frame, and cumulative distribution functions of sway displacements and reliability against overturning were obtained using NESSUS (Numerical Evaluation of Stochastic Structure Under Stress), a stochastic finite element computer code. The geometry of the building and the properties of building members were also considered as random in the NESSUS analysis. The uncertainties of wind pressure, building geometry, and member section property were qualified in terms of their respective sensitivities on the structural response.

  4. Finite element analysis for dental implants subjected to thermal loads

    Directory of Open Access Journals (Sweden)

    Mohamad Reza Khalili

    2013-10-01

    Full Text Available   Background and Aims: Dental implants have been studied for replacement of missing teeth for many years. Productivity of implants is extremely related to the stability and resistance under applied loads and the minimum stress in jaw bone. The purpose of this study was to study numerically the 3D model of implant under thermal loads.   Materials and Methods: Bone and the ITI implant were modeled in “Solidworks” software. To obtain the exact model, the bone was assumed as a linear orthotropic material. The implant system, including implant, abutment, framework and crown were modeled and located in the bone. After importing the model in Abaqus software, the material properties and boundary conditions and loads were applied and after meshing, the model was analyzed. In this analysis, the loads were applied in two steps. In the first step, the mechanical load was applied as tightening torque to the abutment and the abutment was tightened in the implant with 35 N.cm torque. In the second step, the thermal load originated from drinking cold and hot water was applied as thermal flux on the ceramic crown surface in this model.   Results: Thermal analysis results showed that the thermal gradient in the bone was about 5.5 and 4.9 degrees of centigrade in the case of drinking cold and hot water respectively , although the maximum gradient of the whole system was reduced to 14 degrees, which occurred, in the crown by drinking cold water.   Conclusion Thermal stresses were so small and it was because of the low thermal gradient. Maximum stresses occurred in the abutment were due to the tension preloads which were originated from the tightening torque.

  5. LOADS INFLUENCE ANALYSIS ON NOVEL HIGH PRECISION FLEXURE PARALLEL POSITIONER

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A large workspace flexure parallel positioner system is developed, which can attain sub-micron scale accuracy over cubic centimeter motion range for utilizing novel wide-range flexure hinges instead of the conventional mechanism joints. Flexure hinges eliminate backlash and friction, but on the other hand their deformation caused by initial loads influences the positioning accuracy greatly, so discussions about loads' influence analysis on this flexure parallel positioner is very necessary. The stiffness model of the whole mechanism is presented via stiffness assembly method based on the stiffness model of individual flexure hinge. And the analysis results are validated by the finite element analysis (FEA) simulation and experiment tests, which provide essential data to the practical application of this positioner system.

  6. The Research of Method of Malignant Load Identification Based on Wavelet Analysis

    Science.gov (United States)

    Wei, Shaoliang; Qin, Shiqun; Gao, Wenchang; Cheng, Fengyu; Cao, Zhongyue

    Using wavelet analysis to analyze waveforms of various loads, analytical processing with Matlab, to get difference between various capacitive, inductive, and resistive load's waveforms, just to distinguish the malignant power load and general load. It is of great importance to campus apartment for automatic recognition of malignant load, and then to prevent campus fires.

  7. Analysis of the Behavior of Sedimentary Rocks Under Impact Loading

    Science.gov (United States)

    Millon, Oliver; Ruiz-Ripoll, Maria Luisa; Hoerth, Tobias

    2016-11-01

    In multiple engineering fields such as rock drilling or building constructions or extreme events like earthquakes or impacts, the dynamic properties of rock play an important role. A way to model these events and define measures to minimize the damage derived from these events is created by means of numerical analysis. Hence, the knowledge of the dynamic material behavior is essential for studying the effects of such a loading scenario. Solid geological materials, from the family of the sedimentary rocks, have been analyzed under quasi-static loads. However, there is a lack of knowledge when high strain rate loadings are involved. Within this context, the paper focuses on the experimental characterization of two sedimentary rocks, sandstone and limestone, under impact loading using the Hopkinson-Bar spallation and compression tests. The analysis encompasses the determination of the tensile and compressive properties as well as the comparison between the quasi-static and dynamic behavior (dynamic increase factors). The paper fills the gap of information existing about dynamic behavior of sedimentary rocks under strain rates between 100 and 5.2 × 102 s-1. Furthermore, the fragmentation under different strain rates is investigated and conclusions with respect to energy absorption capacity are drawn.

  8. Retrospective Analysis of Inflight Exercise Loading and Physiological Outcomes

    Science.gov (United States)

    Ploutz-Snyder, L. L.; Buxton, R. E.; De Witt, J. K.; Guilliams, M. E.; Hanson, A. M.; Peters, B. T.; Pandorf, M. M. Scott; Sibonga, J. D.

    2014-01-01

    Astronauts perform exercise throughout their missions to counter the health declines that occur as a result of long-term exposure to weightlessness. Although all astronauts perform exercise during their missions, the specific prescriptions, and thus the mechanical loading, differs among individuals. For example, inflight ground reaction force data indicate that subject-specific differences exist in foot forces created when exercising on the second-generation treadmill (T2) [1]. The current exercise devices allow astronauts to complete prescriptions at higher intensities, resulting in greater benefits with increased efficiency. Although physiological outcomes have improved, the specific factors related to the increased benefits are unknown. In-flight exercise hardware collect data that allows for exploratory analyses to determine if specific performance factors relate to physiological outcomes. These analyses are vital for understanding which components of exercise are most critical for optimal human health and performance. The relationship between exercise performance variables and physiological changes during flight has yet to be fully investigated. Identifying the critical performance variables that relate to improved physiological outcomes is vital for creating current and future exercise prescriptions to optimize astronaut health. The specific aims of this project are: 1) To quantify the exercise-related mechanical loading experienced by crewmembers on T2 and ARED during their mission on ISS; 2) To explore relationships between exercise loading variables, bone, and muscle health changes during the mission; 3) To determine if specific mechanical loading variables are more critical than others in protecting physiology; 4) To develop methodology for operational use in monitoring accumulated training loads during crew exercise programs. This retrospective analysis, which is currently in progress, is being conducted using data from astronauts that have flown long

  9. Numerical Analysis of Asphalt Pavements under Moving Wheel Loads

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The responses of the pavement in service are the basis for the design of the semi-rigid base course asphalt pavement.Due to the dynamic characteristics of wheel loads and the temperature loads,the dynamic response analysis is very significant.In this article, the dynamic analysis of asphalt pavement under moving wheel loads is carried out using finite element method coupled with non-reflective boundary method.The influences of the base modulus, thickness, the vehicle velocity, the tire pressure, and the contact condition at the interface are studied using parametric analysis.The results of numerical analysis show that it is not appropriate to simply increase the base modulus or thickness in the design.It would be beneficial if the base design is optimized synthetically.The increase of damping is also beneficial to the pavements because of the surface deflection and the stresses declination.Furthermore, the good contact condition at the interface results in good performance because it combines every layer of the pavement to work together.As overload aggravates the working condition of the pavement, it is not allowed.

  10. Reliability-Analysis of Offshore Structures using Directional Loads

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Bloch, Allan; Sterndorff, M. J.

    2000-01-01

    Reliability analyses of offshore structures such as steel jacket platforms are usually performed using stochastic models for the wave loads based on the omnidirectional wave height. However, reliability analyses with respect to structural failure modes such as total collapse of a structure...... heights from the central part of the North Sea. It is described how the stochastic model for the directional wave heights can be used in a reliability analysis where total collapse of offshore steel jacket platforms is considered....

  11. Analysis of the behavior of sedimentary rocks under impact loading

    OpenAIRE

    Millon, O.; Ruiz Ripoll, M.L.; Hoerth, T.

    2016-01-01

    In multiple engineering fields such as rock drilling or building constructions or extreme events like earthquakes or impacts, the dynamic properties of rock play an important role. A way to model these events and define measures to minimize the damage derived from these events is created by means of numerical analysis. Hence, the knowledge of the dynamic material behavior is essential for studying the effects of such a loading scenario. Solid geological materials, from the family of the sedim...

  12. Analysis of Wave Loads on A Semi-Submersible Platform

    Institute of Scientific and Technical Information of China (English)

    钱昆; 王言英

    2002-01-01

    For the global and structural fatigue strength analysis of a semi-submersible platform, wave loads under design con-ditions are calculated by use of the three-dimensional boundary dement method. Methods for calculating the forward-speed free-surface Green function are discussed and a computer program with this Green function is developed. Accordingto the special rules, the wave loads under several typical design conditions of the platform are calculated. The maximumvertical bending moment, torsion moment and horizontal split force are determined from a series of contour maps of waveloads for the wave period of 5 to 18 seconds at a certain interval and the wave phase of O° to 360° at a certain interval.The wave height is determined by the function of wave period with a given exceedance probability. The maximum waveloads under the combination of wave parameters are used as the input of hydrodynamic pressure in the three-dimensionalfinite element analysis process. The transfer functions of wave loads on the platform are used for the fatigue strength anal-ysis of the K-tubular joint and the sub-model of the structure.

  13. Immediately loaded non-submerged versus delayed loaded submerged dental implants: a meta-analysis.

    Science.gov (United States)

    Chrcanovic, B R; Albrektsson, T; Wennerberg, A

    2015-04-01

    The purpose of the present meta-analysis was to test the null hypothesis of no difference in the implant failure rate, postoperative infection, and marginal bone loss for patients being rehabilitated with immediately loaded non-submerged dental implants or delayed loaded submerged implants, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in March 2014. Eligibility criteria included clinical human studies, either randomized or not. The search strategy resulted in 28 publications. The inverse variance method was used for a random- or fixed-effects model, depending on the heterogeneity. The estimates of an intervention were expressed as the risk ratio (RR) and mean difference (MD) in millimetres. Twenty-three studies were judged to be at high risk of bias, one at moderate risk of bias, and four studies were considered at low risk of bias. The difference between procedures (submerged vs. non-submerged implants) significantly affected the implant failure rate (P = 0.02), with a RR of 1.78 (95% confidence interval (CI) 1.12-2.83). There was no apparent significant effect of non-submerged dental implants on the occurrence of postoperative infection (P = 0.29; RR 2.13, CI 0.52-8.65) or on marginal bone loss (P = 0.77; MD -0.03, 95% CI -0.23 to 0.17).

  14. Cryogenic heat loads analysis from SST-1 plasma experiments

    Science.gov (United States)

    Bairagi, N.; Tanna, V. L.; Pradhan, S.

    2017-02-01

    Cryogenic heat load analysis is an important aspect for stable operation of Tokamaks employing large scale superconducting magnets. Steady State Superconducting Tokamak (SST-1) at IPR is equipped with superconducting magnets system (SCMS) comprising sixteen numbers of modified ‘D’ shaped toroidal field (TF) and nine poloidal field (PF) superconducting coils which are wound using NbTi/Cu based cable-in conduit conductor (CICC). SST-1 magnets operation has flexibility to cool either in two-phase with sub-cooling, two-phase without sub-cooling or single phase (supercritical) helium using a dedicated 1.3 kW helium refrigerator cum liquefier (HRL). Here, we report gross heat losses for integrated TF superconducting magnets of SST-1 during the plasma campaign using cryogenic helium supply/return thermodynamic data from cryoplant. Heat loads mainly comprising of steady state as well as transient loads are smoothly absorbed by SST-1 cryogenic helium plant during plasma experiments. The corresponding heat produced in the coils is totally released to the helium flowing through the TF coils, which in turn is dumped into liquid helium stored in main control Dewar. These results are very useful reference for heat loss analysis for TF as well as PF coils and provides database for future operation of SST-1 machine.

  15. Experimental Testing for Stability Analysis of Distributed Energy Resources Components with Storage Devices and Loads

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Groza, Voicu; Isleifsson, Fridrik Rafn

    2012-01-01

    Experimental Testing for Stability Analysis of Distributed Energy Resources Components with Storage Devices and Loads......Experimental Testing for Stability Analysis of Distributed Energy Resources Components with Storage Devices and Loads...

  16. Energy efficiency analysis of reconfigured distribution system for practical loads

    Directory of Open Access Journals (Sweden)

    Pawan Kumar

    2016-09-01

    Full Text Available In deregulated rate structure, the performance evaluation of distribution system for energy efficiency includes; loss minimization, improved power quality, loadability limit, reliability and availability of supply. Energy efficiency changes with the variation in loading pattern and the load behaviour. Further, the nature of load at each node is not explicitly of any one type rather their characteristics depend upon the node voltages. In most cases, load is assumed to be constant power (real and reactive. In this paper voltage dependent practical loads are represented with composite load model and the energy efficiency performance of distribution system for practical loads is evaluated in different configurations of 33-node system.

  17. An Analysis of Transducer Mass Loading Effect Inshaker Testing

    Directory of Open Access Journals (Sweden)

    A. D. Karle

    2014-06-01

    Full Text Available Modal Analysis has been a developing science in the experimental evaluation of the dynamic properties of the structures. Frequency Response Function (FRF is one of the major steps in modal analysis. Measured frequency response functions (FRFs are used to extract modal parameters. It is also known that the accuracy and the reliability of various analyses using the measured FRFs depend strongly on the quality of measured data. It is well known that the quality of measured frequency response functions (FRFs is adversely affected by many factors, most significant sources being noise and systematic errors like mass loading effects of transducers. A transducer mounted on a vibrating system changes the dynamics of the structure due to the addition of extra mass and introduces errors into measured FRFs. One problem with this is the production of unrealistic results, which cause the measured resonant frequencies to be less than the correct values. These errors also lead to incorrect prediction of modal parameters. In many situations, the mass loading effect is ignored in the analytical and experimental process, based on a usual assumption that the transducer mass is negligible compared to that of the structure under test. However, when light-weighted structures are investigated, this effect can be significant.

  18. Analysis of foot load during ballet dancers' gait.

    Science.gov (United States)

    Prochazkova, Marketa; Tepla, Lucie; Svoboda, Zdenek; Janura, Miroslav; Cieslarová, Miloslava

    2014-01-01

    Ballet is an art that puts extreme demands on the dancer's musculoskeletal system and therefore significantly affects motor behavior of the dancers. The aim of our research was to compare plantar pressure distribution during stance phase of gait between a group of professional ballet dancers and non-dancers. Thirteen professional dancers (5 men, 8 women; mean age of 24.1 ± 3.8 years) and 13 nondancers (5 men, 8 women; mean age of 26.1 ± 5.3 years) participated in this study. Foot pressure analysis during gait was collected using a 2 m pressure plate. The participants were instructed to walk across the platform at a self-selected pace barefoot. Three gait cycles were necessary for the data analysis. The results revealed higher (p < 0.05) pressure peaks in medial edge of forefoot during gait for dancers in comparison with nondancers. Furthermore, differences in total foot loading and foot loading duration of rearfoot was higher (p < 0.05) in dancers as well. We can attribute these differences to long-term and intensive dancing exercises that can change the dancer's gait stereotype.

  19. Requalification analysis of a circular composite slab for seismic load

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, M.G.; Kot, C.A.

    1992-11-01

    The circular roof slab of an existing facility was analyzed to requalify the structure for supporting a significant seismic load that it was not originally designed for. The slab has a clear span of 66 ft and consists of a 48 in thick reinforced concrete member and a steel liner plate. Besides a number of smaller penetrations, the slab contains two significant cutouts: a 9 ft square opening and a 3 ft dia hole. The issues that complicated the analysis of this non-typical structure, i.e., composite action and nonlinear stiffness of reinforced concrete (R. C.) sections, are discussed. It was possible to circumvent the difficulties by making conservative and simplifying assumptions. If codes incorporate guidelines on practical methods for dynamic analysis of R. C. structures, some of the unneeded conservatism could be eliminated in future designs.

  20. Further finite element structural analysis of FAST Load Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Frosi, Paolo, E-mail: paolo.frosi@enea.it [Associazione Euratom ENEA sulla Fusione, C.R. Frascati, Via E. Fermi 45, 00044 Frascati, Rome (Italy); Crescenzi, F.; Cucchiaro, A.; Roccella, S. [Associazione Euratom ENEA sulla Fusione, C.R. Frascati, Via E. Fermi 45, 00044 Frascati, Rome (Italy)

    2013-10-15

    The FAST (Fusion Advanced Study Torus) machine is a compact high magnetic field tokamak, that will allow to study in an integrated way the main operational issues relating to plasma-wall interaction, plasma operation and burning plasma physics in conditions relevant for ITER and DEMO. The present work deals with the structural analysis of the machine Load Assembly for a proposed new plasma scenario (10 MA – 8.5 T), aimed to increase the operational limits of the machine. A previous paper has dealt with an integrated set of finite element models (regarding a former reference scenario: 6.5 MA – 7.5 T) of the load assembly, including the Toroidal and Poloidal Field Coils and the supporting structure. This set of models has regarded the evaluation of magnetic field values, the evaluation of the electromagnetic forces and the temperatures in all the current-carrying conductors: these analysis have been a preparatory step for the evaluation of the stresses of the main structural components. The previous models have been analyzed further on and improved in some details, including the computation of the out-of-plane electromagnetic forces coming from the interaction between the poloidal magnetic field and the current flowing in the toroidal magnets. After this updating, the structural analysis has been executed, where all forces and temperatures, coming from the formerly mentioned most demanding scenario (10 MA – 8.5 T) and acting on the tokamak's main components, have been considered. The two sets of analysis regarding the reference scenario and the extreme one have been executed and a useful comparison has been carried on. The analyses were carried out by using the FEM code Ansys rel. 13.

  1. Lateral Load Analysis of a Building with & Without Knee Bracing

    Directory of Open Access Journals (Sweden)

    Pravin S. Kamble

    2016-05-01

    Full Text Available In last decades steel structures has played an important role in construction industry. Providing strength, stability and ductility are major purposes of seismic design. It is necessary to design a structure to perform well under seismic loads. Steel braced frame is one of the structural systems used to resist earthquake loads in structures. Steel bracing is economical, easy to erect, occupies less space and has flexibility to design for meeting the required strength and stiffness. Bracing can be used as retrofit as well. There are various types of steel bracings such as Diagonal, X, K, V, inverted V type or chevron and global type concentric bracings. In the present study, it was shown that modelling of the G+4 steel bare frame with various bracings (X, V, inverted V, and Knee bracing by computer software SAP2000 and pushover analysis results are obtained. Comparison between the seismic parameters such as base shear, roof displacement, time period, storey drift, performance point for steel bare frame with different bracing patterns are studied. It is found that the X type of steel bracings significantly contributes to the structural stiffness and reduces the maximum interstate drift of steel building than other bracing systems

  2. Buoyancy-corrected gravimetric analysis of lightly loaded filters.

    Science.gov (United States)

    Rasmussen, Pat E; Gardner, H David; Niu, Jianjun

    2010-09-01

    Numerous sources of uncertainty are associated with the gravimetric analysis of lightly loaded air filter samples (cut sizes (0.056-9.9 microm). By maintaining tight controls on humidity (within 0.5% RH of control setting) throughout pre- and postweighing at each stepwise increase in RH, it was possible to quantify error due to water absorption: 45% of the total mass change due to water absorption occurred between 16 and 50% RH, and 55% occurred between 50 and 60% RH. The buoyancy corrections ranged from -3.5 to +5.8 microg in magnitude and improved relative standard deviation (RSD) from 21.3% (uncorrected) to 5.6% (corrected) for a 7.2 microg sample. It is recommended that protocols for weighing low-mass particle samples (e.g., nanoparticle samples) should include buoyancy corrections and tight temperature/humidity controls. In some cases, conditioning times longer than 24 hr may be warranted.

  3. ANALYSIS OF EXPOSURE OF REINFORCED CONCRETE BUILDINGS TO TEMPERATURE LOADS

    Directory of Open Access Journals (Sweden)

    Mkrtychev Oleg Vartanovich

    2012-10-01

    Full Text Available The co-authors consider the problem of analysis of building structures in respect of combined effects of forces and temperatures. Results of fire tests of reinforced concrete walls and slabs are presented. Overview of the analysis of the fire resistance of reinforced-concrete buildings is also provided. As a result of the research, numerical solutions were obtained in respect of deflections, stresses, deformations and internal forces arising in a reinforced concrete bearing wall and plate exposed to a combination of forces and thermal loads. Comparative analysis of the experimental data and the results of the numerical solution was performed. The conclusion is that the experimental data are in good fit to the results of the numerical solution. Overall limit state of the monolithic building under consideration in terms of its fire resistance means its failure as a result of collapse. The limit state value is equal to 60; therefore, it is equal to 60 minutes. This value, if considered in respect of separate bearing elements, fits the fire resistance limit of buildings of Grade III (Fire Resistance that is equal to 45. Evidently, assurance of higher fire resistance limits of the building under consideration requires special fire safety actions to be applied.

  4. Load-Sharing Characteristics of Power-Split Transmission System Based on Deformation Compatibility and Loaded Tooth Contact Analysis

    Directory of Open Access Journals (Sweden)

    Hao Dong

    2015-01-01

    Full Text Available In order to implement the uniform load distribution of the power-split transmission system, a pseudostatic model is built. Based on the loaded tooth contact analysis (LTCA technique, the actual meshing process of each gear pair is simulated and the fitting curve of time-varying mesh stiffness is obtained. And then, the torsional angle deformation compatibility conditions are proposed according to the closed-loop characteristic of power flow, which will be combined with the torque equilibrium conditions and elastic support conditions to calculate the transfer torque of each gear pair. Finally, the load-sharing coefficient of the power-split transmission system is obtained, and the influences of the installation errors are analyzed. The results show that the above-mentioned installation errors comprehensively influence the load-sharing characteristics, and the reduction of only one error could not effectively achieve perfect load-sharing characteristics. Allowing for the spline clearance floating and constrained by the radial spacing ring, the influence of the floating pinion is analyzed. It shows that the floating pinion can improve the load-sharing characteristics. Through the comparison between the theoretical and related experimental data, the reasonability and feasibility of the above-proposed method and model are verified.

  5. Performance analysis of dynamic load balancing algorithm for multiprocessor interconnection network

    Directory of Open Access Journals (Sweden)

    M.U. Bokhari

    2016-09-01

    Full Text Available Multiprocessor interconnection network have become powerful parallel computing system for real-time applications. Nowadays the many researchers posses studies on the dynamic load balancing in multiprocessor system. Load balancing is the method of dividing the total load among the processors of the distributed system to progress task's response time as well as resource utilization whereas ignoring a condition where few processors are overloaded or underloaded or moderately loaded. However, in dynamic load balancing algorithm presumes no priori information about behaviour of tasks or the global state of the system. There are numerous issues while designing an efficient dynamic load balancing algorithm that involves utilization of system, amount of information transferred among processors, selection of tasks for migration, load evaluation, comparison of load levels and many more. This paper enlightens the performance analysis on dynamic load balancing strategy (DLBS algorithm, used for hypercube network in multiprocessor system.

  6. Numerical Analysis of Structural Progressive Collapse to Blast Loads

    Institute of Scientific and Technical Information of China (English)

    HAO Hong; WU Chengqing; LI Zhongxian; ABDULLAH A K

    2006-01-01

    After the progressive collapse of Ronan Point apartment in UK in 1968,intensive research effort had been spent on developing guidelines for design of new or strengthening the existing structures to prevent progressive collapse.However,only very few building design codes provide some rather general guidance,no detailed design requirement is given.Progressive collapse of the Alfred P.Murrah Federal building in Oklahoma City and the World Trade Centre (WTC) sparked again tremendous research interest on progressive collapse of structures.Recently,US Department of Defence (DoD) and US General Service Administration (GSA) issued guidelines for structure progressive collapse analysis.These two guidelines are most commonly used,but their accuracy is not known.This paper presents numerical analysis of progressive collapse of an example frame structure to blast loads.The DoD and GSA procedures are also used to analyse the same example structure.Numerical results are compared and discussed.The accuracy and the applicability of the two design guidelines are evaluated.

  7. Metatarsal Loading During Gait-A Musculoskeletal Analysis.

    Science.gov (United States)

    Al-Munajjed, Amir A; Bischoff, Jeffrey E; Dharia, Mehul A; Telfer, Scott; Woodburn, James; Carbes, Sylvain

    2016-03-01

    Detailed knowledge of the loading conditions within the human body is essential for the development and optimization of treatments for disorders and injuries of the musculoskeletal system. While loads in the major joints of the lower limb have been the subject of extensive study, relatively little is known about the forces applied to the individual bones of the foot. The objective of this study was to use a detailed musculoskeletal model to compute the loads applied to the metatarsal bones during gait across several healthy subjects. Motion-captured gait trials and computed tomography (CT) foot scans from four healthy subjects were used as the inputs to inverse dynamic simulations that allowed the computation of loads at the metatarsal joints. Low loads in the metatarsophalangeal (MTP) joint were predicted before terminal stance, however, increased to an average peak of 1.9 times body weight (BW) before toe-off in the first metatarsal. At the first tarsometatarsal (TMT) joint, loads of up to 1.0 times BW were seen during the early part of stance, reflecting tension in the ligaments and muscles. These loads subsequently increased to an average peak of 3.0 times BW. Loads in the first ray were higher compared to rays 2-5. The joints were primarily loaded in the longitudinal direction of the bone.

  8. Stress analysis in curved composites due to thermal loading

    Science.gov (United States)

    Polk, Jared Cornelius

    Many structures in aircraft, cars, trucks, ships, machines, tools, bridges, and buildings, consist of curved sections. These sections vary from straight line segments that have curvature at either one or both ends, segments with compound curvatures, segments with two mutually perpendicular curvatures or Gaussian curvatures, and segments with a simple curvature. With the advancements made in multi-purpose composites over the past 60 years, composites slowly but steadily have been appearing in these various vehicles, compound structures, and buildings. These composite sections provide added benefits over isotropic, polymeric, and ceramic materials by generally having a higher specific strength, higher specific stiffnesses, longer fatigue life, lower density, possibilities in reduction of life cycle and/or acquisition cost, and greater adaptability to intended function of structure via material composition and geometry. To be able to design and manufacture a safe composite laminate or structure, it is imperative that the stress distributions, their causes, and effects are thoroughly understood in order to successfully accomplish mission objectives and manufacture a safe and reliable composite. The objective of the thesis work is to expand upon the knowledge of simply curved composite structures by exploring and ascertaining all pertinent parameters, phenomenon, and trends in stress variations in curved laminates due to thermal loading. The simply curved composites consist of composites with one radius of curvature throughout the span of the specimen about only one axis. Analytical beam theory, classical lamination theory, and finite element analysis were used to ascertain stress variations in a flat, isotropic beam. An analytical method was developed to ascertain the stress variations in an isotropic, simply curved beam under thermal loading that is under both free-free and fixed-fixed constraint conditions. This is the first such solution to Author's best knowledge

  9. Load flow analysis for variable speed offshore wind farms

    DEFF Research Database (Denmark)

    Chen, Zhe; Zhao, Menghua; Blaabjerg, Frede

    2009-01-01

    A serial AC-DC integrated load flow algorithm for variable speed offshore wind farms is proposed. It divides the electrical system of a wind farm into several local networks, and different load flow methods are used for these local networks sequentially. This method is fast, more accurate, and many...... and integrated into the load flow algorithm: one takes into account the control strategy of converters and the other considers the power losses of converters. In addition, different types of variable speed wind turbine systems with different control methods are investigated. Finally, the method is demonstrated...

  10. Limit Load and Buckling Analysis for Assessing Hanford Single-Shell Tank Dome Structural Integrity - 12278

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Ken I.; Deibler, John E.; Karri, Naveen K.; Pilli, Siva P. [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Julyk, Larry J. [M and D Professional Services, Inc., Richland, Washington 99352 (United States)

    2012-07-01

    The U.S. Department of Energy, Office of River Protection has commissioned a structural analysis of record for the Hanford single shell tanks to assess their structural integrity. The analysis used finite element techniques to predict the tank response to the historical thermal and operating loads. The analysis also addressed the potential tank response to a postulated design basis earthquake. The combined response to static and seismic loads was then evaluated against the design requirements of American Concrete Institute standard, ACI-349-06, for nuclear safety-related concrete structures. Further analysis was conducted to estimate the plastic limit load and the elastic-plastic buckling capacity of the tanks. The limit load and buckling analyses estimate the margin between the applied loads and the limiting load capacities of the tank structure. The potential for additional dome loads from waste retrieval equipment and the addition of large dome penetrations to accommodate retrieval equipment has generated additional interest in the limit load and buckling analyses. This paper summarizes the structural analysis methods that were used to evaluate the limit load and buckling of the single shell tanks. This paper summarizes the structural analysis methods that were used to evaluate the limit load and buckling limit states of the underground single shell tanks at the Hanford site. The limit loads were calculated using nonlinear finite element models that capture the progressive deformation and damage to the concrete as it approaches the limit load. Both uniform and concentrated loads over the tank dome were considered, and the analysis shows how adding a penetration in the center of the tank would affect the limit loads. For uniform surface loads, the penetration does not affect the limit load because concrete crushing and rebar yielding initiates first at the top of the wall, away from the penetration. For concentrated loads, crushing initiates at the center of the

  11. Evaluation of Load Analysis Methods for NASAs GIII Adaptive Compliant Trailing Edge Project

    Science.gov (United States)

    Cruz, Josue; Miller, Eric J.

    2016-01-01

    The Air Force Research Laboratory (AFRL), NASA Armstrong Flight Research Center (AFRC), and FlexSys Inc. (Ann Arbor, Michigan) have collaborated to flight test the Adaptive Compliant Trailing Edge (ACTE) flaps. These flaps were installed on a Gulfstream Aerospace Corporation (GAC) GIII aircraft and tested at AFRC at various deflection angles over a range of flight conditions. External aerodynamic and inertial load analyses were conducted with the intention to ensure that the change in wing loads due to the deployed ACTE flap did not overload the existing baseline GIII wing box structure. The objective of this paper was to substantiate the analysis tools used for predicting wing loads at AFRC. Computational fluid dynamics (CFD) models and distributed mass inertial models were developed for predicting the loads on the wing. The analysis tools included TRANAIR (full potential) and CMARC (panel) models. Aerodynamic pressure data from the analysis codes were validated against static pressure port data collected in-flight. Combined results from the CFD predictions and the inertial load analysis were used to predict the normal force, bending moment, and torque loads on the wing. Wing loads obtained from calibrated strain gages installed on the wing were used for substantiation of the load prediction tools. The load predictions exhibited good agreement compared to the flight load results obtained from calibrated strain gage measurements.

  12. Reliability analysis of wind turbines exposed to dynamic loads

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2014-01-01

    . Therefore the turbine components should be designed to have sufficient reliability with respect to both extreme and fatigue loads also not be too costly (and safe). This paper presents models for uncertainty modeling and reliability assessment of especially the structural components such as tower, blades...... the reliability of the structural components. Illustrative examples are presented considering uncertainty modeling and reliability assessment for structural wind turbine components exposed to extreme loads and fatigue, respectively.......Wind turbines are exposed to highly dynamic loads that cause fatigue and extreme load effects which are subject to significant uncertainties. Further, reduction of cost of energy for wind turbines are very important in order to make wind energy competitive compared to other energy sources...

  13. A Systematic Analysis for Shells of Revolution with Nonsymmetric Loads.

    Science.gov (United States)

    EDGE EFFECT SOLUTIONS. However, a ystematic technique for evaluating the arbitrary constant for each harmonic of loading from the boundary conditions has been lacking. The solutions, including the particular solutions for surface loads and temperature effects, the deformations for the membrane solutions, and the curvature changes for the inextensional deformation, are presented in what may be their simplest form for the shell of arbitrary meridian. The relative order of magnitude of the contribution of each solution to the various stresses and displacements is

  14. Joint Procrustes Analysis for Simultaneous Nonsingular Transformation of Component Score and Loading Matrices

    Science.gov (United States)

    Adachi, Kohei

    2009-01-01

    In component analysis solutions, post-multiplying a component score matrix by a nonsingular matrix can be compensated by applying its inverse to the corresponding loading matrix. To eliminate this indeterminacy on nonsingular transformation, we propose Joint Procrustes Analysis (JPA) in which component score and loading matrices are simultaneously…

  15. Use of fuzzy techniques for analysis of dynamic loads in power systems

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Presents the use of fuzzy techniques for analysis of dynamic load characteristics of power systems to identify the voltage stability (collapse) of a weak bus and concludes from the consistent results obtained that this is a useful tool for analysis of load charactersitics of sophiscated power systems and their components.

  16. Shunted Piezoelectric Vibration Damping Analysis Including Centrifugal Loading Effects

    Science.gov (United States)

    Min, James B.; Duffy, Kirsten P.; Provenza, Andrew J.

    2011-01-01

    Excessive vibration of turbomachinery blades causes high cycle fatigue problems which require damping treatments to mitigate vibration levels. One method is the use of piezoelectric materials as passive or active dampers. Based on the technical challenges and requirements learned from previous turbomachinery rotor blades research, an effort has been made to investigate the effectiveness of a shunted piezoelectric for the turbomachinery rotor blades vibration control, specifically for a condition with centrifugal rotation. While ample research has been performed on the use of a piezoelectric material with electric circuits to attempt to control the structural vibration damping, very little study has been done regarding rotational effects. The present study attempts to fill this void. Specifically, the objectives of this study are: (a) to create and analyze finite element models for harmonic forced response vibration analysis coupled with shunted piezoelectric circuits for engine blade operational conditions, (b) to validate the experimental test approaches with numerical results and vice versa, and (c) to establish a numerical modeling capability for vibration control using shunted piezoelectric circuits under rotation. Study has focused on a resonant damping control using shunted piezoelectric patches on plate specimens. Tests and analyses were performed for both non-spinning and spinning conditions. The finite element (FE) shunted piezoelectric circuit damping simulations were performed using the ANSYS Multiphysics code for the resistive and inductive circuit piezoelectric simulations of both conditions. The FE results showed a good correlation with experimental test results. Tests and analyses of shunted piezoelectric damping control, demonstrating with plate specimens, show a great potential to reduce blade vibrations under centrifugal loading.

  17. Limit Load and Buckling Analysis for Assessing Hanford Single-Shell Tank Dome Structural Integrity

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Kenneth I.; Deibler, John E.; Julyk, Larry J.; Karri, Naveen K.; Pilli, Siva Prasad

    2012-12-07

    The U.S. Department of Energy, Office of River Protection has commissioned a structural analysis of record (AOR) for the Hanford single shell tanks (SSTs) to assess their structural integrity. The analysis used finite element techniques to predict the tank response to the historical thermal and operating loads. The analysis also addressed the potential tank response to a postulated design basis earthquake. The combined response to static and seismic loads was then evaluated against the design requirements of American Concrete Institute (ACI) standard, ACI-349-06, for nuclear safety-related concrete structures. Further analysis was conducted to estimate the plastic limit load and the elastic-plastic buckling capacity of the tanks. The limit load and buckling analyses estimate the margin between the applied loads and the limiting load capacities of the tank structure. The potential for additional dome loads from waste retrieval equipment and the addition of large dome penetrations to accommodate retrieval equipment has generated additional interest in the limit load and buckling analyses. This paper summarizes the structural analysis methods that were used to evaluate the limit load and buckling of the single shell tanks.

  18. Load-Aware Modeling and Analysis of Heterogeneous Cellular Networks

    CERN Document Server

    Dhillon, Harpreet S; Andrews, Jeffrey G

    2012-01-01

    Random spatial models are attractive for modeling heterogeneous cellular networks (HCNs) due to their realism, tractability, and scalability. A major limitation of such models to date in the context of HCNs is the neglect of network traffic and load: all base stations (BSs) have typically been assumed to always be transmitting. Small cells in particular will have a lighter load than macrocells, and so their contribution to the network interference may be significantly overstated in a fully loaded model. This paper incorporates a flexible notion of BS load by introducing a new idea of conditionally thinning the interference field. For a $K$-tier HCN where BSs across tiers differ in terms of transmit power, supported data rate, deployment density, and now load, we derive the coverage probability for a typical mobile, which connects to the strongest BS signal. Conditioned on this connection, the interfering BSs of the $i^{th}$ tier are assumed to transmit independently with probability $p_i$, which models the lo...

  19. A Study of Load Flow Analysis Using Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Deepak Saini

    2015-01-01

    Full Text Available Load flow study is done to determine the power system static states (voltage magnitudes and voltage angles at each bus to find the steady state working condition of a power system. It is important and most frequently carried out study performed by power utilities for power system planning, optimization, operation and control. In this project a Particle Swarm Optimization (PSO is proposed to solve load flow problem under different loading/ contingency conditions for computing bus voltage magnitudes and angles of the power system. With the increasing size of power system, this is very necessary to finding the solution to maximize the utilization of existing system and to provide adequate voltage support. For this the good voltage profile is must. STATCOM, if placed optimally can be effective in providing good voltage profile and in turn resulting into stable power system. The study presents a hybrid particle swarm based methodology for solving load flow in electrical power systems. Load flow is an electrical engineering well-known problem which provides the system status in the steady-state and is required by several functions performed in power system control centers.

  20. Analysis of Dynamic Properties of Piezoelectric Structure under Impact Load

    Directory of Open Access Journals (Sweden)

    Taotao Zhang

    2015-10-01

    Full Text Available An analytical model of the dynamic properties is established for a piezoelectric structure under impact load, without considering noise and perturbations in this paper. Based on the general theory of piezo-elasticity and impact mechanics, the theoretical solutions of the mechanical and electrical fields of the smart structure are obtained with the standing and traveling wave methods, respectively. The comparisons between the two methods have shown that the standing wave method is better for studying long-time response after an impact load. In addition, good agreements are found between the theoretical and the numerical results. To simulate the impact load, both triangle and step pulse loads are used and comparisons are given. Furthermore, the influence of several parameters is discussed so as to provide some advices for practical use. It can be seen that the proposed analytical model would benefit, to some extent, the design and application (especially the airport runway of the related smart devices by taking into account their impact load performance.

  1. Study on fatigue analysis for operational load histories

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelm, Paul; Rudolph, Juergen [AREVA GmbH, Erlangen (Germany); Steinmann, Paul [Erlangen-Nuernberg Univ. (Germany). Chair of Applied Mechanics

    2013-07-01

    Some laboratories performed fatigue tests in dissolved oxygen water at elevated temperature to better understand the influence of a long hold-time within cyclic loading. Also, the combined effect of complex waveform and surface finish was examined. The data show a less severe influence compared to the prediction model from Argonne National Laboratory; an increase in fatigue life was noticed and attributed to different effects. To evaluate an operational load history with this experimental data an algorithm is developed, which finds hold-times and the examined complex waveform in a stress-time series. All those cycles, which are either geometrically comparable to the complex loading signal or containing a hold period, are evaluated with the test results and not with the formula from Argonne National Laboratory. The reduction of the cumulative usage factor is calculated. Based on this discussion a realistic test condition is derived for further research activities.

  2. Muscular adaptations in low- versus high-load resistance training: A meta-analysis.

    Science.gov (United States)

    Schoenfeld, Brad J; Wilson, Jacob M; Lowery, Ryan P; Krieger, James W

    2016-01-01

    There has been much debate as to optimal loading strategies for maximising the adaptive response to resistance exercise. The purpose of this paper therefore was to conduct a meta-analysis of randomised controlled trials to compare the effects of low-load (≤60% 1 repetition maximum [RM]) versus high-load (≥65% 1 RM) training in enhancing post-exercise muscular adaptations. The strength analysis comprised 251 subjects and 32 effect sizes (ESs), nested within 20 treatment groups and 9 studies. The hypertrophy analysis comprised 191 subjects and 34 ESs, nested with 17 treatment groups and 8 studies. There was a trend for strength outcomes to be greater with high loads compared to low loads (difference = 1.07 ± 0.60; CI: -0.18, 2.32; p = 0.09). The mean ES for low loads was 1.23 ± 0.43 (CI: 0.32, 2.13). The mean ES for high loads was 2.30 ± 0.43 (CI: 1.41, 3.19). There was a trend for hypertrophy outcomes to be greater with high loads compared to low loads (difference = 0.43 ± 0.24; CI: -0.05, 0.92; p = 0.076). The mean ES for low loads was 0.39 ± 0.17 (CI: 0.05, 0.73). The mean ES for high loads was 0.82 ± 0.17 (CI: 0.49, 1.16). In conclusion, training with loads ≤50% 1 RM was found to promote substantial increases in muscle strength and hypertrophy in untrained individuals, but a trend was noted for superiority of heavy loading with respect to these outcome measures with null findings likely attributed to a relatively small number of studies on the topic.

  3. Analysis of Bearing Capacity of Suction Bucket Foundation Subjected to Horizontal and Moment Loadings

    OpenAIRE

    W.U. Ke; M.A. Mingyue

    2013-01-01

    The suction bucket foundation is not only supporting the vertical loading such as the sea platform and weight itself, but also subjecting to horizontal and moment loading due to wind and wave. The response of bucket foundation to combined Horizontal (H) and Moment (M) loading has been studied using 3D finite element analysis Then the proposed method is numerically implemented in the framework of the general-purpose FEM software ABAQUS. Relationship curve between the coefficient of ultimate be...

  4. Nonlinear analysis of a structure loaded by a stochastic excitation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    For a non-linear system excited by a stochastic load which is expressed as a time series, a recursive method based on the Z-transform is presented. To identify the obtained response time series, a discrete wavelet transform (DWT) technique is proposed.

  5. X-ray stress analysis during cyclic loading

    Energy Technology Data Exchange (ETDEWEB)

    Ohya, Shin-ichi [Musashi Inst. of Tech., Tokyo (Japan)

    1997-06-01

    For an aim to make possible to conduct speed-up and time-serial measurement of x-ray stress measurement in the fatigue test, a diffraction intensity curve at each loading stress stage in a repeating stress period was measured in time-serial sharing and devised ``a time-sharing continuous stress measuring method by a single incident method`` to measure the stress continuously. Then, by using this method an actual stress change measurement was conducted in a four points supporting bending test, to investigate on precision of the stress measurement and effectiveness of this method. As a result, the results shown as follows were elucidated. An actual stress change in a fatigue test could be observed directly. And, it was confirmed that an actual stress state in each loading stress stage in one loading stress period is independent on repeating speed under about 8 Hz and is an algebraic sum of residual and loading stresses. Furthermore, it was found that by this method a dynamic fatigue cleavage phenomena could be observed. (G.K.)

  6. Analysis and design of residential load centers. Volume 2: Appendices

    Science.gov (United States)

    Mehalick, E. M.; Lamders, R.; Obrien, G.; Tully, G. F.; Parker, J.

    1982-03-01

    These three appendices present information on residential load center classification information. Emphasis is given to: residential development trends and residential housing classifications; detached house site layout alternatives; and legal and institional issues, including condominium ownership, commercial ownership of photovoltaic systems in mobile homes, and utility ownership of photovoltaic systems.

  7. Kinematic analysis of males with transtibial amputation carrying military loads

    Directory of Open Access Journals (Sweden)

    Barri L. Schnall, MPT

    2015-03-01

    Full Text Available The biomechanical responses to load carriage, a common task for dismounted troops, have been well studied in nondisabled individuals. However, with recent shifts in the rehabilitation and retention process of injured servicemembers, there remains a substantial need for understanding these responses in persons with lower-limb amputations. Temporal-spatial and kinematic gait parameters were analyzed among 10 male servicemembers with unilateral transtibial amputation (TTA and 10 uninjured male controls. Participants completed six treadmill walking trials in all combinations of two speeds (1.34 and 1.52 m/s and three loads (none, 21.8, and 32.7 kg. Persons with TTA exhibited biomechanical compensations to carried loads that are comparable to those observed in uninjured individuals. However, several distinct gait changes appear to be unique to those with TTA, notably, increased dorsiflexion (deformation of the prosthetic foot/ankle, less stance knee flexion on the prosthetic limb, and altered trunk forward lean/excursion. Such evidence supports the need for future work to assess the risk for overuse injuries with carried loads in this population in addition to guiding the development of adaptive prosthetic feet/components to meet the needs of redeployed servicemembers or veterans/civilians in physically demanding occupations.

  8. Finite element models for the steady state analysis of moving loads

    NARCIS (Netherlands)

    Kok, A.W.M.

    2000-01-01

    The analysis of structures subjected to fast moving loads is a subject of growing interest in railway and pavement engineering. The applications of transient analyses using finite element models, however, are still very limited. The faster a load moves the more elements we need to model the structu

  9. Cargo response to railcar impact and tiedown load analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, R.J.

    1978-09-01

    An analytical study of the loads produced during coupling of railcars carrying heavy shipping containers is presented. The structural model of the impact event is represented by a lumped-parameter technique. Each discrete mass lump possesses longitudinal, vertical, and rotational degrees of freedom. The resulting computer simulation provides for nonlinear railcar coupler stiffness and linear damping forces in the coupler and container tiedowns. Results include response to parametric variations in container weight, impact speed, and tiedown stiffness. Container dynamic response and tiedown loads are found to depend heavily on these parameters. Also, railcar bending and subsequent vertical motion are shown to be important contributors to these responses. When experimentally substantiated, the model developed can serve as a useful tool in the design and evaluation of shipping container tiedown structures.

  10. Cargo response to railcar impact and tiedown load analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, R.J.

    1978-01-01

    An analytical study that investigated the loads produced during coupling of railcars carrying heavy shipping containers is described. The structural model of the impact event is represented by a lumped parameter technique. Each discrete mass lump possesses longitudinal, vertical, and rotational degrees of freedom. The resulting computer simulation provides for nonlinear railcar coupler stiffness and linear damping forces in the coupler and container tiedowns. Results include response to parametric variations in container weight, impact speed, and tiedown stiffness. Container dynamic response and tiedown loads are found to depend heavily on these parameters. Also, railcar bending and subsequent vertical motion are shown to be important contributors to these responses. When experimentally substantiated, the model can serve as a useful tool in the design and evaluation of shipping container tiedown structures.

  11. Load Flow Analysis Using Real Coded Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Himakar Udatha

    2014-02-01

    Full Text Available This paper presents a Real Coded Genetic Algorithm (RCGA for finding the load flow solution of electrical power systems. The proposed method is based on the minimization of the real and reactive power mismatches at various buses. The traditional methods such as Gauss-Seidel method and Newton-Raphson (NR method have certain drawbacks under abnormal operating condition. In order to overcome these problems, the load flow solution based on Real Coded Genetic Algorithm (RCGA is presented in this paper. Two cross over techniques, Arithmetic crossover and heuristic crossover are used to solve the power flow problem. The proposed method is applied for 3-bus, 5-bus and 6-bus systems and the results are presented.

  12. Plug and Process Loads Capacity and Power Requirements Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sheppy, M.; Gentile-Polese, L.

    2014-09-01

    This report addresses gaps in actionable knowledge that would help reduce the plug load capacities designed into buildings. Prospective building occupants and real estate brokers lack accurate references for plug and process load (PPL) capacity requirements, so they often request 5-10 W/ft2 in their lease agreements. Limited initial data, however, suggest that actual PPL densities in leased buildings are substantially lower. Overestimating PPL capacity leads designers to oversize electrical infrastructure and cooling systems. Better guidance will enable improved sizing and design of these systems, decrease upfront capital costs, and allow systems to operate more energy efficiently. The main focus of this report is to provide industry with reliable, objective third-party guidance to address the information gap in typical PPL densities for commercial building tenants. This could drive changes in negotiations about PPL energy demands.

  13. An analysis of representative heating load lines for residential HSPF ratings

    Energy Technology Data Exchange (ETDEWEB)

    Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-07-01

    This report describes an analysis to investigate representative heating loads for single-family detached homes using current EnergyPlus simulations (DOE 2014a). Hourly delivered load results are used to determine binned load lines using US Department of Energy (DOE) residential prototype building models (DOE 2014b) developed by Pacific Northwest National Laboratory (PNNL). The selected residential single-family prototype buildings are based on the 2006 International Energy Conservation Code (IECC 2006) in the DOE climate regions. The resulting load lines are compared with the American National Standards Institute (ANSI)/Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 210/240 (AHRI 2008) minimum and maximum design heating requirement (DHR) load lines of the heating seasonal performance factor (HSPF) ratings procedure for each region. The results indicate that a heating load line closer to the maximum DHR load line, and with a lower zero load ambient temperature, is more representative of heating loads predicted for EnergyPlus prototype residential buildings than the minimum DHR load line presently used to determine HSPF ratings. An alternative heating load line equation was developed and compared to binned load lines obtained from the EnergyPlus simulation results. The effect on HSPF of the alternative heating load line was evaluated for single-speed and two-capacity heat pumps, and an average HSPF reduction of 16% was found. The alternative heating load line relationship is tied to the rated cooling capacity of the heat pump based on EnergyPlus autosizing, which is more representative of the house load characteristics than the rated heating capacity. The alternative heating load line equation was found to be independent of climate for the six DOE climate regions investigated, provided an adjustable zero load ambient temperature is used. For Region IV, the default DOE climate region used for HSPF ratings, the higher load line results in an ~28

  14. Analysis and Load Rating of Pre-flex Composite Beams

    Science.gov (United States)

    2011-09-01

    buildings and bridges in Asia and Europe (Staquet et al. 2004). The Southern Tower (Tour du Midi) in Belgium employs this system. Other common ...specified by its manufac- turers and varies from 19.62 kN (4,410 lb) to 44.1 kN (9,920 lb). Common practice in the design of reinforced concrete assumes... Mallow = maximum moment allowed Ppf = maximum pre-flexion load fs = allowable stress in steel section Sx = section modulus of steel

  15. Numerical Analysis of Dynamic Behavior of RC Slabs Under Blast Loading

    Institute of Scientific and Technical Information of China (English)

    DU Hao; LI Zhongxian

    2009-01-01

    In Order to reduce economic and life losses due to terrorism or accidental explosion threats,reinforced concrete(RC)slabs of buildings need to be designed or retrofitted to resist blast loading.In this paper the dynamic behavior Of RC slabs under blast loading and its influencing factors are studied.The numerical model of an RC slab subjected to blast loading is established using the explicit dynamic analysis software.Both the strain rate effect and the damage accumulation are taken into account in the material model.The dynamic responses of the RC slab subiected to blast loading are analyzed,and the influence of concrete strength,thickness and reinforcement ratio on the behavior of the RC slab under blast loading iS numerically investigated.Based on the numerical results.some principles for blast-resistant design and retrofitting are proposed to improve the behavior of the RC slab subjected to blast loading.

  16. The Dynamic Response Analysis of Auto Body Sheets to Node Loads

    Directory of Open Access Journals (Sweden)

    Luo Yun

    2014-01-01

    Full Text Available The 3D vehicle body model was built using UG NX6.0, then it was imported into the Workbench of Finite Elment Analyis Software ANSYS V12.1. In the Workbench, the modal analysis and harmonic response analysis of auto body sheets with 4 kinds of node load environment are implemented. Meanwhile the harmonic response analysis of engine’s single sine vibration is obtained in stimulation processing based on the modal calculation. Then the rule of influence on the auto body sheets to node load environment was explored further. Node load environment increased the resonance amplitude of harmonic response analysis. What’s more, the resonance amplitude increased as the increasing of node loads, which would increase the probability of vehicle structure failure.

  17. Loads Analysis of a Floating Offshore Wind Turbine Using Fully Coupled Simulation: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jonkman, J. M.; Buhl, M. L., Jr.

    2007-06-01

    This paper presents the use of fully coupled aero-hydro-servo-elastic simulation tools to perform a loads analysis of a 5-MW offshore wind turbine supported by a barge with moorings, one of many promising floating platform concepts.

  18. Analysis of structural response under blast loads using the coupled SPH-FEM approach

    Institute of Scientific and Technical Information of China (English)

    Jun-xiang XU; Xi-la LIU

    2008-01-01

    A numerical model using the coupled smoothed particle hydrodynamics-finite element method(SPH-FEM)approach is presented for analysis of structures under blast loads.The analyses on two numerical cases,one for free field explosive and the other for structural response under blast loads,are performed to model the whole processes from the propagation of the pressure wave to the response of structures.Based on the simulation,it is concluded that this model can be used for reasonably accurte explosive analysis of structures.The resulting information would be valuable for protecting structures under blast loads.

  19. Load Dump Analysis in a 42/14V DC-DC Converter for Automotive Applications

    Directory of Open Access Journals (Sweden)

    Mohamed Abdualla Shrud

    2013-07-01

    Full Text Available The paper presents a model for a dc-dc centralised based architecture using Matlab/Simulink for load dump analysis. As the electrical load varies for various driving conditions such as day or night, summer or winter; and city or country side, the analysis of load change is a very important parameter for system behaviour. In order to study the 42V power generation dynamic performance under load variations, step change in loads have been investigated. A detailed mathematical model for a 3-phase, 4 kW and 42V Lundell alternator average electrical equivalent circuit along with the DC/DC converter based architectures for dual-voltage systems has been covered in previous publications. Aspects of the steady-state output current capabilities, transient behaviour due to load dump on the 14/42V buses and the behaviour of the system model under different loads are assessed and results discussed. The performance of the 42V Lundell alternator with the interleaved six-phase buck dc-to-dc converter system is modelled using Simulink software to assess the effectiveness of the model and its transient behaviour. The simulated results are presented for the transient characteristics of the system for load dumps.

  20. An Analysis of Philosophical Connotation of "Unique Features" Loaded on Sports%An Analysis of Philosophical Connotation of "Unique Features" Loaded on Sports

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    JIN Qing-kai (School of Physical Education, West Anhui University, Lu' an, Anhui 237012, China) Abstract: By studying the traditional implication and philosophical connotation of "unique features", the writer of this article expounds the scientific meaning of "unique features" loaded on sports, which refers to a pattern of modality, rule, practice and theory formed in the optimized combination of the commonality with individuality of a certain object. Meanwhile, the writer makes an induction and analysis of the basic modality of "unique features" in sports field, and illustrates the aspects that we should pay attention to in understanding "unique features" loaded on sports.

  1. Experimental Dynamic Analysis of Nonlinear Beams under Moving Loads

    Directory of Open Access Journals (Sweden)

    A. Bellino

    2012-01-01

    Full Text Available It is well known that nonlinear systems, as well as linear time-varying systems, are characterized by non-stationary response signals. In this sense, they both show natural frequencies that are not constant over time; this variation has however different origins: for a time-varying system the mass, and possibly the stiffness distributions, are changing over time, while for a nonlinear system the natural frequencies are amplitude-dependent. An interesting case of time-varying system occurs when analyzing the transit of a train over a railway bridge, easily simulated by the crossing of a moving load over a beam. In this case, the presence of a nonlinearity in the beam behaviour can cause a significant alteration of the modal parameters extracted from the linearized model, such that the contributions of the two effects are no more distinguishable.

  2. Fatigue Analysis of Load-Carrying Fillet Welds

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Tychsen, Jesper; Andersen, Jens Ulfkjær

    2006-01-01

    is a doubler plate connection, which is often applied in connection with modifications of offshore structures. As a part of the present work, fatigue tests have been performed with test specimens fabricated by the current industry standard for welded offshore steel structures. The fatigue tests show......The fatigue strength of load-carrying fillet welds is, in most codes of practice, performed neglecting the influence of bending in the weld throat section. However, some commonly applied structural details give rise to significant bending in the weld throat section. An example of such a detail...... that the degree of bending (DOB) has an influence on the fatigue lifetime. The fatigue lifetime decreases significantly when increasing the bending stress. In order to take into account the effect of the bending, a new fatigue stress definition applicable for fillet welds failing through the weld is presented...

  3. Analysis and Synthesis of Load Forecasting Data for Renewable Integration Studies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Steckler, N.; Florita, A.; Zhang, J.; Hodge, B. M.

    2013-11-01

    As renewable energy constitutes greater portions of the generation fleet, the importance of modeling uncertainty as part of integration studies also increases. In pursuit of optimal system operations, it is important to capture not only the definitive behavior of power plants, but also the risks associated with systemwide interactions. This research examines the dependence of load forecast errors on external predictor variables such as temperature, day type, and time of day. The analysis was utilized to create statistically relevant instances of sequential load forecasts with only a time series of historic, measured load available. The creation of such load forecasts relies on Bayesian techniques for informing and updating the model, thus providing a basis for networked and adaptive load forecast models in future operational applications.

  4. Hierarchical models for failure analysis of plates bent by distributed and localized transverse loadings

    Institute of Scientific and Technical Information of China (English)

    Erasmo CARRERA; Gaetano GIUNTA

    2008-01-01

    The failure analysis of simply supported, isotropic, square plates is addressed. Attention focuses on minimum failure load amplitudes and failure locations, von Mises' equivalent stress along the plate thickness is also addressed. Several distributed and localized loading conditions are considered. Loads act on the top of the plate. Bi-sinusoidal and uniform loads are taken into account for distributed loadings, while stepwise constant centric and off-centric loadings are addressed in the case of localized loadings. Analysis is performed considering plates whose length-to-thickness ratio a/h can be as high as 100 (thin plates) and as low as 2 (very thick plates). Results are obtained via several 2D plate models. Classical theories (CTs) and higher order models are applied. Those theories are based on polynomial approximation of the displacement field. Among the higher order theories (HOTs), HOTsd models account for the transverse shear deformations, while HOTs models account for both transverse shear and transverse normal deformations. LHOTs represent a local application of the higher order theories. A layerwise approach is thus assumed: by means of mathematical interfaces, the plate is considered to be made of several fictitious layers. The exact 3D solution is presented in order to determine the accuracy of the results obtained via the 2D models. In this way a hierarchy among the 2D theories is established. CTs provide highly accurate results for a/h greater than 10 in the case of distributed loadings and greater than 20 for localized Ioadings. Results obtained via HOTs are highly accurate in the case of very thick plates for bi-sinusoidal and centric loadings. In the case of uniform and off-centric loadings a high gradient is present in the neighborhood of the plate top. In those cases, LHOTs yield results that match the exact solution.

  5. Load Express Analysis of the Car Running Against the Bumps in the Road

    Directory of Open Access Journals (Sweden)

    Yu. N. Baryshnikov

    2014-01-01

    Full Text Available In many fields of technology when calculating the strength there are options available to choose design cases and loads in compliance with different operating conditions. In the automotive industry there are no such standards yet. This is due to both a variety of operating conditions, and a complexity of calculating the actual loads.K. Ert`s article is considered to be a pioneering work in this regard. There the author makes a hypothesis of the linear dependence of torque acting on the car, and of the height of bumps in the road. All formulas were obtained for vehicles with the leaf spring suspensions. An appearing entire class of new cars made it necessary to generalize the experience.This paper proposes an engineering method for calculating the vertical loads acting on the car when bumping in the road. We derive general formulas to calculate the height of the road bumps (irregularities on the way of a running car with various types of suspension. A dump truck BELAZ with various types nonlinear of suspension has been used to test the obtained formulas. The results analysis has shown that under equal conditions a car with dependent rear suspension will bear the lower loads than its prototype with a different type of suspension.The paper presents the relationships between the hights of bumps, which cause an equivalent load when different wheels bump against them. It shows a relation between the loads acting on the car when bumping against the same road irregularity by different wheels. The practical significance of the equations is the possibility to calculate loads in various cases in the road using the one-test results. A comparative results analysis of analytical calculation of loads and numerical experiments is based on the nonlinear model of the vehicle.The proposed method is an effective tool for the rapid analysis of loads in the design and fine-tuning the car.

  6. Dealing with periodical loads and harmonics in operational modal analysis using time-varying transmissibility functions

    Science.gov (United States)

    Weijtjens, Wout; Lataire, John; Devriendt, Christof; Guillaume, Patrick

    2014-12-01

    Periodical loads, such as waves and rotating machinery, form a problem for operational modal analysis (OMA). In OMA only the vibrations of a structure of interest are measured and little to nothing is known about the loads causing these vibrations. Therefore, it is often assumed that all dynamics in the measured data are linked to the system of interest. Periodical loads defy this assumption as their periodical behavior is often visible within the measured vibrations. As a consequence most OMA techniques falsely associate the dynamics of the periodical load with the system of interest. Without additional information about the load, one is not able to correctly differentiate between structural dynamics and the dynamics of the load. In several applications, e.g. turbines and helicopters, it was observed that because of periodical loads one was unable to correctly identify one or multiple modes. Transmissibility based OMA (TOMA) is a completely different approach to OMA. By using transmissibility functions to estimate the structural dynamics of the system of interest, all influence of the load-spectrum can be eliminated. TOMA therefore allows to identify the modal parameters without being influenced by the presence of periodical loads, such as harmonics. One of the difficulties of TOMA is that the analyst is required to find two independent datasets, each associated with a different loading condition of the system of interest. This poses a dilemma for TOMA; how can an analyst identify two different loading conditions when little is known about the loads on the system? This paper tackles that problem by assuming that the loading conditions vary continuously over time, e.g. the changing wind directions. From this assumption TOMA is developed into a time-varying framework. This development allows TOMA to not only cope with the continuously changing loading conditions. The time-varying framework also enables the identification of the modal parameters from a single dataset

  7. VISAR Unfold Analysis of Load Current in MagLIF Experiments

    Science.gov (United States)

    Hess, Mark; McBride, Ryan; Martin, Matthew

    2013-10-01

    An accurate prediction of the load current is essential in the performance of MagLIF experiments on the Z-Machine at Sandia. At present, the most accurate diagnostic for measuring load current on the Z-machine is the well-established VISAR technique. The VISAR diagnostic measures the velocity of a thin aluminum foil placed near the load, which is subject to the magnetic pressure produced by the load current, using a laser interferometer. The load current unfold analysis is highly nonlinear due to the equation of state/conductivity models, along with the MHD equations governing the foil. Nevertheless, an accurate load current unfold from the VISAR measurement is possible using an MHD code, in conjunction with an optimization algorithm. We will review the VISAR unfold analysis, and show recent current unfolds of MagLIF experiments in comparison to load current measurements using B-dot probes. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  8. Plastic Limit Load Analysis of Cylindrical Pressure Vessels with Different Nozzle Inclination

    Science.gov (United States)

    Prakash, Anupam; Raval, Harit Kishorchandra; Gandhi, Anish; Pawar, Dipak Bapu

    2016-04-01

    Sudden change in geometry of pressure vessel due to nozzle cutout, leads to local stress concentration and deformation, decreasing its strength. Elastic plastic analysis of cylindrical pressure vessels with different inclination angles of nozzle is important to estimate plastic limit load. In the present study, cylindrical pressure vessels with combined inclination of nozzles (i.e. in longitudinal and radial plane) are considered for elastic plastic limit load analysis. Three dimensional static nonlinear finite element analyses of cylindrical pressure vessels with nozzle are performed for incremental pressure loading. The von Mises stress distribution on pressure vessel shows higher stress zones at shell-nozzle junction. Approximate plastic limit load is obtained by twice elastic slope method. Variation in limit pressure with different combined inclination angle of nozzle is analyzed and found to be distinct in nature. Reported results can be helpful in optimizing pressure vessel design.

  9. Analysis of Bearing Capacity of Suction Bucket Foundation Subjected to Horizontal and Moment Loadings

    Directory of Open Access Journals (Sweden)

    W.U. Ke

    2013-07-01

    Full Text Available The suction bucket foundation is not only supporting the vertical loading such as the sea platform and weight itself, but also subjecting to horizontal and moment loading due to wind and wave. The response of bucket foundation to combined Horizontal (H and Moment (M loading has been studied using 3D finite element analysis Then the proposed method is numerically implemented in the framework of the general-purpose FEM software ABAQUS. Relationship curve between the coefficient of ultimate bearing capacity and displacement is obtained by the application of load-displacement controlled method in homogeneous soft foundation the failure envelope of foundation in the M-H is obtained by the application of swipe testing. The behavior is explained using upper bound plasticity mechanisms suggested by the soil deformation mechanisms observed in the finite element analysis. The numerical results computed by the proposed method will be helpful in engineering practices.

  10. Loading-unloading test analysis of anisotropic columnar jointed basalts

    Institute of Scientific and Technical Information of China (English)

    Zhi-gang SHAN; Sheng-jie DI

    2013-01-01

    To evaluate the columnar jointed basalts in the dam site of Baihetan hydropower station in southwest China,we developed a basic conceptual model of single jointed rock mass.Considering that the rock mass deformation consists of rock block deformation and joints deformation,the linear mechanical characteristics of the cell(including the elastic joints and the nonlinear mechanical behaviors of the cell)with a combined frictional-elastic interface were analyzed.We developed formulas to calculate the rock block deformation,which can be adapted for multiple jointed rock mass and columnar jointed basalts.The formulas are effective in calculating the equivalent modulus of multiple jointed rock mass,and precisely reveal the anisotropic properties of columnar jointed basalts.Furthermore,the in situ rigid bearing plate tests were analyzed and calculated,and the types of loading-unloading curves and the equivalent modulus along different directions of columnar jointed basalts were obtained.The analytical results are in close compliance with the test results.

  11. Reliability analysis of production ships with emphasis on load combination and ultimate strength

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaozhi

    1995-05-01

    This thesis deals with ultimate strength and reliability analysis of offshore production ships, accounting for stochastic load combinations, using a typical North Sea production ship for reference. A review of methods for structural reliability analysis is presented. Probabilistic methods are established for the still water and vertical wave bending moments. Linear stress analysis of a midships transverse frame is carried out, four different finite element models are assessed. Upon verification of the general finite element code ABAQUS with a typical ship transverse girder example, for which test results are available, ultimate strength analysis of the reference transverse frame is made to obtain the ultimate load factors associated with the specified pressure loads in Det norske Veritas Classification rules for ships and rules for production vessels. Reliability analysis is performed to develop appropriate design criteria for the transverse structure. It is found that the transverse frame failure mode does not seem to contribute to the system collapse. Ultimate strength analysis of the longitudinally stiffened panels is performed, accounting for the combined biaxial and lateral loading. Reliability based design of the longitudinally stiffened bottom and deck panels is accomplished regarding the collapse mode under combined biaxial and lateral loads. 107 refs., 76 refs., 37 tabs.

  12. ANALYSIS OF EXPOSURE OF REINFORCED CONCRETE BUILDINGS TO TEMPERATURE LOADS

    OpenAIRE

    2012-01-01

    The co-authors consider the problem of analysis of building structures in respect of combined effects of forces and temperatures. Results of fire tests of reinforced concrete walls and slabs are presented. Overview of the analysis of the fire resistance of reinforced-concrete buildings is also provided. As a result of the research, numerical solutions were obtained in respect of deflections, stresses, deformations and internal forces arising in a reinforced concrete bearing wall and plate...

  13. Numerical methods for analysis of structure and ground vibration from moving loads

    DEFF Research Database (Denmark)

    Andersen, L.; Nielsen, S.R.K.; Krenk, Steen

    2007-01-01

    An overview of the main theoretical aspects of finite-element and boundary-element modelling of the response to moving loads is given. The moving loads represent sources of noise and vibration generated by moving vehicles, and the analysis describes the propagation of the disturbances generated i...... recent results from the Danish research programme 'Damping Mechanisms in Dynamics of Structures and Materials' as a basis for a general discussion and review of the recent literature on the subject....

  14. Modeling and Analysis Tools for Linear and Nonlinear Mechanical Systems Subjected to Extreme Impulsive Loading

    Science.gov (United States)

    2015-03-23

    TITLE AND SUBTITLE Modeling and Analysis Tools for Linear and Nonlinear Mechanical Systems Subjected to Extreme Impulsive Loading 5a. CONTRACT...and Nonlinear Mechanical Systems Subjected to Extreme Impulsive Loading AFOSR GRANT FA9550-11-1-0108 A. J. Dick Department of Mechanical Engineering...For linear systems, the convolution integral of a system’s impulse response and the applied force results in the response of the system. This

  15. Wind/Wave Misalignment in the Loads Analysis of a Floating Offshore Wind Turbine: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Barj, L.; Stewart, S.; Stewart, G.; Lackner, M.; Jonkman, J.; Robertson, A.

    2014-02-01

    Wind resources far from the shore and in deeper seas have encouraged the offshore wind industry to look into floating platforms. The International Electrotechnical Commission (IEC) is developing a new technical specification for the design of floating offshore wind turbines that extends existing design standards for land-based and fixed-bottom offshore wind turbines. The work summarized in this paper supports the development of best practices and simulation requirements in the loads analysis of floating offshore wind turbines by examining the impact of wind/wave misalignment on the system loads under normal operation. Simulations of the OC3-Hywind floating offshore wind turbine system under a wide range of wind speeds, significant wave heights, peak-spectral periods and wind/wave misalignments have been carried out with the aero-servo-hydro-elastic tool FAST [4]. The extreme and fatigue loads have been calculated for all the simulations. The extreme and fatigue loading as a function of wind/wave misalignment have been represented as load roses and a directional binning sensitivity study has been carried out. This study focused on identifying the number and type of wind/wave misalignment simulations needed to accurately capture the extreme and fatigue loads of the system in all possible metocean conditions considered, and for a down-selected set identified as the generic US East Coast site. For this axisymmetric platform, perpendicular wind and waves play an important role in the support structure and including these cases in the design loads analysis can improve the estimation of extreme and fatigue loads. However, most structural locations see their highest extreme and fatigue loads with aligned wind and waves. These results are specific to the spar type platform, but it is expected that the results presented here will be similar to other floating platforms.

  16. MSC/NASTRAN DMAP Alter Used for Closed-Form Static Analysis With Inertia Relief and Displacement-Dependent Loads

    Science.gov (United States)

    1996-01-01

    Solving for the displacements of free-free coupled systems acted upon by static loads is a common task in the aerospace industry. Often, these problems are solved by static analysis with inertia relief. This technique allows for a free-free static analysis by balancing the applied loads with the inertia loads generated by the applied loads. For some engineering applications, the displacements of the free-free coupled system induce additional static loads. Hence, the applied loads are equal to the original loads plus the displacement-dependent loads. A launch vehicle being acted upon by an aerodynamic loading can have such applied loads. The final displacements of such systems are commonly determined with iterative solution techniques. Unfortunately, these techniques can be time consuming and labor intensive. Because the coupled system equations for free-free systems with displacement-dependent loads can be written in closed form, it is advantageous to solve for the displacements in this manner. Implementing closed-form equations in static analysis with inertia relief is analogous to implementing transfer functions in dynamic analysis. An MSC/NASTRAN (MacNeal-Schwendler Corporation/NASA Structural Analysis) DMAP (Direct Matrix Abstraction Program) Alter was used to include displacement-dependent loads in static analysis with inertia relief. It efficiently solved a common aerospace problem that typically has been solved with an iterative technique.

  17. Emergency Load Shedding Strategy Based on Sensitivity Analysis of Relay Operation Margin against Cascading Events

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Sun, Haishun Sun;

    2012-01-01

    In order to prevent long term voltage instability and induced cascading events, a load shedding strategy based on the sensitivity of relay operation margin to load powers is discussed and proposed in this paper. The operation margin of critical impedance backup relay is defined to identify the ru...... into account to compensate load shedding amount calculation. And the multi-agent technology is applied for the whole strategy implementation. A test system is built in real time digital simulator (RTDS) and has demonstrated the effectiveness of the proposed strategy.......In order to prevent long term voltage instability and induced cascading events, a load shedding strategy based on the sensitivity of relay operation margin to load powers is discussed and proposed in this paper. The operation margin of critical impedance backup relay is defined to identify...... the runtime emergent states of related system component. Based on sensitivity analysis between the relay operation margin and power system state variables, an optimal load shedding strategy is applied to adjust the emergent states timely before the unwanted relay operation. Load dynamics is also taken...

  18. Buckling analysis of curved composite sandwich panels subjected to inplane loadings

    Science.gov (United States)

    Cruz, Juan R.

    1993-01-01

    Composite sandwich structures are being considered for primary structure in aircraft such as subsonic and high speed civil transports. The response of sandwich structures must be understood and predictable to use such structures effectively. Buckling is one of the most important response mechanisms of sandwich structures. A simple buckling analysis is derived for sandwich structures. This analysis is limited to flat, rectangular sandwich panels loaded by uniaxial compression (N(sub x)) and having simply supported edges. In most aerospace applications, however, the structure's geometry, boundary conditions, and loading are usually very complex. Thus, a general capability for analyzing the buckling behavior of sandwich structures is needed. The present paper describes and evaluates an improved buckling analysis for cylindrically curved composite sandwich panels. This analysis includes orthotropic facesheets and first-order transverse shearing effects. Both simple support and clamped boundary conditions are also included in the analysis. The panels can be subjected to linearly varying normal loads N(sub x) and N(sub y) in addition to a constant shear load N(sub xy). The analysis is based on the modified Donnell's equations for shallow shells. The governing equations are solved by direct application of Galerkin's method. The accuracy of the present analysis is verified by comparing results with those obtained from finite element analysis for a variety of geometries, loads, and boundary conditions. The limitations of the present analysis are investigated, in particular those related to the shallow shell assumptions in the governing equations. Finally, the computational efficiency of the present analysis is considered.

  19. Generalized Analysis Method for a Class of Novel Wideband Loaded-Stub Phase Shifters

    Directory of Open Access Journals (Sweden)

    Sensong An

    2015-12-01

    Full Text Available In this paper, an analysis method of wideband loaded-stub phase shifters and a fast designing procedure is presented. These kinds of phase shifters use a transmission line loaded with one or two open stubs and a reference line to achieve up to 135° phase shift. Analysis results shows that lower than -10dB return loss and precise phase shift can be achieved over a 100% bandwidth employing the ideal open stubs. To approach the ideal impedance value of the open stubs, an arrow-shaped stub and several means to control its impedance is proposed. As verification of the analysis method, a 90° two-stub loaded phase shifter is easily designed and fabricated. Measured results show the design achieves better than ±4° phase ripple, less than 0.5dB insertion loss, and better than 10dB return loss over an 85% wideband.

  20. Influences of load pattern selection and higher modes on pushover analysis for R.C. structures

    Institute of Scientific and Technical Information of China (English)

    HOU Shuang; OU Jin-ping

    2008-01-01

    Load pattern selection is one of the critical issues in pushover analysis (POA) when the influence of higher modes is evident. In terms of interstory drift, comparisons between the nonlinear time history analysis (NL-THA) and the pushover analysis (POA) were conducted for three typical RC frame buildings under a va-riety of ground motion levels. Eight typical earthquake inputs, including four earthquake records and four artifi-cial earthquake waves, were employed as the input of NL-THA; five typical lateral load patterns were consid-ered in POA. By means of modal participation factor, the higher mode effect in POA was quantified considering floor numbers and the ground motion intensity. Suggestions about load pattern selection in POA were provided when higher mode influence was found evident.

  1. Interface load analysis for computer-aided design of below-knee prosthetic sockets.

    Science.gov (United States)

    Reynolds, D P; Lord, M

    1992-07-01

    A finite-element analysis is made for the compression of soft tissues of the residual lower limb contained in a prosthetic socket. The analysis is relevant to static loading during stance in a patellar-tendon-bearing, below-knee design of socket. Values of Young's modulus are obtained experimentally for use in the model. One of the main objectives is to study the sensitivity of the loading to these values and also to other assumed conditions. Using direct pressure at the limb/socket interface and vertical stiffness as indicators, changes in material properties, socket alignment and socket rectification are investigated; assumptions about the frictional characteristic at the interface are seen to be critical in determination of load distribution. This type of analysis may provide the next stage of refinement for computer-aided socket design systems.

  2. Risk Analysis of Breakwater Caisson Under Wave Attack Using Load Surface Approximation

    Institute of Scientific and Technical Information of China (English)

    Dong Hyawn KIM

    2014-01-01

    A new load surface based approach to the reliability analysis of caisson-type breakwater is proposed. Uncertainties of the horizontal and vertical wave loads acting on breakwater are considered by using the so-called load surfaces, which can be estimated as functions of wave height, water level, and so on. Then, the first-order reliability method (FORM) can be applied to determine the probability of failure under the wave action. In this way, the reliability analysis of breakwaters with uncertainties both in wave height and in water level is possible. Moreover, the uncertainty in wave breaking can be taken into account by considering a random variable for wave height ratio which relates the significant wave height to the maximum wave height. The proposed approach is applied numerically to the reliability analysis of caisson breakwater under wave attack that may undergo partial or full wave breaking.

  3. Dynamic Analysis of A Pontoon-Separated Floating Bridge ubjected to A Moving Load

    Institute of Scientific and Technical Information of China (English)

    WANG Cong; FU Shi-xiao; LI Ning; CUI Wei-cheng; LIN Zhu-ming

    2006-01-01

    For the design and operation of a floating bridge, the understanding of its dynamic behavior under a moving load is of great importance. The purpose of this paper is to investigate the dynamic performances of a new type floating bridge, the pontoon-separated floating bridge, under the effect of a moving load. In the paper, a brief summary of the dynamic analysis of the floating bridge is first introduced. The motion equations for a pontoon-separated floating bridge, considering the nonlinear properties of connectors and vehicles' inertia effects, are proposed. The super-element method is applied to reduce the numerical analysis scale to solve the reduced equations. Based on the static analysis, the dynamic features of the new type floating bridge subjected to a moving load are investigated. It is found that the dynamic behavior of the pontoon-separated floating bridge is superior to that of the ribbon bridge by taking the nonlinearity of connectors into account.

  4. Linear and Non-linear Analysis of Fibre Reinforced Plastic Bridge Deck due to Vehicle Loads

    Science.gov (United States)

    Ray, Chaitali; Mandal, Bibekananda

    2015-06-01

    The present work deals with linear and nonlinear static analysis of fibre reinforced plastics composite bridge deck structures using the finite element method. The nonlinear static analysis has been carried out considering geometric nonlinearity. The analysis of bridge deck has been carried out under vehicle load as specified by IRC Class B wheel load classification. The formulation has been carried out using the finite element software package ANSYS 14.0 and the SHELL281 element is used to model the bridge deck. The bridge deck has also been modeled as a plate stiffened with closely spaced hollow box sections and a computer code is developed based on this formulation. The results obtained from the present formulation are compared with those available in the published literature. A parametric study on the stiffened bridge deck has also been carried out with varying dimensions of the stiffeners under vehicle loads.

  5. Microbial Load Analysis in Silicone Gel Breast Implants

    Directory of Open Access Journals (Sweden)

    GLAUCIA CRISTINA MELLO SANTOS

    2010-06-01

    Full Text Available Silicone breast implants consist of biomaterials widely used in breast reconstitution surgeries or in mammary augmentation for esthetic reasons. A preliminary stage of the implant production process is vulcanization, which consists of heating the implant to 165±5°C for approximately 9 hours. The aim of this work was to evaluate the bioburden of silicone breast implants prior to the vulcanization process and the decline in bioburden due to this process, and to confirm the sterility of the gel contained in the membrane. Breast implant production stages were evaluated by microbial counting in different steps, according to the USP 32 methodology. To evaluation of decrease in microbial load, spores strips were introduced inside the implant, and after vulcanization cycles the strips were removed from the implant. The strips were transferred to tubes containing TSB, followed by incubation for 7 days at 30-35°C. The results obtained showed that the level of microbial contamination of gel implants is relatively low, and that vulcanization allowed for the inactivation of up to 108 spores. This study led us to the conclusion that vulcanization leaded to sterility of the gel inside the product. Thus, the final sterilizing process contributed to an increase in the Sterility Assurance Level 1. Keywords: Silicone. Breast implant. Sterilization. Dry heat. Vulcanization. Bioburden. RESUMO Análise da Carga Microbiana de Implantes Mamários de Silicone Os implantes mamários de silicone constituem-se em biomateriais que têm sido amplamente utilizados em cirurgias para reconstituição da mama ou para o aumento do tamanho da mama por motivos estéticos. Uma etapa preliminar do processo produtivo do implante é a vulcanização, que consiste no aquecimento do implante a 165±5°C por aproximadamente 9 horas. O objetivo deste estudo foi avaliar a carga microbiana dos implantes mamários de silicone antes do processo de vulcanização, o decaimento

  6. Service Oriented Architectural Model for Load Flow Analysis in Power Systems

    Science.gov (United States)

    Muthu, Balasingh Moses; Veilumuthu, Ramachandran; Ponnusamy, Lakshmi

    2011-07-01

    The main objective of this paper is to develop the Service Oriented Architectural (SOA) Model for representation of power systems, especially of computing load flow analysis of large interconnected power systems. The proposed SOA model has three elements namely load flow service provider, power systems registry and client. The exchange of data using XML makes the power system services standardized and adaptable. The load flow service is provided by the service provider, which is published in power systems registry for enabling universal visibility and access to the service. The message oriented style of SOA using Simple Object Access Protocol (SOAP) makes the service provider and the power systems client to exist in a loosely coupled environment. This proposed model, portraits the load flow services as Web services in service oriented environment. To suit the power system industry needs, it easily integrates with the Web applications which enables faster power system operations.

  7. DYNAMIC ANALYSIS OF UNDERGROUND COMPOSITE STRUCTURES UNDER EXPLOSION LOADING

    Institute of Scientific and Technical Information of China (English)

    赵晓兵; 薛大为; 赵玉祥

    2004-01-01

    In selecting rational types of underground structures resisting explosion, in order to improve stress states of the structural section and make full use of material strength of each part of the section, the research method of composite structures is presented. Adopting the analysis method of micro-section free body, equilibrium equations, constraint equations and deformation coordination equations are given. Making use of the concept of generalized work and directly introducing Lagrange multiplier specific in physical meaning, the validity of the constructed generalized functional is proved by using variation method. The rational rigidity matching relationship of composite structure section is presented through example calculations.

  8. Selecting boundary conditions in physiological strain analysis of the femur: Balanced loads, inertia relief method and follower load.

    Science.gov (United States)

    Heyland, Mark; Trepczynski, Adam; Duda, Georg N; Zehn, Manfred; Schaser, Klaus-Dieter; Märdian, Sven

    2015-12-01

    Selection of boundary constraints may influence amount and distribution of loads. The purpose of this study is to analyze the potential of inertia relief and follower load to maintain the effects of musculoskeletal loads even under large deflections in patient specific finite element models of intact or fractured bone compared to empiric boundary constraints which have been shown to lead to physiological displacements and surface strains. The goal is to elucidate the use of boundary conditions in strain analyses of bones. Finite element models of the intact femur and a model of clinically relevant fracture stabilization by locking plate fixation were analyzed with normal walking loading conditions for different boundary conditions, specifically re-balanced loading, inertia relief and follower load. Peak principal cortex surface strains for different boundary conditions are consistent (maximum deviation 13.7%) except for inertia relief without force balancing (maximum deviation 108.4%). Influence of follower load on displacements increases with higher deflection in fracture model (from 3% to 7% for force balanced model). For load balanced models, follower load had only minor influence, though the effect increases strongly with higher deflection. Conventional constraints of fixed nodes in space should be carefully reconsidered because their type and position are challenging to justify and for their potential to introduce relevant non-physiological reaction forces. Inertia relief provides an alternative method which yields physiological strain results.

  9. Response Analysis for Steel Reinforced Concrete Frame Structures under Earthquake Load

    OpenAIRE

    Hua Wei; Jiye Zhang; Haijun Wang

    2013-01-01

    In order to understand the whole process of the steel reinforced concrete frame structure from elastic to elasto-plastic cracking gradually, damage until the collapse, the elasto-plastic finite element analysis theory and ETABS structural analysis software were used, then the spatial three-dimensional truss system model of frame structures was established. Based on the analysis of the elasto-plastic response for the frame structure under one-dimensional and two-dimensional earthquake load, th...

  10. Validation of analysis methods for assessing flawed piping subjected to dynamic loading

    Energy Technology Data Exchange (ETDEWEB)

    Olson, R.J.; Wolterman, R.L.; Wilkowski, G.M. [Battelle, Columbus, OH (United States); Kot, C.A. [Argonne National Lab., IL (United States)

    1994-08-01

    Argonne National Laboratory and Battelle have jointly conducted a research program for the USNRC to evaluate the ability of current engineering analysis methods and one state-of-the-art analysis method to predict the behavior of circumferentially surface-cracked pipe system water-hammer experiment. The experimental data used in the evaluation were from the HDR Test Group E31 series conducted by the Kernforschungszentrum Karlsruhe (KfK) in Germany. The incentive for this evaluation was that simplified engineering methods, as well as newer ``state-of-the-art`` fracture analysis methods, have been typically validated only with static experimental data. Hence, these dynamic experiments were of high interest. High-rate dynamic loading can be classified as either repeating, e.g., seismic, or nonrepeating, e.g., water hammer. Development of experimental data and validation of cracked pipe analyses under seismic loading (repeating dynamic loads) are being pursued separately within the NRC`s International Piping Integrity Research Group (IPIRG) program. This report describes developmental and validation efforts to predict crack stability under water hammer loading, as well as comparisons using currently used analysis procedures. Current fracture analysis methods use the elastic stress analysis loads decoupled from the fracture mechanics analysis, while state-of-the-art methods employ nonlinear cracked-pipe time-history finite element analyses. The results showed that the current decoupled methods were conservative in their predictions, whereas the cracked pipe finite element analyses were more accurate, yet slightly conservative. The nonlinear time-history cracked-pipe finite element analyses conducted in this program were also attractive in that they were done on a small Apollo DN5500 workstation, whereas other cracked-pipe dynamic analyses conducted in Europe on the same experiments required the use of a CRAY2 supercomputer, and were less accurate.

  11. Energy Analysis for TMD-Structure Systems Subjected to Impact Loading

    Institute of Scientific and Technical Information of China (English)

    王树青; 李华军; 嵇春艳; 焦桂英

    2002-01-01

    This paper investigates the characteristics of reduction of the lateral vibration by use of a Tuned Mass Damper(TMD) for offshore jacket platforms under impact loading. Unlike traditional analysis, the present analysis focnses on theenergy concept of TMD/structure systems. In this study, a time domain is taken. The platform is modeled as a simplifiedsingle-degree-of-freedom (SDOF) system by extraction of the first vibration mode of the structure and the excited force isassumed to be impact loading. The energy dissipation and energy transmission of the structure-TMD system are studied.Finally, an optimized TMD design for the modeled platform is demonstrated based on a new type of cost function - maxi-mum dissipated energy by TMD. Results indicate that TMD control is effective in reducing the standard deviation of thedeck motion but less effective in reducing the maximum response under impact loading.

  12. Fluctuation analysis of high frequency electric power load in the Czech Republic

    CERN Document Server

    Kracík, Jiří

    2016-01-01

    We analyze the electric power load in the Czech Republic (CR) which exhibits a seasonality as well as other oscillations typical for European countries. Moreover, we detect 1/f noise property of electrical power load with extra additional peaks that allows to separate it into a deterministic and stochastic part. We then focus on the analysis of the stochastic part using improved Multi-fractal Detrended Fluctuation Analysis method (MFDFA) to investigate power load datasets with a minute resolution. Extracting the noise part of the signal by using Fourier transform allows us to apply this method to obtain the fluctuation function and to estimate the generalized Hurst exponent together with the correlated Hurst exponent, its improvement for the non-Gaussian datasets. The results exhibit a strong presence of persistent behaviour and the dataset is characterized by a non-Gaussian skewed distribution. There are also indications for the presence of the probability distribution that has heavier tail than the Gaussian...

  13. Variables that influence HIV-1 cerebrospinal fluid viral load in cryptococcal meningitis: a linear regression analysis

    Directory of Open Access Journals (Sweden)

    Cecchini Diego M

    2009-11-01

    Full Text Available Abstract Background The central nervous system is considered a sanctuary site for HIV-1 replication. Variables associated with HIV cerebrospinal fluid (CSF viral load in the context of opportunistic CNS infections are poorly understood. Our objective was to evaluate the relation between: (1 CSF HIV-1 viral load and CSF cytological and biochemical characteristics (leukocyte count, protein concentration, cryptococcal antigen titer; (2 CSF HIV-1 viral load and HIV-1 plasma viral load; and (3 CSF leukocyte count and the peripheral blood CD4+ T lymphocyte count. Methods Our approach was to use a prospective collection and analysis of pre-treatment, paired CSF and plasma samples from antiretroviral-naive HIV-positive patients with cryptococcal meningitis and assisted at the Francisco J Muñiz Hospital, Buenos Aires, Argentina (period: 2004 to 2006. We measured HIV CSF and plasma levels by polymerase chain reaction using the Cobas Amplicor HIV-1 Monitor Test version 1.5 (Roche. Data were processed with Statistix 7.0 software (linear regression analysis. Results Samples from 34 patients were analyzed. CSF leukocyte count showed statistically significant correlation with CSF HIV-1 viral load (r = 0.4, 95% CI = 0.13-0.63, p = 0.01. No correlation was found with the plasma viral load, CSF protein concentration and cryptococcal antigen titer. A positive correlation was found between peripheral blood CD4+ T lymphocyte count and the CSF leukocyte count (r = 0.44, 95% CI = 0.125-0.674, p = 0.0123. Conclusion Our study suggests that CSF leukocyte count influences CSF HIV-1 viral load in patients with meningitis caused by Cryptococcus neoformans.

  14. Criticality Safety Analysis Of As-loaded Spent Nuclear Fuel Casks

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Kaushik [ORNL; Scaglione, John M [ORNL

    2015-01-01

    The final safety analysis report (FSAR) or the safety analysis report (SAR) for a particular spent nuclear fuel (SNF) cask system documents models and calculations used to demonstrate that a system meets the regulatory requirements under all normal, off-normal, and accident conditions of spent fuel storage, and normal and accident conditions of transportation. FSAR/SAR calculations and approved content specifications are intended to be bounding in nature to certify cask systems for a variety of fuel characteristics with simplified SNF loading requirements. Therefore, in general, loaded cask systems possess excess and uncredited criticality margins (i.e., the difference between the licensing basis and the as-loaded calculations). This uncredited margin could be quantified by employing more detailed cask-specific evaluations that credit the actual as-loaded cask inventory, and taking into account full (actinide and fission product) burnup credit. This uncredited criticality margin could be potentially used to offset (1) uncertainties in the safety basis that needs to account for the effects of system aging during extended dry storage prior to transportation, and (2) increases in SNF system reactivity over a repository performance period (e.g., 10,000 years or more) as the system undergoes degradation and internal geometry changes. This paper summarizes an assessment of cask-specific, as-loaded criticality margins for SNF stored at eight reactor sites (215 loaded casks were analyzed) under fully flooded conditions to assess the margins available during transportation after extended storage. It is observed that the calculated keff margin varies from 0.05 to almost 0.3 Δkeff for the eight selected reactor sites, demonstrating that significant uncredited safety margins are present. In addition, this paper evaluates the sufficiency of this excess margin in applications involving direct disposal of currently loaded SNF casks.

  15. Three dimensional finite element analysis of acetabulum loaded by static stress and its biomechanical significance

    Institute of Scientific and Technical Information of China (English)

    SU Jia-can; ZHANG Ben; YU Bao-qing; ZHANG Chun-cai; CHEN Xue-qiang; WANG Bao-hua; DING Zu-quan

    2005-01-01

    Objective:To explore the mechanical behavior of acetabulum loaded by static stress and provide the mechanical basis for clinical analysis and judgement on acetabular mechanical distribution and effect of static stress. Methods:By means of computer simulation, acetabular three dimensional model was input into three dimensional finite element analysis software ANSYS7.0. The acetabular mechanical behavior was calculated and the main stress value, stress distribution and acetabular unit displacement in the direction of main stress were analyzed when anterior wall of acetabulum and acetabular crest were loaded by 1 000 N static stress. Results :When acetabular anterior wall loaded by X direction and Z direction composition force, the stress passed along 4 directions: (1)from acetabular anterior wall to pubic symphysis a long superior branch of pubis firstly, (2)from acetabular anterior wall to cacroiliac joint along pelvic ring,(3)in the acetabulum, (4)from the suffered point to ischium. When acetabular crest loaded by X direction and Y direction composition force, the stress transmitted to 4 directions: (1)from acetabular crest to ilium firstly, (2)from suffered point to cacroiliac joint along pelvic ring, (3) in the acetabulum , (4)along the pubic branch ,but no stress transmitted to the ischium branch. Conclusion:Analyzing the stress distribution of acetabulum and units displacement when static stress loaded can provide internal fixation point for acetabular fracture treatment and help understand the stress distribution of acetabulum.

  16. Analysis of the multistage cyclic loading test on resilient modulus value64

    Directory of Open Access Journals (Sweden)

    Sas Wojciech

    2016-03-01

    Full Text Available Analysis of the multistage cyclic loading test on resilient modulus value. Upon cyclic excitation of soil mass, two types of strain can be recognized, namely elastic and plastic one. Proper analysis of these two types of deformations can help engineers in designing more reliable structures. In this study, a multistage uniaxial cyclic loading in unconfined conditions was performed. Tests were performed in order to characterize strain response to repeated excitation. Soil sample under cyclic loading was recognized as exhibiting the symptoms of a plastic strain growth during the cyclic loading process with exponential manner, when compared to number of cycles. Soil in this study was reconstituted and compacted by using the Proctor method to simulate conditions similar to those affecting the road subbase. The soil was recognized as sandy clay. Results were analysed and a proposition of empirical formula for plastic strain calculation with the use of characteristic stress values was presented. The resilient modulus values were also calculated. The Mr value was within range from 45 to 105 MPa. The conclusions concerning the cyclically loaded soil in uniaxial conditions were presented.

  17. Biomechanical analysis of reducing sacroiliac joint shear load by optimization of pelvic muscle and ligament forces

    NARCIS (Netherlands)

    J.J.M. Pel (Johan); C.W. Spoor (Cornelis); A.L. Pool-Goudzwaard (Annelies); G.A. Hoek van Dijke; C.J. Snijders (Chris)

    2008-01-01

    textabstractEffective stabilization of the sacroiliac joints (SIJ) is essential, since spinal loading is transferred via the SIJ to the coxal bones, and further to the legs. We performed a biomechanical analysis of SIJ stability in terms of reduced SIJ shear force in standing posture using a validat

  18. Response Analysis for Steel Reinforced Concrete Frame Structures under Earthquake Load

    Directory of Open Access Journals (Sweden)

    Hua Wei

    2013-07-01

    Full Text Available In order to understand the whole process of the steel reinforced concrete frame structure from elastic to elasto-plastic cracking gradually, damage until the collapse, the elasto-plastic finite element analysis theory and ETABS structural analysis software were used, then the spatial three-dimensional truss system model of frame structures was established. Based on the analysis of the elasto-plastic response for the frame structure under one-dimensional and two-dimensional earthquake load, the interbedded displacement angle-time curve and horizontal displacement-time curve were obtained. Through the analysis of the model, the sequence of appearance of plastic hinges in the frame structure under earthquake load was cleared and the weak location of the frame structure was detected.

  19. Structural Analysis of Cuban Typical Model of Telecommunication Self-Supporting Towers under Seismic Load

    Directory of Open Access Journals (Sweden)

    Patricia Martín Rodríguez

    2012-07-01

    Full Text Available Self-supporting lattice towers are slender structures with low damping and high flexibility. They are sensitive to dynamic loads such as wind and earthquake. In the West of Cuba, structures should be analyzed under extreme winds and seismic effects, which raised their frequency during 2010 year. Self-supporting towers do not have the same dynamic behavior as buildings under seismic loads. Their specific structure features are not developed at design seismic codes, for that reason it is necessary to study methods of seismic analysis for self-supporting towers. The methods selected in this research are Modal Analysis Method proposed by Cuban Seismic Code (NC-46:1999 and modal superposition lineal dynamic analysis named Time History. It was selected for the study two self-supporting towers designed in Cuba, Versalles Model (3-legged and Najasa Model (4-legged. Comparative analysis between both methods is realized with extreme values of internal forces at element towers.

  20. Probabilistic Sensitivity Analysis for Launch Vehicles with Varying Payloads and Adapters for Structural Dynamics and Loads

    Science.gov (United States)

    McGhee, David S.; Peck, Jeff A.; McDonald, Emmett J.

    2012-01-01

    This paper examines Probabilistic Sensitivity Analysis (PSA) methods and tools in an effort to understand their utility in vehicle loads and dynamic analysis. Specifically, this study addresses how these methods may be used to establish limits on payload mass and cg location and requirements on adaptor stiffnesses while maintaining vehicle loads and frequencies within established bounds. To this end, PSA methods and tools are applied to a realistic, but manageable, integrated launch vehicle analysis where payload and payload adaptor parameters are modeled as random variables. This analysis is used to study both Regional Response PSA (RRPSA) and Global Response PSA (GRPSA) methods, with a primary focus on sampling based techniques. For contrast, some MPP based approaches are also examined.

  1. Deterministic and Probabilistic Analysis of NPP Communication Bridge Resistance Due to Extreme Loads

    Directory of Open Access Journals (Sweden)

    Králik Juraj

    2014-12-01

    Full Text Available This paper presents the experiences from the deterministic and probability analysis of the reliability of communication bridge structure resistance due to extreme loads - wind and earthquake. On the example of the steel bridge between two NPP buildings is considered the efficiency of the bracing systems. The advantages and disadvantages of the deterministic and probabilistic analysis of the structure resistance are discussed. The advantages of the utilization the LHS method to analyze the safety and reliability of the structures is presented

  2. Reliability Analysis for Adhesive Bonded Composite Stepped Lap Joints Loaded in Fatigue

    DEFF Research Database (Denmark)

    Kimiaeifar, Amin; Sørensen, John Dalsgaard; Lund, Erik

    2012-01-01

    This paper describes a probabilistic approach to calculate the reliability of adhesive bonded composite stepped lap joints loaded in fatigue using three- dimensional finite element analysis (FEA). A method for progressive damage modelling is used to assess fatigue damage accumulation and residual...... strength under fully reversed cyclic loading based on stiffness/strength degradation. The FEA simulations are conducted using the commercial FEA code ANSYS 12.1. A design equation for fatigue failure of wind turbine blades is chosen based on recommendations given in the wind turbine standard IEC 61400...

  3. Analysis of load transfer stability control strategy in hydraulic synchronized continuous slippage

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-bo; WU Jian-zhong; ZHANG Xuan

    2006-01-01

    Hydraulic synchronized continuous slippage technique,which integrates mechanical,electrical and hydraulic control,is introduced in this paper for the practical requirements of some construction projects.The core of this technique (the stability of the load transfer) is illustrated in detail.Three speed control strategies to transfer the load-excessive,lower and same speed-are presented to accomplish the smoothness and stability in the process of slippage.An optimization of the speed control strategy (same speed) is deduced from the modeling analysis and its validity and maneuverability are tested by practical application,which provides evidence for similar engineering in theory and practice.

  4. Numerical analysis of loaded stress and central displacement of deep groove ball bearing

    Institute of Scientific and Technical Information of China (English)

    杨磊; 邓松; 李红星

    2016-01-01

    The aim of this work is to develop a three-dimensional model of deep groove ball bearing to investigate the loaded stresses and central displacements of bearing rings. The equivalent stresses and central displacements of bearing rings are obtained based on the simulated analysis. Moreover, several parameters, such as load magnitude, raceway groove curvature radius (RGCR), thicknesses of outer and inner rings, are varied to investigate their effects on the equivalent stresses and central displacements of bearing rings. Research results provide useful guidelines for determining the design parameters.

  5. Closed-form Static Analysis with Inertia Relief and Displacement-Dependent Loads Using a MSC/NASTRAN DMAP Alter

    Science.gov (United States)

    Barnett, Alan R.; Widrick, Timothy W.; Ludwiczak, Damian R.

    1995-01-01

    Solving for the displacements of free-free coupled systems acted upon by static loads is commonly performed throughout the aerospace industry. Many times, these problems are solved using static analysis with inertia relief. This solution technique allows for a free-free static analysis by balancing the applied loads with inertia loads generated by the applied loads. For some engineering applications, the displacements of the free-free coupled system induce additional static loads. Hence, the applied loads are equal to the original loads plus displacement-dependent loads. Solving for the final displacements of such systems is commonly performed using iterative solution techniques. Unfortunately, these techniques can be time-consuming and labor-intensive. Since the coupled system equations for free-free systems with displacement-dependent loads can be written in closed-form, it is advantageous to solve for the displacements in this manner. Implementing closed-form equations in static analysis with inertia relief is analogous to implementing transfer functions in dynamic analysis. Using a MSC/NASTRAN DMAP Alter, displacement-dependent loads have been included in static analysis with inertia relief. Such an Alter has been used successfully to solve efficiently a common aerospace problem typically solved using an iterative technique.

  6. Direct methods of soil-structure interaction analysis for earthquake loadings (IV)

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J. B.; Kim, D. S.; Choi, J. S.; Kwon, K. C.; Kim, Y. J.; Lee, H. J.; Kim, S. B.; Kim, D. K. [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1996-07-15

    Methodologies of SSI analysis for earthquake loadings have been reviewed. Based on the finite element method incorporating infinite element technique for the unbounded exterior region, a computer program for the nonlinear seismic analysis named as 'KIESSI-QK' has been developed. The computer program has been verified using a free-field site-response problem. The Hualien FVT stochastic finite element analysis after backfill and the blind prediction of earthquake responses have been carried out utilizing the developed computer program. The earthquake response analysis for the LSST structure has also been performed and compared with the measured data.

  7. Prediction of In Vivo Knee Joint Loads Using a Global Probabilistic Analysis.

    Science.gov (United States)

    Navacchia, Alessandro; Myers, Casey A; Rullkoetter, Paul J; Shelburne, Kevin B

    2016-03-01

    Musculoskeletal models are powerful tools that allow biomechanical investigations and predictions of muscle forces not accessible with experiments. A core challenge modelers must confront is validation. Measurements of muscle activity and joint loading are used for qualitative and indirect validation of muscle force predictions. Subject-specific models have reached high levels of complexity and can predict contact loads with surprising accuracy. However, every deterministic musculoskeletal model contains an intrinsic uncertainty due to the high number of parameters not identifiable in vivo. The objective of this work is to test the impact of intrinsic uncertainty in a scaled-generic model on estimates of muscle and joint loads. Uncertainties in marker placement, limb coronal alignment, body segment parameters, Hill-type muscle parameters, and muscle geometry were modeled with a global probabilistic approach (multiple uncertainties included in a single analysis). 5-95% confidence bounds and input/output sensitivities of predicted knee compressive loads and varus/valgus contact moments were estimated for a gait activity of three subjects with telemetric knee implants from the "Grand Challenge Competition." Compressive load predicted for the three subjects showed confidence bounds of 333 ± 248 N, 408 ± 333 N, and 379 ± 244 N when all the sources of uncertainty were included. The measured loads lay inside the predicted 5-95% confidence bounds for 77%, 83%, and 76% of the stance phase. Muscle maximum isometric force, muscle geometry, and marker placement uncertainty most impacted the joint load results. This study demonstrated that identification of these parameters is crucial when subject-specific models are developed.

  8. Dynamic Analysis of the Titanium Alloy Plate under Thermal-acoustic Loadings

    Directory of Open Access Journals (Sweden)

    Zou Xuefeng

    2015-01-01

    Full Text Available Hypersonic vehicles structures suffer complex combined loadings generally. For the thin-walled structures and thermal protection systems of the aircraft, high temperature and intensity acoustic loadings are the significant factors that leading to their break. The object of this paper is typical simply supported titanium alloy plate, the finite element method was adopted to calculate the critical thermal buckling temperature the ordinal coupling method and Newmark method were adopted to calculate the thermal-acoustic dynamic response. Based on the FEM analysis, the power spectrum densities (PSD of center point was presented. Research results show that the thermal buckling of the typical simply supported titanium alloy plate occurs easily because of the low critical thermal buckling temperature, dynamic response of the thermal buckled plate suffering acoustic loads performs strong nonlinear characteristics and complex forms of exercise.

  9. Dynamic response analysis of an aircraft structure under thermal-acoustic loads

    Science.gov (United States)

    Cheng, H.; Li, H. B.; Zhang, W.; Wu, Z. Q.; Liu, B. R.

    2016-09-01

    Future hypersonic aircraft will be exposed to extreme combined environments includes large magnitude thermal and acoustic loads. It presents a significant challenge for the integrity of these vehicles. Thermal-acoustic test is used to test structures for dynamic response and sonic fatigue due to combined loads. In this research, the numerical simulation process for the thermal acoustic test is presented, and the effects of thermal loads on vibro-acoustic response are investigated. To simulate the radiation heating system, Monte Carlo theory and thermal network theory was used to calculate the temperature distribution. Considering the thermal stress, the high temperature modal parameters are obtained with structural finite element methods. Based on acoustic finite element, modal-based vibro-acoustic analysis is carried out to compute structural responses. These researches are very vital to optimum thermal-acoustic test and structure designs for future hypersonic vehicles structure

  10. Three dimensional damage mechanics analysis of real life reactor piping components under various loading conditions

    Energy Technology Data Exchange (ETDEWEB)

    Durgaprasad, P.V.; Sahu, M.K.; Dutta, B.K. (Reactor Safety Division, Bhabha Atomic Research Centre Trombay, Mumbai (India)), e-mail: pvdp@barc.gov.in

    2009-07-01

    In this work, the Gurson-Tvergaard-Needleman (GTN) damage mechanics model is used for the crack growth analysis of real life reactor piping components. The paper also addresses the challenges involved in such analyses. As a part of component integrity testing, a comprehensive experimental program has been pursued to generate the fracture behavior of reactor piping components. Several real life pipes and elbows with various flaw sizes have been tested under different loading conditions like temperature, pressure, bending etc. In the present work, some of the selected components have been analyzed numerically by using parallel in-house finite element code 'MADAM' with GTN constitutive model. The strength of the micro mechanical models has been demonstrated by comparing the numerical results like load v/s. load-line displacements, J-R curves with the experimental data

  11. Analysis of the Space Shuttle Orbiter skin panels under simulated hydrodynamic loads

    Science.gov (United States)

    Carden, Huey D.; Fasanella, Edwin L.; Jones, Lisa E.

    1988-01-01

    The Space Shuttle orbiter skin panels were analyzed under pressure loads simulating hydrodynamic loads to determine their capability to sustain a potential ditching and to determine pressures that typically would produce failures. Two Dynamic Crash Analysis of Structures (DYCAST) finite element models were used. One model was used to represent skin panels (bays) in the center body, while a second model was used to analyze a fuselage bay in the wing region of the orbiter. From an assessment of the DYCAST nonlinear computer results, it is concluded that the probability is extremely high that most, if not all, of the lower skin panels would rupture under ditching conditions. Extremely high pressure loads which are produced under hydrodynamic planning conditions far exceed the very low predicted failure pressures for the skin panels. Consequently, a ditching of the orbiter is not considered to have a high probability of success and should not be considered a means of emergency landing unless no other option exists.

  12. Elastoplastic analysis for infinite plate with centric crack loaded by two pairs of point shear forces

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiao-ping; LING Tong-hua

    2005-01-01

    The near crack line analysis method was used to investigate a crack loaded by two pairs of point shear forces in an infinite plate in an elastic-perfectly plastic solid, and the analytical solution was obtained. The solutions include: the unit normal vector of the elastic-plastic boundary near the crack line, the elastic-plastic stress fields near crack line, law that the length of the plastic zone along the crack line is varied with an external loads, and the bearing capacity of an infinite plate with a center crack loaded by two pairs of point shear forces. The results are sufficiently precise near the crack line because the assumptions of the small scale yielding theory have not been made and no other assumption have been taken.

  13. Analysis of uplift loads of precast-concrete piles in porous soils

    Directory of Open Access Journals (Sweden)

    Stélio Maia Menezes

    2006-01-01

    Full Text Available This paper presents the analysis of uplift load tests in three precast-concrete piles carried out in a collapsible sandy soil. The piles with 12 meters (m length and 0.17 x 0.17 square meter (m2 cross section were instrumented with strain gauges, in order to know the load transfer in depth. Three tests performed in a slow maintained load way were conducted in a natural condition of moisture content soil. A fourth test was carried out after the previous soaking of the soil around the pile head. The tests were performed in the experimental research site at the Universidade Estadual Paulista “Júlio de Mesquita Filho” (Unesp. The results obtained were evaluated by analytical and empirical methods.

  14. Analysis of transmission lines loaded with pairs of coupled resonant elements and application to sensors

    Energy Technology Data Exchange (ETDEWEB)

    Naqui, J.; Su, L., E-mail: lijuan.suri.su@gmail.com; Mata, J.; Martín, F., E-mail: Ferran.Martin@uab.es

    2015-06-01

    This paper is focused on the analysis of transmission lines loaded with pairs of magnetically coupled resonators. We have considered two different structures: (i) a microstrip line loaded with pairs of stepped impedance resonators (SIRs), and (ii) a coplanar waveguide (CPW) transmission line loaded with pairs of split ring resonators (SRRs). In both cases, the line exhibits a single resonance frequency (transmission zero) if the resonators are identical (symmetric structure with regard to the line axis), and this resonance is different to the one of the line loaded with a single resonator due to inter-resonator coupling. If the structures are asymmetric, inter-resonator coupling enhances the distance between the two split resonance frequencies that arise. In spite that the considered lines and loading resonators are very different and are described by different lumped element equivalent circuit models, the phenomenology associated to the effects of coupling is exactly the same, and the resonance frequencies are given by identical expressions. The reported lumped element circuit models of both structures are validated by comparing the circuit simulations with extracted parameters with both electromagnetic simulations and experimental data. These structures can be useful for the implementation of microwave sensors based on symmetry properties. - Highlights: • Magnetic-coupling between resonant elements affects transmission properties. • Inter-resonant coupling enhances the distance of two resonant frequencies. • The structures are useful for sensors and comparators, etc.

  15. Value analysis of district heating system with gas-fired peak load boiler in secondary network

    Institute of Scientific and Technical Information of China (English)

    郑雪晶; 穆振英

    2009-01-01

    In district heating(DH) system with gas-fired peak load regulating boiler in the secondary network,by prolonging run time of base load plants under rated condition,the mean energy efficiency could be increased. The fuels of the system,including coal and gas,would cause different environmental impacts. Meanwhile,the reliability of the heating networks would be changed because the peak load regulating boiler could work as a standby heat source. A model for assessment of heating system was established by value analysis to optimize this kind of system. Energy consumption,greenhouse gas emission,pollution emission and system reliability were selected as functional assessment indexes in the model. Weights of each function were determined by analytical hierarchy process (AHP) and experts consultation. Life cycle cost was used as the cost in the model. A real case as an example was discussed to obtain the optimal base load ratio. The result shows that the optimal base load ratio of the case is 0.77.

  16. Analysis of multistoried braced frame subjected to seismic and gravity loading.

    Directory of Open Access Journals (Sweden)

    Dhananjay. S. Pawar

    2015-03-01

    Full Text Available The structure in high seismic areas may be susceptible to the severe damage. Along with gravity load structure has to withstand to lateral load which can develop high stresses. Now-a-days, shear wall in R.C. structure and steel bracings in steel structure are most popular system to resist lateral load due to earthquake, wind, blast etc. bracing is a highly efficient and economical method of resisting horizontal forces in a frame structure. Bracing is efficient because the diagonals work in axial stress and therefore call for minimum member sizes in providing stiffness and strength against horizontal shear. Through the addition of the bracing system, load could be transferred out of the frame and into the braces, by passing the weak columns while increasing strength. In this study Steel Frame is modeled and analyzed three Parts viz., (i Model without Steel bracing (bare frame, (ii Model completely Steel braced (fully braced frame, (iii Model with partially Steel bay wise braced frames. The computer aided analysis is done by using STAAD-PRO to find out the effective lateral load system during earthquake in high seismic areas.

  17. A Hybrid Short-Term Power Load Forecasting Model Based on the Singular Spectrum Analysis and Autoregressive Model

    Directory of Open Access Journals (Sweden)

    Hongze Li

    2014-01-01

    Full Text Available Short-term power load forecasting is one of the most important issues in the economic and reliable operation of electricity power system. Taking the characteristics of randomness, tendency, and periodicity of short-term power load into account, a new method (SSA-AR model which combines the univariate singular spectrum analysis and autoregressive model is proposed. Firstly, the singular spectrum analysis (SSA is employed to decompose and reconstruct the original power load series. Secondly, the autoregressive (AR model is used to forecast based on the reconstructed power load series. The employed data is the hourly power load series of the Mid-Atlantic region in PJM electricity market. Empirical analysis result shows that, compared with the single autoregressive model (AR, SSA-based linear recurrent method (SSA-LRF, and BPNN (backpropagation neural network model, the proposed SSA-AR method has a better performance in terms of short-term power load forecasting.

  18. Computation Analysis of Buckling Loads of Thin-Walled Members with Open Sections

    Directory of Open Access Journals (Sweden)

    Lihua Huang

    2016-01-01

    Full Text Available The computational methods for solving buckling loads of thin-walled members with open sections are not unique when different concerns are emphasized. In this paper, the buckling loads of thin-walled members in linear-elastic, geometrically nonlinear-elastic, and nonlinear-inelastic behaviors are investigated from the views of mathematical formulation, experiment, and numerical solution. The differential equations and their solutions of linear-elastic and geometrically nonlinear-elastic buckling of thin-walled members with various constraints are derived. Taking structural angle as an example, numerical analysis of elastic and inelastic buckling is carried out via ANSYS. Elastic analyses for linearized buckling and nonlinear buckling are realized using finite elements of beam and shell and are compared with the theoretical results. The effect of modeling of constraints on numerical results is studied when shell element is applied. The factors that influence the inelastic buckling load in numerical solution, such as modeling of constraint, loading pattern, adding rib, scale factor of initial defect, and yield strength of material, are studied. The noteworthy problems and their solutions in numerically buckling analysis of thin-walled member with open section are pointed out.

  19. Loading and Contact Stress Analysis on the Thread Teeth in Tubing and Casing Premium Threaded Connection

    Directory of Open Access Journals (Sweden)

    Honglin Xu

    2014-01-01

    Full Text Available Loading and contact stress distribution on the thread teeth in tubing and casing premium threaded connections are of great importance for design optimization, pretightening force control, and thread failure prevention. This paper proposes an analytical method based on the elastic mechanics. This is quite different from other papers, which mainly rely on finite element analysis. The differential equation of load distribution on the thread teeth was established according to equal pitch of the engaged thread after deformation and solved by finite difference method. Furthermore, the relation between load acting on each engaged thread and mean contact stress on its load flank is set up based on the geometric description of thread surface. By comparison, this new analytical method with the finite element analysis for a modified API 177.8 mm premium threaded connection is approved. Comparison of the contact stress on the last engaged thread between analytical model and FEM shows that the accuracy of analytical model will decline with the increase of pretightening force after the material enters into plastic deformation. However, the analytical method can meet the needs of engineering to some extent because its relative error is about 6.2%~18.1% for the in-service level of pretightening force.

  20. Trend analysis of nutrient loadings in the South Saskatchewan River catchment

    Science.gov (United States)

    Morales-Marin, L. A.; Chun, K. P.; Wheater, H. S.; Lindenschmidt, K. E.

    2015-12-01

    Nutrient loadings in river catchments have increased in the past years as a consequence of rapid expansion of agricultural areas, new urban developments and industries, and population growth. Nutrient enrichment of water bodies has intensified eutrophication conditions that degrade water quality and ecosystem health. In large-scale catchments, the assessment of temporal and spatial variability of nutrient loads imply challenges due to climate, land use and geology heterogeneity, and to anthropogenic changes. In this study we carried out a trend analysis of total phosphorus and total nitrogen loads in the South Saskatchewan River (SSR) catchment. This catchment is located in the Canadian Prairie Provinces of Alberta and Saskatchewan. The eastern and central areas of the catchment consist mostly of croplands, pasture lands and livestock farms, whereas the western parts are located on the Rocky Mountains that are the source of most of the catchment's streamflows. The trend analysis was performed applying a novel approach to analyse nutrient time series recorded at long-term water quality stations along the main stems of the SSR river network. Since water quality is taken infrequently, in the proposed approach the time series were complemented using regression analysis methods based on streamflow data recorded at the nearest gauge stations. The time series were subsequently pre-whitened in order to remove the autocorrelation, and then subjected to non-parametric statistical test to detect trends. Seasonal analysis of trends at each of the water quality stations were performed in order to determine the relationships between annual flow regimes and nutrient loads in the catchment, in particular, the influence of the high spring runoff on nutrient export. Decadal analysis was also performed to determine the long-tern relationships of nutrients with anthropogenic changes in the catchment. In particular, the capacity of reservoirs to trap nutrients and the effects of the

  1. Finite Element Analysis of Composite Hardened Walls Subjected to Blast Loads

    Directory of Open Access Journals (Sweden)

    Girum S. Urgessa

    2009-01-01

    Full Text Available Problem statement: There is currently no standard design guideline to determine the number of composites needed to retrofit masonry walls in order to withstand a given explosion. Past design approaches were mainly based on simplified single-degree-of-freedom analysis. A finite element analysis was conducted for concrete masonry walls hardened with composites and subjected to short duration blast loads. Approach: The analysis focused on displacement time history responses which form the basis for retrofit design guidelines against blast loadings. The blast was determined from 0.5 kg equivalent TNT explosive at 1.83 m stand-off distance to simulate small mailroom bombs. Two and four layered retrofitted walls were investigated. Uncertainties in the finite model analysis of walls such as pressure distributions, effect of mid height explosive bursts versus near the ground explosive bursts and variations in modulus of elasticity of the wall were presented. Results: Uniformly distributed blast loads over the retrofitted wall height produced a small difference in peak displacement results when compared to the non-uniform pressure distribution. Ground explosive burst was shown to produce a 62.7% increase in energy and a higher peak displacement response when compared to mid-height explosive burst. Conclusion: The parametric study on the variation of modulus of elasticity of concrete masonry showed no significant effect on peak displacement affirming the use of the resistance deflection contribution of the composite in retrofit designs.

  2. Direct methods of soil-structure interaction analysis for earthquake loadings (V)

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J. B.; Choi, J. S.; Lee, J. J.; Park, D. U. [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-07-15

    Methodologies of SSI analysis for earthquake loadings have been reviewed. Based on the finite method incorporating infinite element technique for the unbounded exterior region, a computer program for the nonlinear seismic analysis named as 'KIESSI' has been developed. The computer program has been verified using a free-field site-response problem. Post-correlation analysis for the Hualien FVT after backfill and the blind prediction of earthquake responses have been carried out utilizing the developed computer program. The earthquake response analyses for three LSST structures (Hualien, Lotung and Tepsco structure) have also been performed and compared with the measured data.

  3. Inverse thermoelastic analysis for thermal and mechanical loads identification using FBG data

    Science.gov (United States)

    Nakamura, Toshiya; Kamimura, Yukihiro; Igawa, Hirotaka; Morino, Yoshiki

    2014-12-01

    Fiber Bragg Grating (FBG) sensors have widely been used to monitor temperature and strain distributions as a part of the structural health monitoring system. Since FBG has the sensitivity to the variations in both temperature and strain, a compensation is required to separate the strain or temperature data from the sensor output which is the shift of the grating's Bragg wavelength. The present study develops a computational inverse thermoelastic analysis method to separately identify the thermal and mechanical boundary conditions (loads) from the output of the FBG sensor. Numerical study has been made for a corrugate-core sandwich integral thermal protection system (TPS) to examine the method. The discussion is focused on the computational stability. The results reveal that the identification of the mechanical load is less stable than that of the heat flux. It is also shown that the condition number of a coefficient matrix serves as the index of the stability of the inverse analysis.

  4. Sensitivity analysis of roll load, torque and material properties in the roll forming process

    Science.gov (United States)

    Abeyrathna, Buddhika; Rolfe, Bernard; Hodgson, Peter; Weiss, Matthias

    2013-12-01

    Advanced High Strength Steel (AHSS) and Ultra High Strength Steel (UHSS) are increasingly used in the current automotive industry because of their high strength and weight saving potential. As a sheet forming process, roll forming is capable of forming such materials with precise dimensions, however a small change in processing may results in significant change in the material properties such as yield strength and hardening exponent from coil to coil or within the same coil. This paper presents the effect of yield strength and the hardening exponent on roll load, torque of the roll forming process and the longitudinal bow. The roll forming process is numerically simulated, and then the regression analysis and Analysis of Variance (ANOVA) techniques are employed to establish the relationships among the aforementioned parameters and to determine the percentage influence of material properties on longitudinal bow, roll load and torque.

  5. Analysis of Cell Load Coupling for LTE Network Planning and Optimization

    CERN Document Server

    Siomina, Iana

    2012-01-01

    System-centric modeling and analysis are of key significance in planning and optimizing cellular networks. In this paper, we provide a mathematical analysis of performance modeling for LTE networks. The system model characterizes the coupling relation between the cell load factors, taking into account non-uniform traffic demand and interference between the cells with arbitrary network topology. Solving the model enables a network-wide performance evaluation in resource consumption. We develop and prove both sufficient and necessary conditions for the feasibility of the load-coupling system, and provide results related to computational aspects for numerically approaching the solution. The theoretical findings are accompanied with experimental results to instructively illustrate the application in optimizing LTE network configuration.

  6. Reduced Expanding Load Method for Simulation-Based Structural System Reliability Analysis

    Institute of Scientific and Technical Information of China (English)

    远方; 宋丽娜; 方江生

    2004-01-01

    The current situation and difficulties of the structural system reliability analysis are mentioned. Then on the basis of Monte Carlo method and computer simulation, a new analysis method reduced expanding load method ( RELM ) is presented, which can be used to solve structural reliability problems effectively and conveniently. In this method, the uncertainties of loads, structural material properties and dimensions can be fully considered. If the statistic parameters of stochastic variables are known, by using this method, the probability of failure can be estimated rather accurately. In contrast with traditional approaches, RELM method gives a much better understanding of structural failure frequency and its reliability indexβ is more meaningful. To illustrate this new idea, a specific example is given.

  7. ANALYSIS OF SHAKEDOWN OF FG BREE PLATE SUBJECTED TO COUPLED THERMAL-MECHANICAL LOADINGS

    Institute of Scientific and Technical Information of China (English)

    Xianghe Peng; Ning Hu; Hengwei Zheng; Cuirong Fang

    2009-01-01

    The static and kinematic shakedown of a functionally graded (FG) Bree plate is analyzed. The plate is subjected to coupled constant mechanical load and cyclically varying tem-perature. The material is assumed linearly elastic and nonlinear isotropic hardening with elastic modulus, yield strength and the thermal expansion coefficient varying exponentially through the thickness of the plate. The boundaries between the shakedown area and the areas of elasticity, incremental collapse and reversed plasticity are determined, respectively. The shakedown of the counterpart made of homogeneous material with average material properties is also analyzed. The comparison between the results obtained in the two cases exhibits distinct qualitative and quantitative difference, indicating the importance of shakedown analysis for FG structures. Since FG structures are usually used in the cases where severe coupled cyclic thermal and mechani-cal loadings are applied, the approach developed and the results obtained are significant for the analysis and design of such kind of structures.

  8. HULL GIRDER PROGRESSIVE COLLAPSE ANALYSIS USING IACS PRESCRIBED AND NLFEM DERIVED LOAD - END SHORTENING CURVES

    Directory of Open Access Journals (Sweden)

    Stanislav Kitarović

    2016-06-01

    Full Text Available This paper considers the hull girder ultimate strength of a bulk carrier at its midship section, as determined by an incremental-iterative progressive collapse analysis method prescribed by the International Association of Classification Societies Common Structural Rules for Bulk Carriers. In addition to the originally prescribed load – end shortening curves, curves determined by the nonlinear finite element method analysis (considering the influence of the idealized initial geometrical imperfections are also considered. Results obtained by both sets of curves are compared and discussed on both local (structural components load – end shortening curve and global (hull girder ulti-mate bending capacity and collapse sequence level, for both sagging and hogging cases.

  9. A Two-step Approach to Progressive Collapse Analysis of Building Structures under Blast Loading

    Institute of Scientific and Technical Information of China (English)

    XU Jun-xian; LIU Xi-la

    2009-01-01

    Structural collapse under blast loads is a very complex process. For several decades, the engineering profession has considered some approaches to analyze the essential physics of collapse phenomena. Recently, the interest in this topic has risen to an apex since the collapse of the World Trade Center towers. A two-step analysis approach to capture the characteristics of structural collapse during explosions is proposed. A numerical example is presented to illustrate the performance of the presented approach.

  10. Structural Integrity Analysis considered Load Combination for the Conceptual Design of Korean HCCR TBM-set

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Won; Jin, Hyung Gon; Lee, Eo Hwak; Yoon, Jae Sung; Kim, Suk Kwon [KAERI, Daejeon (Korea, Republic of); Shin, Kyu In [Gentec Tech, Daejeon (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    HCCR TBM (Test Blanket Module) set is consist of 4-TBM sub module, one blanket manifold (BM), a shield, and 4-key, which has a function of a connection between BM and the shield. And it shall be installed in the equatorial port No.18 of ITER inside the vacuum vessel directly facing the plasma and shall be cooled by a high-temperature helium coolant. In addition, the HCCR TBM-set safety classification follows the ITER (international thermonuclear reactor) safety importance class (SIC) criteria, and satisfies a design requirement according to RCC-MRx. In this study, some of load combination (LC) analysis for the structure integrity of TBM set were carried out based on the reference. And the LC results showed that they satisfied the design requirement. The material of TBM-set was used from the reference, and RCC-MRx for the stress analysis. In this study, the load combination results were met a design requirement. But some load combination case gave a higher maximum stress value than a design requirement and in these case the stress breakdown analysis according to RCC-MRx was performed, and the result were satisfied the design requirement.

  11. Second-Order Nonlinear Analysis of Steel Tapered Beams Subjected to Span Loading

    Directory of Open Access Journals (Sweden)

    Ali Hadidi

    2014-03-01

    Full Text Available A second-order elastic analysis of tapered steel members with I-shaped sections subjected to span distributed and concentrated loadings is developed. Fixed end forces and moments as well as exact stiffness matrix of tapered Timoshenko-Euler beam are obtained with exact geometrical properties of sections. The simultaneous action of bending moment, shear, and axial force including P−δ effects is also considered in the analysis. A computer code has been developed in MATLAB software using a power series method to solve governing second-order differential equation of equilibrium with variable coefficients for beams with distributed span loading. A generalized matrix condensation technique is then utilized for analysis of beams with concentrated span loadings. The accuracy and efficiency of the results of the proposed method are verified through comparing them to those obtained from other approaches such as finite element methods, which indicates the robustness and time saving of this method even for large scale frames with tapered members.

  12. The design and analysis of single flank transmission error tester for loaded gears

    Science.gov (United States)

    Bassett, Duane E.; Houser, Donald R.

    1987-01-01

    To strengthen the understanding of gear transmission error and to verify mathematical models which predict them, a test stand that will measure the transmission error of gear pairs under design loads has been investigated. While most transmission error testers have been used to test gear pairs under unloaded conditions, the goal of this report was to design and perform dynamic analysis of a unique tester with the capability of measuring the transmission error of gears under load. This test stand will have the capability to continuously load a gear pair at torques up to 16,000 in-lb at shaft speeds from 0 to 5 rpm. Error measurement will be accomplished with high resolution optical encoders and the accompanying signal processing unit from an existing unloaded transmission error tester. Input power to the test gear box will be supplied by a dc torque motor while the load will be applied with a similar torque motor. A dual input, dual output control system will regulate the speed and torque of the system. This control system's accuracy and dynamic response were analyzed and it was determined that proportional plus derivative speed control is needed in order to provide the precisely constant torque necessary for error-free measurement.

  13. Reliability Analysis of Jacket Platforms in Malaysia-Environmental Load Factors

    Directory of Open Access Journals (Sweden)

    Nelson J. Cossa

    2012-09-01

    Full Text Available In recent years, there has been a significant trend for adoption of the ISO-19902 standards for design of fixed steel offshore structures. The implementation of this standard aims to provide a harmonized international framework of design. Unlike, the traditional and currently used, WSD-method, the ISO-19902, follows the LRFD-method, that consists of both partial load and resistance factors. These partial factors are usually calibrated through reliability analysis. In these analyses, the performance of a structure is defined by the limit state function for the critical mode of failure. This paper, focuses mainly on the ultimate (strength limit state which is directly related to the (highest environmental loading. The partial environmental load factors contained in the ISO 19902, were calibrated for the Gulf of Mexico and UK's North Sea conditions, which are relatively harsh than those in Malaysia. The study presents the steps taken for the determination of the environmental load factor for tubular members of jacket platforms in Malaysia. The factor was determined such that the reliability of tubular members of jacket designed as per the LRFD-method is at the level of target reliability obtained by the WSD-method.

  14. 3D Finite Element Analysis of a Man Hip Joint Femur under Impact Loads

    Institute of Scientific and Technical Information of China (English)

    YU Xue-zhong; GUO Yi-mu; LI Jun; ZHANG Yun-qiu; HE Rong-xin

    2007-01-01

    The biomechanical characters of the bone fracture of the man femoral hip joint under impact loads are explored. Methods: A biosystem model of the man femoral hip joint by using the GE ( General Electric) lightspeed multi-lay spiral CT is conducted. A 3D finite element model is established by employing the finite element software ANSYS. The FE analysis mainly concentrates on the effects of the impact directions arising from intense movements and the parenchyma on the femoral hip joint on the stress distributions of the proximal femur. Results:The parenchyma on the hip joint has relatively large relaxation effect on the impact loads. Conclusion:Effects of the angle δ of the impact load to the anterior direction and the angle γ of the impact load to the femur shaft on the bone fracture are given;δ has larger effect on the stress and strain distributions than the angle γ, which mainly represents the fracture of the upper femur including the femoral neck fracture when the posterolateral femur is impacted, consistent with the clinical results.

  15. Analysis of the effects of rising temperature for embankments under seismic loads in cold regions

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The effect of temperature rising for frozen soil because of dynamic load was investigated by indoor tests.Roadway and railway embankments are always loaded by dynamic loads such as earthquakes and vehicles.Because the Qinghai-Tibetan Plateau is a re-gion where earthquakes occur frequently,it is essential to consider the temperature-rising effect of earthquakes or vehicles on railway and road embankment.In this paper and according to the theories of heat transfer and dynamic equilibrium equations,as-suming frozen soil as thermal elastic-viscoplastic material,taking the combination of thermal and mechanical stresses into account,we present the numerical formulae of this dynamic problem,and the computer program of the two-dimensional finite element is written.Using the program,the dynamic response analyses for embankments loaded by earthquake are worked out.Analysis in-dicated that the temperature-rising effect result from earthquakes for embankment in nonuniform distribution in some small areas,the maximum rising temperature is 0.16 ?C for consideration in this paper.

  16. Analysis of nonlinear settlement for an unsaturated soil under stage continuous loading

    Institute of Scientific and Technical Information of China (English)

    陈伟志; 蒋关鲁; 赵慧爽; 吴丽君; 李安洪

    2014-01-01

    A new approach was proposed to describe settlement behavior of an unsaturated soil with subgrade filling for high-speed railway. Firstly, based on Terzaghi consolidation theory, equations considering the variation coefficient of consolidation with void ratio and saturation for consolidation of an unsaturated soil under stage continuous loading were derived, and according to analytical solutions of equations, a formula for settlement computation under stage continuous loading was obtained. Then, combined with the width-to-height ratio of subgrade to compute ground reaction, and by means of in-situ plate loading curves, a correctional approach was presented for the analysis of nonlinear settlement of foundation. Also, the comparison between calculated and measured load−settlement behavior for an unsaturated soil in Qingdao−Ji’nan high-speed railway was given to demonstrate the effectiveness and accuracy of the proposed approach. It can be noted that the presented solution can be used to predict the settlement of an unsaturated soil foundation under stage continuous loading in engineering design.

  17. A structural analysis of an ocean going patrol boat subjected to planning loads

    Science.gov (United States)

    Clark, James H.; Lafreniere, Robert; Stoodt, Robert; Wiedenheft, John

    1987-01-01

    A static structural analysis of an ocean going patrol vessel subjected to hydrodynamic planning loads is discussed. The analysis required the development of a detailed model that included hull plating, five structural bulkheads, longitudinal and transverse stiffners, and a coarse representation of the superstructure. The finite element model was developed from fabrication drawings using the Navy computer aided design system. Various stress and displacement contours are shown for the entire hull. Because several critical areas appeared to be overstressed, these areas were remeshed for detail and are presented for completeness.

  18. Elastoplastic numerical analysis of layered soil foundation under the rectangular shallow footing subjected to vertical load

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Finite and infinite coupled element method was used to analyze the strength and deformation in layered soil foundation which was under the rectangular shallow footing subjected to vertical loads. In the numerical analysis, the footing was assumed to be elastic; the soil was assumed to be elastoplastic and the Drucker-Prager constitutive model was applied to describe its mechanic behavior. Corresponding program was employed to compute six kinds of layered soil foundations constituted by different soil layers. The conclusions which are useful in the theory and practice were made according to the analysis of the computation results.

  19. 3D strain map of axially loaded mouse tibia: a numerical analysis validated by experimental measurements.

    Science.gov (United States)

    Stadelmann, Vincent A; Hocke, Jean; Verhelle, Jensen; Forster, Vincent; Merlini, Francesco; Terrier, Alexandre; Pioletti, Dominique P

    2009-02-01

    A combined experimental/numerical study was performed to calculate the 3D octahedral shear strain map in a mouse tibia loaded axially. This study is motivated by the fact that the bone remodelling analysis, in this in vivo mouse model should be performed at the zone of highest mechanical stimulus to maximise the measured effects. Accordingly, it is proposed that quantification of bone remodelling should be performed at the tibial crest and at the distal diaphysis. The numerical model could also be used to furnish a more subtle analysis as a precise correlation between local strain and local biological response can be obtained with the experimentally validated numerical model.

  20. Small-Signal Stability Analysis of Full-Load Converter Interfaced Wind Turbines

    DEFF Research Database (Denmark)

    Knüppel, Thyge; Akhmatov, Vladislav; Nielsen, Jørgen Nygård

    2009-01-01

    Power system stability investigations of wind farms often cover the tasks of low-voltage-fault-ride-through, voltage and reactive power control, and power balancing, but not much attention has yet been paid to the task of small-signal stability. Small-signal stability analysis needs increasing...... focus since the share of wind power increases substituting power generation from conventional power plants. Here, a study based on modal analysis is presented which investigate the effect of large scale integration of full-load converter interfaced wind turbines on inter-area oscillations in a three...

  1. Dynamic Analysis of Tunnel in Weathered Rock Subjected to Internal Blast Loading

    Science.gov (United States)

    Tiwari, Rohit; Chakraborty, Tanusree; Matsagar, Vasant

    2016-11-01

    The present study deals with three-dimensional nonlinear finite element (FE) analyses of a tunnel in rock with reinforced concrete (RC) lining subjected to internal blast loading. The analyses have been performed using the coupled Eulerian-Lagrangian analysis tool available in FE software Abaqus/Explicit. Rock and RC lining are modeled using three-dimensional Lagrangian elements. Beam elements have been used to model reinforcement in RC lining. Three different rock types with different weathering conditions have been used to understand the response of rock when subjected to blast load. The trinitrotoluene (TNT) explosive and surrounding air have been modeled using the Eulerian elements. The Drucker-Prager plasticity model with strain rate-dependent material properties has been used to simulate the stress-strain response of rock. The concrete damaged plasticity model and Johnson-Cook plasticity model have been used for the simulation of stress-strain response of concrete and steel, respectively. The explosive (TNT) has been modeled using Jones-Wilkins-Lee (JWL) equation of state. The analysis results have been studied for stresses, deformation and damage of RC lining and the surrounding rock. It is observed that damage in RC lining results in higher stress in rock. Rocks with low modulus and high weathering conditions show higher attenuation of shock wave. Higher amount of ground shock wave propagation is observed in case of less weathered rock. Ground heave is observed under blast loading for tunnel close to ground surface.

  2. Numerical Analysis of Deteriorated Sub-sea Pipelines under Environmental Loads

    Institute of Scientific and Technical Information of China (English)

    GÜCÜYEN Engin

    2015-01-01

    The significant point is the bidirectional interaction technique in FSI analysis while investigating subsea corrosion effect. By this way, pipe environment is accurately modelled and fluid effects are also considered. The effect of external corrosion defects on structural behaviour of a pipeline is studied by creating a nonlinear numerical model based on the finite element method according to ABAQUS analysis program. Corrosion losses of sections are obtained from experimental results and applied to the model. Numerical model is formed by a span of sub-sea pipeline that is subjected to environmental loads. Seismic and wind-generated irregular wave loads are considered as environmental loads. Irregular wave is represented with equivalent eight regular waves via FFT. The pipe is modelled according to two different types which are non-corroded(intact) and corroded (deteriorated) to demonstrate corrosion effects on it. The visible type of corrosion in marine environment is named ‘pitting’ corrosion, in which the material loss is locally interpenetrated over the surface. By considering this situation, the corroded and non-corroded pipes are modelled as 3D solid elements. The main point is revealing how the subsea corrosion affects the structural behaviour of pipelines on the basis of implementation of experimental results to a model structure due to changes of stresses and displacement.

  3. Bifurcation Analysis of a DC-DC Bidirectional Power Converter Operating with Constant Power Loads

    Science.gov (United States)

    Cristiano, Rony; Pagano, Daniel J.; Benadero, Luis; Ponce, Enrique

    Direct current (DC) microgrids (MGs) are an emergent option to satisfy new demands for power quality and integration of renewable resources in electrical distribution systems. This work addresses the large-signal stability analysis of a DC-DC bidirectional converter (DBC) connected to a storage device in an islanding MG. This converter is responsible for controlling the balance of power (load demand and generation) under constant power loads (CPLs). In order to control the DC bus voltage through a DBC, we propose a robust sliding mode control (SMC) based on a washout filter. Dynamical systems techniques are exploited to assess the quality of this switching control strategy. In this sense, a bifurcation analysis is performed to study the nonlinear stability of a reduced model of this system. The appearance of different bifurcations when load parameters and control gains are changed is studied in detail. In the specific case of Teixeira Singularity (TS) bifurcation, some experimental results are provided, confirming the mathematical predictions. Both a deeper insight in the dynamic behavior of the controlled system and valuable design criteria are obtained.

  4. Fluctuation analysis of high frequency electric power load in the Czech Republic

    Science.gov (United States)

    Kracík, Jiří; Lavička, Hynek

    2016-11-01

    We analyze the electric power load in the Czech Republic (CR) which exhibits a seasonality as well as other oscillations typical for European countries. Moreover, we detect the 1/f noise property of electrical power load with extra additional peaks that allows to separate it into a deterministic and stochastic part. We then focus on the analysis of the stochastic part using improved Multi-fractal Detrended Fluctuation Analysis method (MFDFA) to investigate power load datasets with a minute resolution. Extracting the noise part of the signal by using Fourier transform allows us to apply this method to obtain the fluctuation function and to estimate the generalized Hurst exponent together with the correlated Hurst exponent, its improvement for the non-Gaussian datasets. The results exhibit a strong presence of persistent behavior or strong anti-persistent behavior for the differences and the dataset is characterized by a non-Gaussian skewed distribution. There are also indications for the presence of the probability distribution that has heavier tail than the Gaussian distribution.

  5. Linking trading ratio with TMDL (total maximum daily load) allocation matrix and uncertainty analysis.

    Science.gov (United States)

    Zhang, H X

    2008-01-01

    An innovative approach for total maximum daily load (TMDL) allocation and implementation is the watershed-based pollutant trading. Given the inherent scientific uncertainty for the tradeoffs between point and nonpoint sources, setting of trading ratios can be a contentious issue and was already listed as an obstacle by several pollutant trading programs. One of the fundamental reasons that a trading ratio is often set higher (e.g. greater than 2) is to allow for uncertainty in the level of control needed to attain water quality standards, and to provide a buffer in case traded reductions are less effective than expected. However, most of the available studies did not provide an approach to explicitly address the determination of trading ratio. Uncertainty analysis has rarely been linked to determination of trading ratio.This paper presents a practical methodology in estimating "equivalent trading ratio (ETR)" and links uncertainty analysis with trading ratio determination from TMDL allocation process. Determination of ETR can provide a preliminary evaluation of "tradeoffs" between various combination of point and nonpoint source control strategies on ambient water quality improvement. A greater portion of NPS load reduction in overall TMDL load reduction generally correlates with greater uncertainty and thus requires greater trading ratio. The rigorous quantification of trading ratio will enhance the scientific basis and thus public perception for more informed decision in overall watershed-based pollutant trading program.

  6. Analysis and Behaviour of Sandwich Panels with Profiled Metal Facings under Transverse Load

    Directory of Open Access Journals (Sweden)

    M. Budescu

    2004-01-01

    Full Text Available Sandwich panels with thin steel facings and polyurethane core combine the load-carrying capacity of metal facings and protection functions with core properties. The core separates the two facings and keeps them in a stable condition, transmits shear between external layers, provides most of the shear rigidity and occasionally makes of useful contribution to the bending stiffness of the sandwich construction as a whole [1]. An experimental program on sandwich panels has been organized to prove that the mechanical properties of core and interface satisfy the load-carrying requirements for structural sandwich panels. The analysis of sandwich panels with deep profiles facings for cladding elements, respectively the roof constructions, has been carried out according to the European design norms [1], [5].

  7. Traumatic impact loading on human maxillary incisor: A Dynamic finite element analysis

    Directory of Open Access Journals (Sweden)

    K Jayasudha

    2015-01-01

    Full Text Available Background: The most vulnerable tooth is the maxillary incisor, which sustains 80% of dental injuries. Dynamic Finite element analysis is used to understand the biomechanics of fracture of maxillary incisor under traumatic impact loading. Aim: The aim was to investigate the stress patterns of an upper incisor in a three-dimensional (3D model under traumatic impact loading in various directions. Materials and Methods: A 3D finite element model of the upper incisor and surrounding tissues was established. A sinusoidal force of 800N was applied over a period of 4 ms. Results: Software performs a series of calculations and mathematical equations and yields the simulation results. During the horizontal impact (F1, stresses were concentrated in the cervical area of the crown, reaching peak stress of 125 MPa at 2 ms. Conclusion: A horizontal force exerted on the labial surface of the tooth tends to cause cervical crown fractures, oblique crown root fractures, and oblique root fractures.

  8. Progressive damage analysis of carbon/epoxy laminates under couple laser and mechanical loading

    Science.gov (United States)

    Liu, Wanlei; Chang, Xinlong; Zhang, Xiaojun; Zhang, Youhong

    A multiscale model based bridge theory is proposed for the progressive damage analysis of carbon/epoxy laminates under couple laser and mechanical loading. The ablation model is adopted to calculate ablation temperature changing and ablation surface degradation. The polynomial strengthening model of matrix is used to improve bridging model for reducing parameter input. Stiffness degradation methods of bridging model are also improved in order to analyze the stress redistribution more accurately when the damage occurs. Thermal-mechanical analyses of the composite plate are performed using the ABAQUS/Explicit program with the developed model implemented in the VUMAT. The simulation results show that this model can be used to proclaim the mesoscale damage mechanism of composite laminates under coupled loading.

  9. Stress intensity factor and load transfer analysis of a cracked riveted lap joint

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, P.M.G.P. [DEMEGI, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto (Portugal)]. E-mail: pmgpm@fe.up.pt; Matos, P.F.P. de [DEMEGI, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto (Portugal); Camanho, P.P. [DEMEGI, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto (Portugal); Pastrama, Stefan D. [Department of Strength of Materials, University Politehnica of Bucharest, Splaiul Independentei nr. 313, Sector 6, Bucharest (Romania); Castro, P.M.S.T. de [DEMEGI, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto (Portugal)

    2007-07-01

    One of the main problems of aeronautical structures is the onset and growth of defects due to fatigue loading. This phenomenon is accentuated in areas of stress concentration, for example in the connection of components, such as the riveted joints of fuselage panels. Several geometric configurations can be used in riveted joints of fuselage panels. This work is focused on one geometry, a single-lap splice with three rivets rows and one rivet column. A three-dimensional stress analysis using the finite element method was carried out in order to analyze the load transfer as a function of crack geometry and length, and to determine the stress intensity factors for one or two cracks emanating from the edge of the hole located at the critical cross section.

  10. The analysis of reactively loaded microstrip antennas by finite difference time domain modelling

    Science.gov (United States)

    Hilton, G. S.; Beach, M. A.; Railton, C. J.

    1990-01-01

    In recent years, much interest has been shown in the use of printed circuit antennas in mobile satellite and communications terminals at microwave frequencies. Although such antennas have many advantages in weight and profile size over more conventional reflector/horn configurations, they do, however, suffer from an inherently narrow bandwidth. A way of optimizing the bandwidth of such antennas by an electronic tuning technique using a loaded probe mounted within the antenna structure is examined, and the resulting far-field radiation patterns are shown. Simulation results from a 2D finite difference time domain (FDTD) model for a rectangular microstrip antenna loaded with shorting pins are given and compared to results obtained with an actual antenna. It is hoped that this work will result in a design package for the analysis of microstrip patch antenna elements.

  11. Cyclic Loading of Growing Tissue in a Bioreactor: Mathematical Model and Asymptotic Analysis

    KAUST Repository

    Pohlmeyer, J. V.

    2013-10-24

    A simplified 2D mathematical model for tissue growth within a cyclically-loaded tissue engineering scaffold is presented and analyzed. Such cyclic loading has the potential to improve yield and functionality of tissue such as bone and cartilage when grown on a scaffold within a perfusion bioreactor. The cyclic compression affects the flow of the perfused nutrient, leading to flow properties that are inherently unsteady, though periodic, on a timescale short compared with that of tissue proliferation. A two-timescale analysis based on these well-separated timescales is exploited to derive a closed model for the tissue growth on the long timescale of proliferation. Some sample numerical results are given for the final model, and discussed. © 2013 Society for Mathematical Biology.

  12. Load duration curve: A tool for technico-economic analysis of energy solutions

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Alain; Dostie, Michel; Fournier, Michael; Sansregret, Simon [Laboratoire des Technologies de l' Energie, Institut de Recherche d' Hydro-Quebec, 600 avenue de la Montagne, Shawinigan, Que. (Canada)

    2008-07-01

    Accuracy and relevance of energy solution analysis for a customer could be greatly improved when considering the relationship between the electric power demand and time, information which is usually not readily available. In an attempt to fill this gap, the concept of customer load duration curve (LDC) has been investigated. A six parameters relationship has proven to be able to accurately represent measured annual and monthly LDC of 332 commercial, institutional and industrial customers. Plotted against the load factor, the values of each of the six parameters are shown to be constrained within specific ranges. This characteristic has lead to the development of an algorithm for the generation of realistic synthetic LDC. This kind of algorithm can be implemented in a technico-economic model for population studies or risk management through Monte Carlo simulations. Here we present some results for the assessment of a peak shaving application in commercial and industrial markets using Monte Carlo simulations. (author)

  13. Modeling and numerical analysis of granite rock specimen under mechanical loading and fire

    Institute of Scientific and Technical Information of China (English)

    Luc Leroy Ngueyep. Mambou; Joseph Ndop; Jean-Marie Bienvenu Ndjaka

    2015-01-01

    The effect of ISO 834 fire on the mechanical properties of granite rock specimen submitted to uniaxial loading is numerically investigated. Based on Newton’s second law, the rate-equation model of granite rock specimen under mechanical load and fire is established. The effect of heat treatment on the me-chanical performance of granite is analyzed at the center and the ends of specimen. At the free end of granite rock specimen, it is shown that from 20 ?C to 500 ?C, the internal stress and internal strain are weak; whereas above 500 ?C, they start to increase rapidly, announcing the imminent collapse. At the center of specimen, the analysis of the internal stress and internal strain reveals that the fire reduces the mechanical performance of granite significantly. Moreover, it is found that after 3 min of exposure to fire, the mechanical energy necessary to fragment the granite can be reduced up to 80%.

  14. Partially Loaded Cavity Analysis by Using the 2-D FDTD Method

    Institute of Scientific and Technical Information of China (English)

    YAO Bin; ZHENG Qin-Hong; PENG Jin-Hui; ZHONG Ru-Neng; XIANG Tai; XU Wan-Song

    2011-01-01

    A compact two-dimensional (2-D) finite-difference time-domain (FDTD) method is proposed to calculate the resonant frequencies and quality factors ofa partially loaded cavity that is uniform in the z-direction and has an arbitrary cross section in the x-y plane.With the description of z dependence by kz,the three-dimensional (3-D) problem can be transformed into a 2-D problem.Therefore,less memory and CPU time are required as compared to the conventional 3-D FDTD method.Three representative examples,a half-loaded rectangular cavity,an inhomogeneous cylindrical cavity and a cubic cavity loaded with dielectric post,are presented to validate the utility and efficiency of the proposed method.Since the finite-difference time-domain (FDTD)method was first introduced by Yee,[1] it has been widely used to solve electromagnetic problems.[2,3]Among them,endeavors have been made to achieve faster resonator computation and some numerical techniques have been combined with the FDTD method for faster computation.The numerical teehniques include digital filtering,the modern spectrum estimation technique,Prony analysis,Padé approximation and the Baker algorithm.[4-8] Benefiting from these techniques,the analysis time of resonators has been greatly reduced.However,there are two deficiencies in the above-mentioned literature.First,these approaches are still based on a three-dimensional (3-D)mesh,which needs numerous computational resources.%A compact two-dimensioned (2-D) finite-difference time-domain (FDTD) method is proposed to calculate the resonant frequencies and quality factors of a partially loaded cavity that is uniform in the z-direction and has an arbitrary cross section in the x-y plane. With the description of z dependence by kz, the three-dimensional (3-D) problem can be transformed into a 2-D problem. Therefore, less memory and CPU time are required as compared to the conventional 3-D FDTD method. Three representative examples, a half-loaded rectangular cavity, an

  15. Cavitation erosion prediction based on analysis of flow dynamics and impact load spectra

    Energy Technology Data Exchange (ETDEWEB)

    Mihatsch, Michael S., E-mail: michael.mihatsch@aer.mw.tum.de; Schmidt, Steffen J.; Adams, Nikolaus A. [Institute of Aerodynamics and Fluid Mechanics, Technische Universität München, Boltzmannstr. 15, D-85748 Garching (Germany)

    2015-10-15

    Cavitation erosion is the consequence of repeated collapse-induced high pressure-loads on a material surface. The present paper assesses the prediction of impact load spectra of cavitating flows, i.e., the rate and intensity distribution of collapse events based on a detailed analysis of flow dynamics. Data are obtained from a numerical simulation which employs a density-based finite volume method, taking into account the compressibility of both phases, and resolves collapse-induced pressure waves. To determine the spectrum of collapse events in the fluid domain, we detect and quantify the collapse of isolated vapor structures. As reference configuration we consider the expansion of a liquid into a radially divergent gap which exhibits unsteady sheet and cloud cavitation. Analysis of simulation data shows that global cavitation dynamics and dominant flow events are well resolved, even though the spatial resolution is too coarse to resolve individual vapor bubbles. The inviscid flow model recovers increasingly fine-scale vapor structures and collapses with increasing resolution. We demonstrate that frequency and intensity of these collapse events scale with grid resolution. Scaling laws based on two reference lengths are introduced for this purpose. We show that upon applying these laws impact load spectra recorded on experimental and numerical pressure sensors agree with each other. Furthermore, correlation between experimental pitting rates and collapse-event rates is found. Locations of high maximum wall pressures and high densities of collapse events near walls obtained numerically agree well with areas of erosion damage in the experiment. The investigation shows that impact load spectra of cavitating flows can be inferred from flow data that captures the main vapor structures and wave dynamics without the need for resolving all flow scales.

  16. Analysis of the load on the knee joint and vertebral column with changes in squatting depth and weight load.

    Science.gov (United States)

    Hartmann, Hagen; Wirth, Klaus; Klusemann, Markus

    2013-10-01

    It has been suggested that deep squats could cause an increased injury risk of the lumbar spine and the knee joints. Avoiding deep flexion has been recommended to minimize the magnitude of knee-joint forces. Unfortunately this suggestion has not taken the influence of the wrapping effect, functional adaptations and soft tissue contact between the back of thigh and calf into account. The aim of this literature review is to assess whether squats with less knee flexion (half/quarter squats) are safer on the musculoskeletal system than deep squats. A search of relevant scientific publications was conducted between March 2011 and January 2013 using PubMed. Over 164 articles were included in the review. There are no realistic estimations of knee-joint forces for knee-flexion angles beyond 50° in the deep squat. Based on biomechanical calculations and measurements of cadaver knee joints, the highest retropatellar compressive forces and stresses can be seen at 90°. With increasing flexion, the wrapping effect contributes to an enhanced load distribution and enhanced force transfer with lower retropatellar compressive forces. Additionally, with further flexion of the knee joint a cranial displacement of facet contact areas with continuous enlargement of the retropatellar articulating surface occurs. Both lead to lower retropatellar compressive stresses. Menisci and cartilage, ligaments and bones are susceptible to anabolic metabolic processes and functional structural adaptations in response to increased activity and mechanical influences. Concerns about degenerative changes of the tendofemoral complex and the apparent higher risk for chondromalacia, osteoarthritis, and osteochondritis in deep squats are unfounded. With the same load configuration as in the deep squat, half and quarter squat training with comparatively supra-maximal loads will favour degenerative changes in the knee joints and spinal joints in the long term. Provided that technique is learned accurately

  17. Fourier and wavelet spectral analysis of EMG signals in supramaximal constant load dynamic exercise.

    Science.gov (United States)

    Camata, Thiago V; Dantas, Jose L; Abrao, Taufik; Brunetto, Maria A C; Moraes, Antonio C; Altimari, Leandro R

    2010-01-01

    Frequency domain analyses of changes in electromyographic (EMG) signals over time are frequently used to assess muscle fatigue. Fourier based approaches are typically used in these analyses, yet Fourier analysis assumes signal stationarity, which is unlikely during dynamic contractions. Wavelet based methods of signal analysis do not assume stationarity and may be more appropriate for joint time-frequency domain analysis. The purpose of this study was to compare Short-Time Fourier Transform (STFT) and Continuous Wavelet Transform (CWT) in assessing muscle fatigue in supramaximal constant load dynamic exercise (110% VO(2peak)). The results of this study indicate that CWT and STFT analyses give similar fatigue estimates (slope of median frequency) in supramaximal constant load dynamic exercise (P>0.05). However, the results of the variance was significantly lower for at least one of the muscles studied in CWT compared to STFT (P signal analysis using STFT. Thus, the stationarity assumption may not be the sole factor responsible for affecting the Fourier based estimates.

  18. Fourier and wavelet spectral analysis of EMG signals in maximal constant load dynamic exercise.

    Science.gov (United States)

    Costa, Marcelo V; Pereira, Lucas A; Oliveira, Ricardo S; Pedro, Rafael E; Camata, Thiago V; Abrao, Taufik; Brunetto, Maria A C; Altimari, Leandro R

    2010-01-01

    Frequency domain analyses of changes in electromyographic (EMG) signals over time are frequently used to assess muscle fatigue. Fourier based approaches are typically used in these analyses, yet Fourier analysis assumes signal stationarity, which is unlikely during dynamic contractions. Wavelet based methods of signal analysis do not assume stationarity and may be more appropriate for joint time-frequency domain analysis. The purpose of this study was to compare Short-Time Fourier Transform (STFT) and Continuous Wavelet Transform (CWT) in assessing muscle fatigue in maximal constant load dynamic exercise (100% W(max)). The results of this study indicate that CWT and STFT analyses give similar fatigue estimates (slope of median frequency) in maximal constant load dynamic exercise (P>0.05). However, the results of the variance was significantly lower for at least one of the muscles studied in CWT compared to STFT (P〈0.05) indicating more variability in the EMG signal analysis using STFT. Thus, the stationarity assumption may not be the sole factor responsible for affecting the Fourier based estimates.

  19. Monte Carlo homogenized limit analysis model for randomly assembled blocks in-plane loaded

    Science.gov (United States)

    Milani, Gabriele; Lourenço, Paulo B.

    2010-11-01

    A simple rigid-plastic homogenization model for the limit analysis of masonry walls in-plane loaded and constituted by the random assemblage of blocks with variable dimensions is proposed. In the model, blocks constituting a masonry wall are supposed infinitely resistant with a Gaussian distribution of height and length, whereas joints are reduced to interfaces with frictional behavior and limited tensile and compressive strength. Block by block, a representative element of volume (REV) is considered, constituted by a central block interconnected with its neighbors by means of rigid-plastic interfaces. The model is characterized by a few material parameters, is numerically inexpensive and very stable. A sub-class of elementary deformation modes is a-priori chosen in the REV, mimicking typical failures due to joints cracking and crushing. Masonry strength domains are obtained equating the power dissipated in the heterogeneous model with the power dissipated by a fictitious homogeneous macroscopic plate. Due to the inexpensiveness of the approach proposed, Monte Carlo simulations can be repeated on the REV in order to have a stochastic estimation of in-plane masonry strength at different orientations of the bed joints with respect to external loads accounting for the geometrical statistical variability of blocks dimensions. Two cases are discussed, the former consisting on full stochastic REV assemblages (obtained considering a random variability of both blocks height an length) and the latter assuming the presence of a horizontal alignment along bed joints, i.e. allowing blocks height variability only row by row. The case of deterministic blocks height (quasi-periodic texture) can be obtained as a subclass of this latter case. Masonry homogenized failure surfaces are finally implemented in an upper bound FE limit analysis code for the analysis at collapse of entire walls in-plane loaded. Two cases of engineering practice, consisting on the prediction of the failure

  20. Markov Chain Modelling of Reliability Analysis and Prediction under Mixed Mode Loading

    Institute of Scientific and Technical Information of China (English)

    SINGH Salvinder; ABDULLAH Shahrum; NIK MOHAMED Nik Abdullah; MOHD NOORANI Mohd Salmi

    2015-01-01

    The reliability assessment for an automobile crankshaft provides an important understanding in dealing with the design life of the component in order to eliminate or reduce the likelihood of failure and safety risks. The failures of the crankshafts are considered as a catastrophic failure that leads towards a severe failure of the engine block and its other connecting subcomponents. The reliability of an automotive crankshaft under mixed mode loading using the Markov Chain Model is studied. The Markov Chain is modelled by using a two-state condition to represent the bending and torsion loads that would occur on the crankshaft. The automotive crankshaft represents a good case study of a component under mixed mode loading due to the rotating bending and torsion stresses. An estimation of the Weibull shape parameter is used to obtain the probability density function, cumulative distribution function, hazard and reliability rate functions, the bathtub curve and the mean time to failure. The various properties of the shape parameter is used to model the failure characteristic through the bathtub curve is shown. Likewise, an understanding of the patterns posed by the hazard rate onto the component can be used to improve the design and increase the life cycle based on the reliability and dependability of the component. The proposed reliability assessment provides an accurate, efficient, fast and cost effective reliability analysis in contrast to costly and lengthy experimental techniques.

  1. Reliability analysis of the bulk cargo loading system including dependent components

    Science.gov (United States)

    Blokus-Roszkowska, Agnieszka

    2016-06-01

    In the paper an innovative approach to the reliability analysis of multistate series-parallel systems assuming their components' dependency is presented. The reliability function of a multistate series system with components dependent according to the local load sharing rule is determined. Linking these results for series systems with results for parallel systems with independent components, we obtain the reliability function of a multistate series-parallel system assuming dependence of components' departures from the reliability states subsets in series subsystem and assuming independence between these subsystems. As a particular case, the reliability function of a multistate series-parallel system composed of dependent components having exponential reliability functions is fixed. Theoretical results are applied practically to the reliability evaluation of a bulk cargo transportation system, which main area is to load bulk cargo on board the ships. The reliability function and other reliability characteristics of the loading system are determined in case its components have exponential reliability functions with interdependent departures rates from the subsets of their reliability states. Finally, the obtained results are compared with results for the bulk cargo transportation system composed of independent components.

  2. Metal loading in Soda Butte Creek upstream of Yellowstone National Park, Montana and Wyoming; a retrospective analysis of previous research; and quantification of metal loading, August 1999

    Science.gov (United States)

    Boughton, G.K.

    2001-01-01

    Acid drainage from historic mining activities has affected the water quality and aquatic biota of Soda Butte Creek upstream of Yellowstone National Park. Numerous investigations focusing on metals contamination have been conducted in the Soda Butte Creek basin, but interpretations of how metals contamination is currently impacting Soda Butte Creek differ greatly. A retrospective analysis of previous research on metal loading in Soda Butte Creek was completed to provide summaries of studies pertinent to metal loading in Soda Butte Creek and to identify data gaps warranting further investigation. Identification and quantification of the sources of metal loading to Soda Butte Creek was recognized as a significant data gap. The McLaren Mine tailings impoundment and mill site has long been identified as a source of metals but its contribution relative to the total metal load entering Yellowstone National Park was unknown. A tracer-injection and synoptic-sampling study was designed to determine metal loads upstream of Yellowstone National Park.A tracer-injection and synoptic-sampling study was conducted on an 8,511-meter reach of Soda Butte Creek from upstream of the McLaren Mine tailings impoundment and mill site downstream to the Yellowstone National Park boundary in August 1999. Synoptic-sampling sites were selected to divide the creek into discrete segments. A lithium bromide tracer was injected continuously into Soda Butte Creek for 24.5 hours. Downstream dilution of the tracer and current-meter measurements were used to calculate the stream discharge. Stream discharge values, combined with constituent concentrations obtained by synoptic sampling, were used to quantify constituent loading in each segment of Soda Butte Creek.Loads were calculated for dissolved calcium, silica, and sulfate, as well as for dissolved and total-recoverable iron, aluminum, and manganese. Loads were not calculated for cadmium, copper, lead, and zinc because these elements were infrequently

  3. Total protein analysis as a reliable loading control for quantitative fluorescent Western blotting.

    Directory of Open Access Journals (Sweden)

    Samantha L Eaton

    Full Text Available Western blotting has been a key technique for determining the relative expression of proteins within complex biological samples since the first publications in 1979. Recent developments in sensitive fluorescent labels, with truly quantifiable linear ranges and greater limits of detection, have allowed biologists to probe tissue specific pathways and processes with higher resolution than ever before. However, the application of quantitative Western blotting (QWB to a range of healthy tissues and those from degenerative models has highlighted a problem with significant consequences for quantitative protein analysis: how can researchers conduct comparative expression analyses when many of the commonly used reference proteins (e.g. loading controls are differentially expressed? Here we demonstrate that common controls, including actin and tubulin, are differentially expressed in tissues from a wide range of animal models of neurodegeneration. We highlight the prevalence of such alterations through examination of published "-omics" data, and demonstrate similar responses in sensitive QWB experiments. For example, QWB analysis of spinal cord from a murine model of Spinal Muscular Atrophy using an Odyssey scanner revealed that beta-actin expression was decreased by 19.3±2% compared to healthy littermate controls. Thus, normalising QWB data to β-actin in these circumstances could result in 'skewing' of all data by ∼20%. We further demonstrate that differential expression of commonly used loading controls was not restricted to the nervous system, but was also detectable across multiple tissues, including bone, fat and internal organs. Moreover, expression of these "control" proteins was not consistent between different portions of the same tissue, highlighting the importance of careful and consistent tissue sampling for QWB experiments. Finally, having illustrated the problem of selecting appropriate single protein loading controls, we demonstrate

  4. Nonlinear analysis for a reinforced concrete frame structure under extreme loads

    Directory of Open Access Journals (Sweden)

    Catalin BACIU

    2012-07-01

    Full Text Available Terrorist actions of the last decade obviously determine a reconsideration of the buildings safety, especially for those with special destinations (embassies, military facilities, nuclear plants etc.. Thus, the conception phase should include nowadays scenarios with exceptional actions, other than seismic loads: impact, explosion, failure of supports.It is well-known that, after earthquakes, the most situations of structural collapse are determined by the terrorist attack using explosive. Even more, it has been assessed that the main reason of loss of life is not the explosion itself, but the partial or total collapse of the exposed building.In order to secure the structural integrity, collapse analysis should be taken into account as a complex phenomenon, composed of many processes that could be studied separately or as an ensemble. These processes are: the extreme action causes, design requirements, vulnerability of the structure, starting and development of the collapse, its final effects. Study of these processes leads to additional special measures for design stage and, on the other hand, to valuable knowledge for controlled demolition of tall buildings, as part of bold urbanism projects in densely populated zones.Considering the above mentioned facts, this paper presents the results of a thorough analysis of a frame structure under explosive loads. The first part of the paper refers to the analysis of a phenomena assembly related to explosion and to the effects resulting from a terrorist attack using explosives (structural elements deterioration and failure, collapse initiation and eventual total failure. The second part of the paper presents an original approach to analyze a building structure under extreme loads, using both classical (pushover and modern (applied element method.

  5. Reliability analysis and prediction of mixed mode load using Markov Chain Model

    Energy Technology Data Exchange (ETDEWEB)

    Nikabdullah, N. [Department of Mechanical and Materials Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia and Institute of Space Science (ANGKASA), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (Malaysia); Singh, S. S. K.; Alebrahim, R.; Azizi, M. A. [Department of Mechanical and Materials Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (Malaysia); K, Elwaleed A. [Institute of Space Science (ANGKASA), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (Malaysia); Noorani, M. S. M. [School of Mathematical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (Malaysia)

    2014-06-19

    The aim of this paper is to present the reliability analysis and prediction of mixed mode loading by using a simple two state Markov Chain Model for an automotive crankshaft. The reliability analysis and prediction for any automotive component or structure is important for analyzing and measuring the failure to increase the design life, eliminate or reduce the likelihood of failures and safety risk. The mechanical failures of the crankshaft are due of high bending and torsion stress concentration from high cycle and low rotating bending and torsional stress. The Markov Chain was used to model the two states based on the probability of failure due to bending and torsion stress. In most investigations it revealed that bending stress is much serve than torsional stress, therefore the probability criteria for the bending state would be higher compared to the torsion state. A statistical comparison between the developed Markov Chain Model and field data was done to observe the percentage of error. The reliability analysis and prediction was derived and illustrated from the Markov Chain Model were shown in the Weibull probability and cumulative distribution function, hazard rate and reliability curve and the bathtub curve. It can be concluded that Markov Chain Model has the ability to generate near similar data with minimal percentage of error and for a practical application; the proposed model provides a good accuracy in determining the reliability for the crankshaft under mixed mode loading.

  6. Comparative analysis of pulse shape discrimination methods in a {sup 6}Li loaded plastic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Balmer, Matthew J.I., E-mail: m.balmer@lancaster.ac.uk [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Gamage, Kelum A.A. [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Taylor, Graeme C. [Neutron Metrology Group, National Physical Laboratory, Teddington, TW11 0LW (United Kingdom)

    2015-07-11

    Three algorithms for discriminating between fast neutrons, thermal neutrons and gamma rays in a {sup 6}Li loaded plastic scintillator have been compared. Following a literature review of existing pulse shape discrimination techniques, the performance of the charge comparison method, triangular filtering and frequency gradient analysis were investigated in this work. The scintillator was exposed to three different mixed gamma/neutron radiation fields. The figure of merit of neutron/gamma separation was investigated over a broad energy range, as well as for the neutron capture energy region. After optimisation, all three methods were found to perform similarly in terms of neutron/gamma separation.

  7. Reliability Analysis of Piezoelectric Truss Structures Under Joint Action of Electric and Mechanical Loading

    Institute of Scientific and Technical Information of China (English)

    YANG Duo-he; AN Wei-guang; ZHU Rong-rong; MIAO Han

    2006-01-01

    Based on the finite element method(FEM) for the dynamical analysis of piezoelectric truss structures, the expressions of safety margins of strength fracture and damage electric field in the structure element are given considering electromechanical coupling effect under the joint action of electric and mechanical load. By importing the stochastic FEM,reliability of piezoelectric truss structures is analyzed by solving for partial derivative in the process of solving dynamical response of structure system with mode-superposition method. The influence of electromechanical coupling effect to reliability index is then analyzed through an example.

  8. Analysis of the role of PCNA-DNA contacts during clamp loading

    Directory of Open Access Journals (Sweden)

    Goedken Eric R

    2010-01-01

    Full Text Available Abstract Background Sliding clamps, such as Proliferating Cell Nuclear Antigen (PCNA in eukaryotes, are ring-shaped protein complexes that encircle DNA and enable highly processive DNA replication by serving as docking sites for DNA polymerases. In an ATP-dependent reaction, clamp loader complexes, such as the Replication Factor-C (RFC complex in eukaryotes, open the clamp and load it around primer-template DNA. Results We built a model of RFC bound to PCNA and DNA based on existing crystal structures of clamp loaders. This model suggests that DNA would enter the clamp at an angle during clamp loading, thereby interacting with positively charged residues in the center of PCNA. We show that simultaneous mutation of Lys 20, Lys 77, Arg 80, and Arg 149, which interact with DNA in the RFC-PCNA-DNA model, compromises the ability of yeast PCNA to stimulate the DNA-dependent ATPase activity of RFC when the DNA is long enough to extend through the clamp. Fluorescence anisotropy binding experiments show that the inability of the mutant clamp proteins to stimulate RFC ATPase activity is likely caused by reduction in the affinity of the RFC-PCNA complex for DNA. We obtained several crystal forms of yeast PCNA-DNA complexes, measuring X-ray diffraction data to 3.0 Å resolution for one such complex. The resulting electron density maps show that DNA is bound in a tilted orientation relative to PCNA, but makes different contacts than those implicated in clamp loading. Because of apparent partial disorder in the DNA, we restricted refinement of the DNA to a rigid body model. This result contrasts with previous analysis of a bacterial clamp bound to DNA, where the DNA was well resolved. Conclusion Mutational analysis of PCNA suggests that positively charged residues in the center of the clamp create a binding surface that makes contact with DNA. Disruption of this positive surface, which had not previously been implicated in clamp loading function, reduces RFC

  9. Analysis of resistance to loading by a helical cutting drum of a shearer loader

    Energy Technology Data Exchange (ETDEWEB)

    Matyja, S.; Krauze, K.

    1977-01-01

    This report analyzes coal handling by helical cutting drums on a shearer loader. Formulae which describe effects of drum specifications on coal resistance to loading are derived. Loads on the cutting drums associated with coal resistance to loading are calculated. Analyses show that with growing haulage speed and constant cutting speed, coal resistance to loading also increases. Under conditions of constant haulage speed, increasing cutting speed causes a decrease in coal resistance to loading. Performance tests show that loading moment amounts to 13-60% of the cutting moment. Higher cutting speeds correspond with lower loading moment. Recommendations for design of shearer loaders and optimum mining schemes are made. 5 refs.

  10. Analysis of differential gene expression in rat tibia after an osteogenic stimulus in vivo: mechanical loading regulates osteopontin and myeloperoxidase.

    Science.gov (United States)

    Miles, R R; Turner, C H; Santerre, R; Tu, Y; McClelland, P; Argot, J; DeHoff, B S; Mundy, C W; Rosteck, P R; Bidwell, J; Sluka, J P; Hock, J; Onyia, J E

    1998-03-01

    The skeleton has the ability to alter its mass, geometry, and strength in response to mechanical stress. In order to elucidate the molecular mechanisms underlying this phenomenon, differential display reverse transcriptase-polymerase chain reaction (DDRT-PCR) was used to analyze gene expression in endocortical bone of mature female rats. Female Sprague-Dawley rats, approximately 8 months old, received either a sham or bending load using a four-point loading apparatus on the right tibia. RNA was collected at 1 h and 24 h after load was applied, reverse-transcribed into cDNA, and used in DDRT-PCR. Parallel display of samples from sham and loaded bones on a sequencing gel showed several regulated bands. Further analysis of seven of these bands allowed us to isolate two genes that are regulated in response to a loading stimulus. Nucleotide analysis showed that one of the differentially expressed bands shares 99% sequence identity with rat osteopontin (OPN), a noncollagenous bone matrix protein. Northern blot analysis confirms that OPN mRNA expression is increased by nearly 4-fold, at 6 h and 24 h after loading. The second band shares 90% homology with mouse myeloperoxidase (MPO), a bactericidal enzyme found primarily in neutrophils and monocytes. Semiquantitative PCR confirms that MPO expression is decreased 4- to 10-fold, at 1 h and 24 h after loading. Tissue distribution analysis confirmed MPO expression in bone but not in other tissues examined. In vitro analysis showed that MPO expression was not detectable in total RNA from UMR 106 osteoblastic cells or in confluent primary cultures of osteoblasts derived from either rat primary spongiosa or diaphyseal marrow. Database analysis suggests that MPO is expressed by osteocytes. These findings reinforce the association of OPN expression to bone turnover and describes for the first time, decreased expression of MPO during load-induced bone formation. These results suggest a role for both OPN and MPO expression in bone

  11. Finite element based stress analysis of BWR internals exposed to accident loads

    Energy Technology Data Exchange (ETDEWEB)

    Altstadt, E.; Weiss, F.P.; Werner, M.; Willschuetz, H.G.

    1998-10-01

    During a hypothetical accident the reactor pressure vessel internals of boiling water reactors can be exposed to considerable loads resulting from temperature gradients and pressure waves. Three dimensional FE models were developed for the core shroud, the upper and the lower core supporting structure, the steam separator pipes and the feed water distributor. The models of core shroud, upper core structure and lower core structure were coupled by means of the substructure technique. All FE models can be used for thermal and for structural mechanical analyses. As an example the FE analysis for the case of a station black-out scenario (loss of power supply for the main circulating pumps) with subsequent emergency core cooling is demonstrated. The transient temperature distributions within the core shroud and within the steam dryer pipes as well were calculated based on the fluid temperatures and the heat transfer coefficients provided by thermo-hydraulic codes. At the maximum temperature gradients in the core shroud, the mechanical stress distribution was computed in a static analysis with the actual temperature field being the load. (orig.)

  12. RF-thermal-structural-RF coupled analysis on a travelling wave disk-loaded accelerating structure

    Institute of Scientific and Technical Information of China (English)

    PEI Shi-Lun; CHI Yun-Long; ZHANG Jing-Ru; HOU Mi; LI Xiao-Ping

    2012-01-01

    The travelling wave (TW) disk-loaded accelerating structure is one of the key components in normal conducting (NC) linear accelerators,and has been studied for many years.In the design process,usually after the dimensions of each cell and the two couplers are finalized,the structure is fabricated and tuned,and then the whole structure RF characteristics are measured by using a vector network analyzer.Before fabrication,the whole structure characteristics (including RF,thermal and structural ones) are less simulated due to the limited capability of currently available computers.In this paper,we described a method for performing RF-thermal-structural-RF coupled analysis on a TW disk-loaded structure using only one PC.In order to validate our method,we first analyzed and compared our RF simulation results on the 3 m long BEPC Ⅱ structure with the corresponding experimental results,which shows very good consistency.Finally,the RF-thermal-structure-RF coupled analysis results on the 1.35 m long NSC KIPT linac accelerating structure are presented.

  13. Study on signal characteristic analysis of multi-axis load measurement sensors

    Science.gov (United States)

    Hwang, Sang-Kyun; Hwang, Hui-Yun

    2016-11-01

    This study suggested a tactile sensor with piezoelectric sensors in a fibrous shape to detect multi-axial loads (vertical load and horizontal load) simultaneously for the skins of unmanned robots. The sensor was designed by finite element analyses. A simple detecting scheme of the multi-axial loads was constructed by lab-scale experiments. Verification tests of the developed tactile sensor confirmed that applied vertical and horizontal loads could be detected with less than 4% error.

  14. Stochastic empirical loading and dilution model for analysis of flows, concentrations, and loads of highway runoff constituents

    Science.gov (United States)

    Granato, Gregory E.; Jones, Susan C.

    2014-01-01

    In cooperation with FHWA, the U.S. Geological Survey developed the stochastic empirical loading and dilution model (SELDM) to supersede the 1990 FHWA runoff quality model. The SELDM tool is designed to transform disparate and complex scientific data into meaningful information about the adverse risks of runoff on receiving waters, the potential need for mitigation measures, and the potential effectiveness of such measures for reducing such risks. The SELDM tool is easy to use because much of the information and data needed to run it are embedded in the model and obtained by defining the site location and five simple basin properties. Information and data from thousands of sites across the country were compiled to facilitate the use of the SELDM tool. A case study illustrates how to use the SELDM tool for conducting the types of sensitivity analyses needed to properly assess water quality risks. For example, the use of deterministic values to model upstream stormflows instead of representative variations in prestorm flow and runoff may substantially overestimate the proportion of highway runoff in downstream flows. Also, the risks for total phosphorus excursions are substantially affected by the selected criteria and the modeling methods used. For example, if a single deterministic concentration is used rather than a stochastic population of values to model upstream concentrations, then the percentage of water quality excursions in the downstream receiving waters may depend entirely on the selected upstream concentration.

  15. Recovery of weak factor loadings when adding the mean structure in confirmatory factor analysis: A simulation study

    Directory of Open Access Journals (Sweden)

    Carmen eXiménez

    2016-01-01

    Full Text Available This article extends previous research on the recovery of weak factor loadings in confirmatory factor analysis by exploring the effects of adding the mean structure. This issue has not been examined in previous research. This study is based on the framework of Yung and Bentler (1999 and aims to examine the conditions that affect the recovery of weak factor loadings when the model includes the mean structure, compared to analyzing the covariance structure alone. A simulation study was conducted in which several constraints were defined for one-, two-, and three-factor models. Results show that adding the mean structure improves the recovery of weak factor loadings and reduces the asymptotic variances for the factor loadings, particularly for the models with a smaller number of factors and a small sample size. Therefore, under certain circumstances, modeling the means should be seriously considered for covariance models containing weak factor loadings.

  16. Analysis and behaviour of FRP-confined short concrete columns subjected to eccentric loading

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Fibre-reinforced polymer (FRP) composites were widely utilized in civil engineering structures as the retrofit of reinforced concrete (RC) columns. To design FRP jackets safely and economically, the behaviour of such columns should be predicted first. This paper is concerned with the analysis and behaviour of FRP-confined RC circular and rectangular short columns subjected to eccentric loading. A simple design-oriented stress-strain model for FRP-confined concrete in a section analysis was first proposed. The accuracy was then proved by two test data. Following that, a parametric study including amount of FRP confinement, FRP strain capacity, unconfined concrete strength and shape of column section is provided. Some conclusions were obtained at the end of the paper. The work here will provide a comprehensive understanding of the behaviour of FRP-confined concrete columns. The simplicity of the model also enables a simple equivalent stress block to be developed for direct use in practical design.

  17. Pressure Load Analysis during Severe Accidents for the Evaluation of Late Containment Failure in OPR-1000

    Energy Technology Data Exchange (ETDEWEB)

    Park, S. Y.; Ahn, K. I. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The MAAP code is a system level computer code capable of performing integral analyses of potential severe accident progressions in nuclear power plants, whose main purpose is to support a level 2 probabilistic safety assessment or severe accident management strategy developments. The code employs lots of user-options for supporting a sensitivity and uncertainty analysis. The present application is mainly focused on determining an estimate of the containment building pressure load caused by severe accident sequences. Key modeling parameters and phenomenological models employed for the present uncertainty analysis are closely related to in-vessel hydrogen generation, gas combustion in the containment, corium distribution in the containment after a reactor vessel failure, corium coolability in the reactor cavity, and molten-corium interaction with concrete. The phenomenology of severe accidents is extremely complex. In this paper, a sampling-based phenomenological uncertainty analysis was performed to statistically quantify uncertainties associated with the pressure load of a containment building for a late containment failure evaluation, based on the key modeling parameters employed in the MAAP code and random samples for those parameters. Phenomenological issues surrounding the late containment failure mode are highly complex. Included are the pressurization owing to steam generation in the cavity, molten corium-concrete interaction, late hydrogen burn in the containment, and the secondary heat removal availability. The methodology and calculation results can be applied for the optimum assessment of a late containment failure model. The accident sequences considered were a loss of coolant accidents and loss of offsite accidents expected in the OPR-1000 plant. As a result, uncertainties addressed in the pressure load of the containment building were quantified as a function of time. A realistic evaluation of the mean and variance estimates provides a more complete

  18. Resonant loading of aircraft secondary structure panels for use with thermoelastic stress analysis and digital image correlation

    Science.gov (United States)

    Waugh, Rachael C.; Dulieu-Barton, Janice M.; Quinn, S.

    2015-03-01

    Thermoelastic stress analysis (TSA) is an established active thermographic approach which uses the thermoelastic effect to correlate the temperature change that occurs as a material is subjected to elastic cyclic loading to the sum of the principal stresses on the surface of the component. Digital image correlation (DIC) tracks features on the surface of a material to establish a displacement field of a component subjected to load, which can then be used to calculate the strain field. The application of both DIC and TSA on a composite plate representative of aircraft secondary structure subject to resonant frequency loading using a portable loading device, i.e. `remote loading' is described. Laboratory based loading for TSA and DIC is typically imparted using a test machine, however in the current work a vibration loading system is used which is able to excite the component of interest at resonant frequency which enables TSA and DIC to be carried out. The accuracy of the measurements made under remote loading of both of the optical techniques applied is discussed. The data are compared to extract complimentary information from the two techniques. This work forms a step towards a combined strain based non-destructive evaluation procedure able to identify and quantify the effect of defects more fully, particularly when examining component performance in service applications.

  19. Methods for Progressive Collapse Analysis of Building Structures Under Blast and Impact Loads

    Institute of Scientific and Technical Information of China (English)

    LI Zhongxian; SHI Yanchao

    2008-01-01

    Progressive collapse of building structures under blast and impact lcads has attracted great attention all over the world.Prog ressive collapse analysis is essential for an economic and safe design of building structures against progressive collapse to blast and impact loads.Because of the catastrophic nature of progressive collapse and the potentially high cost of constructing or retrofitting buildings to resist it,is imperative that the progressive collapse analysis methods be reliable.For engineers.their methodology to carry out progressve collapse evaluation need not only be accurate and concise.but also be easily used and works fast.Thus,many researchers have been spending lots of effort in developing reliable,efficient and strajghtforward progressive collapse analysis methods recently.In the present paper,currenf progresslve collapse analysis meth ods available in the literature are reviewed.Their suitability,applicability and reliability are dis cussed.Our recent proposed new method for progressive collapse analysis of relnforced concrete frames under blast lcads is also introduced.

  20. PROBABILISTIC FINITE ELEMENT ANALYSIS OF VERTEBRAE OF THE LUMBAR SPINE UNDER HYPEREXTENSION LOADING

    Directory of Open Access Journals (Sweden)

    M.M. Rahman

    2011-06-01

    Full Text Available The major goal of this study is to determine the stress on vertebrae subjected to hyperextension loading. In addition, probabilistic analysis was adopted in finite element analysis (FEA to verify the parameters that affected failure. Probabilistic finite element (PFE analysis plays an important role today in solving engineering problems in many fields of science and industry and has recently been applied in orthopaedic applications. A finite element model of the L2 vertebra was constructed in SolidWorks and imported by ANSYS 11.0 software for the analysis. For simplicity, vertebra components were modelled as isotropic and linear materials. A tetrahedral solid element was chosen as the element type because it is better suited to and more accurate in modelling problems with curved boundaries such as bone. A Monte Carlo simulation (MCS technique was performed to conduct the probabilistic analysis using a built-in probabilistic module in ANSYS with 100 samples. It was found that the adjacent lower pedicle region depicted the highest stress with 1.21 MPa, and the probability of failure was 3%. The force applied to the facet (FORFCT variable needs to be emphasized after sensitivity assessment revealed that this variable is very sensitive to the stress and displacement output parameters.

  1. Seasonal Hydrological Loading in Southern Tibet Detected by Joint Analysis of GPS and GRACE.

    Science.gov (United States)

    Zou, Rong; Wang, Qi; Freymueller, Jeffrey T; Poutanen, Markku; Cao, Xuelian; Zhang, Caihong; Yang, Shaomin; He, Ping

    2015-12-04

    In southern Tibet, ongoing vertical and horizontal motions due to the collision between India and Eurasia are monitored by large numbers of global positioning system (GPS) continuous and campaign sites installed in the past decade. Displacements measured by GPS usually include tectonic deformation as well as non-tectonic, time-dependent signals. To estimate the regional long-term tectonic deformation using GPS more precisely, seasonal elastic deformation signals associated with surface loading must be removed from the observations. In this study, we focus on seasonal variation in vertical and horizontal motions of southern Tibet by performing a joint analysis of GRACE (Gravity Recovery and Climate Experiment) and GPS data, not only using continuous sites but also GPS campaign-mode sites. We found that the GPS-observed and GRACE-modeled seasonal oscillations are in good agreements, and a seasonal displacement model demonstrates that the main reason for seasonal variations in southern Tibet is from the summer monsoon and its precipitation. The biggest loading appears from July to August in the summer season. Vertical deformations observed by GPS and modeled by GRACE are two to three times larger than horizontal oscillations, and the north components demonstrate larger amplitudes than the east components. We corrected the GPS position time series using the GRACE-modeled seasonal variations, which gives significant reductions in the misfit and weighted root-mean-squares (WRMS). Misfit (χ2 divided by degree of freedom) reductions for campaign sites range between 20% and 56% for the vertical component, and are much smaller for the horizontal components. Moreover, time series of continuous GPS (cGPS) sites near the 2015 Nepal earthquakes must be corrected using appropriate models of seasonal loading for analyzing postseismic deformation to avoid biasing estimates of the postseismic relaxation.

  2. Gait profile score and movement analysis profile in patients with Parkinson's disease during concurrent cognitive load

    Directory of Open Access Journals (Sweden)

    Danielli S. Speciali

    2014-08-01

    Full Text Available Background: Gait disorders are common in individuals with Parkinson's Disease (PD and the concurrent performance of motor and cognitive tasks can have marked effects on gait. The Gait Profile Score (GPS and the Movement Analysis Profile (MAP were developed in order to summarize the data of kinematics and facilitate understanding of the results of gait analysis. Objective: To investigate the effectiveness of the GPS and MAP in the quantification of changes in gait during a concurrent cognitive load while walking in adults with and without PD. Method: Fourteen patients with idiopathic PD and nine healthy subjects participated in the study. All subjects performed single and dual walking tasks. The GPS/MAP was computed from three-dimensional gait analysis data. Results: Differences were found between tasks for GPS (P<0.05 and Gait Variable Score (GVS (pelvic rotation, knee flexion-extension and ankle dorsiflexion-plantarflexion (P<0.05 in the PD group. An interaction between task and group was observed for GPS (P<0.01 for the right side (Cohen's ¯d=0.99, left side (Cohen's ¯d=0.91, and overall (Cohen's ¯d=0.88. No interaction was observed only for hip internal-external rotation and foot internal-external progression GVS variables in the PD group. Conclusions: The results showed gait impairment during the dual task and suggest that GPS/MAP may be used to evaluate the effects of concurrent cognitive load while walking in patients with PD.

  3. Critical analysis of European load management practices. Final report for period January--July 1976

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    Load management has been practiced in Europe for approximately a quarter century. A critical evaluation of the initial objectives and economic justifications for load management given in Europe may help energy policymakers in the U.S. assess the relevance of load management to meeting their current energy goals. Load management was adopted in Europe primarily to promote a growth in energy sales at a rate greater than the increase in capacity requirements. Utilities were able to improve daily load factors during the winter peak period; however, they may not have been successful in maintaining or improving their financial strength through load management. Increased capital and operating expenditures in the generation and distribution systems became necessary as the power system evolved in response to changing load characteristics. Rates charged to customers did not always produce adequate revenues from managed loads to cover the capital and operating costs to supply those loads. Comprehensive studies of the long-term costs and benefits might have prevented some of the load management problems experienced in Europe. Load management was not introduced in Europe to reduce utility production costs, conserve energy or scarce fuels, improve the environment, or influence summer loads. Accordingly, the European experience with load management may not be relevant to energy policymakers in the U.S. who desire to achieve these objectives.

  4. Fatigue Crack Growth Analysis Under Spectrum Loading in Various Environmental Conditions

    Science.gov (United States)

    Mikheevskiy, S.; Glinka, G.; Lee, E.

    2013-03-01

    The fatigue process consists, from the engineering point of view, of three stages: crack initiation, fatigue crack growth, and the final failure. It is also known that the fatigue process near notches and cracks is governed by local strains and stresses in the regions of maximum stress and strain concentrations. Therefore, the fatigue crack growth can be considered as a process of successive crack increments, and the fatigue crack initiation and subsequent growth can be modeled as one repetitive process. The assumptions mentioned above were used to derive a fatigue crack growth model based, called later as the UniGrow model, on the analysis of cyclic elastic-plastic stresses-strains near the crack tip. The fatigue crack growth rate was determined by simulating the cyclic stress-strain response in the material volume adjacent to the crack tip and calculating the accumulated fatigue damage in a manner similar to fatigue analysis of stationary notches. The fatigue crack growth driving force was derived on the basis of the stress and strain history at the crack tip and the Smith-Watson-Topper (SWT) fatigue damage parameter, D = σmaxΔɛ/2. It was subsequently found that the fatigue crack growth was controlled by a two-parameter driving force in the form of a weighted product of the stress intensity range and the maximum stress intensity factor, Δ K p K {max/1- p }. The effect of the internal (residual) stress induced by the reversed cyclic plasticity has been accounted for and therefore the two-parameter driving force made it possible to predict the effect of the mean stress including the influence of the applied compressive stress, tensile overloads, and variable amplitude spectrum loading. It allows estimating the fatigue life under variable amplitude loading without using crack closure concepts. Several experimental fatigue crack growth datasets obtained for the Al 7075 aluminum alloy were used for the verification of the proposed unified fatigue crack growth

  5. Reliability analysis of flood embankments taking into account a stochastic distribution of hydraulic loading

    Directory of Open Access Journals (Sweden)

    Amabile Alessia

    2016-01-01

    Full Text Available Flooding is a worldwide phenomenon. Over the last few decades the world has experienced a rising number of devastating flood events and the trend in such natural disasters is increasing. Furthermore, escalations in both the probability and magnitude of flood hazards are expected as a result of climate change. Flood defence embankments are one of the major flood defence measures and reliability assessment for these structures is therefore a very important process. Routine hydro-mechanical models for the stability of flood embankments are based on the assumptions of steady-state through-flow and zero pore-pressures above the phreatic surface, i.e. negative capillary pressure (suction is ignored. Despite common belief, these assumptions may not always lead to conservative design. In addition, hydraulic loading is stochastic in nature and flood embankment stability should therefore be assessed in probabilistic terms. This cannot be accommodated by steady-state flow models. The paper presents an approach for reliability analysis of flood embankment taking into account the transient water through-flow. The factor of safety of the embankment is assessed in probabilistic terms based on a stochastic distribution for the hydraulic loading. Two different probabilistic approaches are tested to compare and validate the results.

  6. Smart meter deployment optimisation and its analysis for appliance load monitoring

    Directory of Open Access Journals (Sweden)

    Ahmed Shaharyar Khwaja

    2015-04-01

    Full Text Available In this study, the authors study the problem of smart meter deployment optimisation for appliance load monitoring, that is, to monitor a number of devices without any ambiguity using the minimum number of low-cost smart meters. The importance of this problem is due to the fact that the number of meters should be reduced to decrease the deployment cost, improve reliability and decrease congestion. In this way, in future, smart meters can provide additional information about the type and number of distinct devices connected, besides their normal functionalities concerned with providing overall energy measurements and their communication. The authors present two exact smart meter deployment optimisation algorithms, one based on exhaustive search and the other based on efficient implementation of the exhaustive search. They formulate the problem mathematically and present computational complexity analysis of their algorithms. Simulation scenarios show that for a typical number of home appliances, the efficient search method is significantly faster compared to the exhaustive search and can provide the same optimal solution. The authors also show the dependency of their method on the distribution of the load pattern that can potentially be in a typical household.

  7. Passive load follow analysis of the STAR-LM and STAR-H2 systems

    Science.gov (United States)

    Moisseytsev, Anton

    A steady-state model for the calculation of temperature and pressure distributions, and heat and work balance for the STAR-LM and the STAR-H2 systems was developed. The STAR-LM system is designed for electricity production and consists of the lead cooled reactor on natural circulation and the supercritical carbon dioxide Brayton cycle. The STAR-H2 system uses the same reactor which is coupled to the hydrogen production plant, the Brayton cycle, and the water desalination plant. The Brayton cycle produces electricity for the on-site needs. Realistic modules for each system component were developed. The model also performs design calculations for the turbine and compressors for the CO2 Brayton cycle. The model was used to optimize the performance of the entire system as well as every system component. The size of each component was calculated. For the 400 MWt reactor power the STAR-LM produces 174.4 MWe (44% efficiency) and the STAR-H2 system produces 7450 kg H2/hr. The steady state model was used to conduct quasi-static passive load follow analysis. The control strategy was developed for each system; no control action on the reactor is required. As a main safety criterion, the peak cladding temperature is used. It was demonstrated that this temperature remains below the safety limit during both normal operation and load follow.

  8. Analysis of concrete targets with different kinds of reinforcements subjected to blast loading

    Science.gov (United States)

    Oña, M.; Morales-Alonso, G.; Gálvez, F.; Sánchez-Gálvez, V.; Cendón, D.

    2016-05-01

    In this paper we describe an experimental campaign carried out to study and analyse the behaviour of concrete slabs when subjected to blast loading. Four different types of concrete have been tested: normal strength concrete with steel rebar, normal strength concrete with steel rebar retrofitted with Kevlar coating, steel fibre reinforced concrete (SFRC) and polypropylene fibre reinforced concrete (PFRC). The major asset of the experimental setup used is that it allows to subject up to four specimens to the same blast load what, besides being cost effective, makes possible to have a measure of the experimental scatter. The results of SFRC and PFRC concretes have been analysed by using a previously developed material model for the numerical simulation of concrete elements subjected to blast. The experimental campaign and preliminary results of this numerical analysis show how the high strain rates, in spite of improving the mechanical properties of these kinds of fibre reinforced concretes, lead to an embrittlement of the material, which may be dangerous from the point of view of the structural behaviour.

  9. Development of an Aeroelastic Modeling Capability for Transient Nozzle Side Load Analysis

    Science.gov (United States)

    Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

    2013-01-01

    Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development during test. While three-dimensional, transient, turbulent, chemically reacting computational fluid dynamics methodology has been demonstrated to capture major side load physics with rigid nozzles, hot-fire tests often show nozzle structure deformation during major side load events, leading to structural damages if structural strengthening measures were not taken. The modeling picture is incomplete without the capability to address the two-way responses between the structure and fluid. The objective of this study is to develop a coupled aeroelastic modeling capability by implementing the necessary structural dynamics component into an anchored computational fluid dynamics methodology. The computational fluid dynamics component is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, while the computational structural dynamics component is developed in the framework of modal analysis. Transient aeroelastic nozzle startup analyses of the Block I Space Shuttle Main Engine at sea level were performed. The computed results from the aeroelastic nozzle modeling are presented.

  10. New model of load transfer function for pile analysis based on disturbed state model

    Institute of Scientific and Technical Information of China (English)

    LIU Qijian; YANG Linde; WU Jun

    2007-01-01

    Based on the disturbed state concept (DSC),a new model of load transfer function for pile analysis is established by the idea that the deformed material between pile and soil can be treated as a mixture of two constituent parts,which are in intact or critical state and assumed to obey random distribution.Starting from the homogenization theory of heterogeneous materials and statistics method,a parameter D to describe the disturbance degree is proposed,and a formula to determine the parameter has been derived by using the plastic displacement of a pile as distribution variable.In the model,shear intensity of elements in an intact state are simulated by Duncan-Zhang model and that in a critical state by Mohr-Coulomb criterion.The model of this paper has few parameters,which can reflect the aspects of load transfer function,such as hardening,softening and the effects of confining pressure.The well agreement between the in-situ data and the predicted shows that the validity of the model herein.So the proposed model in this paper is easy to be used in engineering practice.

  11. Structural Load Analysis of a Wind Turbine under Pitch Actuator and Controller Faults

    Science.gov (United States)

    Etemaddar, Mahmoud; Gao, Zhen; Moan, Torgeir

    2014-12-01

    In this paper, we investigate the characteristics of a wind turbine under blade pitch angle and shaft speed sensor faults as well as pitch actuator faults. A land-based NREL 5MW variable speed pitch reg- ulated wind turbine is considered as a reference. The conventional collective blade pitch angle controller strategy with independent pitch actuators control is used for load reduction. The wind turbine class is IEC-BII. The main purpose is to investigate the severity of end effects on structural loads and responses and consequently identify the high-risk components according to the type and amplitude of fault using a servo-aero-elastic simulation code, HAWC2. Both transient and steady state effects of faults are studied. Such information is useful for wind turbine fault detection and identification as well as system reliability analysis. Results show the effects of faults on wind turbine power output and responses. Pitch sensor faults mainly affects the vibration of shaft main bearing, while generator power and aerodynamic thrust are not changed significantly, due to independent pitch actuator control of three blades. Shaft speed sensor faults can seriously affect the generator power and aerodynamic thrust. Pitch actuator faults can result in fully pitching of the blade, and consequently rotor stops due to negative aerodynamic torque.

  12. Finite Element Analysis of Laterally Loaded Suction Caisson in Anisotropic Clay

    Institute of Scientific and Technical Information of China (English)

    WANG Dong; JIN Xia

    2006-01-01

    Naturally deposited clay is usually characterized by strength anisotropy; however, the effect of anisotropy on the capacity of a suction caisson was seldom investigated. The conventional Hill yield surface includes undrained strengths in triaxial shear, simple shear and pressuremeter shear simultaneously but it can not specify differences in respect to the mode of loading for a given shearing mode. A new technique of updating strength is integrated into incremental finite element (FE) calculation to consider the mode of loading, which is applied to the study of variation of capacity with the aspect ratio of suction caissons in anisotropic clay. Compared with the upper bound limit analysis, FE simulation is capable of offering the lateral capacity of short caissons. In the normal range of anisotropic strength properties, the Mises yield surface with simple shear strength predicts the horizontal capacity of which the error is less than 10% for rough caissons and 15% for smooth caissons. It is also found that the friction of caisson affects the capacity significantly.

  13. Modeling and numerical analysis of granite rock specimen under mechanical loading and fire

    Directory of Open Access Journals (Sweden)

    Luc Leroy Ngueyep. Mambou

    2015-02-01

    Full Text Available The effect of ISO 834 fire on the mechanical properties of granite rock specimen submitted to uniaxial loading is numerically investigated. Based on Newton's second law, the rate-equation model of granite rock specimen under mechanical load and fire is established. The effect of heat treatment on the mechanical performance of granite is analyzed at the center and the ends of specimen. At the free end of granite rock specimen, it is shown that from 20 °C to 500 °C, the internal stress and internal strain are weak; whereas above 500 °C, they start to increase rapidly, announcing the imminent collapse. At the center of specimen, the analysis of the internal stress and internal strain reveals that the fire reduces the mechanical performance of granite significantly. Moreover, it is found that after 3 min of exposure to fire, the mechanical energy necessary to fragment the granite can be reduced up to 80%.

  14. An Analysis of Mongolian Culture-Loaded Words and Their Translation Strategies

    Science.gov (United States)

    Wang, Jian-Jun; He, Long

    2014-01-01

    With massive cultural exchanges in the world, the translation of culture-loaded words is drawing the attention of translators. Because of different cultural backgrounds and mentalities, the translation of culture-loaded words may lead to misunderstanding or confusion to target readers. Thus, a good mastery of culture-loaded words is a must for…

  15. Loading experiment and thermal analysis for conduction cooled magnet of SMES system

    Institute of Scientific and Technical Information of China (English)

    Gang WU; Huiling WANG; Jiangbo XIE; Yan ZHAO; Yuejin TANG; Jindong LI; Jing SHI

    2009-01-01

    China's first 35kJ high temperature superconducting magnetic energy storage (SMES) system with an experiment equipment was depicted. The dynamic heat analysis of the magnet of the SMES was conducted through the current load test on the directly cooled conduction magnet. The research results were as follows:when the converter charges and discharges the magnet for energy storage, the hysteresis loss is the main part of power loss, and contributes significantly to temperature rise;reducing the current frequency at the side of direct current is conducive to restraining temperature rise. The optimizing factors of the cool-guide structure were analyzed based on the heat stability theory, and it was found that the heat transfer of its key part (at the top of the magnet) must be strengthened to reduce the axial temperature difference of the magnet.

  16. Nonlinear dynamic analysis based on experimental data of RC telecommunication towers subjected to wind loading

    Directory of Open Access Journals (Sweden)

    Marcelo A. Silva

    2006-01-01

    Full Text Available The goal of this paper is to propose a nonlinear dynamic model based on experimental data and NBR-6123-87 to accomplish a nonlinear dynamic analysis of slender structures subjected to wind loading. At first we compute the static answer given by the mean wind speed. In this part of the problem we consider the concept of effective stiffness to represent the physical nonlinearity of material and a P-Delta method to represent the geometrical nonlinearity. Considering the final stiffness obtained in that P-Delta method, we compute the dynamic answer given by the floating wind speed, according to the discrete dynamic model given by NBR-6123-87. A 40 m RC telecommunication tower was analyzed, and the results obtained were compared with those given by linear static and dynamic models.

  17. Comparison and Analysis of Magnetic-Geared Permanent Magnet Electrical Machine at No-Load

    Directory of Open Access Journals (Sweden)

    Liu Xiping

    2014-12-01

    Full Text Available Magnetic-geared permanent magnet (MGPM electrical machine is a new type of machine by incorporating magnetic gear into PM electrical machine, and it may be in operation with low-speed, high-torque and direct-driven. In this paper, three types of MGPM machines are present, and a quantitative comparison among them is performed by finite element analysis (FEA. The magnetic field distribution, stable torque and back EMF are obtained at no-load. The results show that three types of MGPM machine are suitable for different application fields respectively according to their own advantages, such as high torque and back EMF, which form an important foundation for MGPM electrical machine research.

  18. Delay Analysis for Wireless Local Area Networks with Multipacket Reception under Finite Load

    CERN Document Server

    Zhang, Ying Jun; Chen, Darui

    2008-01-01

    To date, most analysis of WLANs has been focused on their operation under saturation condition. This work is an attempt to understand the fundamental performance of WLANs under unsaturated condition. In particular, we are interested in the delay performance when collisions of packets are resolved by an exponential backoff mechanism. Using a multiple-vacation queueing model, we derive an explicit expression for packet delay distribution, from which necessary conditions for finite mean delay and delay jitter are established. It is found that under some circumstances, mean delay and delay jitter may approach infinity even when the traffic load is way below the saturation throughput. Saturation throughput is therefore not a sound measure of WLAN capacity when the underlying applications are delay sensitive. To bridge the gap, we define safe-bounded-mean-delay (SBMD) throughput and safe-bounded-delay-jitter (SBDJ) throughput that reflect the actual network capacity users can enjoy when they require bounded mean de...

  19. Analysis of fracture process zone in brittle rock subjected to shear-compressive loading

    Institute of Scientific and Technical Information of China (English)

    ZHOU De-quan; CHEN Feng; CAO Ping; MA Chun-de

    2005-01-01

    An analytical expression for the prediction of shear-compressive fracture process zone(SCFPZ) is derived by using a proposed local strain energy density criterion, in which the strain energy density is separated into the dilatational and distortional strain energy density, only the former is considered to contribute to the brittle fracture of rock in different loading cases. The theoretical prediction by this criterion shows that the SCFPZ is of asymmetric mulberry leaf in shape, which forms a shear-compression fracture kern. Dilatational strain energy density along the boundary of SCFPZ reaches its maximum value. The dimension of SCFPZ is governed by the ratio of KⅡ to KⅠ . The analytical results are then compared with those from literatures and the tests conducted on double edge cracked Brazilian disk subjected to diametrical compression. The obtained results are useful to the prediction of crack extension and to nonlinear analysis of shear-compressive fracture of brittle rock.

  20. Implementation of DSC model and application for analysis of field pile tests under cyclic loading

    Science.gov (United States)

    Shao, Changming; Desai, Chandra S.

    2000-05-01

    The disturbed state concept (DSC) model, and a new and simplified procedure for unloading and reloading behavior are implemented in a nonlinear finite element procedure for dynamic analysis for coupled response of saturated porous materials. The DSC model is used to characterize the cyclic behavior of saturated clays and clay-steel interfaces. In the DSC, the relative intact (RI) behavior is characterized by using the hierarchical single surface (HISS) plasticity model; and the fully adjusted (FA) behavior is modeled by using the critical state concept. The DSC model is validated with respect to laboratory triaxial tests for clay and shear tests for clay-steel interfaces. The computer procedure is used to predict field behavior of an instrumented pile subjected to cyclic loading. The predictions provide very good correlation with the field data. They also yield improved results compared to those from a HISS model with anisotropic hardening, partly because the DSC model allows for degradation or softening and interface response.

  1. Numerical analysis of two pile caps with sockets embedded, subject the eccentric compression load

    Directory of Open Access Journals (Sweden)

    R. G. Delalibera

    Full Text Available The structural behavior of pile caps with sockets embedded is influenced by interface of column-socket, which can be smooth or rough. With intent to analyze the behavior of two pile caps with embedded socket, considering the friction between the column and the socket, with eccentric normal load, the numerical simulations were carried out, using a program based on the Finite Element Methods (FEM. In the numerical analysis the non-linear behavior of materials was considered, also the friction between the column and the socket. It was considered perfect bond between the reinforcement and the concrete around. It was observed that the embedded length is preponderant factor in the structural behavior of the analyzed element.

  2. Splinting effect on posterior implants under various loading modes: a 3D finite element analysis.

    Science.gov (United States)

    Hauchard, Erwan; Fournier, Benjamin Philippe; Jacq, Romain; Bouton, Antoine; Pierrisnard, Laurent; Naveau, Adrien

    2011-09-01

    This three-dimensional finite element study compared stresses, intensities and displacements of three mandibular posterior implants restored with cemented crowns (two molars and a premolar in straight line), splinted versus non-splinted. Hundred newton occlusal loads were vertically or horizontally applied, either on one single crown or on all of them. Maximal stresses and implants displacements were higher under horizontal loading. Splinting major effects appeared under single horizontal load with a decrease in stresses (34-49%) and displacements (16-19%) of the loaded crown. Splinting seems more appropriate for implant-supported restorations submitted to frequent single horizontal or oblique loads than vertical ones.

  3. Dynamic analysis of high speed gears by using loaded static transmission error

    Science.gov (United States)

    Özgüven, H. Nevzat; Houser, D. R.

    1988-08-01

    A single degree of freedom non-linear model is used for the dynamic analysis of a gear pair. Two methods are suggested and a computer program is developed for calculating the dynamic mesh and tooth forces, dynamic factors based on stresses, and dynamic transmission error from measured or calculated loaded static transmission errors. The analysis includes the effects of variable mesh stiffness and mesh damping, gear errors (pitch, profile and runout errors), profile modifications and backlash. The accuracy of the method, which includes the time variation of both mesh stiffness and damping is demonstrated with numerical examples. In the second method, which is an approximate one, the time average of the mesh stiffness is used. However, the formulation used in the approximate analysis allows for the inclusion of the excitation effect of the variable mesh stiffness. It is concluded from the comparison of the results of the two methods that the displacement excitation resulting from a variable mesh stiffness is more important than the change in system natural frequency resulting from the mesh stiffness variation. Although the theory presented is general and applicable to spur, helical and spiral bevel gears, the computer program prepared is for only spur gears.

  4. Three-dimensional finite element analysis of stress distribution in inlay-restored mandibular first molar under simultaneous thermomechanical loads.

    Science.gov (United States)

    Çelik Köycü, Berrak; Imirzalioğlu, Pervin; Özden, Utku Ahmet

    2016-01-01

    Functional occlusal loads and intraoral temperature changes create stress in teeth. The purpose of this study was to evaluate the impact of simultaneous thermomechanical loads on stress distribution related to inlay restored teeth by three-dimensional finite element analysis. A mandibular first molar was constructed with tooth structures, surrounding bone and inlays of Type II gold alloy, ceramic, and composite resin. Stress patterns on the restorative materials, adhesive resin, enamel and dentin were analyzed after simulated temperature changes from 36°C to 4 or 60°C for 2 s with 200-N oblique loading. The results showed that the three types of inlays had similar stress distribution in the tooth structures and restorative materials. Concerning the adhesive resin, the composite resin inlay model exhibited lower stresses than ceramic and gold alloy inlays. Simultaneous thermomechanical loads caused high stress patterns in inlay-restored teeth. Composite resin inlays may be the better choice to avoid adhesive failure.

  5. Revised Heating Load Line Analysis: Addendum to ORNL/TM-2015/281

    Energy Technology Data Exchange (ETDEWEB)

    Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-07-01

    The original heating load line analysis of ORNL TM-2015/281 was modified to incorporate two adjustments of (1) removing mechanical ventilation and (2) resizing the heat pump units based on new criteria. This resulted in a lowering of the HLL slope factor from the originally rounded 1.3 level to 1.15 in DOE Region IV and V while leaving unchanged the zero-load ambient at a rounded value of 55 F. For the other four DOE regions, the zero-load ambients dropped by 1 to 2 F from those found earlier and the rounded HLL slope factors ranged from 1.05 to 1.3. The average rounded HLL slope factor over all six DOE regions is 1.15. Effects of the revised slope factor on rated HSPFs (Region IV) for single- and two-capacity units dropped from 16% in the original work to 12.6% in this report. For VS units, the HSPF reductions of 14 to 25% in the original report were lowered to a range of 9 to 21%. As in the original report, for VS units that do not limit minimum speed operation below 47 F ambient, the average HSPF reduction for the cases evaluated is approximately the same as for single- and two-capacity units. For VS units that do limit minimum speed operation below 47 F ambient, the lower 1.15 slope factor of this report generally results in small overpredictions of rated HSPF by 1 to 3% compared to functional HSPF. An exception is minimum-speed-limited VS units where the minimum speed COP at 47 F is higher than that at 62 F; one such unit was found to have an HSPF overprediction of over 14% with the 1.15 HLL slope factor level. For such VS exception cases, a default HSPF penalty should be considered. For the more typical VS units that limit minimum speed operation, use of a 1.15 slope factor for rated HSPF was found to still acceptably limit the HSPF error. If slope factors lower than 1.15 are used for HSPF ratings, some means should be considered to appropriately derate the HSPFs for VS units which limit minimum speed operation below 47 F ambient.

  6. Stress Analysis and Fatigue Analysis of Front Axle of Heavy-Duty Truck using ANSYS Ncode Design Life for Different Loading Cases

    Directory of Open Access Journals (Sweden)

    Hemant L. Aghav

    2016-06-01

    Full Text Available Front axle of heavy duty truck is the important component of vehicle and needs good design under the various loading conditions of the complete vehicle. Aim of the project is to stress analysis and predict the life of front axle for vertical, and vertical and braking loading case. The fatigue life of front axle is generally estimated by stress life approach and strain life approach method. Front axle beam assembly was modeled in the NX cad software. Meshing and Stress analysis is performed by ANSYS workbench and fatigue analysis is performed by NCODE design life ANSYS tool under different loading cases. Fatigue life of axle obtained by FEA method is more than 2 x 105 cycles, which is considered as safe for vertical loading case. Similarly, Fatigue life of axle obtained is more than 4 x 103 cycles, which is considered as safe for vertical and braking loading case. The max stress region is below spring pad of axle for vertical loading and in the goose neck of axle for vertical and braking loading case

  7. Modeling and Analysis of Commercial Building Electrical Loads for Demand Side Management

    Science.gov (United States)

    Berardino, Jonathan

    In recent years there has been a push in the electric power industry for more customer involvement in the electricity markets. Traditionally the end user has played a passive role in the planning and operation of the power grid. However, many energy markets have begun opening up opportunities to consumers who wish to commit a certain amount of their electrical load under various demand side management programs. The potential benefits of more demand participation include reduced operating costs and new revenue opportunities for the consumer, as well as more reliable and secure operations for the utilities. The management of these load resources creates challenges and opportunities to the end user that were not present in previous market structures. This work examines the behavior of commercial-type building electrical loads and their capacity for supporting demand side management actions. This work is motivated by the need for accurate and dynamic tools to aid in the advancement of demand side operations. A dynamic load model is proposed for capturing the response of controllable building loads. Building-specific load forecasting techniques are developed, with particular focus paid to the integration of building management system (BMS) information. These approaches are tested using Drexel University building data. The application of building-specific load forecasts and dynamic load modeling to the optimal scheduling of multi-building systems in the energy market is proposed. Sources of potential load uncertainty are introduced in the proposed energy management problem formulation in order to investigate the impact on the resulting load schedule.

  8. Investigating Mass Loading Contributors of Seasonal Oscillations in GPS Observations Using Wavelet Analysis

    Science.gov (United States)

    Xu, Chang

    2016-08-01

    We adopt the cross wavelet transform (XWT) to examine the potential geophysical contributors of seasonal oscillations in GPS observations. Daily vertical GPS position time series and mass loadings [atmospheric, oceanic, and hydrological loading (AOH)] of 30 globally distributed GPS sites, spanning from January 2002 to December 2014, are used to quantify the performance. First, we examine the spectra of GPS time series and AOH. The results confirm the anomalous sub-seasonal peaks in GPS spectra are seen to have not an obvious geophysical explanation. The Akaike information criteria is then used to quantify how well the noise models fit the two series. The Generalized Gauss Markov plus white noise (GGM + WH) model is in most cases the preferred noise model for GPS, and the fifth order autoregressive plus white noise (AR(5) + WH) model is the preferred noise model for AOH. Second, we test the significance of periodic oscillations in GPS residuals and AOH. We find both series have significantly high power located near one cycle per year frequency band, whereas harmonic signals at higher draconitic frequency are identified as non-white process. Finally, we adopt XWT to examine the relative phasing between the two series, and find the annual variations in two series are physically related for most sites. The time variable phase asynchrony obtained using the XWT-based semblance analysis confirms that the annual variations in GPS observations are resulting from a combination of geophysical signals and systematic errors. The weighted least squares fitting method where the covariance matrix follows a specific stochastic noise model is also performed for comparison.

  9. Significant ELCAP analysis results: Summary report. [End-use Load and Consumer Assessment Program

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, R.G.; Conner, C.C.; Drost, M.K.; Miller, N.E.; Cooke, B.A.; Halverson, M.A.; Lebaron, B.A.; Lucas, R.G.; Jo, J.; Richman, E.E.; Sandusky, W.F. (Pacific Northwest Lab., Richland, WA (USA)); Ritland, K.G. (Ritland Associates, Seattle, WA (USA)); Taylor, M.E. (USDOE Bonneville Power Administration, Portland, OR (USA)); Hauser, S.G. (Solar Energy Research Inst., Golden, CO (USA))

    1991-02-01

    The evolution of the End-Use Load and Consumer Assessment Program (ELCAP) since 1983 at Bonneville Power Administration (Bonneville) has been eventful and somewhat tortuous. The birth pangs of a data set so large and encompassing as this have been overwhelming at times. The early adolescent stage of data set development and use has now been reached and preliminary results of early analyses of the data are becoming well known. However, the full maturity of the data set and the corresponding wealth of analytic insights are not fully realized. This document is in some sense a milestone in the brief history of the program. It is a summary of the results of the first five years of the program, principally containing excerpts from a number of previous reports. It is meant to highlight significant accomplishments and analytical results, with a focus on the principal results. Many of the results have a broad application in the utility load research community in general, although the real breadth of the data set remains largely unexplored. The first section of the document introduces the data set: how the buildings were selected, how the metering equipment was installed, and how the data set has been prepared for analysis. Each of the sections that follow the introduction summarize a particular analytic result. A large majority of the analyses to date involve the residential samples, as these were installed first and had highest priority on the analytic agenda. Two exploratory analyses using commercial data are included as an introduction to the commercial analyses that are currently underway. Most of the sections reference more complete technical reports which the reader should refer to for details of the methodology and for more complete discussion of the results. Sections have been processed separately for inclusion on the data base.

  10. Critical load analysis in hazard assessment of metals using a Unit World Model.

    Science.gov (United States)

    Gandhi, Nilima; Bhavsar, Satyendra P; Diamond, Miriam L

    2011-09-01

    A Unit World approach has been used extensively to rank chemicals for their hazards and to understand differences in chemical behavior. Whereas the fate and effects of an organic chemical in a Unit World Model (UWM) analysis vary systematically according to one variable (fraction of organic carbon), and the chemicals have a singular ranking regardless of environmental characteristics, metals can change their hazard ranking according to freshwater chemistry, notably pH and dissolved organic carbon (DOC). Consequently, developing a UWM approach for metals requires selecting a series of representative freshwater chemistries, based on an understanding of the sensitivity of model results to this chemistry. Here we analyze results from a UWM for metals with the goal of informing the selection of appropriate freshwater chemistries for a UWM. The UWM loosely couples the biotic ligand model (BLM) to a geochemical speciation model (Windermere Humic Adsorption Model [WHAM]) and then to the multi-species fate transport-speciation (Transpec) model. The UWM is applied to estimate the critical load (CL) of cationic metals Cd, Cu, Ni, Pb, and Zn, using three lake chemistries that vary in trophic status, pH, and other parameters. The model results indicated a difference of four orders of magnitude in particle-to-total dissolved partitioning (K(d)) that translated into minimal differences in fate because of the short water residence time used. However, a maximum 300-fold difference was calculated in Cu toxicity among the three chemistries and three aquatic organisms. Critical loads were lowest (greatest hazard) in the oligotrophic water chemistry and highest (least hazard) in the eutrophic water chemistry, despite the highest fraction of free metal ion as a function of total metal occurring in the mesotrophic system, where toxicity was ameliorated by competing cations. Water hardness, DOC, and pH had the greatest influence on CL, because of the influence of these factors on aquatic

  11. Voltage stability dynamical analysis by comparing static and dynamical loads; Estudio dinamico de estabilidad de tension comparando modelos de carga estatica y carga dinamica

    Energy Technology Data Exchange (ETDEWEB)

    Aromataris, Luis [Universidad Nacional de Rio Cuarto (UNRC) (Argentina); Arnera, Patricia; Riubrugent, Jean [Universidad Nacional de La Plata, Buenos Aires (Argentina). Facultad de Ingenieria. Instituto de Investigaciones Tecnologicas para Redes y Equipos Electricos

    2001-07-01

    This work investigate the impact produced by the load model on the voltage stability analysis of an electric system. Qualitative and quantitative analyses are approached in connection with the effects of modeling the electric loads by both dynamical and static way. Also it is highlighted the importance of using dynamical models of load, mainly when it is composed by motors.

  12. AN EXPLORATORY ANALYSIS ON HALF-HOURLY ELECTRICITY LOAD PATTERNS LEADING TO HIGHER PERFORMANCES IN NEU

    Directory of Open Access Journals (Sweden)

    K.A.D. Deshani

    2014-05-01

    Full Text Available Accurate prediction of electricity demand can bring extensive benefits to any country as the forecasted values help the relevant authorities to take decisions regarding electricity generation, transmission and distribution appropriately. The literature reveals that, when compared to conventional time series techniques, the improved artificial intelligent approaches provide better prediction accuracies. However, the accuracy of predictions using intelligent approaches like neural networks are strongly influenced by the correct selection of inputs and the number of neuro-forecasters used for prediction. Deshani, Hansen, Attygalle, & Karunarathne (2014 suggested that a cluster analysis could be performed to group similar day types, which contribute towards selecting a better set of neuro-forecasters in neural networks. The cluster analysis was based on the daily total electricity demands as their target was to predict the daily total demands using neural networks. However, predicting half-hourly demand seems more appropriate due to the considerable changes of electricity demand observed during a particular day. As such clusters are identified considering half-hourly data within the daily load distribution curves. Thus, this paper is an improvement to Deshani et. al. (2014, which illustrates how the half hourly demand distribution within a day, is incorporated when selecting the inputs for the neuro-forecasters.

  13. Analysis of the thermomechanical behavior of the IFMIF bayonet target assembly under design loading scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Bernardi, D., E-mail: davide.bernardi@enea.it [ENEA Brasimone, Camugnano, BO (Italy); Arena, P.; Bongiovì, G.; Di Maio, P.A. [Dipartimento di Energia, Ingegneria dell’Informazione e Modelli Matematici, Università di Palermo, Viale delle Scienze, Palermo (Italy); Frisoni, M. [ENEA Bologna, Via Martiri di Monte Sole 4, Bologna (Italy); Miccichè, G.; Serra, M. [ENEA Brasimone, Camugnano, BO (Italy)

    2015-10-15

    In the framework of the IFMIF Engineering Validation and Engineering Design Activities (IFMIF/EVEDA) phase, ENEA is responsible for the design of the European concept of the IFMIF lithium target system which foresees the possibility to periodically replace only the most irradiated and thus critical component (i.e., the backplate) while continuing to operate the rest of the target for a longer period (the so-called bayonet backplate concept). In this work, the results of the steady state thermomechanical analysis of the IFMIF bayonet target assembly under two different design loading scenarios (a “hot” scenario and a “cold” scenario) are briefly reported highlighting the relevant indications obtained with respect to the fulfillment of the design requirements. In particular, the analyses have shown that in the hot scenario the temperatures reached in the target assembly are within the material acceptable limits while in the cold scenario transition below the ductile to brittle transition temperature (DBTT) cannot be excluded. Moreover, results indicate that the contact between backplate and high flux test module is avoided and that the overall structural integrity of the system is assured in both scenarios. However, stress linearization analysis reveals that ITER Structural Design Criteria for In-vessel Components (SDC-IC) design rules are not always met along the selected paths at backplate middle plane section in the hot scenario, thus suggesting the need of a revision of the backplate design or a change of the operating conditions.

  14. Analysis on Dynamic Response of Hard-Soft-Hard Sandwich Panel Under Blast Loading

    Institute of Scientific and Technical Information of China (English)

    DONG Yongxiang; FENG Shunshan; JIN Jun

    2006-01-01

    Surface contact explosion experiments have been performed for the study of dynamic response of the hard-soft-hard sandwich panel under blast loading.Experimental results have shown that there are four damage modes,including explosion cratering,scabbing of the backside,radial cracking induced failure and circumferential cracking induced failure.It also illustrates that the foam material sandwiched in the multi-layered media has an important effect on damage patterns.The phenomena encountered have been analyzed by the calculation with ALE method.Meanwhile,the optimal analysis of foam material thickness and position in the sandwich panel were performed in terms of experimental and numerical analysis.The proper thickness proportion of the soft layer is about 20% to the thickness of sandwich panel and the thickness of the upper hard layer and lower hard layer is in the ratio of 7 to 3 under the condition in this paper when the total thickness of soft layer remains constant.

  15. On dynamic loads in parallel shaft transmissions. 1: Modelling and analysis

    Science.gov (United States)

    Lin, Edward Hsiang-Hsi; Huston, Ronald L.; Coy, John J.

    1987-01-01

    A model of a simple parallel-shaft, spur-gear transmission is presented. The model is developed to simulate dynamic loads in power transmissions. Factors affecting these loads are identified. Included are shaft stiffness, local compliance due to contact stress, load sharing, and friction. Governing differential equations are developed and a solution procedure is outlined. A parameter study of the solutions is presented in NASA TM-100181 (AVSCOM TM-87-C-3).

  16. Experimental Performances Analysis of Load Balancing Algorithms in IEEE 802.11

    CERN Document Server

    Salah, Hamdi; Rached, Tourki

    2009-01-01

    In IEEE 802.11, load balancing algorithms (LBA) consider only the associated stations to balance the load of the available access points (APs). However, although the APs are balanced, it causes a bad situation if the AP has a lower signal length (SNR) less than the neighbor APs. So, balance the load and associate one mobile station to an access point without care about the signal to noise ratio (SNR) of the AP cause possibly an unforeseen QoS, such as the bit rate, the end to end delay, the packet loss. In this way, we study an improvement load balancing algorithm with SNR integration at the selection policy.

  17. The first metatarsal bone under loading conditions: a finite element analysis.

    Science.gov (United States)

    Kristen, K-H; Berger, K; Berger, C; Kampla, W; Anzböck, W; Weitzel, S H

    2005-03-01

    An individual-based, three-dimensional finite element model of the first metatarsal (MT I) bone was created with fine CT. The three-dimensional model of the bone was fixed proximally at the metatarsocuneiform joint and load was applied on the metatarsal head. Loading conditions were simulated, including muscular forces as described for a normal metatarsophalangeal (MTP) joint during three typical phases of gait as the combination of the load in the contact areas of the sesamoid bones and the base of the proximal phalanx. The resultant strain and stress distributions within the loaded MT I were calculated and visualized with the MTP in different positions.

  18. Preliminary In-Flight Loads Analysis of In-Line Launch Vehicles using the VLOADS 1.4 Program

    Science.gov (United States)

    Graham, J. B.; Luz, P. L.

    1998-01-01

    To calculate structural loads of in-line launch vehicles for preliminary design, a very useful computer program is VLOADS 1.4. This software may also be used to calculate structural loads for upper stages and planetary transfer vehicles. Launch vehicle inputs such as aerodynamic coefficients, mass properties, propellants, engine thrusts, and performance data are compiled and analyzed by VLOADS to produce distributed shear loads, bending moments, axial forces, and vehicle line loads as a function of X-station along the vehicle's length. Interface loads, if any, and translational accelerations are also computed. The major strength of the software is that it enables quick turnaround analysis of structural loads for launch vehicles during the preliminary design stage of its development. This represents a significant improvement over the alternative-the time-consuming, and expensive chore of developing finite element models. VLOADS was developed as a Visual BASIC macro in a Microsoft Excel 5.0 work book on a Macintosh. VLOADS has also been implemented on a PC computer using Microsoft Excel 7.0a for Windows 95. VLOADS was developed in 1996, and the current version was released to COSMIC, NASA's Software Technology Transfer Center, in 1997. The program is a copyrighted work with all copyright vested in NASA.

  19. Sensitivity analysis of simulated SOA loadings using a variance-based statistical approach: SENSITIVITY ANALYSIS OF SOA

    Energy Technology Data Exchange (ETDEWEB)

    Shrivastava, Manish [Pacific Northwest National Laboratory, Richland Washington USA; Zhao, Chun [Pacific Northwest National Laboratory, Richland Washington USA; Easter, Richard C. [Pacific Northwest National Laboratory, Richland Washington USA; Qian, Yun [Pacific Northwest National Laboratory, Richland Washington USA; Zelenyuk, Alla [Pacific Northwest National Laboratory, Richland Washington USA; Fast, Jerome D. [Pacific Northwest National Laboratory, Richland Washington USA; Liu, Ying [Pacific Northwest National Laboratory, Richland Washington USA; Zhang, Qi [Department of Environmental Toxicology, University of California Davis, California USA; Guenther, Alex [Department of Earth System Science, University of California, Irvine California USA

    2016-04-08

    We investigate the sensitivity of secondary organic aerosol (SOA) loadings simulated by a regional chemical transport model to 7 selected tunable model parameters: 4 involving emissions of anthropogenic and biogenic volatile organic compounds, anthropogenic semi-volatile and intermediate volatility organics (SIVOCs), and NOx, 2 involving dry deposition of SOA precursor gases, and one involving particle-phase transformation of SOA to low volatility. We adopt a quasi-Monte Carlo sampling approach to effectively sample the high-dimensional parameter space, and perform a 250 member ensemble of simulations using a regional model, accounting for some of the latest advances in SOA treatments based on our recent work. We then conduct a variance-based sensitivity analysis using the generalized linear model method to study the responses of simulated SOA loadings to the tunable parameters. Analysis of SOA variance from all 250 simulations shows that the volatility transformation parameter, which controls whether particle-phase transformation of SOA from semi-volatile SOA to non-volatile is on or off, is the dominant contributor to variance of simulated surface-level daytime SOA (65% domain average contribution). We also split the simulations into 2 subsets of 125 each, depending on whether the volatility transformation is turned on/off. For each subset, the SOA variances are dominated by the parameters involving biogenic VOC and anthropogenic SIVOC emissions. Furthermore, biogenic VOC emissions have a larger contribution to SOA variance when the SOA transformation to non-volatile is on, while anthropogenic SIVOC emissions have a larger contribution when the transformation is off. NOx contributes less than 4.3% to SOA variance, and this low contribution is mainly attributed to dominance of intermediate to high NOx conditions throughout the simulated domain. The two parameters related to dry deposition of SOA precursor gases also have very low contributions to SOA variance

  20. Analysis of Load-Carrying Capacity for Redundant Free-Floating Space Manipulators in Trajectory Tracking Task

    Directory of Open Access Journals (Sweden)

    Qingxuan Jia

    2014-01-01

    Full Text Available The aim of this paper is to analyze load-carrying capacity of redundant free-floating space manipulators (FFSM in trajectory tracking task. Combined with the analysis of influential factors in load-carrying process, evaluation of maximum load-carrying capacity (MLCC is described as multiconstrained nonlinear programming problem. An efficient algorithm based on repeated line search within discontinuous feasible region is presented to determine MLCC for a given trajectory of the end-effector and corresponding joint path. Then, considering the influence of MLCC caused by different initial configurations for the starting point of given trajectory, a kind of maximum payload initial configuration planning method is proposed by using PSO algorithm. Simulations are performed for a particular trajectory tracking task of the 7-DOF space manipulator, of which MLCC is evaluated quantitatively. By in-depth research of the simulation results, significant gap between the values of MLCC when using different initial configurations is analyzed, and the discontinuity of allowable load-carrying capacity is illustrated. The proposed analytical method can be taken as theoretical foundation of feasibility analysis, trajectory optimization, and optimal control of trajectory tracking task in on-orbit load-carrying operations.

  1. Three-dimensional finite element analysis of lumbar vertebra loaded by static stress and its biomechanical significance

    Institute of Scientific and Technical Information of China (English)

    SU Jia-can; LI Zhuo-dong; CAO Lie-hu; YU Bao-qing; ZHANG Chun-cai; LI Ming

    2009-01-01

    To explore the mechanical behavioroflum-bar spine loaded by stress and provide the mechanical ba-sis for clinical analysis and judgement of lumbar spine frac-tare classification, mechanical distribution and static stress. Methods: By means of computer simulation method, the constructed lumbar spine three-dimensional model was introduced into three-dimensional finite element analysis by software Ansys 7.0. The lumbar spine mechanical be-havior in different parts of the stress loading were calculated. Impact load is 0-8000 N. The peak value was 8000 N. The loading time is 0-40 minutes. The values of the main stress, stress distribution and the lumbar spine unit displacement in the direction of main stress were analyzed. Results: The lumbar spine model was divided into a total of 121 239 nodes, 112 491 units. It could objectively reflect the true anatomy of lumbar spine and its biomechani-cal behavior and obtain the end-plate images under differ-ent stress. The stress distribution on the lumbar interverte-bral disc (L-L) under the axial, lateral flexion and extension stress, and the displacement trace of the corresponding pro-cessus articularis were analyzed. Conclusion: It is helpful to analyze the stress distribu-tion of lumbar spine and units displacement in static stress loading in the clinical research of lumbar spine injury and the distribution of internal stress.

  2. Finite Element Analysis for the Structure Optimization Design of the CPUE Load-Bearing Wheel of Tracked Vehicle

    Institute of Scientific and Technical Information of China (English)

    于立彪; 郑慕侨; 张英

    2003-01-01

    A new kind of material cast polyurethane elastomers (CPUE) is introduced to take the place of rubber on load-bearing wheel for the first time. Based on load-bearing wheel dimensions, material properties and operating conditions, the structure of wheel flange is optimized by zero-order finite element method. A detailed three-dimensional finite element model of flange of load-bearing wheel is developed and utilized to optimize structure of wheel flange. Its service life, which is affected by flange structure parameter, is analyzed by comparing the optimization results with those of prototype of wheel. The results of optimization are presented and the stress field of load-bearing wheel in optimal dimension obtained by using finite element analysis method is demonstrated. The finite element analysis and optimization results show that the CPUE load-bearing wheel is feasible and suitable for the tracked vehicle and has a guiding value in practice of the weighting design of the whole tracked vehicle.

  3. Carbohydrates, glycemic index, glycemic load, and colorectal cancer risk: a systematic review and meta-analysis of cohort studies.

    NARCIS (Netherlands)

    Aune, D.; Chan, D.S.; Lau, R.; Vieira, R.; Greenwood, D.C.; Kampman, E.; Norat, T.

    2012-01-01

    BACKGROUND: Dietary carbohydrate, glycemic index, and glycemic load are thought to influence colorectal cancer risk through hyperinsulinemia. We review and quantitatively summarize in a meta-analysis the evidence from prospective cohort studies. METHODS: We searched the PubMed database for prospecti

  4. Carbohydrates, glycemic index, glycemic load, and colorectal cancer risk : a systematic review and meta-analysis of cohort studies

    NARCIS (Netherlands)

    Aune, D.; Chan, D.S.M.; Lau, R.; Vieira, R.; Greenwood, D.C.; Kampman, E.; Norat, T.

    2012-01-01

    Background Dietary carbohydrate, glycemic index, and glycemic load are thought to influence colorectal cancer risk through hyperinsulinemia. We review and quantitatively summarize in a meta-analysis the evidence from prospective cohort studies. Methods We searched the PubMed database for prospective

  5. Analysis of Dissolved Selenium Loading for Selected Sites in the Lower Gunnison River Basin, Colorado, 1978-2005

    Science.gov (United States)

    Thomas, Judith C.; Leib, Kenneth J.; Mayo, John W.

    2008-01-01

    Elevated selenium concentrations in streams are a water-quality concern in western Colorado. The U.S. Geologic Survey, in cooperation with the Colorado Department of Public Health and Environment, summarized selenium loading in the Lower Gunnison River Basin to support the development of total maximum daily selenium loads at sites that represent the cumulative contribution to U.S. Environmental Protection Agency 303(d) list segments. Analysis of selenium loading included quantifying loads and determining the amount of load that would need to be reduced to bring the site into compliance, referred to as 'the load reduction,' with the State chronic aquatic-life standard for dissolved selenium [85th percentile selenium concentration not to exceed 4.6 ?g/L (micrograms per liter)], referred to as 'the water-quality standard.' Streamflow and selenium concentration data for 54 historical water-quality/water-quantity monitoring sites were compiled from U.S. Geological Survey and Colorado Department of Public Health and Environment data sources. Three methods were used for analysis of selenium concentration data to address the variable data density among sites. Mean annual selenium loads were determined for only 10 of the 54 sites due to data availability limitations. Twenty-two sites had 85th percentile selenium concentrations that exceeded the water-quality standard, 3 sites had 85th percentile selenium concentrations less than the State standard, and 29 sites could not be evaluated with respect to 85th percentile selenium concentration (sample count less than 5). To bring selenium concentrations into compliance with the water-quality standard, more than 80 percent of the mean annual selenium load would need to be reduced at Red Rock Canyon, Dry Cedar Creek, Cedar Creek, Loutzenhizer Arroyo, Sunflower Drain, and Whitewater Creek. More than 50 percent of the mean annual load would need to be reduced at Dry Creek to bring the site into compliance with the water

  6. Structural analysis of the ITER Vacuum Vessel regarding 2012 ITER Project-Level Loads

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, J.-M., E-mail: jean-marc.martinez@live.fr [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); Jun, C.H.; Portafaix, C.; Choi, C.-H.; Ioki, K.; Sannazzaro, G.; Sborchia, C. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); Cambazar, M.; Corti, Ph.; Pinori, K.; Sfarni, S.; Tailhardat, O. [Assystem EOS, 117 rue Jacquard, L' Atrium, 84120 Pertuis (France); Borrelly, S. [Sogeti High Tech, RE2, 180 rue René Descartes, Le Millenium – Bat C, 13857 Aix en Provence (France); Albin, V.; Pelletier, N. [SOM Calcul – Groupe ORTEC, 121 ancien Chemin de Cassis – Immeuble Grand Pré, 13009 Marseille (France)

    2014-10-15

    Highlights: • ITER Vacuum Vessel is a part of the first barrier to confine the plasma. • ITER Vacuum Vessel as Nuclear Pressure Equipment (NPE) necessitates a third party organization authorized by the French nuclear regulator to assure design, fabrication, conformance testing and quality assurance, i.e. Agreed Notified Body (ANB). • A revision of the ITER Project-Level Load Specification was implemented in April 2012. • ITER Vacuum Vessel Loads (seismic, pressure, thermal and electromagnetic loads) were summarized. • ITER Vacuum Vessel Structural Margins with regards to RCC-MR code were summarized. - Abstract: A revision of the ITER Project-Level Load Specification (to be used for all systems of the ITER machine) was implemented in April 2012. This revision supports ITER's licensing by accommodating requests from the French regulator to maintain consistency with the plasma physics database and our present understanding of plasma transients and electro-magnetic (EM) loads, to investigate the possibility of removing unnecessary conservatism in the load requirements and to review the list and definition of incidental cases. The purpose of this paper is to present the impact of this 2012 revision of the ITER Project-Level Load Specification (LS) on the ITER Vacuum Vessel (VV) loads and the main structural margins required by the applicable French code, RCC-MR.

  7. Performance Analysis of Savonius Rotor Based Hydropower Generation Scheme with Electronic Load Controller

    Directory of Open Access Journals (Sweden)

    Rajen Pudur

    2016-01-01

    Full Text Available This paper describes the performance of electronic load controller (ELC of asynchronous generator (AG coupled to an uncontrolled Savonius turbine and variable water velocity. An AC-DC-AC converter with a dc link capacitor is employed to maintain the required frequency. The ELC which is feeding a resistive dump load is connected in parallel with the generating system and the power consumption is varied through the duty cycle of the chopper. Gate triggering of ELC is accomplished through sinusoidal pulse width modulation (SPWM by sensing the load current. A MATLAB/Simulink model of Savonius rotor, asynchronous generator, ELC, and three-phase load is presented. The proposed scheme is tested under various load conditions under varying water velocities and the performances are observed to be satisfactory.

  8. Vertical random vibration analysis of adjacent building induced by highway traffic load

    Directory of Open Access Journals (Sweden)

    Wentao Xu

    2016-08-01

    Full Text Available Vehicle–pavement coupling systems may produce strong vertical random vibration due to the road surface unevenness and then further induce random vibration of adjacent buildings. It is usually difficult to numerical analyze efficiently as the model precision and calculation scale of complicated random analysis. In this article, a longitudinal infinite Kirchhoff plate with Kelvin foundation is employed to model the pavement system, and by proving the symplectic orthogonal characteristic for the damped chain substructure, the infinitely long road surface is regarded as a periodic chain-type substructure, the model is accurate, and computation scale is reduced. Models of a half vehicle and an adjacent building are coupled to the plate to produce a unified finite element model. The plate element stiffness matrix is formulated in the coordinate moving with the load, a typical model of road substructure is built, and the two-dimensional moving element method of vertical coupling random vibration is formulated, and then the time-varying non-stationary random vibration may be transformed into time-invariant stationary system. Using the pseudo-excitation method, vertical dynamic responses of the unified model of vibration source, supporting structure, and vibrated structure are analyzed. The computation efficiency of this method is numerically justified and some vibration influence rules of vehicle to building are drawn.

  9. Topological analysis of plasma flow control on corner separation in a highly loaded compressor cascade

    Institute of Scientific and Technical Information of China (English)

    Xiao-Hu Zhao; Yun Wu; Ying-Hong Li; Xue-De Wang; Qin Zhao

    2012-01-01

    In this paper,flow behavior and topology structure in a highly loaded compressor cascade with and without plasma aerodynamic actuation (PAA) are investigated.Streamline pattern,total pressure loss coefficient,outlet flow angle and topological analysis are considered to study the effect and mechanism of the plasma flow control on corner separation.Results presented include the boundary layer flow behavior,effects of three types of PAA on separated flows and performance parameters,topology structures and sequences of singular points with and without PAA.Two separation lines,reversed flow and backflow exist on the suction surface.The cross flow on the endwall is an important element for the corner separation.PAA can reduce the undertuming and overturning as well as the total pressure loss,leading to an overall increase of flow turning and enhancement of aerodynamic performance.PAA can change the topology structure,sequences of singular points and their corresponding separation lines.Types Ⅱ and Ⅲ PAA are much more efficient in controlling corner separation and enhancing aerodynamic performances than type Ⅰ.

  10. Static Analysis of Functionally Graded Piezoelectric Beams under Thermo-Electro-Mechanical Loads

    Directory of Open Access Journals (Sweden)

    Amin Komeili

    2011-01-01

    Full Text Available This paper presents the analysis of static bending of beams made of functionally graded piezoelectric materials (FGPMs under a combined thermo-electro-mechanical load. The Euler Bernoulli theory (EBT, first-order shear deformation theory (FSDT and third-order shear deformation theory (TSDT were employed to compare the accuracy and the reliability of each theory in applications. The material properties vary continuously through the thickness direction. The material compositions were selected from the PZT family. The governing equations were derived from Hamilton's principle and solved using the finite element method and Fourier series method. Cubic Hermit interpolation shape function was used for estimating the transverse deflection, and the linear interpolation function was used for the axial displacement and the shear rotation as well. Fourier series expansion, based on the boundary conditions, were employed to solve the governing equations analytically. The accuracy of the method was validated by comparing the results with the previous studies. Finite element results were compared with the analytical results presented in this paper. A comprehensive parametric study is conducted to show the influence of the voltage, shear deformation, material composition, end supports, and the slenderness ratio on the thermo-electro-mechanical characteristic.

  11. Differential-algebraic approach to large deformation analysis of frame structures subjected to dynamic loads

    Institute of Scientific and Technical Information of China (English)

    HU Yu-jia; ZHU Yuan-yuan; CHENG Chang-jun

    2008-01-01

    A nonlinear mathematical model for the analysis of large deformation of frame structures with discontinuity conditions and initial displacements,subject to dynamic loads is formulated with arc-coordinates.The differential quadrature element method (DQEM)is then applied to discretize the nonlinear mathematical model in the spatial domain.An effective method is presented to deal with discontinuity conditions of multivariables in the application of DQEM.A set of DQEM discretization equations are obtained,which are a set of nonlinear differential-algebraic equations with singularity in the time domain.This paper also presents a method to solve nonlinear differential-algebra equations.As application,static and dynamical analyses of large deformation of frames and combined frame structures,subjected to concentrated and distributed forces,are presented.The obtained results are compared with those in the literatares.Numerical results show that the proposed method is general,and effective in dealing with discontinuity conditions of multi-variables and solving difierential-algebraic equations.It requires only a small number of nodes and has low computation complexity with high precision and a good convergence property.

  12. Throughput analysis of the IEEE 802.4 token bus standard under heavy load

    Science.gov (United States)

    Pang, Joseph; Tobagi, Fouad

    1987-03-01

    It has become clear in the last few years that there is a trend towards integrated digital services. Parallel to the development of public Integrated Services Digital Network (ISDN) is service integration in the local area (e.g., a campus, a building, an aircraft). The types of services to be integrated depend very much on the specific local environment. However, applications tend to generate data traffic belonging to one of two classes. According to IEEE 802.4 terminology, the first major class of traffic is termed synchronous, such as packetized voice and data generated from other applications with real-time constraints, and the second class is called asynchronous which includes most computer data traffic such as file transfer or facsimile. The IEEE 802.4 token bus protocol which was designed to support both synchronous and asynchronous traffic is examined. The protocol is basically a timer-controlled token bus access scheme. By a suitable choice of the design parameters, it can be shown that access delay is bounded for synchronous traffic. As well, the bandwidth allocated to asynchronous traffic can be controlled. A throughput analysis of the protocol under heavy load with constant channel occupation of synchronous traffic and constant token-passing times is presented.

  13. Finite Element Analysis of Aluminum Honeycombs Subjected to Dynamic Indentation and Compression Loads

    Directory of Open Access Journals (Sweden)

    A.S.M. Ayman Ashab

    2016-03-01

    Full Text Available The mechanical behavior of aluminum hexagonal honeycombs subjected to out-of-plane dynamic indentation and compression loads has been investigated numerically using ANSYS/LS-DYNA in this paper. The finite element (FE models have been verified by previous experimental results in terms of deformation pattern, stress-strain curve, and energy dissipation. The verified FE models have then been used in comprehensive numerical analysis of different aluminum honeycombs. Plateau stress, σpl, and dissipated energy (EI for indentation and EC for compression have been calculated at different strain rates ranging from 102 to 104 s−1. The effects of strain rate and t/l ratio on the plateau stress, dissipated energy, and tearing energy have been discussed. An empirical formula is proposed to describe the relationship between the tearing energy per unit fracture area, relative density, and strain rate for honeycombs. Moreover, it has been found that a generic formula can be used to describe the relationship between tearing energy per unit fracture area and relative density for both aluminum honeycombs and foams.

  14. Quantitative analysis of the nonlinear displacement-load behavior of the lumbar spine.

    Science.gov (United States)

    Hanlon, Andrew D; Cook, Daniel J; Yeager, Matthew S; Cheng, Boyle C

    2014-08-01

    There is currently no universal model or fitting method to characterize the visco-elastic behavior of the lumbar spine observed in displacement versus load hysteresis loops. In this study, proposed methods for fitting these loops, along with the metrics obtained, were thoroughly analyzed. A spline fitting technique was shown to provide a consistent approximation of spinal kinetic behavior that can be differentiated and integrated. Using this tool, previously established metrics were analyzed using data from two separate studies evaluating different motion preservation technologies. Many of the metrics, however, provided no significant differences beyond range of motion analysis. Particular attention was paid to how different definitions of the neutral zone capture the high-flexibility region often seen in lumbar hysteresis loops. As a result, the maximum slope was introduced and shown to be well defined. This new parameter offers promise as a descriptive measurement of spinal instability in vitro and may have future implications in clinical diagnosis and treatment of spinal instability. In particular, it could help in assigning treatments to specific stabilizing effects in the lumbar spine.

  15. Soil Plasticity Model for Analysis of Collapse Load on Layers Soil

    Directory of Open Access Journals (Sweden)

    Md Nujid Masyitah

    2016-01-01

    Full Text Available Natural soil consist of soil deposits which is a soil layer overlying a thick stratum of another soil. The bearing capacity of layered soil studies have been conducted using different approach whether theoretical, experimental and combination of both. Numerical method in computer programme has become a powerful tool in solving complex geotechnical problems. Thus in numerical modelling, stress-strain soil behaviour is well predicted, design and interpreted using appropriate soil model. It is also important to identify parameters and soil model involve in prediction real soil problem. The sand layer overlaid clay layer soil is modelled with Mohr-Coulomb and Drucker-Prager criterion. The bearing capacity in loaddisplacement analysis from COMSOL Multiphysics is obtained and presented. In addition the stress distribution and evolution of plastic strain for each thickness ratio below centre of footing are investigated. The results indicate the linear relation on load-displacement which have similar trend for both soil models while stress and plastic strain increase as thickness ratio increase.

  16. Correspondence Analysis of Soil around Micropile Composite Structures under Horizontal Load

    Directory of Open Access Journals (Sweden)

    Hai Shi

    2015-01-01

    Full Text Available The current approach, which is based on conformal transformation, is to map micropile holes in comparison with unit circle domain. The stress field of soil around a pile plane, as well as the plane strain solution to displacement field distribution, can be obtained by adopting complex variable functions of elastic mechanics. This paper proposes an approach based on Winkler Foundation Beam Model, with the assumption that the soil around the micropiles stemmed from a series of independent springs. The rigidity coefficient of the springs is to be obtained from the planar solution. Based on the deflection curve differential equation of Euler-Bernoulli beams, one can derive the pile deformation and internal force calculation method of micropile composite structures under horizontal load. In the end, we propose reinforcing highway landslides with micropile composite structure and conducting on-site pile pushing tests. The obtained results from the experiment were then compared with the theoretical approach. It has been indicated through validation analysis that the results obtained from the established theoretical approach display a reasonable degree of accuracy and reliability.

  17. Transient Analysis of Lumped Circuit Networks Loaded Thin Wires By DGTD Method

    KAUST Repository

    Li, Ping

    2016-03-31

    With the purpose of avoiding very fine mesh cells in the proximity of a thin wire, the modified telegrapher’s equations (MTEs) are employed to describe the thin wire voltage and current distributions, which consequently results in reduced number of unknowns and augmented Courant-Friedrichs-Lewy (CFL) number. As hyperbolic systems, both the MTEs and the Maxwell’s equations are solved by the discontinuous Galerkin time-domain (DGTD) method. In realistic situations, the thin wires could be either driven or loaded by circuit networks. The thin wire-circuit interface performs as a boundary condition for the thin wire solver, where the thin wire voltage and current used for the incoming flux evaluation involved in the DGTD analyzed MTEs are not available. To obtain this voltage and current, an auxiliary current flowing through the thin wire-circuit interface is introduced at each interface. Corresponding auxiliary equations derived from the invariable property of characteristic variable for hyperbolic systems are developed and solved together with the circuit equations established by the modified nodal analysis (MNA) modality. Furthermore, in order to characterize the field and thin wire interactions, a weighted electric field and a volume current density are added into the MTEs and Maxwell-Ampere’s law equation, respectively. To validate the proposed algorithm, three representative examples are presented.

  18. New Analysis for The FGM Thick Cylinders Under Combined Pressure and Temperature Loading

    Directory of Open Access Journals (Sweden)

    K. Abrinia

    2008-01-01

    Full Text Available An analytical solution for computing the radial and circumferential stresses in a FGM thick cylindrical vessel under the influence of internal pressure and temperature is presented in this paper. It has been assumed that the modulus of elasticity and thermal coefficient of expansion were varying through thickness of the FGM material according to a power law relationship. Nevertheless the value of the Poisson ratio was taken as constant throughout the material. In the analysis presented here the effect of non-homogeneity in FGM thick cylinder was implemented by choosing a dimensionless parameter, named β, which could be assigned an arbitrary value affecting the stresses in the cylinder. Using Maple 9.5, distribution of stresses in radial and circumferential directions for FGM cylinders under the influence of internal pressure and temperature gradient were obtained. Graphs of variations of stress versus radius of the cylinder were plotted for different values of β. Cases of pressure, temperature and combined loadings were considered separately. It was concluded that by changing the value of β, the properties of FGM could be so modified that the lowest stress levels were reached. The stresses which were produced in FGM and homogeneous material with the same boundary conditions were compared to obtain the optimum value of β.

  19. Analysis of pressure distributions on combinations of cylinders due to the effect of wind loading

    Science.gov (United States)

    Ghosh, Kapil; Saha, Anup; Islam, Md. Quamrul; Ali, Mohammad

    2016-07-01

    With the rapid growth of population, design and construction of taller buildings are being emphasized now-a-days. Especially the design of the group of tall buildings is economic to take care of the housing problem of the huge population. As buildings become taller, effect of wind on them also increases. In this research work, experiments have been conducted to investigate the wind effect on a combination of pentagonal and hexagonal cylinders. The test was conducted in an open circuit wind tunnel at a Reynolds number of Re = 4.22 × 104 based on the face width of the cylinder across the flow direction in a uniform flow velocity of 13.5 m/s. A pentagonal cylinder was placed in the upstream and another two hexagonal cylinders were in the downstream. The transverse and longitudinal spacing between the cylinders were varied and the surface static pressures at the different locations of the cylinders were measured with the help of inclined multi-manometers. From the measured values of surface static pressures, pressure coefficients were calculated. Due to the non-dimensional analysis, the results may be applied directly for engineering problems regarding wind loads around a group of skyscrapers, chimneys, towers, oil rigs or marine structures.

  20. Ultrastructural analysis of guided nerve regeneration using progesterone- and pregnenolone-loaded chitosan prostheses.

    Science.gov (United States)

    Chávez-Delgado, M E; Gomez-Pinedo, U; Feria-Velasco, A; Huerta-Viera, M; Castañeda, S Castro; Toral, F A López-Dellamary; Parducz, A; Anda, S Luquín-De; Mora-Galindo, J; García-Estrada, J

    2005-07-01

    Recently, numerous guide chambers for the treatment of injured nerves made up of different biomaterials have been designed, capable of hosting living cells or carrying neurotrophic or neuroactive substances to be directly released to the injured tissue. In this study, chitosan prostheses containing neurosteroids (progesterone and pregnenolone) were used for bridging a 10-mm gap in the rabbit facial nerve. Gas chromatography was used to quantify neurosteroid content in the prostheses prior to and after subcutaneous implantation at different periods of up to 60 days. The regeneration of the nerve fibers were evaluated at 15 and 45 days after axotomy by means of ultrastructural morphometric analysis. Different nerve fibers regenerative patterns were seen depending the groups studied and the analyzed stages. At 15 days after axotomy, the newly regenerating tissue revealed Schwann cells holding nonmyelinated nerve fiber bundles in an incipient and organized regenerative pattern. At 45 days, the regenerating tissue showed myelinated nerve fibers of different sizes, shapes, and myelin sheath thickness. Although the regeneration of the nerve fibers under neurosteroid treatment showed statistically significant differences in comparison with vehicle regenerated tissue, progesterone-loaded chitosan prostheses produced the best guided nerve regeneration response. These findings indicate that chitosan prostheses allowed regeneration of nerve fibers in their lumen, and when containing neurosteroids produced a faster guided nerve regeneration acting as a long-lasting release delivery vehicle.

  1. [Effect analysis on the two total load control methods for poisonous heavy metals].

    Science.gov (United States)

    Fu, Guo-Wei

    2012-12-01

    Firstly it should be made clear that implementation of source total load control for the first type of pollutants is necessary for environmental pollution control legislation and economic structure regulation. This kind of surveillance method has been more practical to be implemented since the Manual of the Industry Discharge Coefficient of First National Pollution Sources Investigation was published. The source total load control and water environment total load control are independent of each other and none of them is redundant, on the other side they can be complementary to each other. In the present, some local planning managers are blurring and confusing the contents and styles of the two surveillance methods. They just use the water total load control to manage all the pollutants, and source total load control is discarded, which results in the loss of control for the first type of pollutants especially for the drinking water source surveillance. There is a big difference between the water quality standards and the water environmental background concentration values for the first type of pollutants in the Environmental quality standard for surface water (GB 3838-88), which means that there are problems such as "relaxing the pollutant discharge permit" and "risk induced by valence state change". Taking an enterprise with 10t electrolytic lead production capacity as an example, there is a big difference between the allowable lead discharged loads by the two total load surveillance methods. In summary, it will bring a lot of harmful effects if the water total load control is implemented for the two types of pollutants, so the source total load control and water environmental total load control should be implemented strictly at the same time.

  2. Finite Element Analysis on the Pre-load Structures of the Central Solenoid for the HT-7U Device

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The central solenoid is an important part of the HT-7U device. In this paper, the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the finite element analysis system COSMOS/M2.0 under room and/or operating temperature. According to the analytical results, the clip aprons and compression plates are all satisfied with safety design criteria.

  3. A new modeling of loading margin and its sensitivities using rectangular voltage coordinates in voltage stability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Vander Menengoy da; Rosa, Arlei Lucas de Sousa [Department of Electrical Engineering, Federal University of Juiz de Fora, Campus Universitario - Bairro Martelos, 36036-330 Juiz de Fora - MG (Brazil); Guedes, Magda Rocha [Federal Center of Technologic Education of Minas Gerais - CEFET, Rua Jose Peres, 558 36700-000 Leopoldina - MG (Brazil); Cantarino, Marcelo [Centrais Eletricas Brasileiras S.A - ELETROBRAS, Av. Rio Branco, 53, Centro, 14 andar, 20090-004 Rio de Janeiro - RJ (Brazil)

    2010-05-15

    This paper presents new mathematical models to compute the loading margin, as well as to perform the sensitivity analysis of loading margin with respect to different electric system parameters. The innovative idea consists of evaluating the performance of these methods when the power flow equations are expressed with the voltages in rectangular coordinates. The objective is to establish a comparative process with the conventional models expressed in terms of power flow equations with the voltages in polar coordinates. IEEE test system and a South-Southeastern Brazilian network are used in the simulations. (author)

  4. Safety Analysis of Dual Purpose Metal Cask Subjected to Impulsive Loads due to Aircraft Engine Crash

    Science.gov (United States)

    Shirai, Koji; Namba, Kosuke; Saegusa, Toshiari

    In Japan, the first Interim Storage Facility of spent nuclear fuel away from reactor site is being planned to start its commercial operation around 2010, in use of dual-purpose metal cask in the northern part of Main Japan Island. Business License Examination for safety design approval has started since March, 2007. To demonstrate the more scientific and rational performance of safety regulation activities on each phase for the first license procedure, CREPEI has executed demonstration tests with full scale casks, such as drop tests onto real targets without impact limiters(1) and seismic tests subjected to strong earthquake motions(2). Moreover, it is important to develop the knowledge for the inherent security of metal casks under extreme mechanical-impact conditions, especially for increasing interest since the terrorist attacks from 11th September 2001(3)-(6). This paper presents dynamic mechanical behavior of the metal cask lid closure system caused by direct aircraft engine crash and describes calculated results (especially, leak tightness based on relative dynamic displacements between metallic seals). Firstly, the local penetration damage of the interim storage facility building by a big passenger aircraft engine crash (diameter 2.7m, length 4.3m, weight 4.4ton, impact velocity 90m/s) has been examined. The reduced velocity is calculated by the local damage formula for concrete structure with its thickness of 70cm. The load vs. time function for this reduced velocity (60m/s) is estimated by the impact analysis using Finite Element code LS-DYNA with the full scale engine model onto a hypothetically rigid target. Secondly, as the most critical scenarios for the metal cask, two impact scenarios (horizontal impact hitting the cask and vertical impact onto the lid metallic seal system) are chosen. To consider the geometry of all bolts for two lids, the gasket reaction forces and the inner pressure of the cask cavity, the detailed three dimensional FEM models are

  5. Expanded Analysis of Hot Isostatic Pressed Iodine-Loaded Silver-Exchanged Mordenite

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R. T. [ORNL; Bruffey, S. H. [ORNL; Patton, K. K. [ORNL

    2014-09-30

    Reduced silver-exchanged mordenite (Ag0Z) is being evaluated as a potential material to control the release of radioactive iodine that is released during the reprocessing of used nuclear fuel into the plant off-gas streams. The purpose of this study was to determine if hot pressing could directly convert this iodine loaded sorbent into a waste form suitable for long-term disposition. The minimal pretreatment required for production of pressed pellets makes hot pressing a technically and economically desirable process. Initial scoping studies utilized hot uniaxial pressing (HUPing) to prepare samples of non-iodine-loaded reduced silver exchanged mordenite (Ag0Z). The resulting samples were very fragile due to the low pressure (~ 28 MPa) used. It was recommended that hot isostatic pressing (HIPing), performed at higher temperatures and pressures, be investigated. HIPing was carried out in two phases, with a third and final phase currently underway. Phase I evaluated the effects of pressure and temperature conditions on the manufacture of a pressed sample. The base material was an engineered form of silver zeolite. Six samples of Ag0Z and two samples of I-Ag0Z were pressed. It was found that HIPing produced a pressed pellet of high density. Analysis of each pressed pellet by scanning electron microscopy-energy dispersive spectrophotometry (SEM-EDS) and X-ray diffraction (XRD) demonstrated that under the conditions used for pressing, the majority of the material transforms into an amorphous structure. The only crystalline phase observed in the pressed Ag0Z material was SiO2. For the samples loaded with iodine (I-Ag0Z) iodine was present as AgI clusters at low temperatures, and transformed into AgIO4 at high temperatures. Surface mapping and EDS demonstrate segregation between silver iodide phases and silicon dioxide phases. Based on the results of the Phase I study, an expanded test matrix was developed to examine the effects of multiple source materials, compositional

  6. Synergism Analysis of Bedding Slope with Piles and Anchor Cable Support under Sine Wave Vehicle Load

    Directory of Open Access Journals (Sweden)

    Li Dan-Feng

    2016-01-01

    Full Text Available Slope instability under dynamic load is the technical difficulty in the engineering; the evaluation of slope stability under dynamic load and the control of dynamic load is particularly important. In this paper, taking the right side slope of K27+140 m~380 m typical section (K27 slope for short in Chongqing Fuling-Fengdu-Shizhu expresses highway as an example to calculate and analyze. The K27 slope is under sinusoidal vehicle load and supported by anchor cable and antislide pile to resist downslide strength; at the same time, the combined effect of them is studied. Three-dimensional finite element methodology (FEM is used to simulate the bedding slope with piles and anchor cable support; furthermore, the eigenvalue can be obtained. In order to reduce error of the elastic boundary conditions caused by the reflection effect of wavelengths, the combination of Lysmer surface viscous boundary and traditional ground support boundaries is utilized to analyze and calculate the time-histories during bedding slope under dynamic load. The dynamic response of pile anchor support to resist sliding force is obtained. The concept of the pile anchor supporting coordinate interval is put forward. Furthermore, it is verified that the pile anchor supporting coordinate interval can be used to evaluate the stability of the slope under dynamic load and provide a new method for the control of the dynamic load.

  7. Factor Analysis of the Aggregated Electric Vehicle Load Based on Data Mining

    Directory of Open Access Journals (Sweden)

    Yao Wang

    2012-06-01

    Full Text Available Electric vehicles (EVs and the related infrastructure are being developed rapidly. In order to evaluate the impact of factors on the aggregated EV load and to coordinate charging, a model is established to capture the relationship between the charging load and important factors based on data mining. The factors can be categorized as internal and external. The internal factors include the EV battery size, charging rate at different places, penetration of the charging infrastructure, and charging habits. The external factor is the time-of-use pricing (TOU policy. As a massive input data is necessary for data mining, an algorithm is implemented to generate a massive sample as input data which considers real-world travel patterns based on a historical travel dataset. With the input data, linear regression was used to build a linear model whose inputs were the internal factors. The impact of the internal factors on the EV load can be quantified by analyzing the sign, value, and temporal distribution of the model coefficients. The results showed that when no TOU policy is implemented, the rate of charging at home and range anxiety exerts the greatest influence on EV load. For the external factor, a support vector regression technique was used to build a relationship between the TOU policy and EV load. Then, an optimization model based on the relationship was proposed to devise a TOU policy that levels the load. The results suggest that implementing a TOU policy reduces the difference between the peak and valley loads remarkably.

  8. Effect of Thermal Bridges in Insulated Walls on Air-Conditioning Loads Using Whole Building Energy Analysis

    Directory of Open Access Journals (Sweden)

    Mohamed F. Zedan

    2016-06-01

    Full Text Available Thermal bridges in building walls are usually caused by mortar joints between insulated building blocks and by the presence of concrete columns and beams within the building envelope. These bridges create an easy path for heat transmission and therefore increase air-conditioning loads. In this study, the effects of mortar joints only on cooling and heating loads in a typical two-story villa in Riyadh are investigated using whole building energy analysis. All loads found in the villa, which broadly include ventilation, transmission, solar and internal loads, are considered with schedules based on local lifestyles. The thermal bridging effect of mortar joints is simulated by reducing wall thermal resistance by a percentage that depends on the bridges to wall area ratio (TB area ratio or Amj/Atot and the nominal thermal insulation thickness (Lins. These percentage reductions are obtained from a correlation developed by using a rigorous 2D dynamic model of heat transmission through walls with mortar joints. The reduction in thermal resistance is achieved through minor reductions in insulation thickness, thereby keeping the thermal mass of the wall essentially unchanged. Results indicate that yearly and monthly cooling loads increase almost linearly with the thermal bridge to wall area ratio. The increase in the villa’s yearly loads varies from about 3% for Amj/Atot = 0.02 to about 11% for Amj/Atot = 0.08. The monthly increase is not uniform over the year and reaches a maximum in August, where it ranges from 5% for Amj/Atot = 0.02 to 15% for Amj/Atot = 0.08. In winter, results show that yearly heating loads are generally very small compared to cooling loads and that heating is only needed in December, January and February, starting from late night to late morning. Monthly heating loads increase with the thermal bridge area ratio; however, the variation is not as linear as observed in cooling loads. The present results highlight the importance of

  9. Deflection analysis of reinforced concrete beams strengthened with carbon fibre reinforced polymer under long-term load action

    Institute of Scientific and Technical Information of China (English)

    Mykolas DAUGEVI(C)IUS; Juozas VALIVONIS; Gediminas MAR(C)IUKAITIS

    2012-01-01

    This paper presents the results of an experimental research on reinforced concrete beams strengthened with an external carbon fibre reinforced polymer (CFRP) layer under long-term load action that lasted for 330 d.We describe the characteristics of deflection development of the beams strengthened with different additional anchorages of the external carbon fibre composite layer during the period of interest.The conducted experiments showed that the additional anchorage influences the slip of the extemal layer with respect to the strengthened element.Thus,concrete and carbon fibre composite interface stiffness decreases with a long-term load action.Therefore,the proposed method of analysis based on the built-up-bars theory can be used to estimate concrete and carbon fibre composite interface stiffness in the case of long-term load.

  10. Loads Analysis of Flanges of a Transonic and Supersonic Wind Tunnel Wide Angle Diffuser

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-bing; WANG Rui; CAI Qing-qing; GAO Xin-yu

    2012-01-01

    Compared with general circular flanges, flanges on conical shells have different configurations. In the Chinese national code GBISO, however, there are no related contents about flange design of this kind of type. So, it needs to study loads of flanges of this kind of type. This paper takes the flange connection of a wide angle diffuser in a transonic and supersonic wind tunnel as the background, according to the principles of flange design in Chinese national code GB150, combining the characteristics of flanges of a wide angle diffuser, the loads of flanges have been analyzed, and the equations of loads and their locations have been presented.

  11. Analysis of postural load during tasks related to milking cows-a case study.

    Science.gov (United States)

    Groborz, Anna; Tokarski, Tomasz; Roman-Liu, Danuta

    2011-01-01

    The aim of this study was to analyse postural load during tasks related to milking cows of 2 farmers on 2 different farms (one with a manual milk transport system, the other with a fully automated milk transport system) as a case study. The participants were full-time farmers, they were both healthy and experienced in their job. The Ovako Working Posture Analyzing System (OWAS) was used to evaluate postural load and postural risk. Postural load was medium for the farmer on the farm with a manual milk transport system and high for the farmer working on the farm with a fully automated milk transport system. Thus, it can be concluded that a higher level of farm mechanization not always mean that the farmer's postural load is lower, but limitation of OWAS should be considered.

  12. Finite element analysis of dynamic stability of skeletal structures under periodic loading

    Institute of Scientific and Technical Information of China (English)

    THANA Hemantha Kumar; AMEEN Mohammed

    2007-01-01

    This paper addresses the dynamic stability problem of columns and frames subjected to axially applied periodic loads. Such a structure can become unstable under certain combinations of amplitudes and frequencies of the imposed load acting on its columns/beams. These are usually shown in the form of plots which describe regions of instability. The finite element method (FEM) is used in this work to analyse dynamic stability problems of columns. Two-noded beam elements are used for this purpose.The periodic loading is decomposed into various harmonics using Fourier series expansion. Computer codes in C++ using object oriented concepts are developed to determine the stability regions of columns subjected to periodic loading. A number of numerical examples are presented to illustrate the working of the program. The direct integration of the equations of motions of the discretised system is carried out using Newmark's method to verify the results.

  13. Deterministic and probabilistic analysis of damping device resistance under impact loads from nuclear fuel container drop

    Science.gov (United States)

    Kala, J.; Bajer, M.; Barnat, J.; Smutný, J.

    2010-12-01

    Pedestrian-induced vibrations are a criterion for serviceability. This loading is significant for light-weight footbridge structures, but was established as a basic loading for the ceilings of various ordinary buildings. Wide variations of this action exist. To verify the different conclusions of various authors, vertical pressure measurements invoked during walking were performed. In the article the approaches of different design codes are also shown.

  14. Equivalence of physically based statistical fracture theories for reliability analysis of ceramics in multiaxial loading

    Science.gov (United States)

    Chao, Luen-Yuan; Shetty, Dinesh K.

    1990-01-01

    The present comparison of the Batdorf (1974) flaw density and orientation distribution approach with Evans' (1978) elemental strength approach, with a view to identities in fracture criteria and distribution functions, notes that despite their fundamental differences in multiaxial loading fracture probabilities, the two approaches yield identical predictions. Lamon's (1988) assertion to the contrary, in light of different theoretical predictions by the two methods for the case of alumina disks loaded in flexure, is demonstrated to be in error.

  15. A numerical analysis of empty and foam-filled aluminium conical tubes under oblique impact loading

    Science.gov (United States)

    Mat, Fauziah; Ismail, Khairul Azwan; Yaacob, Sazali

    2015-05-01

    In real impact applications, an energy absorber rarely sustains dynamic loading either axial or oblique but a combination of both. Established studies have proved that thin-walled tube is an excellent energy absorber under dynamic loading. Furthermore, the introduction of foam filling successfully enhanced the energy absorption capacity of thin-walled tube. However, the understanding of its response under oblique loading has yet been fully explored. Moreover, emerging in automotive industry has lead to increase interests on lightweight materials such as aluminium alloy. As such, this paper presents the crushing behaviour of empty and foam-filled aluminium alloy (AA6061-T6) conical tubes under oblique impact loading using a validated nonlinear finite element (FE) code, LS-DYNA. The study aims to assess the effect of foam filling on the energy absorption of AA6061-T6 tubes for variations in filler density. In fact, to the best of our knowledge, this study is the first attempt to evaluate a response of empty and foam-filled aluminum conical tube by using an experimentally validated model under oblique dynamic loading conditions. Good correlations between the numerical and experimental results were observed. The study show that initial peak force and the energy absorption increase with increasing filler density under axial and oblique loading. On the other hand, the effect of foam filling (0.534 g/cm3 aluminium foam filler) is less pronounced for the initial peak force under axial impact loading. Furthermore, the initial peak force and dynamic force of empty and foam-filled AA6061-T6 conical tubes decrease as the load angle increases from 0 deg to 20 deg hence reduces the energy absorption capacity.

  16. Mechanical Analysis of Dead Load Crown and Structure Parameter of Hydraulic Elastic Bulging Roll

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chang-cai; LI Wei-min; LIU Zhu-bai

    2003-01-01

    The dead load crown of hydraulic elastic bulging roll was discussed using the theory of elastically supported beam, and the dead load experiment was carried out. The theoretical calculation is consistent with the experimental result. The structure parameters for the thickness of roll sleeve, the length of the oil groove and the crown of roll were discussed. The fundamental principle of determining the parameters was put forward. The theoretical basis of the application of the hydraulic elastic bulging roll was established.

  17. Explicit nonlinear finite element geometric analysis of parabolic leaf springs under various loads.

    Science.gov (United States)

    Kong, Y S; Omar, M Z; Chua, L B; Abdullah, S

    2013-01-01

    This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability.

  18. Explicit Nonlinear Finite Element Geometric Analysis of Parabolic Leaf Springs under Various Loads

    Directory of Open Access Journals (Sweden)

    Y. S. Kong

    2013-01-01

    Full Text Available This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability.

  19. Analysis of the cryogenic system behavior for pulsed heat load in EAST

    Science.gov (United States)

    Hu, L. B.; Zhuang, M.; Zhou, Z. W.; Xia, G. H.

    2014-01-01

    EAST is the first full superconducting fusion device. The plasma is confined by the magnetic fields generated from a large set of superconducting magnets which are made of cable in-conduit conductor (CICC). In operation, these magnets suffer heat loads from thermal and nuclear radiation from the surrounding components and plasma as well as the eddy currents and the AC losses generated within the magnets, together with the heat conduction through supports and the resistive heat generated at the current lead transiting to room temperature. The cryogenic system of our EAST consists of a 2kW/4K helium refrigerator and a distribution system for the cooling of poloidal field (PF) and toroidal field (TF) coils, structures, thermal shields, buslines and current leads. Pulsed heat load is the main difference between the cryogenic system of a full superconducting Tokamak system and other large scale cryogenic systems. The cryogenic system operates in a pulsed heat loads mode requiring the helium refrigerator to remove periodically large heat loads in time. At the same time, the cryogenic system parameters such as helium cooling superconducting magnets, helium refrigerator and helium distribution system are changing. In this paper, the variation range of the parameters of superconducting magnets and refrigerator has been analyzed in the typical plasma discharge mode. The control scheme for the pulsed loads characteristics of the cryogenic system has been proposed, the implementation of which helps to smooth the pulse loads and to improve the stability of the operation of the cryogenic system.

  20. Analysis steel frames subjected to wind load by using three design codes

    Directory of Open Access Journals (Sweden)

    Ahya Malekpour

    2016-09-01

    Full Text Available Wind forces are complex. The effect of wind on a building depends on the interaction of many variables. Natural variables include wind speed, wind height, ground surface features, and the properties of the air. Building variables include the shape, location, and physical properties of structures. Together, these variables create differences in pressure that push and pull on the exterior surfaces of buildings.Globalization of the construction industry and the development of international codes and standards has intensified the need of better understanding the underlying differences betweenstandards of the wind loading. This paper, discuses the linear analysis of steelframes2,4,7,10,15and20floors, explained by using three design codes,ANSI 7-10, NBCC 05andIranian building code ,part 6. In this paper we discuss the criteria that include: the Overturning moment and drift. Note that the drift is a good indicator of structural and non-structural damage so in comparison, so the structural safety based is defined onthecriteria .One result ofthisstudyindicates thatthe proposedrulesin thebylaws ofAmerica, CanadaandIranfor the building that are analyses in a linear static way, insome cases, do notprovideadequate safetyagainst wind. According to sixth topic the basic cutting is less than the cutting according to NBCC regulations and the cutting according to NBCC regulation is less than ANSI regulation. According to the sixth issue in every frame the overturning moment is less than the NBCC regulation and the overturning moment in NBCC regulation is less than the ANSI regulation.

  1. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure. Part 1; Ultimate Design Loads

    Science.gov (United States)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

    2016-01-01

    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses finite element analysis and testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part I of the paper considers the five most critical load conditions, which are internal pressure only and positive and negative g-loads with and without internal pressure. Analysis results are compared with measurements acquired during testing. Performance of the test article is found to be closely aligned with predictions and, consequently, able to support the hybrid wing body design loads in pristine and barely visible impact damage conditions.

  2. Relation between Breast Cancer and High Glycemic Index or Glycemic Load: A Meta-analysis of Prospective Cohort Studies.

    Science.gov (United States)

    Mullie, Patrick; Koechlin, Alice; Boniol, Mathieu; Autier, Philippe; Boyle, Peter

    2016-01-01

    Breast cancer is the commonest form of cancer in women worldwide. It has been suggested that chronic hyperinsulinemia associated with insulin resistance plays a role in breast cancer etiology. To test the hyperinsulinemia hypothesis, a dietary pattern associated with a high glycemic index and glycemic load, both proxies for chronic hyperinsulinemia, should be associated with an increased risk of breast cancer. A meta-analysis restricted to prospective cohort studies was undertaken using a random effects model with tests for statistical significance, publication bias and heterogeneity. The metric for analysis was the risk of breast cancer in the highest relative to the lowest glycemic index and glycemic load dietary pattern. A dietary pattern with a high glycemic index was associated with a summary relative risk (SRR) of 1.05 (95% CI: 1.00, 1.11), and a high glycemic load with a SRR of 1.06 (95% CI: 1.00, 1.13). Adjustments for body mass index [BMI], physical activity and other lifestyle factors did not influence the SRR, nor did menopausal status and estrogen receptor status of the tumor. In conclusion, the current evidence supports a modest association between a dietary pattern with high glycemic index or glycemic load and the risk of breast cancer.

  3. Proof of fatigue strength of nuclear components part II: Numerical fatigue analysis for transient stratification loading considering environmental effects

    Energy Technology Data Exchange (ETDEWEB)

    Kraetschmer, D.; Roos, E.; Schuler, X. [Materialpruefungsanstalt (MPA) Universitaet Stuttgart, Pfaffenwaldring 32, 70569 Stuttgart (Germany); Herter, K.-H., E-mail: herter@mpa.uni-stuttgart.de [Materialpruefungsanstalt (MPA) Universitaet Stuttgart, Pfaffenwaldring 32, 70569 Stuttgart (Germany)

    2012-04-15

    For the construction, design and operation of nuclear components and systems the appropriate technical codes and standards provide detailed analysis procedures which guarantee a reliable behaviour of the structural components throughout the specified lifetime. Especially for cyclic stress evaluation the different codes and standards provide different fatigue analyses procedures to be performed considering the various mechanical and thermal loading histories and geometric complexities of the components. To consider effects of light water reactor coolant environments, new design curves included in report NUREG/CR-6909 for austenitic stainless steels and for low alloy steels have been presented. For the usage of these new design curves an environmental fatigue correction factor for incorporating environmental effects has to be calculated and used. The application of this environmental correction factor to a fatigue analysis of a nozzle with transient stratification loads, derived by in-service monitoring, has been performed. The results are used to compare with calculated usage factors, based on design curves without taking environmental effects particularly into account. - Highlights: Black-Right-Pointing-Pointer We model an nozzle for fatigue analysis und mechanical and thermal loading conditions. Black-Right-Pointing-Pointer A simplified as well as a general elastic-plastic fatigue analysis considering environmental effects is performed. Black-Right-Pointing-Pointer The influence of different factors calculating the environmental factor F{sub en} are shown. Black-Right-Pointing-Pointer The presented numerical evaluation methodology allows the consideration of all relevant parameters to assess lifetime.

  4. STUDY OF HIGHER MODE EFFECTS AND LATERAL LOAD PATTERNS IN PUSHOVER ANALYSIS OF STEEL FRAMES WITH STEEL SHEAR WALL

    Directory of Open Access Journals (Sweden)

    Mohammad Ghanoonibagha

    2016-03-01

    Full Text Available When an earthquake occurs, the structure will enter into a nonlinear stage; therefore, new approaches based on nonlinear analysis are needed to flourish with the purpose of more realistic investigations on seismic behavior and destruction mechanism of structures. According to the modern philosophy, “Performance-based Earthquake Engineering” is formed in which simple nonlinear static analyses are mostly used in order to determine the structure’s behavior in nonlinear stage. This method assumes that the structure response is only controlled by the main mode and the shape of this mode will remain the same, while it enters the nonlinear stage. Both of these assumptions are approximations, especially in high buildings, which have a long period. It seems that constant load pattern used in these methods cannot consider all of the effects properly. In this paper, an attempt was made to study the accuracy of these methods in comparison to nonlinear dynamic analysis, by considering various load patterns existing in FEMA, also load patterns proportional to higher modes in nonlinear static method, and employing an approximative method of MPA modal analysis, study the accuracy of these methods in comparison to nonlinear dynamic analysis. For this purpose, three steel frames of 4, 8, and 12-stories with steel shear wall have been studied.

  5. Wear mechanism of heavy load friction contact pairs in tracked vehicle by combined ferrography and surface analysis

    Institute of Scientific and Technical Information of China (English)

    LI Li; ZHU You-li; HUANG Yuan-lin; XU Bin-shi; LI Xiao-yan

    2004-01-01

    Ferrography is deemed as one of the most effective methods for wear particle analysis and failure diagnosis. By analyzing the configuration, content and composition of wear particles in the lubricanting grease and the surface state of the worn surface with combined ferrography and surface analysis techniques, the wear mechanism of the ball groove of the master clutch's release device of a heavy load tracked vehicle was determined. Results show that the controlling wear mechanism is combined of abrasion, adhesion, contact fatigue and corrosion wear, which demonstrates the effectiveness of using combined ferrography and worn surface analysis for the study of wear mechanism of contact surface with friction.

  6. Correlation analysis of high-risk human papillomavirus viral load and cervical lesions

    Directory of Open Access Journals (Sweden)

    Xiao-xing MA

    2012-05-01

    Full Text Available Objective  To explore the association between high-risk human papillomavirus (HR-HPV viral load and pathological grades of cervical intraepithelial neoplasia (CIN and cervical cancer. Methods  A total of 1248 patients from General Hospital of PLA, who underwent colposcopy and surgery due to cervical lesions between Jan. 2006 and Aug. 2011 were enrolled in this study, and they were divided five groups: cervicitis, CIN Ⅰ, CIN Ⅱ-Ⅲ, stage Ⅰ cervical cancer and stage Ⅱ cervical cancer. HR-HPV viral load (RLU/CO was determined by the Hybrid Capture Ⅱ (HCⅡ system, and they were categorized into five groups: 0-0.99, 1.00-9.99, 10.00-99.99, 100.00-999.99, ≥1000.00. The mean value and standard deviation of different HR-HPV viral load in the patients with cervicitis or with CIN Ⅰ, CINⅡ-Ⅲ, stage Ⅰ cervical cancer or stage Ⅱ cervical cancer were compared, and the correlation of HR-HPV viral load and pathogenesis of cervical lesions was analyzed. Results  HPV viral loads were significantly higher in CINⅠ(842.1±983.9, CINⅡ-Ⅲ (690.1±795.0, stage Ⅰ cervical cancer (893.1±974.2 and stage Ⅱ cervical cancer (699.5±908.3 patients than in cervicitis patients (274.2±613.6, P < 0.05, and the HPV viral loads in CINⅠ(842.1±983.9 and stage Ⅰ cervical cancer patients were higher than those in CINⅡ-Ⅲ patients (P < 0.05. When HR-HPV viral load was ≥100RLU/CO, the risk of CIN and cervical cancer increased with the increase in viral load, but there was no correlation between the viral load and pathological grades of cervical lesions. In the patients with stage ⅠB-Ⅱ cervical squamous cell carcinoma, when the HR-HPV viral load was ≥100RLU/CO, the risk of lymph node metastasis increased (P < 0.05, and the number of patients with maximum diameter of the cervical tumor ≥4cm also increased (P < 0.05. However, the HR-HPV viral load was not correlated with patient age, pathological type of the lesion, depth of cancer

  7. Biomechanical analysis of loading/unloading a ladder on a truck.

    Science.gov (United States)

    Moriguchi, Cristiane Shinohara; Carnaz, Leticia; de Miranda, Luiz Carlos; Marklin, Richard William; Coury, Helenice Jane Cote Gil

    2012-01-01

    Loading/unloading a ladder on vehicles are frequent tasks and involve overhead handling that may expose workers to risk factors of shoulder musculoskeletal disorders. The objective of the present study was to evaluate posture, forces required and perceived exertion when loading and unloading the ladder on a utility truck. Thirteen male overhead line workers from an electric utility in Brazil participated in this study. Shoulder elevation angle was measured using inclinometers. The required force to load/unload the ladder was measured by dynamometer. Subjective assessment of the perceived exertion was recorded to compare the exertion reported during the test conditions to the field conditions. The task of loading/unloading the ladder presented risks of shoulder musculoskeletal disorders (MSDs) to workers because it requires high levels of force (approximately 60% of the maximal force) combined with overhead posture of the shoulders (more than 100° from the neutral posture). Age and height presented to interfere in biomechanical risks presented in load/unload task. There was no significant difference between the subjective exertion during the test conditions and handling the ladder in the field. Ergonomic intervention is recommended to reduce these risks for shoulder MSDs.

  8. Sensitivity analysis of asphalt-pavement structure dynamic responses under heavy load

    Directory of Open Access Journals (Sweden)

    ZHANG Lijuan

    2015-04-01

    Full Text Available With the 3-Dimensional finite-element dynamic model,the influence of axis-load,axis-speed,and pavement structure parameters on dynamic performance of pavement structure is studied.The results show that with the increase in load,the dynamic response of pavement is nearly proportional to axis-load and increases noticeably;Axis-speed influences the dynamic response to some extent.With the increase of axis-speed,dynamic response of pavement structure increases firstly.With axis-speed further increasing,dynamic response of pavement structure then decreases gradually.For fatigue failure,the influence of heavy-load with common moving speed is much greater than that of static load.Among the pavement structure parameters,thickness of surface-layer has a significant effect on shear stress and the compression stress at road surface.Subgrade modulus has a significant effect on road surface deflection,tensile stress at the bottom of subbase,and compression-strain at the top of subgrade.

  9. Development of Vehicle Model Test for Road Loading Analysis of Sedan Model

    Science.gov (United States)

    Mohd Nor, M. K.; Noordin, A.; Ruzali, M. F. S.; Hussen, M. H.

    2016-11-01

    Simple Structural Surfaces (SSS) method is offered as a means of organizing the process for rationalizing the basic vehicle body structure load paths. The application of this simplified approach is highly beneficial in the design development of modern passenger car structure especially during the conceptual stage. In Malaysia, however, there is no real physical model of SSS available to gain considerable insight and understanding into the function of each major subassembly in the whole vehicle structures. Based on this motivation, a physical model of SSS for sedan model with the corresponding model vehicle tests of bending and torsion is proposed in this work. The proposed approach is relatively easy to understand as compared to Finite Element Method (FEM). The results show that the proposed vehicle model test is capable to show that satisfactory load paths can give a sufficient structural stiffness within the vehicle structure. It is clearly observed that the global bending stiffness reduce significantly when more panels are removed from a complete SSS model. It is identified that parcel shelf is an important subassembly to sustain bending load. The results also match with the theoretical hypothesis, as the stiffness of the structure in an open section condition is shown weak when subjected to torsion load compared to bending load. The proposed approach can potentially be integrated with FEM to speed up the design process of automotive vehicle.

  10. Calculation and characteristics analysis of blade pitch loads for large scale wind turbines

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on the electric pitch system of large scale horizontal-axis wind turbines,the blade pitch loads coming mainly from centrifugal force,aerodynamic force and gravity are analyzed,and the calculation models for them are established in this paper.For illustration,a 1.2 MW wind turbine is introduced as a practical sample,and its blade pitch loads from centrifugal force,aerodynamic force and gravity are calculated and analyzed separately and synthetically.The research results showed that in the process of rotor rotating 360o,the fluctuation of blade pitch loads is similar to cosine curve when the rotor rotational speed,in-flow wind speed and pitch angle are constant.Furthermore,the amplitude of blade pitch load presents quite a difference at a different pitch angle.The ways of calculation for blade pitch loads are of the universality,and are helpful for further research of the individual pitch control system.

  11. Sensitivity Analysis of Depletion Parameters for Heat Load Evaluation of PWR Spent Fuel Storage Pool

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Young; Lee, Un Chul [Seoul National University, Seoul (Korea, Republic of)

    2011-12-15

    As necessity of safety re-evaluation for spent fuel storage facility has emphasized after the Fukushima accident, accuracy improvement of heat load evaluation has become more important to acquire reliable thermal-hydraulic evaluation results. As groundwork, parametric and sensitivity analyses of various storage conditions for Kori Unit 4 spent fuel storage pool and spent fuel depletion parameters such as axial burnup effect, operation history, and specific heat are conducted using ORIGEN2 code. According to heat load evaluation and parametric sensitivity analyses, decay heat of last discharged fuel comprises maximum 80.42% of total heat load of storage facility and there is a negative correlation between effect of depletion parameters and cooling period. It is determined that specific heat is most influential parameter and operation history is secondly influential parameter. And decay heat of just discharged fuel is varied from 0.34 to 1.66 times of average value and decay heat of 1 year cooled fuel is varied from 0.55 to 1.37 times of average value in accordance with change of specific power. Namely depletion parameters can cause large variation in decay heat calculation of short-term cooled fuel. Therefore application of real operation data instead of user selection value is needed to improve evaluation accuracy. It is expected that these results could be used to improve accuracy of heat load assessment and evaluate uncertainty of calculated heat load.

  12. Cascade failure analysis of power grid using new load distribution law and node removal rule

    Science.gov (United States)

    Ren, Hai-Peng; Song, Jihong; Yang, Rong; Baptista, Murilo S.; Grebogi, Celso

    2016-01-01

    The power grid is a directional complex network of generators, substations, and consumers. We propose a new load distribution law to emulate the power grid. We assume that the power flow is transferred through all the paths connecting generators and consumers according to their efficiency. The initial generation of generators and the initial loads of substations are calculated according to the path efficiency and the load of the consumers. If a node fails, it is removed from the power grid, and all paths passing through it will fail to transfer power. In that case, the loads of the corresponding consumers are redistributed within the whole network. During the failure cascading and propagation procedure, our node removal rule is to remove the first overload node along the opposite direction of power flow, then the network distributes load and goes on the cascade procedure. Our new removal rule for nodes does suppress the large scale cascading failures. This work would be very helpful for designing the protective relay system and the tolerant parameters of the grid.

  13. Statistical modelling and power analysis for detecting trends in total suspended sediment loads

    Science.gov (United States)

    Wang, You-Gan; Wang, Shen S. J.; Dunlop, Jason

    2015-01-01

    The export of sediments from coastal catchments can have detrimental impacts on estuaries and near shore reef ecosystems such as the Great Barrier Reef. Catchment management approaches aimed at reducing sediment loads require monitoring to evaluate their effectiveness in reducing loads over time. However, load estimation is not a trivial task due to the complex behaviour of constituents in natural streams, the variability of water flows and often a limited amount of data. Regression is commonly used for load estimation and provides a fundamental tool for trend estimation by standardising the other time specific covariates such as flow. This study investigates whether load estimates and resultant power to detect trends can be enhanced by (i) modelling the error structure so that temporal correlation can be better quantified, (ii) making use of predictive variables, and (iii) by identifying an efficient and feasible sampling strategy that may be used to reduce sampling error. To achieve this, we propose a new regression model that includes an innovative compounding errors model structure and uses two additional predictive variables (average discounted flow and turbidity). By combining this modelling approach with a new, regularly optimised, sampling strategy, which adds uniformity to the event sampling strategy, the predictive power was increased to 90%. Using the enhanced regression model proposed here, it was possible to detect a trend of 20% over 20 years. This result is in stark contrast to previous conclusions presented in the literature.

  14. Computational Design and Analysis of a Micro-Tab Based Aerodynamic Loads Control System for Lifting Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Van Dam, C P; Nakafuji, D Y; Bauer, C; Chao, D; Standish, K

    2002-11-01

    A computational design and analysis of a microtab based aerodynamic loads control system is presented. The microtab consists of a small tab that emerges from a wing approximately perpendicular to its surface in the vicinity of its trailing edge. Tab deployment on the upper side of the wing causes a decrease in the lift generation whereas deployment on the pressure side causes an increase. The computational methods applied in the development of this concept solve the governing Reynolds-averaged Navier-Stokes equations on structured, overset grids. The application of these methods to simulate the flows over lifting surface including the tabs has been paramount in the development of these devices. The numerical results demonstrate the effectiveness of the microtab and that it is possible to carry out a sensitivity analysis on the positioning and sizing of the tabs before they are implemented in successfully controlling the aerodynamic loads.

  15. Recommendations to improve imaging and analysis of brain lesion load and atrophy in longitudinal studies of multiple sclerosis

    DEFF Research Database (Denmark)

    Vrenken, H; Jenkinson, M; Horsfield, M A;

    2013-01-01

    Focal lesions and brain atrophy are the most extensively studied aspects of multiple sclerosis (MS), but the image acquisition and analysis techniques used can be further improved, especially those for studying within-patient changes of lesion load and atrophy longitudinally. Improved accuracy...... and sensitivity will reduce the numbers of patients required to detect a given treatment effect in a trial, and ultimately, will allow reliable characterization of individual patients for personalized treatment. Based on open issues in the field of MS research, and the current state of the art in magnetic...... resonance image analysis methods for assessing brain lesion load and atrophy, this paper makes recommendations to improve these measures for longitudinal studies of MS. Briefly, they are (1) images should be acquired using 3D pulse sequences, with near-isotropic spatial resolution and multiple image...

  16. Sensitivity analysis of air gap motion with respect to wind load and mooring system for semi-submersible platform design

    Science.gov (United States)

    Huo, Fa-li; Nie, Yan; Yang, De-qing; Dong, Gang; Cui, Jin

    2016-07-01

    A design of semi-submersible platform is mainly based on the extreme response analysis due to the forces experienced by the components during lifetime. The external loads can induce the extreme air gap response and potential deck impact to the semi-submersible platform. It is important to predict air gap response of platforms accurately in order to check the strength of local structures which withstand the wave slamming due to negative air gap. The wind load cannot be simulated easily by model test in towing tank whereas it can be simulated accurately in wind tunnel test. Furthermore, full scale simulation of the mooring system in model test is still a tuff work especially the stiffness of the mooring system. Owing to the above mentioned problem, the model test results are not accurate enough for air gap evaluation. The aim of this paper is to present sensitivity analysis results of air gap motion with respect to the mooring system and wind load for the design of semi-submersible platform. Though the model test results are not suitable for the direct evaluation of air gap, they can be used as a good basis for tuning the radiation damping and viscous drag in numerical simulation. In the presented design example, a numerical model is tuned and validated by ANSYS AQWA based on the model test results with a simple 4 line symmetrical horizontal soft mooring system. According to the tuned numerical model, sensitivity analysis studies of air gap motion with respect to the mooring system and wind load are performed in time domain. Three mooring systems and five simulation cases about the presented platform are simulated based on the results of wind tunnel tests and sea-keeping tests. The sensitivity analysis results are valuable for the floating platform design.

  17. Development of Graphical User Interface for Finite Element Analysis of Static Loading of a Column using MATLAB

    OpenAIRE

    Moses Omolayo PETINRIN

    2010-01-01

    In this work, the capability of MATLAB software package to develop graphical user interface (GUI) package was demonstrated. A GUI was successfully developed using MATLAB programming language to study the behaviour of a suspended column under uniaxial static loading by solving the numerical model created based on the finite element method (FEM). The comparison between the exact solution from previous researches and the numerical analysis showed good agreement. The column average strain, averag...

  18. Analysis of Stress and Strain Fields in and around Inclusions of Various Shapes in a Cylindrical Specimen Loaded in Tension

    Directory of Open Access Journals (Sweden)

    Neimitz A.

    2016-06-01

    Full Text Available A numerical analysis is performed of the stress field in and around inclusions of various shapes. Inclusions both stiffer and more compliant than the metal matrix are analysed. The critical stresses required for inclusion fracture are estimated after observation of cavities and inclusions by scanning electron microscopy. Real inclusions were observed after performing uniaxial loading to different amounts of overall strain. The material tested was Hardox-400 steel.

  19. Numerical analysis of dynamic out-of-plane loading of nonwovens

    Science.gov (United States)

    Demirci, E.; Farukh, F.; Acar, M.; Pourdeyhimi, B.; Silberschmidt, V. V.

    2013-07-01

    This paper presents finite element (FE) modelling of deformation behaviour of thermally bonded bicomponent fibre nonwovens under out-of-plane dynamic loading. Nonwoven fabric was treated as an assembly of two regions with distinct mechanical properties. Bond points were treated as composite material having a matrix of the sheath material reinforced with fibres of the core material. Elastic-plastic and viscous properties of the constituent fibres, obtained with tensile and relaxation tests were implemented into the FE model. The mechanical behaviour of the material under out-of-plane dynamic loading was observed with visual techniques. The deformation behaviour of nonwoven under out-of-plane dynamic loading computed with the numerical model was compared with that observed in the tests.

  20. Numerical analysis of high strain rate failure of electro-magnetically loaded steel sheets

    Directory of Open Access Journals (Sweden)

    Erice Borja

    2015-01-01

    Full Text Available Electro-magnetic forces provide a potentially power full means in designing dynamic experiments with active control of the loading conditions. This article deals with the development of computational models to simulate the thermo-mechanical response of electro-magnetically loaded metallic structures. The model assumes linear electromagnetic constitutive equations and time-independent electric induction to estimate the Joule heating and the Lorentz forces. The latter are then taken into account when evaluating stress equilibrium. A thermo-visco-plastic model with Johnson-Cook type of temperature and strain rate dependence and combined Swift-Voce hardening is used to evaluate the material's thermo-mechanical response. As a first application, the model is used to analyse the effect of electro-magnetic loading on the ductility of advanced high strength steels.

  1. The design and analysis of single flank transmission error testor for loaded gears

    Science.gov (United States)

    Houser, D. R.; Bassett, D. E.

    1985-01-01

    Due to geometrical imperfections in gears and finite tooth stiffnesses, the motion transmitted from an input gear shaft to an output gear shaft will not have conjugate action. In order to strengthen the understanding of transmission error and to verify mathematical models of gear transmission error, a test stand that will measure the transmission error of a gear pair at operating loads, but at reduced speeds would be desirable. This document describes the design and development of a loaded transmission error tester. For a gear box with a gear ratio of one, few tooth meshing combinations will occur during a single test. In order to observe the effects of different tooth mesh combinations and to increase the ability to load test gear pairs with higher gear ratios, the system was designed around a gear box with a gear ratio of two.

  2. Analysis of source-grid-load contribution to wind power accommodation

    Science.gov (United States)

    Li, Nan; Zhang, Jinfang; Zhang, Fuqiang

    2017-01-01

    In recent years, China’s wind power is developing rapidly, but wind electricity curtailment becomes a serious problem. This paper evaluates wind power penetration limit from peak regulation, analyses relevant technical elements that impact wind power accommodation, coving the source side, the transmission side and the load side. By taking certain measures around the three aspects, for example, reducing the minimum technical output of conventional units, increasing outbound transmission capacity, or increasing the valley load, wind electricity curtailment will be effectively reduced. This paper quantitatively analyses wind power penetration limit under certain conditions and the source-grid-load contribution to wind power accommodation, and explores the important technical factors that affect wind power accommodation.

  3. Composite slab behavior and strength analysis under static and dynamic loads

    Directory of Open Access Journals (Sweden)

    Florin Radu HARIGA

    2012-07-01

    Full Text Available Steel-framed buildings are typically constructed using steel-deck-reinforced concrete floor slabs. The in-plane (or diaphragm strength and stiffness of the floor system are frequently utilized in the lateral load-resisting system design. This paper presents the results of an experimental research program in which four full size composite diaphragms were vertically loaded to the limit state, under static or dynamic loads. Two test specimens were provided with longitudinal steel-deck ribs, and the other two specimens with cross steel-deck ribs. Typical composite diaphragm limit states are described, and the controlling limit state for each of the full size tests is indicated. The interaction effects between the reinforced concrete slab and the steel girder on the composite slab strength and stiffness were mainly studied.

  4. Diffusion and bulk flow in phloem loading - a theoretical analysis of the polymer trap mechanism

    CERN Document Server

    Dölger, Julia; Liesche, Johannes; Schulz, Alexander; Bohr, Tomas

    2014-01-01

    Plants create sugar in the mesophyll cells of their leaves by photosynthesis. This sugar, mostly sucrose, has to be loaded via the bundle sheath into the phloem vascular system (the sieve elements), where it is distributed to growing parts of the plant. We analyse the feasibility of a particular loading mechanism, active symplasmic loading, also called the polymer trap mechanism, where sucrose is transformed into heavier sugars, such as raffinose and stachyose, in the intermediary-type companion cells bordering the sieve elements in the minor veins of the phloem. Keeping the heavier sugars from diffusing back requires that the plasmodesmata connecting the bundle sheath with the intermediary cell act as extremely precise filters, which are able to distinguish between molecules that differ by less than 20% in size. In our modeling, we take into account the coupled water and sugar movement across the relevant interfaces, without explicitly considering the chemical reactions transforming the sucrose into the heav...

  5. Analysis of pile load-transfer under pile-side softening

    Institute of Scientific and Technical Information of China (English)

    刘杰; 张可能

    2003-01-01

    A set of analytical equations for the variation of the axial force along depth and the pile-top load-settle-ment curve were established, using tri-linear softening model to pile-side soil and bilinear hardening model to pile-end soil . Influences of the pile-side and pile-end soil behavior on the load-settlement curve were discussed, indica-ting that the lowering reason for the variation step degree of the axial force along depth is the softening of the pile-side soil to result in the side friction lowering when the pile-top load is increased. To verify the reliability of thismethod, the parameters used in calculation are obtained from the test in Zhuzhou area. The obtained results are thencompared with the tested results. Contrast shows that the calculated results and the tested values are very close,which illustrates that the proposed method is reliable.

  6. Transient Side Load Analysis of Out-of-Round Film-Cooled Nozzle Extensions

    Science.gov (United States)

    Wang, Ten-See; Lin, Jeff; Ruf, Joe; Guidos, Mike

    2012-01-01

    There was interest in understanding the impact of out-of-round nozzle extension on the nozzle side load during transient startup operations. The out-of-round nozzle extension could be the result of asymmetric internal stresses, deformation induced by previous tests, and asymmetric loads induced by hardware attached to the nozzle. The objective of this study was therefore to computationally investigate the effect of out-of-round nozzle extension on the nozzle side loads during an engine startup transient. The rocket engine studied encompasses a regeneratively cooled chamber and nozzle, along with a film cooled nozzle extension. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and transient inlet boundary flow properties derived from an engine system simulation. Six three-dimensional cases were performed with the out-of-roundness achieved by three different degrees of ovalization, elongated on lateral y and z axes: one slightly out-of-round, one more out-of-round, and one significantly out-of-round. The results show that the separation line jump was the primary source of the peak side loads. Comparing to the peak side load of the perfectly round nozzle, the peak side loads increased for the slightly and more ovalized nozzle extensions, and either increased or decreased for the two significantly ovalized nozzle extensions. A theory based on the counteraction of the flow destabilizing effect of an exacerbated asymmetrical flow caused by a lower degree of ovalization, and the flow stabilizing effect of a more symmetrical flow, created also by ovalization, is presented to explain the observations obtained in this effort.

  7. Transient Three-Dimensional Side Load Analysis of Out-of-Round Film Cooled Nozzles

    Science.gov (United States)

    Wang, Ten-See; Lin, Jeff; Ruf, Joe; Guidos, Mike

    2010-01-01

    The objective of this study is to investigate the effect of nozzle out-of-roundness on the transient startup side loads at a high altitude, with an anchored computational methodology. The out-of-roundness could be the result of asymmetric loads induced by hardware attached to the nozzle, asymmetric internal stresses induced by previous tests, and deformation, such as creep, from previous tests. The rocket engine studied encompasses a regeneratively cooled thrust chamber and a film cooled nozzle extension with film coolant distributed from a turbine exhaust manifold. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and a transient inlet history based on an engine system simulation. Transient startup computations were performed with the out-of-roundness achieved by four different degrees of ovalization: one perfectly round, one slightly out-of-round, one more out-of-round, and one significantly out-of-round. The results show that the separation-line-jump is the peak side load physics for the round, slightly our-of-round, and more out-of-round cases, and the peak side load increases as the degree of out-of-roundness increases. For the significantly out-of-round nozzle, however, the peak side load reduces to comparable to that of the round nozzle and the separation line jump is not the peak side load physics. The counter-intuitive result of the significantly out-of-round case is found to be related to a side force reduction mechanism that splits the effect of the separation-line-jump into two parts, not only in the circumferential direction and most importantly in time.

  8. Micromechanical Analysis of Interfacial Debonding in Metal Matrix Composites Subjected to off-axis Loading

    Institute of Scientific and Technical Information of China (English)

    Xiaojun Zhu; Xuefeng Chen; Zhi Zhai; Qiang Chen; Shaohua Tian; Zhengjia He

    2013-01-01

    This study aims to investigate the effects of interfacial debonding and fiber volume fraction on the stress -strain behavior of the fiber reinforced metal matrix composites subjected to off -axis loading .The generalized method of cells ( GMC) is used to analyze a representative element whose fiber shape is circular .The constant compliant interface model (CCI) is also adopted to study the response of composites with imperfect interfacial bonding .Results show that for the com-posites subjected to off-axis loading ,the mechanical behaviors are affected appreciably by the interfacial debonding and the fiber volume fraction .

  9. Variational analysis of the disc-loaded waveguide slow-wave structures

    Institute of Scientific and Technical Information of China (English)

    Li Jian-Qing; Mo Yuan-Long

    2005-01-01

    The variational method is applied to calculate the dispersion characteristics of disc-loaded waveguide slow-wave structures. The parameters describing the waveguide discontinuities in disc-loaded waveguide are calculated by the variational method. Then the dispersion characteristics of slow-wave structures are obtained using lossless microwave quadrupole theory. Good agreement was observed between results of the variational method and those of field matching method and high frequency structure simulator. In the case of broad band, results of the variational method are better than those of field matching method.

  10. Design and Analysis of Adaptive Load Balancing Approach in Cloud Infrastructure

    Directory of Open Access Journals (Sweden)

    N.R. Ram Mohan

    2014-08-01

    Full Text Available In this study an Adaptive Load Balancing (ALB approach is developed to effectively balance the load distributed across the cloud servers to minimize bandwidth and energy consumption on service provisioning. Cloud computing infrastructure has evolved as highly scalable services with massive computation power and storage capability with the resources being provided as service by the cloud environment and guarantees the Service Level Agreement (SLA. However, the needs of the subscribers have grown to an extent that there requires a big active platform for load balancing even if the resources are shared. Besides, the cloud computing paradigm also needs to optimally balance the load at the middle of the servers in order to avoid hotspot and improve resource utility. To perform energy conservation in cloud infrastructures, the use of chronological traffic data from data centers uses a service request prediction model. Collaborative provable data possession scheme adopt Homomorphic verifiable responses and hash index hierarchy but the drawback is that the match index structure are not matched properly with clustering model. Different level of power tariffs and requests made to the servers affect the decisions, where to serve the cluster needs. SLA Laws on privacy includes a factor that decides whether the loads can be moved in or out of a cluster, whereas they affect the overall energy consumption. ALB approach balances the load from every cluster group by minimizing the bandwidth and energy consumption. With repetitive query messaging, ALB collects the information about the current load of other group and then computes the average energy and bandwidth consumption of each group. The ALB Approach not only balances the energy consumption but also enhances the utilization of resources with minimal bandwidth usage. Extensive level of experimental studies is conducted to illustrate the efficiency and effectiveness of the proposed method. An experimental

  11. Exploratory Analysis of a GGSN’s PDP Context Signaling Load

    Directory of Open Access Journals (Sweden)

    Florian Metzger

    2014-01-01

    Full Text Available This paper takes an exploratory look on control plane signaling in a mobile cellular core network. In contrast to most contributions in this field, our focus does not lie on the wireless or user-oriented parts of the network, but on signaling in the core network. In an investigation of core network data we take a look at statistics related to GTP tunnels and their signaling. Based on the results thereof we propose a definition of load at the GGSN and create an initial load queuing model. We find signs of user devices putting burden on the core network through their behavior.

  12. Quantitative Analysis of Epstein-Barr Virus Load by Using a Real-Time PCR Assay

    OpenAIRE

    1999-01-01

    To measure the virus load in patients with symptomatic Epstein-Barr virus (EBV) infections, we used a real-time PCR assay to quantify the amount of EBV DNA in blood. The real-time PCR assay could detect from 2 to over 107 copies of EBV DNA with a wide linear range. We estimated the virus load in peripheral blood mononuclear cells (PBMNC) from patients with symptomatic EBV infections. The mean EBV-DNA copy number in the PBMNC was 103.7 copies/μg of DNA in patients with EBV-related lymphoprolif...

  13. Analysis of an adhesively bonded single lap joint subjected to eccentric loading

    DEFF Research Database (Denmark)

    Anyfantis, Konstantinos; Tsouvalis, N. G.

    2013-01-01

    is benchmarking of computational tools. The test is based on a Single Lap Joint subjected to Eccentric Loading (SLJ-EL). The basic concept that lies behind this configuration is that the applied in-plane tensile load leads the adhesive layer to develop normal stresses, in-plane and out-of-plane shear stresses...... space and a previously developed mixed-mode model is utilized for the adhesive layer, under the framework of Cohesive Zone Modeling (CZM) techniques. The numerical results are in very good agreement with the corresponding experimental measurements, as regards both the linear and non-linear region...

  14. Analysis of Plug Load Capacities and Power Requirements in Commercial Buildings: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sheppy, M.; Torcellini, P.; Gentile-Polese, L.

    2014-08-01

    Plug and process load power requirements are frequently overestimated because designers often use estimates based on 'nameplate' data, or design assumptions are high because information is not available. This generally results in oversized heating, ventilation, and air-conditioning systems; increased initial construction costs; and increased energy use caused by inefficiencies at low, part-load operation. Rightsizing of chillers in two buildings reduced whole-building energy use by 3%-4%. If an integrated design approach could enable 3% whole-building energy savings in all U.S. office buildings stock, it could save 34 TBtu of site energy per year.

  15. Analysis of load variations on drums with three to four rows of cutting tools

    Energy Technology Data Exchange (ETDEWEB)

    Krauze, K. (Akademia Gorniczo-Hutnicza, Cracow (Poland). Instytut Maszyn Gorniczych Przerobczych i Automatyki)

    1989-11-01

    Comparatively evaluates types of shearer loaders used for longwall mining of black coal in Poland. The following data are discussed: type, web size, rated power of motors, cutter motors, haulage speed, diameter of the cutting drums, revolution rate, cutting rate. Eleven types of shearer loaders with one or two cutting drums are reviewed. Factors that influence load variations on the cutting drums are analyzed: number and arrangement of rows of cutting tools, number of cutting tools in one row, angle of cutting tool attack, cutting tool design and geometry. Curves that describe load variations and factors that influence them are plotted. 1 ref.

  16. A recurrence network approach for the analysis of skin blood flow dynamics in response to loading pressure.

    Science.gov (United States)

    Liao, Fuyuan; Jan, Yih-Kuen

    2012-06-01

    This paper presents a recurrence network approach for the analysis of skin blood flow dynamics in response to loading pressure. Recurrence is a fundamental property of many dynamical systems, which can be explored in phase spaces constructed from observational time series. A visualization tool of recurrence analysis called recurrence plot (RP) has been proved to be highly effective to detect transitions in the dynamics of the system. However, it was found that delay embedding can produce spurious structures in RPs. Network-based concepts have been applied for the analysis of nonlinear time series recently. We demonstrate that time series with different types of dynamics exhibit distinct global clustering coefficients and distributions of local clustering coefficients and that the global clustering coefficient is robust to the embedding parameters. We applied the approach to study skin blood flow oscillations (BFO) response to loading pressure. The results showed that global clustering coefficients of BFO significantly decreased in response to loading pressure (precurrence network approach can practically quantify the nonlinear dynamics of BFO.

  17. Design Load Case Analysis tools for aeroelastic wind turbine simulations with HAWC2

    DEFF Research Database (Denmark)

    2014-01-01

    , prepost and cluster tools are created by David R.S. Verelst. This repository holds a series of scripts and small libraries that aim to help with the process of creating, managing, and post processing design load cases (DLC's) simulations. Note that the work presented here has not been streamlined...

  18. Design and Analysis of CH-47 External Cargo Handling System (Snubbed Load).

    Science.gov (United States)

    1979-10-01

    induced oscillation (potential for " vertical - bounce ") 48 QUANTITATIVE CONFIGURATION COMPARISON 7 CONFIGURATION 1 2 3 4 5 6 8 EVALUATION WT FAC CRITERIA ACFT...they were in early CH-47 aircraft because of incorporation of the ECP-41OR3 thrust control system which alleviates external load vertical bounce . The CH

  19. Analysis of thermal characteristics of electrical wiring for load groups in cattle barns.

    Science.gov (United States)

    Kim, Doo Hyun; Yoo, Sang-Ok; Kim, Sung Chul; Hwang, Dong Kyu

    2015-01-01

    The purpose of the current study is to analyze the thermal characteristics of electrical wirings depending on the number of operating load by connecting four types of electrical wirings that are selected by surveying the conditions for the electric fans, automatic waterers and halogen warm lamps that were installed in cattle barns in different years. The conditions of 64 cattle barns were surveyed and an experimental test was conducted at a cattle barn. The condition-survey covered inappropriate design, construction and misuse of electrical facility, including electrical wiring mostly used, and the mode of load current was evaluated. The survey showed that the mode of load current increased as the installation year of the fans, waterers and halogen lamps became older. Accordingly, the cattle barn manager needed to increase the capacity of the circuit breaker, which promoted the degradation of insulation of the electrical wires' sheath and increased possibility for electrical fires in the long-run. The test showed that the saturation temperature of the wire insulated sheath increased depending on the installation year of the load groups, in case of VCTFK and VFF electric wires, therefore, requiring their careful usage in the cattle barns.

  20. [Analysis of the causes of loss of tolerance to standard G-loads by fighter pilots].

    Science.gov (United States)

    Sinopal'nikov, V I; Donin, K M; Boltikov, A N; Pugachev, I V; Migachev, S D

    2003-01-01

    Analytical treatment has been given to causes for the loss of tolerance to radial accelerations by fighter pilots subjected to clinical tests during flight medical certification in recent years. The diagnostic necessity of implementation of additional tests by this cohort of pilots has been demonstrated and methods to improve pilots' cardiovascular adaptability to g-loads during the inpatient medical examination have been proposed.

  1. Analysis of permanent deformations of railway embankments under repeated vehicle loadings in permafrost regions

    Institute of Scientific and Technical Information of China (English)

    Wei Ma; Tuo Chen

    2015-01-01

    By large-scale dynamic tests carried out on a traditional sand-gravel embankment at the Beilu River section along the Qinghai-Tibet Railroad, we collected the acceleration waveforms close to the railway tracks when trains passed. The dynamic train loading was converted into an equivalent creep stress, using an equivalent static force method. Also, the creep equation of frozen soil was introduced according to the results of frozen soil rheological triaxial tests. A coupled creep model based on a time-hardening power function rule and the Druker-Prager yield and failure criterion was estab-lished to analyze the creep effects of a plain fill embankment under repeated train loads. The temperature field of the embankment in the permafrost area was set at the current geothermal conditions. As a result, the permanent deformation of the embankment under train loading was obtained, and the permanent deformation under the train loads to the total em-bankment deformation was also analyzed.

  2. Bi-orthogonality conditions for power flow analysis in fluid-loaded elastic cylindrical shells

    DEFF Research Database (Denmark)

    Ledet, Lasse; Sorokin, Sergey V.; Larsen, Jan Balle

    2015-01-01

    The paper addresses the classical problem of time-harmonic forced vibrations of a fluid-loaded cylindrical shell considered as a multi-modal waveguide carrying infinitely many waves. Firstly, a modal method for formulation of Green’s matrix is derived by means of modal decomposition. The method b...

  3. Nonlocal continuum analysis of a nonlinear uniaxial elastic lattice system under non-uniform axial load

    Science.gov (United States)

    Hérisson, Benjamin; Challamel, Noël; Picandet, Vincent; Perrot, Arnaud

    2016-09-01

    The static behavior of the Fermi-Pasta-Ulam (FPU) axial chain under distributed loading is examined. The FPU system examined in the paper is a nonlinear elastic lattice with linear and quadratic spring interaction. A dimensionless parameter controls the possible loss of convexity of the associated quadratic and cubic energy. Exact analytical solutions based on Hurwitz zeta functions are developed in presence of linear static loading. It is shown that this nonlinear lattice possesses scale effects and possible localization properties in the absence of energy convexity. A continuous approach is then developed to capture the main phenomena observed regarding the discrete axial problem. The associated continuum is built from a continualization procedure that is mainly based on the asymptotic expansion of the difference operators involved in the lattice problem. This associated continuum is an enriched gradient-based or nonlocal axial medium. A Taylor-based and a rational differential method are both considered in the continualization procedures to approximate the FPU lattice response. The Padé approximant used in the continualization procedure fits the response of the discrete system efficiently, even in the vicinity of the limit load when the non-convex FPU energy is examined. It is concluded that the FPU lattice system behaves as a nonlocal axial system in dynamic but also static loading.

  4. Bearing Capacity Factors for Eccentrically Loaded Strip Footings Using Variational Analysis

    Directory of Open Access Journals (Sweden)

    Xinggao Li

    2013-01-01

    Full Text Available Bearing capacity factors for eccentrically loaded strip smooth footings on homogenous cohesive frictional material are deduced by the variational limit equilibrium method and by assuming general shear failure along continuous curved slip surface. From the calculated results, the effective width rule suggested by Meyerhof for bearing capacity factors due to cohesion of soil is justified, and the superposition principle of bearing capacity for eccentrically loaded strip smooth footings is derived together with the bearing capacity factors for cohesion and unit weight of soil. The two factors are represented by soil strength parameters and eccentricity of load. The bearing capacity factor related to unit weight for cohesionless soil is less than that for cohesive frictional soil. The reason for this discrepancy lies in the existence of the soil cohesion, for the shape of the critical rupture surface of footing soil depends on both soil strength parameters rather than on friction angle alone in the previous limit equilibrium solutions. The contact between footing and soil is decided by both the load and the mechanical properties of soil. Under conditions of higher eccentricity and less strength properties of soil, part of the footing will separate from the underlying soil.

  5. Gas-well liquid-loading-field-data analysis and multiphase-flow modeling

    NARCIS (Netherlands)

    Veeken, C.A.M.; Hu, B.; Schiferli, W.

    2010-01-01

    Gas-well liquid loading occurs when gas production becomes insufficient to lift the associated liquids to surface. When that happens, gas production becomes intermittent and eventually stops. In depleting gas reservoirs, the technical abandonment pressure and ultimate recovery are typically governed

  6. Rocket Engine Nozzle Side Load Transient Analysis Methodology: A Practical Approach

    Science.gov (United States)

    Shi, John J.

    2005-01-01

    At the sea level, a phenomenon common with all rocket engines, especially for a highly over-expanded nozzle, during ignition and shutdown is that of flow separation as the plume fills and empties the nozzle, Since the flow will be separated randomly. it will generate side loads, i.e. non-axial forces. Since rocket engines are designed to produce axial thrust to power the vehicles, it is not desirable to be excited by non-axial input forcing functions, In the past, several engine failures were attributed to side loads. During the development stage, in order to design/size the rocket engine components and to reduce the risks, the local dynamic environments as well as dynamic interface loads have to be defined. The methodology developed here is the way to determine the peak loads and shock environments for new engine components. In the past it is not feasible to predict the shock environments, e.g. shock response spectra, from one engine to the other, because it is not scaleable. Therefore, the problem has been resolved and the shock environments can be defined in the early stage of new engine development. Additional information is included in the original extended abstract.

  7. Perceived Discrimination among African American Adolescents and Allostatic Load: A Longitudinal Analysis with Buffering Effects

    Science.gov (United States)

    Brody, Gene H.; Lei, Man-Kit; Chae, David H.; Yu, Tianyi; Kogan, Steven M.; Beach, Steven R. H.

    2014-01-01

    This study was designed to examine the prospective relations of perceived racial discrimination with allostatic load (AL), along with a possible buffer of the association. A sample of 331 African Americans in the rural South provided assessments of perceived discrimination from ages 16 to 18 years. When youth were 18 years, caregivers reported…

  8. Cluster analysis of residential heat load profiles and the role of technical and household characteristics

    DEFF Research Database (Denmark)

    Carmo, Carolina; Christensen, Toke Haunstrup

    2016-01-01

    segments; a main cluster with a relatively constant load profile and a minor cluster with a more distinct variation during the day. The difference between the clusters is primarily correlated with building characteristics like floor area, building year and type of space heating distribution system, while...

  9. Monitoring organic loading to swimming pools by fluorescence excitation–emission matrix with parallel factor analysis (PARAFAC)

    DEFF Research Database (Denmark)

    Seredynska-Sobecka, Bozena; Stedmon, Colin; Boe-Hansen, Rasmus

    2011-01-01

    Fluorescence Excitation–Emission Matrix spectroscopy combined with parallel factor analysis was employed to monitor water quality and organic contamination in swimming pools. The fluorescence signal of the swimming pool organic matter was low but increased slightly through the day. The analysis...... revealed that the organic matter fluorescence was characterised by five different components, one of which was unique to swimming pool organic matter and one which was specific to organic contamination. The latter component had emission peaks at 420nm and was found to be a sensitive indicator of organic...... loading in swimming pool water. The fluorescence at 420nm gradually increased during opening hours and represented material accumulating through the day....

  10. Strength and stability analysis of load-bearing structures of a high-rise building with account for actual positions of reinforced concrete structural members

    Directory of Open Access Journals (Sweden)

    Belostotskiy Aleksandr Mikhaylovich

    2015-04-01

    Full Text Available The given paper is devoted to strength and stability analysis of load-bearing structures of a high-rise (54-storey building with allowance for actual positions of reinforced concrete structural members (columns and walls. Finite element method (FEM is used for structural analysis. The authors present formulations of problems, governing equations, information about basic three-dimensional finite element models (so-called “design” (ideal model, the first “actual” model (taking into account the deviations of positions of columns from the project and the second “actual” model (taking into account the deviations of positions of walls from the project of the coupled system “high-rise building - foundation” within ANSYS Mechanical software and their verification, numerical approach to structural analysis and corresponding solvers. Finite element models include mainly 4-node structural shell elements (suitable for analyzing foundation slabs, floor slabs and load-bearing walls and three-dimensional 2-node beam elements (suitable for analyzing beams and columns, special spring-damper elements and multipoint constraint elements. Detailed finite element mesh on the bottom foundation slab is agreed with the location of piles. The advanced model of Prof. Yu.K. Zaretsky is used for approximation of soil behavior. Construction sequence and various types of nonlinearities are taken into account. The results of modal analysis, static and dynamic analysis with various load combinations (gravity load, facade load, dead (constant loads, temporary loads, wind load, snow load, crown load etc. are considered, the results of the regulatory assessment of the strength of structures (obtained with the use of corresponding software in accordance with design codes of the Russian Federation are under consideration as well. The corresponding displacements, stresses, natural vibration frequencies can be used for research and development of the correct monitoring

  11. Modeling and Finite Element Analysis of Load-Carrying Performance of a Wind Turbine Considering the Influence of Assembly Factors

    Directory of Open Access Journals (Sweden)

    Jianmei Wang

    2017-03-01

    Full Text Available In this work, a wind turbine shrink disk is used as the research object to investigate load-carrying performance of a multi-layer interference fit, and the theoretical model and finite element model are constructed. According to those models, a MW-level turbine shrink disk is designed, and a test device is developed to apply torque to this turbine shrink disk by hydraulic jack. Then, the circumferential slip between the contact surfaces is monitored and the slip of all contact surfaces is zero. This conclusion verifies the reasonability of the proposed models. The effect of the key influencing factors, such as machining deviation, assembly clearance and propel stroke, were analyzed. The contact pressure and load torque of the mating surfaces were obtained by building typical models with different parameters using finite element analysis (FEA. The results show that the minimum assembly clearance and the machining deviation within the machining range have little influence on load-carrying performance of multi-layer interference fit, while having a greater influence on the maximum assembly clearance and the propel stroke. The results also show that the load-carrying performance of a multiple-layer interference fit can be ensured only if the key factors are set within a reasonable design range. To avoid the abnormal operation of equipment caused by insufficient load torque, the propel stroke during practical assembly should be at least 0.95 times the designed propel stroke, which is significant in guiding the design and assembly of the multi-layer interference fit.

  12. Containment loads due to direct containment heating and associated hydrogen behavior: Analysis and calculations with the CONTAIN code

    Energy Technology Data Exchange (ETDEWEB)

    Williams, D C; Bergeron, K D; Carroll, D E; Gasser, R D; Tills, J L; Washington, K E

    1987-05-01

    One of the most important unresolved issues governing risk in many nuclear power plants involves the phenomenon called direct containment heating (DCH), in which it is postulated that molten corium ejected under high pressure from the reactor vessel is dispersed into the containment atmosphere, thereby causing sufficient heating and pressurization to threaten containment integrity. Models for the calculation of potential DCH loads have been developed and incorporated into the CONTAIN code for severe accident analysis. Using CONTAIN, DCH scenarios in PWR plants having three different representative containment types have been analyzed: Surry (subatmospheric large dry containment), Sequoyah (ice condenser containment), and Bellefonte (atmospheric large dry containment). A large number of parameter variation and phenomenological uncertainty studies were performed. Response of DCH loads to these variations was found to be quite complex; often the results differ substantially from what has been previously assumed concerning DCH. Containment compartmentalization offers the potential of greatly mitigating DCH loads relative to what might be calculated using single-cell representations of containments, but the actual degree of mitigation to be expected is sensitive to many uncertainties. Dominant uncertainties include hydrogen combustion phenomena in the extreme environments produced by DCH scenarios, and factors which affect the rate of transport of DCH energy to the upper containment. In addition, DCH loads can be aggravated by rapid blowdown of the primary system, co-dispersal of moderate quantities of water with the debris, and quenching of de-entrained debris in water; these factors act by increasing steam flows which, in turn, accelerates energy transport. It may be noted that containment-threatening loads were calculated for a substantial portion of the scenarios treated for some of the plants considered.

  13. Analysis of osteon morphotype scoring schemes for interpreting load history: evaluation in the chimpanzee femur.

    Science.gov (United States)

    Skedros, John G; Kiser, Casey J; Keenan, Kendra E; Thomas, Samuel C

    2011-05-01

    Osteon morphotype scores (MTSs) allow for quantification of mechanically important collagen/lamellar variations between secondary osteons when viewed in circularly polarized ight (CPL). We recently modified the 6-point MTS method of Martin et al. (Martin RB, Gibson VA, Stover SM, Gibeling JC, Griffin LV (1996a) Osteonal structure in the equine third metacarpus. Bone 19, 165-71) and reported superiority of this modified method in correlating with 'tension' and 'compression' cortices of both chimpanzee proximal femoral diaphyses and diaphyses of other non-anthropoid bones that are loaded in habitual bending (Skedros et al. 2009, 2011). In these studies, the 'tension' and 'compression' cortices differed significantly in predominant collagen fiber orientation (CFO) based on weighted-mean gray levels (CFO/WMGLs) in CPL images. In chimpanzee femora, however, some osteons were difficult to score with the 6-point method; namely, 'hybrids' with peripherally bright 'hoops' and variability in alternating rings within the osteon wall. We hypothesized that some of these hybrids would be more prevalent in regions subject to torsion than bending. In this perspective the present study was aimed at expanding our 6-point scoring method (S-6-MTS) into two 12-point methods with six additional morphotypes that considered these hybrids. Three- and 4-point methods were also evaluated. We hypothesized that at least one of these other methods would out-perform the S-6-MTS in terms of accuracy, reliability, and interpreting torsion vs. bending load histories. Osteon morphotypes were quantified in CPL images from transverse sections of eight adult chimpanzee femora (neck, proximal diaphysis, mid-diaphysis), where the mid-diaphysis and base- and mid-neck locations have relatively more complex loading (e.g. torsion + bending) than the proximal diaphysis, where bending predominates. Correlation coefficients between CFO/WMGL and MTSs showed that the S-6-MTS method was either stronger or

  14. The Small Signal Analysis of a Centered Dielectric-Rod Loaded, Arbitrarily-Shaped Helical Groove Traveling-Wave-Tube

    Science.gov (United States)

    Wei, Yanyu; Liu, Hongtao; He, Jun; Gong, Yubin; Yue, Lingna; Wang, Wenxiang; Park, Gun-Sik

    2007-12-01

    Properties of traveling wave-beam interaction in a centered dielectric-rod loaded, arbitrarily-shaped helical groove slow-wave structure (SWS) are investigated for a thin annular electron beam. The “hot” dispersion equation is obtained by means of the self-consistent field theory, and the small signal analysis is carried out including the effects of the dielectric-rod parameters and the groove shapes. The numerical results show that the bandwidth of the helical groove TWT is expanded by loading dielectric-rod, however, the small-signal gain is reduced; and when the groove shape changes from the swallow-tail shape to the triangle shape, the working frequency increases , while the peak gain decreases.

  15. Stability analysis of the governor-turbine-hydraulic system of pumped storage plant during small load variation

    Science.gov (United States)

    Yu, X. D.; Zhang, J.; Chen, S.; Liu, J. C.

    2016-11-01

    Governor-turbine-hydraulic (GTH) system is complex because of strong couplings of hydraulic, mechanical and electrical system. This paper presents a convenient mathematical model of the GTH system of a pumped storage plant (PSP) during small load variation. By using state space method and eigenvalue method, the stability of the GTH system is analyzed and the stable regions of the system can be given as well, which would help to optimize system design or the turning of governors. The proposed method is used to analyze the stability of a practical pumped storage plant during small load variation, which is also simulated in time domain on the basis of characteristics method. The theoretical analysis is in good agreement with numerical simulations. Based on the proposed method, the effect of the system parameters and operating conditions on the stable regions is investigated. These results are useful for the design of the GTH system of pumped storage plants.

  16. Development of Graphical User Interface for Finite Element Analysis of Static Loading of a Column using MATLAB

    Directory of Open Access Journals (Sweden)

    Moses Omolayo PETINRIN

    2010-12-01

    Full Text Available In this work, the capability of MATLAB software package to develop graphical user interface (GUI package was demonstrated. A GUI was successfully developed using MATLAB programming language to study the behaviour of a suspended column under uniaxial static loading by solving the numerical model created based on the finite element method (FEM. The comparison between the exact solution from previous researches and the numerical analysis showed good agreement. The column average strain, average stress and average load are equivalent but more accurate to the ones obtained when the whole column is taken as one element (two nodes for one dimensional linear finite element problem. It was established in this work that MATLAB is not only a software package for numerical computation but also for application development.

  17. Nonlinear Dynamic Analysis of Deepwater Drilling Risers Subjected to Random Loads

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Excited by ocean currents, random wave and vessel motion, deepwater drilling risers exhibit significant dynamic response. In time domain, a method is proposed to calculate the nonlinear dynamic response of deepwater drilling risers subjected to random wave and dynamic large displacement vessel motion boundary condition. Structural and functional loads, external and internal pressure, free surface effect of irregular wave, hydrodynamic forces induced by current and wave, as well as wave and low frequency (drift) motion of the drilling vessel are all accounted for. An example is presented which illustrates the application of the proposed method. The study shows that long term drift motion of the vessel has profound effect on the envelopes of bending stress and lateral displacement, as well as the range of lower flex joint angle of the deepwater riser. It can also be concluded that vessel motion is the principal dynamic loading of nonlinear dynamic response for the deepwater risers rather than wave force.

  18. Development of educational software for beam loading analysis using pen-based user interfaces

    Directory of Open Access Journals (Sweden)

    Yong S. Suh

    2014-01-01

    Full Text Available Most engineering software tools use typical menu-based user interfaces, and they may not be suitable for learning tools because the solution processes are hidden and students can only see the results. An educational tool for simple beam analyses is developed using a pen-based user interface with a computer so students can write and sketch by hand. The geometry of beam sections is sketched, and a shape matching technique is used to recognize the sketch. Various beam loads are added by sketching gestures or writing singularity functions. Students sketch the distributions of the loadings by sketching the graphs, and they are automatically checked and the system provides aids in grading the graphs. Students receive interactive graphical feedback for better learning experiences while they are working on solving the problems.

  19. [Analysis on preparation and characterization of asiaticoside-loaded flexible nanoliposomes].

    Science.gov (United States)

    Ren, Yan; He, Xing-Dong; Shang, Bei-Cheng; Bao, Xiu-Kun; Wang, Yan-Fang; Ma, Ji-Sheng

    2013-10-01

    Asiaticoside is a compound extracted from traditional Chinese medicine Centella asiatica, and mainly used in wound healing and scar repair in clinical, with notable efficacy. However, its poor transdermal absorption and short action time restrict its wide application. In this experiment, the reserve-phase-extrusion-lyophilization method was conducted to prepare the lyophilized asiaticoside-loaded flexible nanoliposomes (LAFL). Its characteristics including electron microscope structure, particle size, Zeta potential, entrapment rate, drug-loading rate, stability and drug release were determined with the intelligent transdermal absorption instrument. LAFL were white spheroids, with pH, particle size and zeta potential of 7. 03, 70. 14 nm and - 36. 5 mV, respectively. The average entrapment rate of the 3 batch samples were 31. 43% , and the average asiaticoside content in 1 mg lyophilized simple was 0. 134 mg. The results indicated that LAFL have good physicochemical properties and pharmaceutical characteristics, with an improved transdermal performance.

  20. Non-stationary Buffeting Response Analysis of Long Span Suspension Bridge Under Strong Wind Loading

    Institute of Scientific and Technical Information of China (English)

    Wenfeng Huang; Kongqing Zou

    2016-01-01

    The non⁃stationary buffeting response of long span suspension bridge in time domain under strong wind loading is computed. Modeling method for generating non⁃stationary fluctuating winds with probabilistic model for non⁃stationary strong wind fields is first presented. Non⁃stationary wind forces induced by strong winds on bridge deck and tower are then given a brief introduction. Finally, Non⁃stationary buffeting response of Pulite Bridge in China, a long span suspension bridge, is computed by using ANSYS software under four working conditions with different combination of time⁃varying mean wind and time⁃varying variance. The case study further confirms that it is necessity of considering non⁃stationary buffeting response for long span suspension bridge under strong wind loading, rather than only stationary buffeting response.

  1. Vibration analysis of nanomechanical mass sensor using carbon nanotubes under axial tensile loads

    Science.gov (United States)

    Natsuki, Toshiaki; Matsuyama, Nobuhiro; Shi, Jin-Xing; Ni, Qing-Qing

    2014-09-01

    Carbon nanotubes (CNTs) are nanomaterials with many potential applications due to their excellent mechanical and physical properties. In this paper, we proposed that CNTs with clamped boundary condition under axial tensile loads were considered as CNT-based resonators. Moreover, the resonant frequencies and frequency shifts of the CNTs with attached mass were investigated based on two theoretical methods, which are Euler-Bernoulli beam theory and Rayleigh's energy method. Using the present methods, we analyzed and discussed the effects of the aspect ratio, the concentrated mass and the axial force on the resonant frequency of the CNTs. The results indicate that the length of CNTs could be easily changed and could provide higher sensitivity as nanomechanical mass sensor. Moreover, the resonant frequency shifts of the CNT resonator increase significantly with increasing tensile load acting on the CNTs.

  2. Design and Analysis of the Distributed Resistor-loading GPR Antenna with Reflected Cavity

    Directory of Open Access Journals (Sweden)

    Wu Bing-heng

    2015-10-01

    Full Text Available In this study, we investigated the use of a half-ellipse dipole with distributed resistor-loading. By improving the structure of the antenna arms and using distributed resistor-loading technology, the current reflection at the end of dipole is significantly reduced, the input impedance is improved, and the operation bandwidth is widened. We decreased the backward radiation of the antenna with a cubic metal-reflective cavity and also improved the ground penetration ability. The proposed antenna was simulated and designed with electromagnetic computing software; on the basis of the design results, we fabricated the antenna sample. Measurement results of the return loss and radiation characteristics of the proposed antenna confirm the validity of the simulation. We applied the proposed antenna in a GPR system as an underground target detection experiment; on the basis of the experimental results, we conclude that the antenna is able to meet the needs of GPR systems.

  3. Numerical analysis of energy piles under different boundary conditions and thermal loading cycles

    Directory of Open Access Journals (Sweden)

    Khosravi Ali

    2016-01-01

    Full Text Available The thermo- mechanical behavior of energy piles has been studied extensively in recent years. In the present study, a numerical model was adapted to study the effect of various parameters (e.g. heating/cooling temperature, head loading condition and soil stiffness on the thermo-mechanical behavior of an energy pile installed in unsaturated sandstone. The results from the simulations were compared with measurements from a thermal response test on a prototype energy pile installed beneath a 1-story building at the US Air Force Academy (USAFA in Colorado Springs, CO. A good agreement was achieved between the results obtained from the prototype and the numerical models. A parametric evaluation were also carried out which indicated the significance of the stiffness of the unsaturated sandstone and pile’s head loading condition on stress-strain response of the energy pile during heating/cooling cycles.

  4. Nonlinear analysis of pile load-settlement behavior in layered soil

    Institute of Scientific and Technical Information of China (English)

    吕述晖; 王奎华; 张鹏; C. J. LEO3

    2015-01-01

    A simplified approach is presented to analyze the single pile settlement in multilayered soil. First, a fictitious soil−pile model is employed to consider the effect of layered soil beneath pile toe on pile settlement behavior. Two approximation methods are proposed to simplify the nonlinear load transfer function and simulate the nonlinear compression of fictitious soil−pile, respectively. On this basis, an efficient program is developed. The procedures for determining the main parameters of mathematical model are discussed. Comparisons with two well-documented field experimental pile loading tests are conducted to verify the rationality of the present method. Further studies are also made to evaluate the practicability of the proposed approach when a soft substratum exists, and the results suggest that the proposed method can provide a constructive means for assessing the settlement of a single pile for use in engineering design.

  5. Quantitative Analysis of the Loads Acting on the Abrasive Grits in the Diamond Sawing of Granites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An experimental study was carried out to quantitati ve ly evaluate the loads acting on the diamond grits during circular sawing of two kinds of typical granite with diamond segmented saw blade. Measurements were mad e of the horizontal and vertical force components and the consumed power in order to obtain the tangential and the normal force components. The temperatures at the diamond-granite contact zone were measured using a foil thermocouple. T he measurement, together with the net sawing power, was...

  6. Analysis of the blasting effect on the electric shove loading efficiency of the open pit

    Institute of Scientific and Technical Information of China (English)

    FU Tian-guang; SUN Ying

    2008-01-01

    The connection between blasting cost and comprehensive cost is the main concern. Some blasting effect factors (such as unit explosive consumption, uniformity of blockness, shape and porosity of blasting heap), which had an influence on electric shove loading efficiency, were analyzed. In the end a project to properly increase in blasting cost to decrease the comprehensive cost was put forward. At the same time, the hole-by-hole blasting is effective technology to improve blasting effect.

  7. The effect of load imbalances on the performance of Monte Carlo algorithms in LWR analysis

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, A.R., E-mail: siegela@mcs.anl.gov [Argonne National Laboratory, Nuclear Engineering Division (United States); Argonne National Laboratory, Mathematics and Computer Science Division (United States); Smith, K., E-mail: kord@mit.edu [Massachusetts Institute of Technology, Department of Nuclear Science and Engineering (United States); Romano, P.K., E-mail: romano7@mit.edu [Massachusetts Institute of Technology, Department of Nuclear Science and Engineering (United States); Forget, B., E-mail: bforget@mit.edu [Massachusetts Institute of Technology, Department of Nuclear Science and Engineering (United States); Felker, K., E-mail: felker@mcs.anl.gov [Argonne National Laboratory, Mathematics and Computer Science Division (United States)

    2013-02-15

    A model is developed to predict the impact of particle load imbalances on the performance of domain-decomposed Monte Carlo neutron transport algorithms. Expressions for upper bound performance “penalties” are derived in terms of simple machine characteristics, material characterizations and initial particle distributions. The hope is that these relations can be used to evaluate tradeoffs among different memory decomposition strategies in next generation Monte Carlo codes, and perhaps as a metric for triggering particle redistribution in production codes.

  8. Fatigue Strain and Damage Analysis of Concrete in Reinforced Concrete Beams under Constant Amplitude Fatigue Loading

    Directory of Open Access Journals (Sweden)

    Fangping Liu

    2016-01-01

    Full Text Available Concrete fatigue strain evolution plays a very important role in the evaluation of the material properties of concrete. To study fatigue strain and fatigue damage of concrete in reinforced concrete beams under constant amplitude bending fatigue loading, constant amplitude bending fatigue experiments with reinforced concrete beams with rectangular sections were first carried out in the laboratory. Then, by analyzing the shortcomings and limitations of existing fatigue strain evolution equations, the level-S nonlinear evolution model of fatigue strain was constructed, and the physical meaning of the parameters was discussed. Finally, the evolution of fatigue strain and fatigue damage of concrete in the compression zone of the experimental beam was analyzed based on the level-S nonlinear evolution model. The results show that, initially, fatigue strain grows rapidly. In the middle stages, fatigue strain is nearly a linear change. Because the experimental data for the third stage are relatively scarce, the evolution of the strain therefore degenerated into two phases. The model has strong adaptability and high accuracy and can reflect the evolution of fatigue strain. The fatigue damage evolution expression based on fatigue strain shows that fatigue strain and fatigue damage have similar variations, and, with the same load cycles, the greater the load level, the larger the damage, in line with the general rules of damage.

  9. Stress State Analysis and Failure Mechanisms of Masonry Columns Reinforced with FRP under Concentric Compressive Load

    Directory of Open Access Journals (Sweden)

    Jiří Witzany

    2016-04-01

    Full Text Available The strengthening and stabilization of damaged compressed masonry columns with composites based on fabrics of high-strength fibers and epoxy resin, or polymer-modified cement mixtures, belongs to novel, partially non-invasive and reversible progressive methods. The stabilizing and reinforcing effect of these fabrics significantly applies to masonry structures under concentric compressive loading whose failure mechanism is characterized by the appearance and development of vertical tensile cracks accompanied by an increase in horizontal masonry strain. During the appearance of micro and hairline cracks (10−3 to 10−1 mm, the effect of non-pre-stressed wrapping composite is very small. The favorable effect of passive wrapping is only intensively manifested after the appearance of cracks (10−1 mm and bigger at higher loading levels. In the case of “optimum” reinforcement of a masonry column, the experimental research showed an increase in vertical displacements δy (up to 247%, horizontal displacements δx (up to 742% and ultimate load-bearing capacity (up to 136% compared to the values reached in unreinforced masonry columns. In the case of masonry structures in which no intensive “bed joint filler–masonry unit” interaction occurs, e.g., in regular coursed masonry with little differences in the mechanical characteristics of masonry units and the binder, the reinforcing effect of the fabric applies only partially.

  10. Blasting Vibration Safety Criterion Analysis with Equivalent Elastic Boundary: Based on Accurate Loading Model

    Directory of Open Access Journals (Sweden)

    Qingwen Li

    2015-01-01

    Full Text Available In the tunnel and underground space engineering, the blasting wave will attenuate from shock wave to stress wave to elastic seismic wave in the host rock. Also, the host rock will form crushed zone, fractured zone, and elastic seismic zone under the blasting loading and waves. In this paper, an accurate mathematical dynamic loading model was built. And the crushed zone as well as fractured zone was considered as the blasting vibration source thus deducting the partial energy for cutting host rock. So this complicated dynamic problem of segmented differential blasting was regarded as an equivalent elastic boundary problem by taking advantage of Saint-Venant’s Theorem. At last, a 3D model in finite element software FLAC3D accepted the constitutive parameters, uniformly distributed mutative loading, and the cylindrical attenuation law to predict the velocity curves and effective tensile curves for calculating safety criterion formulas of surrounding rock and tunnel liner after verifying well with the in situ monitoring data.

  11. A new meshless approach to map electromagnetic loads for FEM analysis on DEMO TF coil system

    Energy Technology Data Exchange (ETDEWEB)

    Biancolini, Marco Evangelos, E-mail: biancolini@ing.uniroma2.it [Università di Roma Tor Vergata, Dip. Ingegneria dell’Impresa “Mario Lucertini”, Via del Politecnico 1, 00133 Roma (Italy); Brutti, Carlo, E-mail: brutti@uniroma2.it [Università di Roma Tor Vergata, Dip. Ingegneria dell’Impresa “Mario Lucertini”, Via del Politecnico 1, 00133 Roma (Italy); Giorgetti, Francesco, E-mail: francesco.giorgetti@uniroma2.it [Università di Roma Tor Vergata, Dip. Ingegneria dell’Impresa “Mario Lucertini”, Via del Politecnico 1, 00133 Roma (Italy); Muzzi, Luigi, E-mail: luigi.muzzi@enea.it [ENEA, Laboratorio Superconduttività, Unità Tecnica Fusione, Via E. Fermi 45, 00044 Frascati (RM) (Italy); Turtù, Simonetta, E-mail: simonetta.turtu@enea.it [ENEA, Laboratorio Superconduttività, Unità Tecnica Fusione, Via E. Fermi 45, 00044 Frascati (RM) (Italy); Anemona, Alessandro, E-mail: alessandro.anemona@enea.it [ENEA, Laboratorio Superconduttività, Unità Tecnica Fusione, Via E. Fermi 45, 00044 Frascati (RM) (Italy)

    2015-11-15

    Graphical abstract: - Highlights: • Generation and mapping of magnetic load on DEMO using radial basis function. • Good agreement between RBF interpolation and EM TOSCA computations. • Resultant forces are stable with respect to the target mesh used. • Stress results are robust and accurate even if a coarse cloud is used for RBF interpolation. - Abstract: Demonstration fusion reactors (DEMO) are being envisaged to be able to produce commercial electrical power. The design of the DEMO magnets and of the constituting conductors is a crucial issue in the overall engineering design of such a large fusion machine. In the frame of the EU roadmap of the so-called fast track approach, mechanical studies of preliminary DEMO toroidal field (TF) coil system conceptual designs are being enforced. The magnetic field load acting on the DEMO TF coil conductor has to be evaluated as input in the FEM model mesh, in order to evaluate the stresses on the mechanical structure. To gain flexibility, a novel approach based on the meshless method of radial basis functions (RBF) has been implemented. The present paper describes this original and flexible approach for the generation and mapping of magnetic load on DEMO TF coil system.

  12. Harmonic Differential Quadrature Analysis of Soft-Core Sandwich Panels under Locally Distributed Loads

    Directory of Open Access Journals (Sweden)

    Xinwei Wang

    2016-11-01

    Full Text Available Sandwich structures are widely used in practice and thus various engineering theories adopting simplifying assumptions are available. However, most engineering theories of beams, plates and shells cannot recover all stresses accurately through their constitutive equations. Therefore, the soft-core is directly modeled by two-dimensional (2D elasticity theory without any pre-assumption on the displacement field. The top and bottom faces act like the elastic supports on the top and bottom edges of the core. The differential equations of the 2D core are then solved by the harmonic differential quadrature method (HDQM. To circumvent the difficulties in dealing with the locally distributed load by point discrete methods such as the HDQM, a general and rigorous way is proposed to treat the locally distributed load. Detailed formulations are provided. The static behavior of sandwich panels under different locally distributed loads is investigated. For verification, results are compared with data obtained by ABAQUS with very fine meshes. A high degree of accuracy on both displacement and stress has been observed.

  13. Analysis of the Impact of Urban Microclimate on Air Conditioning Load Control

    Directory of Open Access Journals (Sweden)

    Hu Xiaoqing

    2016-01-01

    Full Text Available Due to the presence of urban heat island effect (UHIE, high humidity and other urban microclimate, temperature of city central area rises. This causes that the actual air-conditioning energy consumption (ACEC in the urban central area is much higher than that in the suburbs. Load control of air-conditioners (ACs is considered to be equivalent to a power plant of the same capacity, and it can greatly reduce the system pressure to peak load shift. In this paper, a simplified second order transfer function control model of ACs is presented, and its parameters will be influenced by the ambient temperature and urban microclimate. The temperature is obtained by using the temperature inversion algorithm of the heat island effect. Then, the heat index is calculated by combining temperature and humidity. The ambient temperature index of urban central area is modified based on the above microclimate, and the second order linear time invariant model of aggregated ACs is upgraded to the linear time varying model. Furthermore, the consequent parameter changes of the second order transfer function model are studied and the influence of urban microclimate on AC load control is analyzed. The proposed method is verified on numerical examples

  14. Theoretical Analysis on Mechanical Behavior of Axially Loaded Recycled Aggregate Concrete Filled Steel Tubes

    Directory of Open Access Journals (Sweden)

    Yijie Huang

    2015-01-01

    Full Text Available A new mechanical model for analysing the behaviour of axially loaded recycled aggregate concrete filled steel tubes (RACFSTs stub columns is presented in this study. The model is derived from the typical elastoplasticity, the nonlinear elastic mechanics, and the properties of materials. Based on the mechanical model, a novel numerical program is developed. The mechanical model and the numerical program are adopted to study the effect of recycled coarse aggregate (RCA replacement percentage on RACFST mechanical behaviour. The complete load-deformation relationship of specimens, the steel tube axial and circumferential stresses, and the performance of the confined core concrete and the variation of interaction are also investigated. The analytical results indicate that this model is able to capture the mechanical behaviour of RACFST. It is also found that the axial and circumferential stresses of steel tube change nonlinearly during the loading stages. It is concluded that the behaviour of the confined core concrete is significantly influenced by the confining pressure. The steel tube confinement could improve the mechanical behaviour of RAC effectively and the RCA replacement percentage slightly changes the response of core concrete. Finally, the relations between confined core concrete and confining pressure are analysed.

  15. Analysis of soft and hard strip-loaded horns using a circular cylindrical model

    Science.gov (United States)

    Lier, Erik

    1990-06-01

    Strip-loaded horns with transverse (soft) and longitudinal (hard) strips are analyzed theoretically. The method is based on a circular cylindrical and uniform waveguide model with a periodic strip structure. The field is represented by an infinite series of space harmonics (Floquet modes) in the air-filled central region and in the dielectrically filled wall region. The tangential field is forced to be continuous across the air-dielectric boundary. The propagation constant and the total field (including the hybrid factor) can be determined by solving the resulting matrix equations. The convergence of the solution has been accelerated by calculating the higher-order terms analytically. It is shown that the soft-strip-loaded horn in principle exhibits the same electrical behavior as a corrugated horn. The horn represents an interesting alternative to the corrugated horn in wide-band or dual-band applications, in particular for millimeter waves and for lightweight applications onboard satellites. The hard-strip-loaded horn has potentially high gain and low cross polarization over a certain frequency range, dependent on the horn dimensions, thickness of the dielectric wall and on how strongly the stripline modes are being excited.

  16. Analysis of the Dynamic Response in Blast-Loaded CFRP-Strengthened Metallic Beams

    Directory of Open Access Journals (Sweden)

    Zhenyu Wang

    2013-01-01

    Full Text Available Carbon fiber-reinforced polymer composites (CFRPs are good candidates in enhancing the blast resistant performance of vulnerable public buildings and in reinforcing old buildings. The use of CFRP in retrofitting and strengthening applications is traditionally associated with concrete structures. Nevertheless, more recently, there has been a remarkable aspiration in strengthening metallic structures and components using CFRP. This paper presents a relatively simple analytical solution for the deformation and ultimate strength calculation of hybrid metal-CFRP beams when subjected to pulse loading, with a particular focus on blast loading. The analytical model is based on a full interaction between the metal and the FRP and is capable of producing reasonable results in a dynamic loading scenario. A nonlinear finite element (FE model is also developed to reveal the full dynamic behavior of the CFRP-epoxy-steel hybrid beam, considering the detailed effects, that is, large strains, high strain rates in metal, and different failure modes of the hybrid beam. Experimental results confirm the analytical and the FE results and show a strong correlation.

  17. Results of the second Round Robin on opening-load measurement conducted by ASTM Task Group E24.04.04 on crack closure measurement and analysis

    Science.gov (United States)

    Phillips, E. P.

    1993-01-01

    A second experimental Round Robin on the measurement of the crack opening load in fatigue crack growth tests has been completed by the ASTM Task Group E24.04.04 on Crack Closure Measurement and Analysis. Fourteen laboratories participated in the testing of aluminum alloy compact tension specimens. Opening-load measurements were made at three crack lengths during constant Delta K, constant stress ratio tests by most of the participants. Four participants made opening-load measurements during threshold tests. All opening-load measurements were based on the analysis of specimens compliance behavior, where the displacement/strain was measured either at the crack mouth or the mid-height back face location. The Round Robin data were analyzed for opening load using two non-subjective analysis methods: the compliance offset and the correlation coefficient methods. The scatter in the opening load results was significantly reduced when some of the results were excluded from the analysis population based on an accept/reject criterion for raw data quality. The compliance offset and correlation coefficient opening load analysis methods produced similar results for data populations that had been screened to eliminate poor quality data.

  18. Results of the Round Robin on opening-load measurement conducted by ASTM Task Group E24.04.04 on Crack Closure Measurement and Analysis

    Science.gov (United States)

    Phillips, Edward P.

    1989-01-01

    An experimental Round Robin on the measurement of the opening load in fatigue crack growth tests was conducted on Crack Closure Measurement and Analysis. The Round Robin evaluated the current level of consistency of opening load measurements among laboratories and to identify causes for observed inconsistency. Eleven laboratories participated in the testing of compact and middle-crack specimens. Opening-load measurements were made for crack growth at two stress-intensity factor levels, three crack lengths, and following an overload. All opening-load measurements were based on the analysis of specimen compliance data. When all of the results reported (from all participants, all measurement methods, and all data analysis methods) for a given test condition were pooled, the range of opening loads was very large--typically spanning the lower half of the fatigue loading cycle. Part of the large scatter in the reported opening-load results was ascribed to consistent differences in results produced by the various methods used to measure specimen compliance and to evaluate the opening load from the compliance data. Another significant portion of the scatter was ascribed to lab-to-lab differences in producing the compliance data when using nominally the same method of measurement.

  19. An experimental analysis of bed load transport in gravel-bed braided rivers with high grain Reynolds numbers

    Science.gov (United States)

    De Vincenzo, Annamaria; Brancati, Francesco; Pannone, Marilena

    2016-08-01

    Laboratory experiments were performed with nearly uniform fluvial gravel (D50=9 mm, D10=5 mm and D90=13 mm) to analyse the relationship between stream power and bed load transport rate in gravel-bed braided rivers at high grain Reynolds numbers. The values of the unit-width dimensionless bed-load rate qb* and unit-width dimensionless stream power ω* were evaluated in equilibrium conditions based on ten different experimental runs. Then, they were plotted along with values obtained during particularly representative field studies documented in the literature, and a regression law was derived. For comparison, a regression analysis was performed using the data obtained from laboratory experiments characterized by smaller grain sizes and, therefore, referring to relatively low grain Reynolds numbers. A numerical integration of Exner's equation was performed to reconstruct the local and time-dependent functional dependence of qb* and ω*. The results led to the following conclusions: 1) At equilibrium, the reach-averaged bed load transport rate is related to the reach-averaged stream power by different regression laws at high and low grain Reynolds numbers. Additionally, the transition from bed to suspended load transport is accelerated by low Re*, with the corresponding bed load discharge increasing with stream power at a lower, linear rate. 2) When tested against the gravel laboratory measurements, the high Re* power law derived in the present study performs considerably better than do previous formulas. 3) The longitudinal variability of the section-averaged equilibrium stream power is much more pronounced than that characterizing the bed load rate, at least for high Re*. Thus, the stream power and its local-scale heterogeneity seem to be directly responsible for transverse sediment re-distribution and, ultimately, for the determination of the spatial and temporal scales that characterize the gravel bedforms. 4) Finally, the stochastic interpretation of the wetted

  20. Pressure loads and aerodynamic force information for the -89A space shuttle orbiter configuration, volume 2. [for structural strength analysis

    Science.gov (United States)

    Mennell, R. C.

    1973-01-01

    Experimental aerodynamic investigations were conducted on an 0.0405 scale representation of the Rockwell -89A Light Weight Space Shuttle Orbiter. The test purpose was to obtain pressure loads data in the presence of the ground for orbiter structural strength analysis. Aerodynamic force data was also recorded to allow correlation with all pressure loads information. Angles of attack from minus 3 deg to 18 deg and angles of sideslip of 0 deg, plus or minus 50 deg, and plus or minus 10 deg were tested in the presence of the NAAL ground plane. Static pressure bugs were used to obtain a pressure loads survey of the basic configuration, elevon deflections of 5 deg, 10 deg, 15 deg, and minus 20 deg and a rudder deflection of minus 15 deg, at a tunnel dynamic pressure of 40 psi. The test procedure was to locate a maximum of 30 static pressure bugs on the model surface at various locations calculated to prevent aerodynamic and physical interference. Then by various combinations of location the pressure bugs output was to define a complete pressure survey for the fuselages, wing, vertical tail, and main landing gear door.

  1. Direct Time Domain Numerical Analysis of Transient Behavior of a VLFS during Unsteady External Loads in Wave Condition

    Directory of Open Access Journals (Sweden)

    Yong Cheng

    2014-01-01

    Full Text Available The transient response of the VLFS subjected to arbitrary external load is systematically investigated by a direct time domain modal expansion method, in which the BEM solutions based on time domain Kelvin sources are used for hydrodynamic forces. In the analysis, the time domain free-surface Green functions with sufficient accuracy are rapidly evaluated in finite water depth by the interpolation-tabulation method, and the boundary integral equation with a quarter VLFS model is established taking advantage of symmetry of flow field and structure. The validity of the present method is verified by comparing with the time histories of vertical displacements of the VLFS during a mass drop and airplane landing and takeoff in still water conditions, respectively. Then the developed numerical scheme is used in wave conditions to study the combined action taking into account the mass drop/airplane landing/takeoff loads as well as incident wave action. It is found that the elevation of structural waves due to mass drop load can be significantly changed near the impact region, while the vertical motion of runway in wave conditions is dominant as compared with that only generated by airplane.

  2. Analysis of thermomechanical response of polycrystalline HMX under impact loading through mesoscale simulations

    Directory of Open Access Journals (Sweden)

    D. B. Hardin

    2014-09-01

    Full Text Available We investigate the response of polycrystalline HMX (Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine under impact loading through a 3-dimensional mesoscale model that explicitly accounts for anisotropic elasticity, crystalline plasticity, and heat conduction. This model is used to quantify the variability in temperature and stress fields due to random distributions of the orientations of crystalline grains in HMX under the loading scenarios considered. The simulations carried out concern the response of fully dense HMX polycrystalline ensembles under impact loading at imposed boundary velocities from 50 to 400 m/s. The polycrystalline ensemble studied consists of a geometrically arranged distribution of bi-modally sized and shaped grains. To quantify the effect of crystalline slip, two models with different numbers of available slip systems are used, reflecting differing characterizations of the slip systems of the HMX molecular crystal in the literature. The effects of microstructure and anisotropy on the distribution of heating and stress evolution are investigated. The results obtained indicate that crystalline response anisotropy at the microstructure level plays an important role in influencing both the overall response and the localization of stress and temperature. The overall longitudinal stress is up to 16% higher and the average temperature rise is only half in the material with fewer potential slip systems compared to those in the material with more available slip systems. Local stresses can be as high as twice the average stresses. The results show that crystalline anisotropy induces significant heterogeneities in both mechanical and thermal fields that previously have been neglected in the analyses of the behavior of HMX-based energetic materials.

  3. Morphological analysis of force/velocity relationship in dynamic exercise at varying loads.

    Science.gov (United States)

    Limonta, Eloisa; Sacchi, Massimiliano

    2010-08-01

    This study examined the force/velocity (F/V) curve morphology among the entire concentric phase of the countermovement squat (CMS). The hypothesis is that F/V curve shape of the lower limb muscles complex is different from F/V isolated muscle curve and that these analyses could be useful in characterizing athletes' muscular capacity and training programs. Squat exercise was performed by 29 subjects (15 men and 14 women, divided into resistance and endurance athletes). The protocol was 6 x 1 CMS at maximal speed with increasing loads: 20, 35, 50, 65, 80, 90% of 1 repetition maximum (1RM). Displacement, speed, and acceleration of the weight bar, joint knee angles, knee angular speed, and total and normalized forces were collected. F/V relation was obtained by force and velocity values of each 10 degrees angular interval of the concentric phase for any load. Results show that the F/V relationship does not follow a linear shape and an equivalent criterion for all loads. We observed a "second peak force" statistically higher (p men showed a "second peak" higher and larger than that shown by endurance trained men. This indicated a higher ability to produce and maintain greater force at higher relative speed. These results may be helpful to identify the muscle characteristics of the athletes at various speeds and joint positions. With a phase division of the specific move, it will be possible to determine an individualized program to monitor the specific phases of technical moves and to evaluate the training effect in long run.

  4. Cervical Spine Injuries: A Whole-Body Musculoskeletal Model for the Analysis of Spinal Loading

    Science.gov (United States)

    Holsgrove, Timothy P.; Preatoni, Ezio; Gill, Harinderjit S.; Trewartha, Grant

    2017-01-01

    Cervical spine trauma from sport or traffic collisions can have devastating consequences for individuals and a high societal cost. The precise mechanisms of such injuries are still unknown as investigation is hampered by the difficulty in experimentally replicating the conditions under which these injuries occur. We harness the benefits of computer simulation to report on the creation and validation of i) a generic musculoskeletal model (MASI) for the analyses of cervical spine loading in healthy subjects, and ii) a population-specific version of the model (Rugby Model), for investigating cervical spine injury mechanisms during rugby activities. The musculoskeletal models were created in OpenSim, and validated against in vivo data of a healthy subject and a rugby player performing neck and upper limb movements. The novel aspects of the Rugby Model comprise i) population-specific inertial properties and muscle parameters representing rugby forward players, and ii) a custom scapula-clavicular joint that allows the application of multiple external loads. We confirm the utility of the developed generic and population-specific models via verification steps and validation of kinematics, joint moments and neuromuscular activations during rugby scrummaging and neck functional movements, which achieve results comparable with in vivo and in vitro data. The Rugby Model was validated and used for the first time to provide insight into anatomical loading and cervical spine injury mechanisms related to rugby, whilst the MASI introduces a new computational tool to allow investigation of spinal injuries arising from other sporting activities, transport, and ergonomic applications. The models used in this study are freely available at simtk.org and allow to integrate in silico analyses with experimental approaches in injury prevention. PMID:28052130

  5. Deformation mechanisms of carbon nanotube fibres under tensile loading by in situ Raman spectroscopy analysis.

    Science.gov (United States)

    Li, Qiu; Kang, Yi-Lan; Qiu, Wei; Li, Ya-Li; Huang, Gan-Yun; Guo, Jian-Gang; Deng, Wei-Lin; Zhong, Xiao-Hua

    2011-06-03

    Deformation mechanisms of carbon nanotube (CNT) fibres under tensile loading are studied by means of in situ Raman spectroscopy to detect the CNT deformation and stress distributions in the fibres. The G' band in the Raman spectrum responds distinctly to the tensile stress in Raman shift, width and intensity. The G' band changes with the tensile deformation of the fibre at different stages, namely elastic deformation, strengthening and damage-fracture. It is deduced that the individual CNTs only deform elastically without obvious damage or bond breaking. The yield and fracture of fibres can be due to the slippage among the CNTs.

  6. Tests and limit analysis of loop connections between precast concrete elements loaded in tension

    DEFF Research Database (Denmark)

    Jørgensen, Henrik Brøner; Hoang, Linh Cao

    2013-01-01

    is influenced by important design parameters such as the overlapping length of the U-bars, the spacing between adjacent U-bars and the amount of transverse reinforcement. Knowledge about the parameters that have an effect on the failure of the joint concrete is important in order to avoid this failure mode...... by yielding of the U-bars or by failure in the joint concrete. Only few investigations of the case of concrete failure can be found in the literature. This paper presents an experimental program dedicated to study loop connections critical to concrete failure. The results show that the ultimate load...

  7. Roughness’s shapes comparative analysis of some reinforced earth elements under monotonous loading

    Directory of Open Access Journals (Sweden)

    Mohamed Khemissa

    2015-09-01

    Full Text Available This paper presents and analyzes the experimental and numerical results of a series of pullout tests under monotonous loading performed on five steel strips presenting various forms of roughness (smooth, ribbed, punched, W-shaped, chain and embedded in the same dry sand massif constituting the backfill. The pullout tests were conducted by means of a small-scale model and the calculations carried out by using a finite elements computer program. Obtained results show a good agreement between the experimental and numerical data. They show in addition that the rough strips are more advantageous than the smooth strip. Among the rough strips considered, chain is most relevant.

  8. Community Energy: Analysis of Hydrogen Distributed Energy Systems with Photovoltaics for Load Leveling and Vehicle Refueling

    Energy Technology Data Exchange (ETDEWEB)

    Steward, D.; Zuboy, J.

    2014-10-01

    Energy storage could complement PV electricity generation at the community level. Because PV generation is intermittent, strategies must be implemented to integrate it into the electricity system. Hydrogen and fuel cell technologies offer possible PV integration strategies, including the community-level approaches analyzed in this report: (1) using hydrogen production, storage, and reconversion to electricity to level PV generation and grid loads (reconversion scenario); (2) using hydrogen production and storage to capture peak PV generation and refuel hydrogen fuel cell electric vehicles (FCEVs) (hydrogen fueling scenario); and (3) a comparison scenario using a battery system to store electricity for EV nighttime charging (electric charging scenario).

  9. Validity of simplified Analysis of Stability of Caison Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Andersen, Lars; Burcharth, Hans F.; Andersen, Thomas Lykke

    2011-01-01

    Wave slamming on vertical breakwaters cause a sudden, impulsive load that may cause a caisson to slide on its foundation. Alternatively, geotechnical failure may occur in the subsoil. This paper investigates whether simple analytical solutions, accounting only for the sliding along the caisson–fo......, a fully coupled dynamic pore-water-flow model is introduced. The computational examples clearly demonstrate that the deformations of the soil as well as the pore pressures must be accounted for in order to get a reliable prediction of caisson deformations during wave impact....

  10. Analysis of vibrational load influence upon passengers in trains with a compulsory body tilt

    Science.gov (United States)

    Antipin, D. Ya; Kobishchanov, V. V.; Lapshin, V. F.; Mitrakov, A. S.; Shorokhov, S. G.

    2017-02-01

    The procedure for forecasting the vibrational load influence upon passengers of trains of rolling stocks equipped with a system of a compulsory body tilt on railroad curves is offered. The procedure is based on the use of computer simulation methods and application of solid-state models of anthropometrical mannequins. As a result of the carried out investigations, there are substantiated criteria of the comfort level estimate for passengers in the rolling-stock under consideration. The procedure is approved by the example of the promising domestic rolling stock with a compulsory body tilt on railroad curves.

  11. Performance Analysis of Doubly Fed Induction Generator Based Wind turbine under Faulty and RLC Load Conditions

    Directory of Open Access Journals (Sweden)

    Rekha Parashar

    2015-02-01

    Full Text Available This paper presents the performance of Doubly Fed Induction Generator based wind turbine system during different types of grid fault. The doubly fed induction generator (DFIG based wind turbine (WT system provides better power delivery towards the demand. The design and response of the DFIG based wind turbine system during different fault conditions, various load conditions and integrated system consisting of DFIG based WT system have been verified using MATLAB/ Simulink. The simulation results are shown with the model of DFIG based wind energy generation system.

  12. Dispersion of halloysite loaded with natural antimicrobials into pectins: Characterization and controlled release analysis.

    Science.gov (United States)

    Gorrasi, Giuliana

    2015-01-01

    This paper reports the preparation and characterization of green composites based on pectins and nano-hybrids composed of halloysite nanotubes (HNTs) loaded with rosemary essential oil. Different hybrid percentages were mixed into a pectin matrix, by ball milling in the presence of water. Cast films were obtained and analyzed. Structural organization and physical properties (thermal, mechanical, barrier to water vapor) were correlated to the nano-hybrid content. A preliminary study on the kinetics of release of the rosmarinic acid, chosen as a model molecule, was also performed. This work showed the potential of these systems in the active packaging field where controlled release of active species is required.

  13. LOADING CAPACITY ANALYSIS OF THE MISALIGNED CONICAL-CYLINDRICAL BEARING WITH NON-NEWTONIAN LUBRICANTS

    Institute of Scientific and Technical Information of China (English)

    Yang Yongkuang; Yang Rongtai; Ho Minghsiung; Jheng Mingchang

    2004-01-01

    A novel numerical method to lubricate a conventional finite diameter conical(cylindrical bearing with a non-Newtonian lubricant, while adhering to the power-law model, is presented. The elastic deformation of bearing and varied viscosity of lubrication due to the pressure distribution of film thickness are also considered. Simulation results indicate that the normal load carrying capacity is more pronounced for higher values of flow behavior index n, higher eccentricity ratios and larger misalignment factors. It is found that the viscosity-pressure to the effect of lubricant viscosity is significant.

  14. ANALYSIS OF THE PRE-ROTATION ENGINE LOADS IN THE AUTOGYRO

    Directory of Open Access Journals (Sweden)

    Zbigniew Czyż

    2016-09-01

    Full Text Available The paper presents the analyzes of the pre-rotation engine loads in the Taurus autogyro manufactured by Aviation Artur Trendak from Poland. Based on the NACA-9 H-12 airfoil characteristics of the drag coefficient, on which the rotor blade was made, forces acting on the rotor during pre-rotation have been calculated. The paper presents the characteristics of the drag coefficient as a function of angle of attack for Re = 1,800,000 and Re = 2,600,000. For the speed range of 0 to 400 rpm torque resulting from the drag forces and the power required to drive the rotor were calculated.

  15. Analysis of the blasting effect on the electric shove loading efficiency of the open pit

    Institute of Scientific and Technical Information of China (English)

    FU Tian-guang; SUN Ying

    2008-01-01

    The connection between blasting cost and comprehensive cost is the main concern.Some blasting effect factors (such as unit explosive consumption,uniformity of blockness,shape and porosity of blasting heap),which had an influence on electric shove loading efficiency,were analyzed.In the end a project to properly increase in blasting cost to decrease the comprehensive cost was put forward.At the same time,the hole-by-hole blasting is effective technology to improve blasting effect.

  16. 基于承载接触分析的双重功率分流机构均载特性%Load Sharing Characteristics Analysis of Dual Power-split Gear Train Based on Loaded Tooth Contact Analysis

    Institute of Scientific and Technical Information of China (English)

    董皓; 方宗德; 王宝宾; 杜进辅

    2013-01-01

    In order to research load sharing characteristics of the dual power-split gear train, the mechanical structure model was established. With the method of the tooth contact analysis and loaded tooth contact analysis, the actual meshing process of gear pair was simulated and the time-varying mesh stiffness was obtained, which can enhance the precision of the computation. According to the closed-loop characteristic of the power flow of the system, the reverse angle deformation coordination conditions were deduced, which were combined with the mechanical equilibrium equations and elastic support conditions to calculate the transfer torque and load sharing coefficient of system. The influences of errors on the power split characteristics were analyzed. It provided an important role in the reference for the design of the dual power-split transmission system.%建立了双重功率分流系统弹性支承下的力学模型.运用轮齿几何接触分析(TCA)和承载接触分析(LTCA)方法对齿轮副实际啮合过程进行仿真,拟合了齿轮副的时变啮合刚度,提高了计算精确度.根据系统构成功率流闭环的特点推导出系统的变形协调条件,并结合力矩平衡方程和弹性支承条件计算各齿轮副传递的扭矩,得到系统的均载系数.讨论了各种误差对系统功率分流的影响,为双重功率分流传动系统的设计提供了参考.

  17. Kinetics of viral loads and genotypic analysis of elephant endotheliotropic herpesvirus-1 infection in captive Asian elephants (Elephas maximus).

    Science.gov (United States)

    Stanton, Jeffrey J; Zong, Jian-Chao; Eng, Crystal; Howard, Lauren; Flanagan, Joe; Stevens, Martina; Schmitt, Dennis; Wiedner, Ellen; Graham, Danielle; Junge, Randall E; Weber, Martha A; Fischer, Martha; Mejia, Alicia; Tan, Jie; Latimer, Erin; Herron, Alan; Hayward, Gary S; Ling, Paul D

    2013-03-01

    Elephant endotheliotropic herpesviruses (EEHVs) can cause fatal hemorrhagic disease in juvenile Asian elephants (Elphas maximus); however, sporadic shedding of virus in trunk washes collected from healthy elephants also has been detected. Data regarding the relationship of viral loads in blood compared with trunk washes are lacking, and questions about whether elephants can undergo multiple infections with EEHVs have not been addressed previously. Real-time quantitative polymerase chain reaction was used to determine the kinetics of EEHV1 loads, and genotypic analysis was performed on EEHV1 DNA detected in various fluid samples obtained from five Asian elephants that survived detectable EEHV1 DNAemia on at least two separate occasions. In three elephants displaying clinical signs of illness, preclinical EEHV1 DNAemia was detectable, and peak whole-blood viral loads occurred 3-8 days after the onset of clinical signs. In two elephants with EEHV1 DNAemia that persisted for 7-21 days, no clinical signs of illness were observed. Detection of EEHV1 DNA in trunk washes peaked approximately 21 days after DNAemia, and viral genotypes detected during DNAemia matched those detected in subsequent trunk washes from the same elephant. In each of the five elephants, two distinct EEHV1 genotypes were identified in whole blood and trunk washes at different time points. In each case, these genotypes represented both an EEHV1A and an EEHV1B subtype. These data suggest that knowledge of viral loads could be useful for the management of elephants before or during clinical illness. Furthermore, sequential infection with both EEHV1 subtypes occurs in Asian elephants, suggesting that they do not elicit cross-protective sterilizing immunity. These data will be useful to individuals involved in the husbandry and clinical care of Asian elephants.

  18. Scale up, optimization and stability analysis of Curcumin C3 complex-loaded nanoparticles for cancer therapy

    Directory of Open Access Journals (Sweden)

    Ranjan Amalendu P

    2012-08-01

    Full Text Available Abstract Background Nanoparticle based delivery of anticancer drugs have been widely investigated. However, a very important process for Research & Development in any pharmaceutical industry is scaling nanoparticle formulation techniques so as to produce large batches for preclinical and clinical trials. This process is not only critical but also difficult as it involves various formulation parameters to be modulated all in the same process. Methods In our present study, we formulated curcumin loaded poly (lactic acid-co-glycolic acid nanoparticles (PLGA-CURC. This improved the bioavailability of curcumin, a potent natural anticancer drug, making it suitable for cancer therapy. Post formulation, we optimized our process by Reponse Surface Methodology (RSM using Central Composite Design (CCD and scaled up the formulation process in four stages with final scale-up process yielding 5 g of curcumin loaded nanoparticles within the laboratory setup. The nanoparticles formed after scale-up process were characterized for particle size, drug loading and encapsulation efficiency, surface morphology, in vitro release kinetics and pharmacokinetics. Stability analysis and gamma sterilization were also carried out. Results Results revealed that that process scale-up is being mastered for elaboration to 5 g level. The mean nanoparticle size of the scaled up batch was found to be 158.5 ± 9.8 nm and the drug loading was determined to be 10.32 ± 1.4%. The in vitro release study illustrated a slow sustained release corresponding to 75% drug over a period of 10 days. The pharmacokinetic profile of PLGA-CURC in rats following i.v. administration showed two compartmental model with the area under the curve (AUC0-∞ being 6.139 mg/L h. Gamma sterilization showed no significant change in the particle size or drug loading of the nanoparticles. Stability analysis revealed long term physiochemical stability of the PLGA-CURC formulation. Conclusions A successful

  19. HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT SUMMARY OF COMBINED THERMAL AND OPERATING LOADS WITH SEISMIC ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    MACKEY TC; DEIBLER JE; RINKER MW; JOHNSON KI; ABATT FG; KARRI NK; PILLI SP; STOOPS KL

    2009-01-15

    This report summarizes the results of the Double-Shell Tank Thermal and Operating Loads Analysis (TaLA) combined with the Seismic Analysis. This combined analysis provides a thorough, defensible, and documented analysis that will become a part of the overall analysis of record for the Hanford double-shell tanks (DSTs). The bases of the analytical work presented herein are two ANSYS{reg_sign} finite element models that were developed to represent a bounding-case tank. The TaLA model includes the effects of temperature on material properties, creep, concrete cracking, and various waste and annulus pressure-loading conditions. The seismic model considers the interaction of the tanks with the surrounding soil including a range of soil properties, and the effects of the waste contents during a seismic event. The structural evaluations completed with the representative tank models do not reveal any structural deficiencies with the integrity of the DSTs. The analyses represent 60 years of use, which extends well beyond the current date. In addition, the temperature loads imposed on the model are significantly more severe than any service to date or proposed for the future. Bounding material properties were also selected to provide the most severe combinations. While the focus of the analyses was a bounding-case tank, it was necessary during various evaluations to conduct tank-specific analyses. The primary tank buckling evaluation was carried out on a tank-specific basis because of the sensitivity to waste height, specific gravity, tank wall thickness, and primary tank vapor space vacuum limit. For this analysis, the occurrence of maximum tank vacuum was classified as a service level C, emergency load condition. The only area of potential concern in the analysis was with the buckling evaluation of the AP tank, which showed the current limit on demand of l2-inch water gauge vacuum to exceed the allowable of 10.4 inches. This determination was based on analysis at the

  20. Safety Analysis of the Patch Load Resistance of Plate Girders: Influence of Model Error and Variability

    Directory of Open Access Journals (Sweden)

    Farzad Shahabian

    2013-12-01

    Full Text Available This study aims to undertake a statistical study to evaluate the accuracy of nine models that have been previously proposed for estimating the ultimate resistance of plate girders subjected to patch loading. For each model, mean errors and standard errors, as well as the probability of underestimating or overestimating patch load resistance, are estimated and the resultant values are compared one to another. Prior to that, the models are initially calibrated in order to improve interaction formulae using an experimental data set collected from the literature. The models are then analyzed by computing design factors associated with a target risk level (probability of exceedance. These models are compared one to another considering uncertainties existed in material and geometrical properties. The Monte Carlo simulation method is used to generate random variables. The statistical parameters of the calibrated models are calculated for various coefficients of variations regardless of their correlation with the random resistance variables. These probabilistic results are very useful for evaluating the stochastic sensitivity of the calibrated models.

  1. Critical analysis of rhinovirus RNA load quantification by real-time reverse transcription-PCR.

    Science.gov (United States)

    Schibler, Manuel; Yerly, Sabine; Vieille, Gaël; Docquier, Mylène; Turin, Lara; Kaiser, Laurent; Tapparel, Caroline

    2012-09-01

    Rhinoviruses are the most frequent cause of human respiratory infections, and quantitative rhinovirus diagnostic tools are needed for clinical investigations. Although results obtained by real-time reverse-transcription PCR (RT-PCR) assays are frequently converted to viral RNA loads, this presents several limitations regarding accurate virus RNA quantification, particularly given the need to reliably quantify all known rhinovirus genotypes with a single assay. Using an internal extraction control and serial dilutions of an in vitro-transcribed rhinovirus RNA reference standard, we validated a quantitative one-step real-time PCR assay. We then used chimeric rhinovirus genomes with 5'-untranslated regions (5'UTRs) originating from the three rhinovirus species and from one enterovirus to estimate the impact of the 5'UTR diversity. Respiratory specimens from infected patients were then also analyzed. The assay quantification ability ranged from 4.10 to 9.10 log RNA copies/ml, with an estimated error margin of ±10%. This variation was mainly linked to target variability and interassay variability. Taken together, our results indicate that our assay can reliably estimate rhinovirus RNA load, provided that the appropriate error margin is used. In contrast, due to the lack of a universal rhinovirus RNA standard and the variability related to sample collection procedures, accurate absolute rhinovirus RNA quantification in respiratory specimens is currently hardly feasible.

  2. Analysis on capability of load following for nuclear power plants abroad and its enlightenment

    Science.gov (United States)

    Zheng, Kuan; Zhang, Fu-qiang; Deng, Ting-ting; Zhang, Jin-fang; Hao, Weihua

    2017-01-01

    With the acceleration adjustment of China’s energy structure, the development of nuclear power plants in China has been going back to the fast track. While as the trend of slowing electric power demand is now unmistakable, it enforces the power system to face much greater pressure in some coastal zones where the nuclear power plants are of a comparative big proportion, such as Fujian province and Liaoning province. In this paper, the capability of load following of nuclear power plants of some developed countries with high proportion of nuclear power generation such as France, US and Japan are analysed, also from the aspects including the safety, the economy and their practical operation experience is studied. The feasibility of nuclear power plants to participate in the peak regulation of system is also studied and summarized. The results of this paper could be of good reference value for the China’s nuclear power plants to participate in system load following, and also of great significance for the development of the nuclear power plants in China.

  3. Lumbar spinal loading during bowling in cricket: a kinetic analysis using a musculoskeletal modelling approach.

    Science.gov (United States)

    Zhang, Yanxin; Ma, Ye; Liu, Guangyu

    2016-01-01

    The objective of the study was to evaluate two types of cricket bowling techniques by comparing the lumbar spinal loading using a musculoskeletal modelling approach. Three-dimensional kinematic data were recorded by a Vicon motion capture system under two cricket bowling conditions: (1) participants bowled at their absolute maximal speeds (max condition), and (2) participants bowled at their absolute maximal speeds while simultaneously forcing their navel down towards their thighs starting just prior to ball release (max-trunk condition). A three-dimensional musculoskeletal model comprised of the pelvis, sacrum, lumbar vertebrae and torso segments, which enabled the motion of the individual lumbar vertebrae in the sagittal, frontal and coronal planes to be actuated by 210 muscle-tendon units, was used to simulate spinal loading based on the recorded kinematic data. The maximal lumbar spine compressive force is 4.89 ± 0.88BW for the max condition and 4.58 ± 0.54BW for the max-trunk condition. Results showed that there was no significant difference between the two techniques in trunk moments and lumbar spine forces. This indicates that the max-trunk technique may not increase lower back injury risks. The method proposed in this study could be served as a tool to evaluate lower back injury risks for cricket bowling as well as other throwing activities.

  4. Diffusion and Gas Conversion Analysis of Solid Oxide Fuel Cells at Loads via AC Impedance

    Directory of Open Access Journals (Sweden)

    Robert U. Payne

    2011-01-01

    Full Text Available Impedance measurements were conducted under practical load conditions in solid oxide fuel cells of differing sizes. For a 2 cm2 button cell, impedance spectra data were separately measured for the anode, cathode, and total cell. Improved equivalent circuit models are proposed and applied to simulate each of measured impedance data. Circuit elements related to the chemical and physical processes have been added to the total-cell model to account for an extra relaxation process in the spectra not measured at either electrode. The processes to which elements are attributed have been deduced by varying cell temperature, load current, and hydrogen concentration. Spectra data were also obtained for a planar stack of five 61 cm2 cells and the individual cells therein, which were fitted to a simplified equivalent circuit model of the total button cell. Similar to the button cell, the planar cells and stack exhibit a pronounced low-frequency relaxation process, which has been attributed to concentration losses, that is, the combined effects of diffusion and gas conversion. The simplified total-cell model approximates well the dynamic behavior of the SOFC cells and the whole stack.

  5. Use of Residential Smart Appliances for Peak Load Shifting & Spinning Reserves: Cost Benefit Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, Chellury; Pratt, Robert G.

    2010-12-01

    Abstract In this paper, we present the results of an analytical cost-benefit study of residential smart appliances in support of a joint stakeholder petition to the EPA and DOE to provide a 5% credit to meet ENERGY STAR eligibility criteria for products that meet the definition of a smart appliance. The underlying hypothesis is that smart appliances can play a critical role in addressing some of the challenges associated with increased electricity demand, and increased penetration of renewable sources of power. Our analytical model utilizes current annual appliance electricity consumption data, and estimates what the wholesale grid operating cost savings would be if some percentage of appliance loads were shifted away from peak hours to run during off-peak hours, and appliance loads serve power system balancing needs such as spinning reserves that would otherwise have to be provided by generators. Historical wholesale market clearing prices (location marginal and spinning reserve) from major wholesale power markets in the United States are used to estimate savings. The savings are then compared with the five percent credit, to determine if the savings in grid operating costs (benefits) are at least as high as the credit (cost) if not higher.

  6. Enhanced probability-selection artificial bee colony algorithm for economic load dispatch: A comprehensive analysis

    Science.gov (United States)

    Ghani Abro, Abdul; Mohamad-Saleh, Junita

    2014-10-01

    The prime motive of economic load dispatch (ELD) is to optimize the production cost of electrical power generation through appropriate division of load demand among online generating units. Bio-inspired optimization algorithms have outperformed classical techniques for optimizing the production cost. Probability-selection artificial bee colony (PS-ABC) algorithm is a recently proposed variant of ABC optimization algorithm. PS-ABC generates optimal solutions using three different mutation equations simultaneously. The results show improved performance of PS-ABC over the ABC algorithm. Nevertheless, all the mutation equations of PS-ABC are excessively self-reinforced and, hence, PS-ABC is prone to premature convergence. Therefore, this research work has replaced the mutation equations and has improved the scout-bee stage of PS-ABC for enhancing the algorithm's performance. The proposed algorithm has been compared with many ABC variants and numerous other optimization algorithms on benchmark functions and ELD test cases. The adapted ELD test cases comprise of transmission losses, multiple-fuel effect, valve-point effect and toxic gases emission constraints. The results reveal that the proposed algorithm has the best capability to yield the optimal solution for the problem among the compared algorithms.

  7. Load Measurements

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regarding...... the fatigue loads, the rotor, blades and tower moments are presented. The fatigue loads are evaluated using rainflow counting described in detail in Ref. [1]. The 1Hz equivalent load ranges are calculated at different wind speeds. All information regarding the instrumentation is collected in [ref 4] and [ref...

  8. ANALYSIS OF ENERGY EFFICIENCY OF OPERATING MODES OF ELECTRICAL SYSTEMS WITH THE TRACTION LOADS

    Directory of Open Access Journals (Sweden)

    V. E. Bondarenko

    2017-03-01

    Full Text Available Innovative scenarios of reliable energy supply of transportation process aimed at reducing the specific energy consumption and increase energy efficiency of the systems of electric traction. The paper suggests innovative energy saving directions in traction networks of railways and new circuit solutions accessing traction substations in energy systems networks, ensure energy security of the transportation process. To ensure the energy security of rail transport special schemes were developed to propose the concept of external power traction substations, which would increase the number of connections to the networks of 220 – 330 kV, as well as the creation of transport and energy corridors, development of its own supply of electric networks of 110 kV substations and mobile RP-110 kV of next generation. Therefore, the investment program of the structures owned by the Ukrainian Railways (Ukrzaliznytsia need to be synchronized in their technological characteristics, as well as the criteria of reliability and quality of power supply with the same external energy investment programs. It is found that without any load on left or right supplying arm one of two less loaded phases of traction transformer begins generating specific modes in the supplying three-phase line. Thus, modes of mobile substation cause leakage in one of the phases of the supply line of traction transformers of active-capacitive current, and as a result generating energy in the main power line of 154 kV, which is fixed and calculated by electricity meters. For these three phase mode supply network is necessary to use 1st algorithm, i.e. taking into account the amount of electricity as the energy in all phases. For effective application of reactive power compensation devices in the AC traction power supply systems it is proposed to develop regulatory documentation on necessity of application and the order of choice of parameters and placement of compensation systems taking into

  9. Detailed Load Analysis of the baseline 5MW DeepWind Concept

    DEFF Research Database (Denmark)

    Verelst, David Robert; Aagaard Madsen, Helge; Kragh, Knud Abildgaard

    This report presents an overview of the design of the DeepWind vertical axis oating wind turbine. One could present this as the "nal design", however, it is hoped that more design iterations will follow in the future, but under the umbrella of new and dierent projects. The state of the design...... that is reported here will be called version 2.2.0. The numbering system has just been introduced at the present design version, but the rst 5MW design called the "baseline design" [1] was developed in 2011 and this will therefore be called version 1.0.0. In this report, the design loads of the DeepWind 5 MW...

  10. Quantitative analysis of the deformation of polypropylene foam under dynamic loading

    Science.gov (United States)

    Plougonven, Erwan; Bernard, Dominique; Viot, Philippe

    2006-08-01

    A dynamic crash loading experiment is performed on a polypropylene foam. Several interrupted shocks are conducted, in between which microtomographic acquisitions are made, showing the evolution of the sample during its compression. This data can help construct and validate predictive models, although, because this material is multiscale (consitutive grains at the mesoscopic scale are made of microscopic closed cells), image processing is required to extract useful quantitative measures. Such processing is described here, so as to determine a representative volume for each grain of the sample, in order to associate to each grain and to each stage of the compression values such as grain density. This can help build a predictive model at the mesoscopic scale.

  11. Nonlinear Analysis and Scaling Laws for Noncircular Composite Structures Subjected to Combined Loads

    Science.gov (United States)

    Hilburger, Mark W.; Rose, Cheryl A.; Starnes, James H., Jr.

    2001-01-01

    Results from an analytical study of the response of a built-up, multi-cell noncircular composite structure subjected to combined internal pressure and mechanical loads are presented. Nondimensional parameters and scaling laws based on a first-order shear-deformation plate theory are derived for this noncircular composite structure. The scaling laws are used to design sub-scale structural models for predicting the structural response of a full-scale structure representative of a portion of a blended-wing-body transport aircraft. Because of the complexity of the full-scale structure, some of the similitude conditions are relaxed for the sub-scale structural models. Results from a systematic parametric study are used to determine the effects of relaxing selected similitude conditions on the sensitivity of the effectiveness of using the sub-scale structural model response characteristics for predicting the full-scale structure response characteristics.

  12. Power and loads for wind turbines in yawed conditions. Analysis of field measurements and aerodynamic predictions

    Energy Technology Data Exchange (ETDEWEB)

    Boorsma, K. [ECN Wind Energy, Petten (Netherlands)

    2012-11-15

    A description is given of the work carried out within the framework of the FLOW (Far and Large Offshore Wind) project on single turbine performance in yawed flow conditions. Hereto both field measurements as well as calculations with an aerodynamic code are analyzed. The rotors of horizontal axis wind turbines follow the changes in the wind direction for optimal performance. The reason is that the power is expected to decrease for badly oriented rotors. So, insight in the effects of the yaw angle on performance is important for optimization of the yaw control of each individual turbine. The effect of misalignment on performance and loads of a single 2.5 MW wind turbine during normal operation is investigated. Hereto measurements at the ECN Wind Turbine Test Site Wieringermeer (EWTW) are analyzed from December 2004 until April 2009. Also, the influence of yaw is studied using a design code and results from this design code are compared with wind tunnel measurements.

  13. Strength Estimation of Self-Piercing Rivets using Lower Bound Limit Load Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xin; Khaleel, Mohammad A.

    2005-08-01

    This paper summarizes the authors' work on strength and failure mode estimation of self-piercing rivets (SPR) for automotive applications. First, the static cross tension strength of an SPR joint is estimated using a lower bound limit load based strength estimator. Failure mode associated with the predicted failure strength can also be identified. It is shown that the cross tension strength of an SPR joint depends on the material and gage combinations, rivet design, die design and riveting direction. The analytical rivet strength estimator is then validated by experimental rivet strength measurements and failure mode observations from nine SPR joint populations with various material and gage combinations. Next, the estimator is used to optimize rivet strength. Two illustrative examples are presented in which rivet strength is improved by changing rivet length and riveting direction from the original manufacturing parameters.

  14. DC Motor Load Analysis and Cooling Consideration to Optimise the Power Consumption- Case Study

    Directory of Open Access Journals (Sweden)

    Mr. K.G. Bante

    2013-06-01

    Full Text Available The need of energy conservation is the increased requirement of all industries as the cost of the energy increasing day by day. DC motors have been the workhorse of variable speed drives in the continuous steel rolling mills for many years. DC motors in the steel rolling mills are usually separately ventilated by providing air blower, heat exchanger and water. Cooling air is circulated inside the motor by air blower. Water circulates through the heat exchanger and cools the air. Energy consumption by the air blower plays a vital role in optimizing the energy consumption. This article indicates that the loading pattern of the DC motor should decide the control strategy for effective and efficient cooling arrangement.

  15. Numeric simulation analysis of load-settlement relation of pile in layer foundation

    Institute of Scientific and Technical Information of China (English)

    WANG You-qing

    2006-01-01

    Considering the level distribution of soil layers, the soils surrounding pile are simulated with level finite layer elements. Supposing that the vertical deformation of the soil elements surrounding pile varies in the form of exponent function with radial distance, and considering the nonlinear constitutive relation of stress and strain, the stiffness matrix is established. The mechanics behavior of the pile-soil interface is simulated with a nonlinear interface element. This method can truly express the behavior of the pile-soil system. The load-settlement relation Q-S curves of two big diameter prototype piles on bearing test are analyzed, and satisfying results are obtained. This method is reasonable in theory and feasible in engineering.

  16. Nonlinear dynamic analysis of a rotor-bearing-seal system under two loading conditions

    Science.gov (United States)

    Ma, Hui; Li, Hui; Niu, Heqiang; Song, Rongze; Wen, Bangchun

    2013-11-01

    The operating speed of the rotating machinery often exceeds the second or even higher order critical speeds to pursue higher efficiency. Thus, how to restrain the higher order mode instability caused by the nonlinear oil-film force and seal force at high speed as far as possible has become more and more important. In this study, a lumped mass model of a rotor-bearing-seal system considering the gyroscopic effect is established. The graphite self-lubricating bearing and the sliding bearing are simulated by a spring-damping model and a nonlinear oil-film force model based on the assumption of short bearings, respectively. The seal is simulated by Muszynska nonlinear seal force model. Effects of the seal force and oil-film force on the first and second mode instabilities are investigated under two loading conditions which are determined by API Standard 617 (Axial and Centrifugal Compressors and Expander-compressors for Petroleum, Chemical and Gas Industry Services, Seventh Edition). The research focuses on the effects of exciting force forms and their magnitudes on the first and second mode whips in a rotor-bearing-seal system by using the spectrum cascades, vibration waveforms, orbits and Poincaré maps. The first and second mode instability laws are compared by including and excluding the seal effect in a rotor system with single-diameter shaft and two same discs. Meanwhile, the instability laws are also verified in a rotor system with multi-diameter shaft and two different discs. The results show that the second loading condition (out-of-phase unbalances of two discs) and the nonlinear seal force can mainly restrain the first mode instability and have slight effects on the second mode instability. This study may contribute to a further understanding about the higher order mode instability of such a rotor system with fluid-induced forces from the oil-film bearings and seals.

  17. Dispersion and treatment performance analysis of an UASB reactor under different hydraulic loading rates.

    Science.gov (United States)

    Peña, M R; Mara, D D; Avella, G P

    2006-02-01

    Mixing and transport phenomena affect the efficiency of all bioreactor configurations. An even mixing pattern at the macro-level is desirable to provide good conditions for substrate transport to, and from, the microbial aggregates. The state of segregation of particulate material in the reactor is also important. The production of biogas in anaerobic reactors is another factor that affects mixing intensity and hence the interactions between the liquid, solid and gaseous phases. The CSTR model with some degree of short-circuiting, dead zones and bypassing flows seems to describe the overall hydrodynamics of UASBs. However, few data are available in the literature for full-scale reactors that relate process performance to mixing characteristics. Dispersion studies using LiCl were done for four hydraulic loading rates on a full-scale UASB treating domestic wastewater in Ginebra, Valle del Cauca, southwest Colombia. COD, TSS, and Settleable Solids were used to evaluate the performance of organic matter removal. The UASB showed a complete mixing pattern for hydraulic loading rates close to the design value (i.e. Q = 10-13l s(-1) and HRT=8-6 h). Gross mixing distortions and localised stagnant zones, short-circuiting and bypass flows were found in the sludge bed and blanket zones for both extreme conditions (underloading and overloading). The liquid volume contained below the gas-liquid-solid separator was found to contribute to the overall stagnant volume, particularly when the reactor was underloaded. The removal of organic matter showed a log-linear correlation with the dispersion number.

  18. Site-specific, adult bone benefits attributed to loading during youth: A preliminary longitudinal analysis.

    Science.gov (United States)

    Scerpella, Tamara A; Bernardoni, Brittney; Wang, Sijian; Rathouz, Paul J; Li, Quefeng; Dowthwaite, Jodi N

    2016-04-01

    We examined site-specific bone development in relation to childhood and adolescent artistic gymnastics exposure, comparing up to 10years of prospectively acquired longitudinal data in 44 subjects, including 31 non-gymnasts (NON) and 13 gymnasts (GYM) who participated in gymnastics from pre-menarche to ≥1.9years post-menarche. Subjects underwent annual regional and whole-body DXA scans; indices of bone geometry and strength were calculated. Anthropometrics, physical activity, and maturity were assessed annually, coincident with DXA scans. Non-linear mixed effect models centered growth in bone outcomes at menarche and adjusted for menarcheal age, height, and non-bone fat-free mass to evaluate GYM-NON differences. A POST-QUIT variable assessed the withdrawal effect of quitting gymnastics. Curves for bone area, mass (BMC), and strength indices were higher in GYM than NON at both distal radius metaphysis and diaphysis (pGYM BMC (pGYM endosteal diameter (pGYM advantages in narrow neck cortical thickness and buckling ratio (both pGYM than NON (pGYM slopes increased for distal radius diaphysis parameters (p≤0.01) and for narrow neck BR (p=0.02). At the distal radius metaphysis, GYM BMC and compressive strength slopes decreased, as did slopes for lumbar spine BMC, femoral neck BMC, and narrow neck cortical thickness (p<0.02). In conclusion, advantages in bone mass, geometry, and strength at multiple skeletal sites were noted across growth and into young adulthood in girls who participated in gymnastics loading to at least 1.9years post-menarche. Following gymnastics cessation, advantages at cortical bone sites improved or stabilized, while advantages at corticocancellous sites stabilized or diminished. Additional longitudinal observation is necessary to determine whether residual loading benefits enhance lifelong skeletal strength.

  19. Analysis of Unsteady Tip and Endwall Heat Transfer in a Highly Loaded Transonic Turbine Stage

    Science.gov (United States)

    Shyam, Vikram; Ameri, Ali; Chen, Jen-Ping

    2010-01-01

    In a previous study, vane-rotor shock interactions and heat transfer on the rotor blade of a highly loaded transonic turbine stage were simulated. The geometry consists of a high pressure turbine vane and downstream rotor blade. This study focuses on the physics of flow and heat transfer in the rotor tip, casing and hub regions. The simulation was performed using the Unsteady Reynolds-Averaged Navier-Stokes (URANS) code MSU-TURBO. A low Reynolds number k-epsilon model was utilized to model turbulence. The rotor blade in question has a tip gap height of 2.1 percent of the blade height. The Reynolds number of the flow is approximately 3x10(exp 6) per meter. Unsteadiness was observed at the tip surface that results in intermittent "hot spots". It is demonstrated that unsteadiness in the tip gap is governed by inviscid effects due to high speed flow and is not strongly dependent on pressure ratio across the tip gap contrary to published observations that have primarily dealt with subsonic tip flows. The high relative Mach numbers in the tip gap lead to a choking of the leakage flow that translates to a relative attenuation of losses at higher loading. The efficacy of new tip geometry is discussed to minimize heat flux at the tip while maintaining choked conditions. In addition, an explanation is provided that shows the mechanism behind the rise in stagnation temperature on the casing to values above the absolute total temperature at the inlet. It is concluded that even in steady mode, work transfer to the near tip fluid occurs due to relative shearing by the casing. This is believed to be the first such explanation of the work transfer phenomenon in the open literature. The difference in pattern between steady and time-averaged heat flux at the hub is also explained.

  20. Folate Functionalized PLGA Nanoparticles Loaded with Plasmid pVAX1-NH36: Mathematical Analysis of Release

    Directory of Open Access Journals (Sweden)

    Cindy Alejandra Gutiérrez-Valenzuela

    2016-11-01

    Full Text Available Plasmid DNA (pVAX1-NH36 was encapsulated in nanoparticles of poly-dl-lactic-co-glycolic (PLGA functionalized with polyethylene glycol (PEG and folic acid (PLGA-PEG-FA without losing integrity. PLGA-PEG-FA nanoparticles loaded with pVAX1-NH36 (pDNA-NPs were prepared by using a double emulsification-solvent evaporation technique. PLGA-PEG-FA synthesis was verified by FT-IR and spectrophotometry methods. pVAX1-NH36 was replicated in Escherichia coli (E. coli cell cultures. Atomic force microscopy (AFM analysis confirmed pDNA-NPs size with an average diameter of 177–229 nm, depending on pVAX1-NH36 loading and zeta potentials were below −24 mV for all preparations. In vitro release studies confirmed a multiphase release profile for the duration of more than 30-days. Plasmid release kinetics were analyzed with a release model that considered simultaneous contributions of initial burst and degradation-relaxation of nanoparticles. Fitting of release model against experimental data presented excellent correlation. This mathematical analysis presents a novel approach to describe and predict the release of plasmid DNA from biodegradable nanoparticles.

  1. Coupled RELAP5, 3D CFD and FEM analysis of postulated cracks in RPVs subjected to PTS loading

    Energy Technology Data Exchange (ETDEWEB)

    González-Albuixech, V.F., E-mail: vicente.gonzalez@psi.ch [Paul Scherrer Institut (PSI), Nuclear Energy and Safety Department, Structural Integrity Group, Villigen CH-5232 (Switzerland); Qian, G., E-mail: guian.qian@psi.ch [Paul Scherrer Institut (PSI), Nuclear Energy and Safety Department, Structural Integrity Group, Villigen CH-5232 (Switzerland); Sharabi, M. [Paul Scherrer Institut (PSI), Nuclear Energy and Safety Department, Structural Integrity Group, Villigen CH-5232 (Switzerland); Mechanical Power Engineering Department, Faculty of Engineering, Mansoura University, 35516 Mansoura (Egypt); Niffenegger, M.; Niceno, B.; Lafferty, N. [Paul Scherrer Institut (PSI), Nuclear Energy and Safety Department, Structural Integrity Group, Villigen CH-5232 (Switzerland)

    2016-02-15

    Highlights: • RPV fracture mechanics model based on RELAP5. • RPV fracture mechanics model based on CFD. • RPV fracture mechanics analysis. - Abstract: The fracture mechanic analysis of a reactor pressure vessel subjected to pressurized thermal shock loading is one of the most important issues for the assessment of life time extension of a nuclear power plant. The most severe scenario occurs during cold water injection in the cold leg due to a Loss-Of-Coolant Accident (LOCA). In the present study a comprehensive fracture mechanics analysis is performed. Two hypothetical LOCAs are assumed for an adopted reference design of a two-loop Pressurized Water Reactor. Boundary conditions obtained from the RELAP5 code are used as input for Computational Fluid Dynamics (CFD) simulations. For the structural integrity analysis, submodeling technique and the eXtended Finite Element Method (XFEM) based on temperatures calculated by CFD are applied. The results from the 3D FEM calculations are compared to those from a simplified axisymmetric model based on axisymmetric thermal hydraulic model results. The analysis identifies the worst crack orientation and location. It also proves that a complete model is needed for a correct analysis as the simplified model is not conservative and fails to describe accurately the local plume effect.

  2. Dynamic analysis of multibodies system with a floating base for rolling of ro-ro ship caused by wave and slip of heavy load

    Institute of Scientific and Technical Information of China (English)

    SHEN Qing; LI Yue; CHEN Xu-jun

    2003-01-01

    Common effect of wave and slip of internal heavy load will make rolling of the roll-on ship serious. This is one of the important reasons for overturn of ro-ro ships. The multibodies System with a floating base is composed of ro-ro ship and slipping heavy load. This paper takes the rolling angle of the ship and the transverse displacement of the heavy load on desk as two freedoms. Making use of analysis of apparent gravitation and apparent buoyancy, the wave rolling moment is derived. By use of dynamic method of multibodies system with a floating base, dynamic equations of the system are established. Taking a certain channel ferry as an example, a set of numerical calculation have been carried out for rolling response of the ship and displacement response of the slipping heavy load under common effect of synchro-slipping heavy loads and wave.

  3. Loading and stress analysis of gas pipeline structures; Analise de esforcos e tensoes em estruturas de gasodutos durante despressurizacoes

    Energy Technology Data Exchange (ETDEWEB)

    Frisoli, Caetano [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil); Frota, Cristiane Souto [TBG - Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Rio de Janeiro, RJ (Brazil); Silva, Luis Fernando Figueira da; Carvalho, Marcio da Silveira [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica; Savi, Marcelo Amorim [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Dept. de Engenharia Mecanica; Pacheco, Pedro Manuel Calas Lopes [Centro Federal de Educacao Tecnologica do Rio de Janeiro (CEFET-RJ), Rio de Janeiro, RJ (Brazil)

    2003-07-01

    Repairing and maintenance activities on Bolivia-Brazil gas pipeline often need blow down lines. During the blow down process, the high speed of discharging gases imposes great efforts to the structures. A detailed analysis of this situation is essential for a safe operation. This paper describes two phases of a project, developed under TBG coordination. It consists in analyzing the stress and forces involved in this operation, in order to design facilities to blow down pipes and develop a safe blow down procedure for the gas pipeline. The first phase consists of a supersonic flowing simulation in the blow down gas pipeline device. The pressure behavior, mass flow and the speed at the device's ending point are calculated for different operational conditions. In the second phase, the equivalent loading caused by blow down operations is used as input in a stress analysis program to determine stress, critical sessions evaluation and material recommendations for blow down devices. (author)

  4. Load Measurements

    DEFF Research Database (Denmark)

    Vesth, Allan; Kock, Carsten Weber

    The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regardi...

  5. ULTIMATE LOAD-CAPACITY ANALYSIS OF LIGHT-WEIGHT STEEL PORTAL FRAMES UNDER WIND AND SNOW LOADING%风雪荷载下轻钢门式刚架极限承载力分析

    Institute of Scientific and Technical Information of China (English)

    李勰; 陈水福

    2013-01-01

    Nonlinear ultimate limit state analysis was performed to a typical frame of an existing light-weight steel portal frame industrial building located at the coastal region of China using the refined finite element method. The wind and snow load combinations were determined from the current load code of China, and the corresponding wind-resistant and snow-resistant load-capacity redundant factors of the frame were then found through the analysis. The obtained results indicate that although the load-capacities of the frame under the two load combinations meet the current code requirement, the load-capacity redundant factors are relatively low if initial imperfections of the frame are considered. Furthermore the failure mode of the frame would change from a material yielding format to a local buckling format under consideration of initial imperfections.%以我国沿海一既有门式刚架轻钢厂房为例,按现行规范取用风荷载组合和雪荷载组合,采用精细有限元方法对厂房中的典型刚架进行了非线性的极限承载力分析,获得了刚架抗风与抗雪的承载力冗余系数以及达到极限状态时的破坏模式.结果表明,刚架在不同荷载组合下的承载力虽能满足规范要求,但当考虑初始缺陷时,其承载力冗余系数偏低,且失效模式由无缺陷时的材料屈服模式转变为局部屈曲模式.

  6. Comparative uncertainty analysis of copper loads in stormwater systems using GLUE and grey-box modeling

    DEFF Research Database (Denmark)

    Lindblom, Erik Ulfson; Madsen, Henrik; Mikkelsen, Peter Steen

    2007-01-01

    . With the proposed model and input data, the GLUE analysis show that the total sampled copper mass can be predicted within a range of +/- 50% of the median value ( 385 g), whereas the grey-box analysis showed a prediction uncertainty of less than +/- 30%. Future work will clarify the pros and cons of the two methods...

  7. Global cost modeling analysis of HIV-1 and HCV viral load assays.

    Science.gov (United States)

    Elbeik, Tarek; Chen, Yi-Ming Arthur; Soutchkov, Serguei V; Loftus, Richard A; Beringer, Scott

    2003-08-01

    This review addresses hidden costs associated with the Bayer VERSANT assay, Roche AMPLICOR MONITOR test and COBAS AMPLICOR MONITOR test and how these influence the final per reportable cost to a testing laboratory in resource-rich and -poor countries. An in-depth evaluation and recommendation of the most cost-effective approach for these tests is presented. The analyses demonstrate the need for manufacturers to consider labor and supply costs when marketing a kit in resource-poor countries, noting that marketing strategies need to change. In the absence of any proven monitoring alternative, emphasis is placed on increasing market share to promote significant reduction in kit prices to suit the demands of markets in resource-poor countries. Finally, recommendations are made to improve the overall cost structure of viral load testing. This review is intended as a tool to optimize assay usage in attaining the lowest performance costs by assay and is not to endorse any test, as will become apparent.

  8. Finite Element Analysis of the Deformation of Functionally Graded Plates under Thermomechanical Loads

    Directory of Open Access Journals (Sweden)

    A. E. Alshorbagy

    2013-01-01

    Full Text Available The first-order shear deformation plate model, accounting for the exact neutral plane position, is exploited to investigate the uncoupled thermomechanical behavior of functionally graded (FG plates. Functionally graded materials are mainly constructed to operate in high temperature environments. Also, FG plates are used in many applications (such as mechanical, electrical, and magnetic, where an amount of heat may be generated into the FG plate whenever other forms of energy (electrical, magnetic, etc. are converted into thermal energy. Several simulations are performed to study the behavior of FG plates, subjected to thermomechanical loadings, and focus the attention on the effect of the heat source intensity. Most of the previous studies have considered the midplane neutral one, while the actual position of neutral plane for functionally graded plates is shifted and should be firstly determined. A comparative study is performed to illustrate the effect of considering the neutral plane position. The volume fraction of the two constituent materials of the FG plate is varied smoothly and continuously, as a continuous power function of the material position, along the thickness of the plate.

  9. Discrete dislocation plasticity analysis of loading rate-dependent static friction

    Science.gov (United States)

    Song, H.; Deshpande, V. S.; Van der Giessen, E.

    2016-08-01

    From a microscopic point of view, the frictional force associated with the relative sliding of rough surfaces originates from deformation of the material in contact, by adhesion in the contact interface or both. We know that plastic deformation at the size scale of micrometres is not only dependent on the size of the contact, but also on the rate of deformation. Moreover, depending on its physical origin, adhesion can also be size and rate dependent, albeit different from plasticity. We present a two-dimensional model that incorporates both discrete dislocation plasticity inside a face-centred cubic crystal and adhesion in the interface to understand the rate dependence of friction caused by micrometre-size asperities. The friction strength is the outcome of the competition between adhesion and discrete dislocation plasticity. As a function of contact size, the friction strength contains two plateaus: at small contact length (≲0.6 μ m), the onset of sliding is fully controlled by adhesion while for large contact length (≳10 μ m), the friction strength approaches the size-independent plastic shear yield strength. The transition regime at intermediate contact size is a result of partial de-cohesion and size-dependent dislocation plasticity, and is determined by dislocation properties, interfacial properties as well as by the loading rate.

  10. Application of microtomography and image analysis to the quantification of fragmentation in ceramics after impact loading

    Science.gov (United States)

    Forquin, Pascal; Ando, Edward

    2017-01-01

    Silicon carbide ceramics are widely used in personal body armour and protective solutions. However, during impact, an intense fragmentation develops in the ceramic tile due to high-strain-rate tensile loadings. In this work, microtomography equipment was used to analyse the fragmentation patterns of two silicon carbide grades subjected to edge-on impact (EOI) tests. The EOI experiments were conducted in two configurations. The so-called open configuration relies on the use of an ultra-high-speed camera to visualize the fragmentation process with an interframe time set to 1 µs. The so-called sarcophagus configuration consists in confining the target in a metallic casing to avoid any dispersion of fragments. The target is infiltrated after impact so the final damage pattern is entirely scanned using X-ray tomography and a microfocus source. Thereafter, a three-dimensional (3D) segmentation algorithm was tested and applied in order to separate fragments in 3D allowing a particle size distribution to be obtained. Significant differences between the two specimens of different SiC grades were noted. To explain such experimental results, numerical simulations were conducted considering the Denoual-Forquin-Hild anisotropic damage model. According to the calculations, the difference of crack pattern in EOI tests is related to the population of defects within the two ceramics. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  11. FINITE DIFFERENCE ANALYSIS OF ACOUSTIC REFLECTION AND RADIATION FROM FLUID-LOADED PLATES

    Institute of Scientific and Technical Information of China (English)

    赵汉中

    2003-01-01

    A finite difference/boundary integral procedure to determine the acoustic reflected pressure from a fluid-loaded bi-laminate plate is described. The bi-laminate is composed of a piezoelectric layer and an elastic layer in contact with the fluid. The plate is either of finite length and held at its two ends in an acoustically hard baffle or of infinite length with periodically etched electrodes.In the numerical model, the fluid pressure at fluid/solid interface is replaced by a continuum of point sources weighted by the normal acceleration of the elastic plate, and the governing equation system is solved in the solid domain. It is demonstrated that an appropriate applied voltage potential across the baffled piezoelectric layer has the effect of cancelling the reflected pressure at any chosen field points,and a piecewise constant voltage potential with properly chosen amplitude and phase in the periodic structure has the effect of cancelling the fundamental propagating mode of the reflected waves.

  12. Carbohydrate Intake, Glycemic Index, Glycemic Load, and Stroke: A Meta-analysis of Prospective Cohort Studies.

    Science.gov (United States)

    Cai, Xianlei; Wang, Chen; Wang, Shan; Cao, Gaoyang; Jin, Chao; Yu, Jiawei; Li, Xiuyang; Yan, Jing; Wang, Fudi; Yu, Wei; Ding, Fang

    2015-07-01

    The objective of this study was to investigate associations between carbohydrate intake/glycemic index (GI)/glycemic load (GL) and stroke risk. A literature search of MEDLINE, Embase, Web of Science, and CBM databases was performed to retrieve eligible studies published up to March 2014. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were used to evaluate the strength of this association. Publication bias was assessed by the Egger's regression asymmetry test and Begg's rank correlation test with Begg's funnel plot. All analyses were conducted using software STATA 12.0 (StataCorp LP, College Station, TX) and SAS version 9.1 (SAS Institute Inc, Cary, NC). We identified 7 prospective studies that met the inclusion criteria and processed data from cohort studies to update available evidence. There were 25 independent estimates and 225 000 participants free of diabetes from 6 different countries; 3046 stroke events were included; and the follow-up range was 5 to 18 years. High GI was not associated with risk of stroke events (pooled RR = 1.10; 95% CI: 0.99-1.21); GL was a risk factor for stroke (pooled RR = 1.19; 95% CI: 1.05-1.36). There was no significant association between high carbohydrate intake and stroke risk (RR = 1.12; 95% CI: 0.93-1.35). A daily high GL diet is the risk factor of stroke event, and further researches need to verify the meta-analyses results and study associated mechanisms.

  13. Finite element analysis of the dynamic behavior of pear under impact loading

    Directory of Open Access Journals (Sweden)

    Alireza Salarikia

    2017-03-01

    Full Text Available Pear fruit is susceptible to bruising from mechanical impact during field harvesting operations and at all stages of postharvest handling. The postharvest shelf life of bruised fruits were shorter, and they softened rapidly under cold storage compared with non-bruised samples. Developing strategies for reducing bruising during the supply chain requires an understanding of fruit dynamic behavior to different enforced loadings. Finite Element Method (FEM is among the best techniques, in terms of accuracy and cost-efficiency, for studying the factors effective in impact-induced bruising. In this research, the drop test of pear sample was simulated using FEM. The simulation was conducted on a 3D solid model of the pear that was created by using non-contact optical scanning technology. This computer-based study aimed to assess the stress and strain distribution patterns within pear generated by collision of the fruit with a flat surface made of different materials. The contact force between two colliding surfaces is also investigated. The simulations were conducted at two different drop orientations and four different impact surfaces. Results showed that, in both drop orientations, the largest and smallest stresses, strains and contact forces were developed in collision with the steel and rubber surfaces, respectively. In general, these parameters were smaller when fruit collided with the surfaces along its horizontal axis than when collided along its vertical axis. Finally, analyses of stress and strain magnitudes showed that simulation stress and strain values were compatible with experiments data.

  14. Lesson from Tungsten Leading Edge Heat Load Analysis in KSTAR Divertor

    Science.gov (United States)

    Hong, Suk-Ho; Pitts, Richard Anthony; Lee, Hyeong-Ho; Bang, Eunnam; Kang, Chan-Soo; Kim, Kyung-Min; Kim, Hong-Tack; ITER Organization Collaboration; Kstar Team Team

    2016-10-01

    An important design issue for the ITER tungsten (W) divertor and in fact for all such components using metallic plasma-facing elements and which are exposed to high parallel power fluxes, is the question of surface shaping to avoid melting of leading edges. We have fabricated a series of tungsten blocks with a variety of leading edge heights (0.3, 0.6, 1.0, and 2.0 mm), from the ITER worst case to heights even beyond the extreme value tested on JET. They are mounted into adjacent, inertially cooled graphite tile installed in the central divertor region of KSTAR, within the field of view of an infra-red (IR) thermography system with a spatial resolution to 0.4 mm/pixel. Adjustment of the outer divertor strike point position is used to deposit power on the different blocks in different discharges. The measured power flux density on flat regions of the surrounding graphite tiles is used to obtain the parallel power flux, q|| impinging on the various W blocks. Experiments have been performed in Type I ELMing H-mode with Ip = 600 kA, BT = 2 T, PNBI = 3.5 MW, leading to a hot attached divertor with typical pulse lengths of 10 s. Three dimensional ANSYS simulations using q|| and assuming geometric projection of the heat flux are found to be consistent with the observed edge loading. This research was partially supported by Ministry of Science, ICT, and Future Planning under KSTAR project.

  15. Analysis of multistoried braced steel space frame subjected to gravity and seismic loading.

    Directory of Open Access Journals (Sweden)

    Dhananjay.S.Pawar

    2015-09-01

    Full Text Available Steel structures are generally more flexible than other types of structure and lower in weight. Earthquake loads are random in nature. It is difficult to predict them exactly. The action applied to a structure by an earthquake is a ground movement with horizontal and vertical components. The horizontal movement is the most specific feature of earthquake action because of its strength and because structures are generally better designed to resist gravity than horizontal forces. These forces produce large stresses, strains, deformation and displacement particularly in tall structures. To keep displacement within limit generally bracing is provided in steel structure. . Bracings are generally used to increase lateral-stiffness, lateral- strength as well as lateral stability of the frame. Variations in the column stiffness can influence the mode of failure and lateral stiffness of the bracing. In this study steel frame is modeled and analyzed three Parts viz., (i Model without Steel bracing (bare frame, (ii Model completely with fully braced steel frame („Cross‟ bracing, (iii Model completely with fully braced steel frame („Single diagonal‟ bracing.

  16. Nonlinear circuit analysis of harmonic currents in a floating Langmuir probe with a capacitive load

    Science.gov (United States)

    Kim, Kyung-Hyun; Kim, Dong-Hwan; Chung, Chin-Wook

    2017-02-01

    Plasma diagnostics using the floating harmonic technique were first used to obtain the electron temperature in a tokamak plasma. In this technique, the electron temperature depends on the ratio of the harmonic currents in a resistive sheath. Because these harmonic currents are determined by a modulated sheath voltage, calculation of the exact modulated voltage across the sheath is important; in general, the voltage is calculated using a phase of the first harmonic current. However, when a series load capacitance is present, the second harmonic currents are abnormally reduced compared to those expected by the conventional floating harmonic model, resulting in an unreliable measurement of the electron temperature. To describe this phenomenon, we used a modified floating harmonic model by applying the harmonic balance technique, a method that analyzes nonlinear circuits. Theoretical prediction of the harmonic current obtained from the modified model was compared with the experimental results, and they are in good agreement. In addition, the degrees of sheath nonlinearity, defined as the ratio of the second harmonic current (or voltage) to the fundamental current (or voltage), are discussed.

  17. Innate humoural immunity is related to eggshell bacterial load of European birds: a comparative analysis

    Science.gov (United States)

    Soler, Juan José; Peralta-Sánchez, Juan Manuel; Flensted-Jensen, Einar; Martín-Platero, Antonio Manuel; Møller, Anders Pape

    2011-09-01

    Fitness benefits associated with the development of a costly immune system would include not only self-protection against pathogenic microorganisms but also protection of host offspring if it reduces the probability and the rate of vertical transmission of microorganisms. This possibility predicts a negative relationship between probabilities of vertical transmission of symbionts and level of immune response that we here explore inter-specifically. We estimated eggshell bacterial loads by culturing heterotrophic bacteria, Enterococcus, Staphylococcus and Enterobacteriaceae on the eggshells of 29 species of birds as a proxy of vertical transmission of bacteria from mother to offspring. For this pool of species, we also estimated innate immune response (natural antibody and complement (lysis)) of adults, which constitute the main defence against bacterial infection. Multivariate general linear models revealed the predicted negative association between natural antibodies and density of bacteria on the eggshell of 19 species of birds for which we sampled the eggs in more than one nest. Univariate analyses revealed significant associations for heterotrophic bacteria and for Enterobacteriaceae, a group of bacteria that includes important pathogens of avian embryos. Therefore, these results suggest a possible trans-generational benefit of developing a strong immune system by reducing vertical transmission of pathogens.

  18. Direct methods of soil-structure interaction analysis for earthquake loadings(II)

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Chung Bang; Lee, S. R.; Kim, J. M.; Park, K. L.; Oh, S. B.; Choi, J. S.; Kim, Y. S. [Korea Advanced Institute of Science Technology, Daejeon (Korea, Republic of)

    1994-07-15

    In this study, methods for 3-D soil-structure interaction analysis have been studied. They are 3-D axisymmetric analysis method, 3-D axisymmetric finite element method incorporating infinite elements, and 3-D boundary element methods. The computer code, named as 'KIESSI - PF', has been developed which is based on the 3-D axisymmetric finite element method coupled with infinite element method. It is able to simulate forced vibration test results of a soil-structure interaction system. The Hualien FVT post-correlation analysis before backfill and the blind prediction analysis after backfill have been carried out using the developed computer code 'KIESSI - PF'.

  19. New Finite Elements in Shear Stress Analysis of Saint Venant′s Torsional Loaded Beam Structures

    Institute of Scientific and Technical Information of China (English)

    J. Brnic; G. Turkalj

    2003-01-01

    Recent engineering design as well as material processing on the optimization procedure are based and computeroriented. Finite element stress and sensitivity analysis are the most important things in such modern determinationof optimal solution. According

  20. Comprehensive Forced Response Analysis of J2X Turbine Bladed-Discs with 360 Degree Variation in CFD Loading

    Science.gov (United States)

    Elrod, David; Christensen, Eric; Brown, Andrew

    2011-01-01

    The temporal frequency content of the dynamic pressure predicted by a 360 degree computational fluid dynamics (CFD) analysis of a turbine flow field provides indicators of forcing function excitation frequencies (e.g., multiples of blade pass frequency) for turbine components. For the Pratt and Whitney Rocketdyne J-2X engine turbopumps, Campbell diagrams generated using these forcing function frequencies and the results of NASTRAN modal analyses show a number of components with modes in the engine operating range. As a consequence, forced response and static analyses are required for the prediction of combined stress, high cycle fatigue safety factors (HCFSF). Cyclically symmetric structural models have been used to analyze turbine vane and blade rows, not only in modal analyses, but also in forced response and static analyses. Due to the tortuous flow pattern in the turbine, dynamic pressure loading is not cyclically symmetric. Furthermore, CFD analyses predict dynamic pressure waves caused by adjacent and non-adjacent blade/vane rows upstream and downstream of the row analyzed. A MATLAB script has been written to calculate displacements due to the complex cyclically asymmetric dynamic pressure components predicted by CFD analysis, for all grids in a blade/vane row, at a chosen turbopump running speed. The MATLAB displacements are then read into NASTRAN, and dynamic stresses are calculated, including an adjustment for possible mistuning. In a cyclically symmetric NASTRAN static analysis, static stresses due to centrifugal, thermal, and pressure loading at the mode running speed are calculated. MATLAB is used to generate the HCFSF at each grid in the blade/vane row. When compared to an approach assuming cyclic symmetry in the dynamic flow field, the current approach provides better assurance that the worst case safety factor has been identified. An extended example for a J-2X turbopump component is provided.

  1. Forced Vibration of a Timoshenko Beam Subjected to Stationary and Moving Loads Using the Modal Analysis Method

    Directory of Open Access Journals (Sweden)

    Taehyun Kim

    2017-01-01

    Full Text Available The modal analysis method (MAM is very useful for obtaining the dynamic responses of a structure in analytical closed forms. In order to use the MAM, accurate information is needed on the natural frequencies, mode shapes, and orthogonality of the mode shapes a priori. A thorough literature survey reveals that the necessary information reported in the existing literature is sometimes very limited or incomplete, even for simple beam models such as Timoshenko beams. Thus, we present complete information on the natural frequencies, three types of mode shapes, and the orthogonality of the mode shapes for simply supported Timoshenko beams. Based on this information, we use the MAM to derive the forced vibration responses of a simply supported Timoshenko beam subjected to arbitrary initial conditions and to stationary or moving loads (a point transverse force and a point bending moment in analytical closed form. We then conduct numerical studies to investigate the effects of each type of mode shape on the long-term dynamic responses (vibrations, the short-term dynamic responses (waves, and the deformed shapes of an example Timoshenko beam subjected to stationary or moving point loads.

  2. Criticality Analysis for Proposed Maximum Fuel Loading in a Standardized SNF Canister with Type 1a Baskets

    Energy Technology Data Exchange (ETDEWEB)

    Chad Pope; Larry L. Taylor; Soon Sam Kim

    2007-02-01

    This document represents a summary version of the criticality analysis done to support loading SNF in a Type 1a basket/standard canister combination. Specifically, this engineering design file (EDF) captures the information pertinent to the intact condition of four fuel types with different fissile loads and their calculated reactivities. These fuels are then degraded into various configurations inside a canister without the presence of significant moderation. The important aspect of this study is the portrayal of the fuel degradation and its effect on the reactivity of a single canister given the supposition there will be continued moderation exclusion from the canister. Subsequent analyses also investigate the most reactive ‘dry’ canister in a nine canister array inside a hypothetical transport cask, both dry and partial to complete flooding inside the transport cask. The analyses also includes a comparison of the most reactive configuration to other benchmarked fuels using a software package called TSUNAMI, which is part of the SCALE 5.0 suite of software.

  3. Post-strengthening of reinforced concrete beams with prestressed CFRP strips: part 2: analysis under cyclic loading

    Directory of Open Access Journals (Sweden)

    M. R. Garcez

    Full Text Available Different FPR post-strengthening techniques have been developed and applied in existing structures aiming to increase their load capacity. Most of the FRP systems used nowadays consist of carbon fibers embedded in epoxy matrices (CFRP. Regardless of the advantages and the good results shown by the CFRP post-strengthen technique, experimental studies show that, in most cases, the failure of post-strengthened structures is premature. Aiming to better use the tensile strength of the carbon fiber strips used as post-strengthening material, the application of prestressed CFRP strips started to be investigated. The main purpose of this paper is to analyze the effects of the composite prestressing in the performance of the CFRP post strengthening technique. The experimental program was based on flexural tests on post-strengthened reinforced concrete beams subjected to static - part 1 and cyclic - part 2 loading. Experimental results allowed the analysis of the quality and shortcomings of post-strengthen system studied, which resulted in valuable considerations about the analyzed post-strengthened beams.

  4. SINGLE-SHELL TANK INTEGRITY PROJECT ANALYSIS OF RECORD-PRELIMINARY MODELING PLAN FOR THERMAL AND OPERATING LOADS

    Energy Technology Data Exchange (ETDEWEB)

    RAST RS; RINKER MW; BAPANAALLI SK; DEIBLER JE; GUZMAN-LEONG CE; JOHNSON KI; KARRI NK; PILLI SP; SANBORN SE

    2010-10-22

    This document is a Phase I deliverable for the Single-Shell Tank Analysis of Record effort. This document is not the Analysis of Record. The intent of this document is to guide the Phase II detailed modeling effort. Preliminary finite element models for each of the tank types were developed and different case studies were performed on one or more of these tank types. Case studies evaluated include thermal loading, waste level variation, the sensitivity of boundary effects (soil radial extent), excavation slope or run to rise ratio, soil stratigraphic (property and layer thickness) variation at different farm locations, and concrete material property variation and their degradation under thermal loads. The preliminary analysis document reviews and preliminary modeling analysis results are reported herein. In addition, this report provides recommendations for the next phase of the SST AOR project, SST detailed modeling. Efforts and results discussed in this report do not include seismic modeling as seismic modeling is covered by a separate report. The combined results of both static and seismic models are required to complete this effort. The SST AOR project supports the US Department of Energy's (DOE) Office of River Protection (ORP) mission for obtaining a better understanding of the structural integrity of Hanford's SSTs. The 149 SSTs, with six different geometries, have experienced a range of operating histories which would require a large number of unique analyses to fully characterize their individual structural integrity. Preliminary modeling evaluations were conducted to determine the number of analyses required for adequate bounding of each of the SST tank types in the Detailed Modeling Phase of the SST AOR Project. The preliminary modeling was conducted in conjunction with the Evaluation Criteria report, Johnson et al. (2010). Reviews of existing documents were conducted at the initial stage of preliminary modeling. These reviews guided the topics

  5. Analysis of the temperature and thermal stress in pure tungsten monoblock during heat loading and the influences of alloying and dispersion strengthening on these responses

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Makoto, E-mail: makoto.fukuda@qse.tohoku.ac.jp [Tohoku University, 6-6-01-2 Aramaki-aza Aoba, Aobaku, Sendai, 980-8579 (Japan); Nogami, Shuhei; Guan, Wenhai; Hasegawa, Akira [Tohoku University, 6-6-01-2 Aramaki-aza Aoba, Aobaku, Sendai, 980-8579 (Japan); Muroga, Takeo [National Institute for Fusion Science, 322-6 Oroshi-cho, Gifu, 509-5292 (Japan)

    2016-06-15

    Highlights: • The heat load response of pure W and its alloys monoblock was investigated by FEA. • The effect of alloying on heat load response of W was not clearly observed. • The possibility of cracking during cooling phase after heat load was suggested. • The effects of recrystallization and irradiation embrittlement were discussed. • W alloys will show better reliability than pure W during fusion reactor operation. - Abstract: The effects of 3% Re addition and K-bubble dispersion on temperature and stress values and the distributions thereof in a W monoblock during heat loading were investigated using finite element analysis. K-doped W-3%Re exhibited the highest recrystallization resistance but showed a higher surface temperature than pure W or K-doped W during the heat loading. The effect of K-bubble dispersion and 3% Re addition on thermal stress distribution during heat loading was not clearly observed, and residual tensile stress after heat loading, which could possibly cause cracking, was observed at the top surfaces of all materials. Because of the higher strength and temperature at which recrystallization starts for the K-doped W-3%Re and K-doped W, the probability of crack formation at the top surface might be lower compared to that in pure W. The improvement in the material properties and resistance to crack initiation and propagation in W during cyclic heat loading is crucial for the design and development of plasma-facing components. This work suggests possibility of the crack formation in a pure W monoblock in the cooling phase after a 20 MW/m{sup 2} heat loading cycle and the effectiveness of K-bubble dispersion and Re addition for improving the heat loading resistance of monoblock W.

  6. Flight Testing and Real-Time System Identification Analysis of a UH-60A Black Hawk Helicopter with an Instrumented External Sling Load

    Science.gov (United States)

    McCoy, Allen H.

    1998-01-01

    Helicopter external air transportation plays an important role in today's world. For both military and civilian helicopters, external sling load operations offer an efficient and expedient method of handling heavy, oversized cargo. With the ability to reach areas otherwise inaccessible by ground transportation, helicopter external load operations are conducted in industries such as logging, construction, and fire fighting, as well as in support of military tactical transport missions. Historically, helicopter and load combinations have been qualified through flight testing, requiring considerable time and cost. With advancements in simulation and flight test techniques there is potential to substantially reduce costs and increase the safety of helicopter sling load certification. Validated simulation tools make possible accurate prediction of operational flight characteristics before initial flight tests. Real time analysis of test data improves the safety and efficiency of the testing programs. To advance these concepts, the U.S. Army and NASA, in cooperation with the Israeli Air Force and Technion, under a Memorandum of Agreement, seek to develop and validate a numerical model of the UH-60 with sling load and demonstrate a method of near real time flight test analysis. This thesis presents results from flight tests of a U.S. Army Black Hawk helicopter with various external loads. Tests were conducted as the U.S. first phase of this MOA task. The primary load was a container express box (CONEX) which contained a compact instrumentation package. The flights covered the airspeed range from hover to 70 knots. Primary maneuvers were pitch and roll frequency sweeps, steps, and doublets. Results of the test determined the effect of the suspended load on both the aircraft's handling qualities and its control system's stability margins. Included were calculations of the stability characteristics of the load's pendular motion. Utilizing CIFER(R) software, a method for near

  7. On diagnosis measurement under dynamic loading of ball bearing using numerical thermal analysis and infrared thermography

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Dong Pyo; Kim, Ho Jong [School of Mechanical System Engineering, Chonbuk Nationa University, Jeonju (Korea, Republic of); Kim, Won Tae [School of Mechanical and Automotive Engineering, Kongju National University, Kongju (Korea, Republic of)

    2013-08-15

    With the modern machinery towards the direction of high-speed development, the thermal issues of mechanical transmission system and its components is increasingly important. Ball bearing is one of the main parts in rotating machinery system, and is a more easily damaged part. In this paper, bearing thermal fault detection is investigated in details Using infrared thermal imaging technology to the operation state of the ball bearing, a preliminary thermal analysis, and the use of numerical simulation technology by finite element method(FEM) under thermal conditions of the bearing temperature field analysis, initially identified through these two technical analysis, bearing a temperature distribution in the normal state and failure state. It also shows the reliability of the infrared thermal imaging technology with valuable suggestions for the future bearing fault detection.

  8. NONLINEAR ANALYSIS OF CFRP- PRESTRESSED CONCRETE BEAMS SUBJECTED TO INCREMENTAL STATIC LOADING BY FINITE ELEMENTS

    Directory of Open Access Journals (Sweden)

    Husain M. Husain

    2013-05-01

    Full Text Available In this work a program is developed to carry out the nonlinear analysis (material nonlinearity of prestressed concrete beams using tendons of carbon fiber reinforced polymer (CFRP instead of steel. The properties of this material include high strength, light weight, and insusceptibility to corrosion and magnetism. This material is still under investigation, therefore it needs continuous work to make it beneficial in concrete design. Four beams which are tested experimentally by Yan et al. are examined by the developed computer program to reach a certain analytical approach of the design and analysis of such beams because there is no available restrictions or recommendations covering this material in the codes. The program uses the finite element analysis by dividing the beams into isoparametric 20-noded brick elements. The results obtained are good in comparison with experimental results.

  9. Reliability assessment of offshore platforms exposed to wave-in-deck loading. Appendix F: Reliability analysis of offshore jacket structures with wave load on deck using the model correction factor method

    Energy Technology Data Exchange (ETDEWEB)

    Dalsgaard Soerensen, J. [Aalborg Univ., Aalborg (Denmark); Friis-Hansen, P. [Technical Univ. Denmark, Lyngby (Denmark); Bloch, A.; Svejgaard Nielsen, J. [Ramboell, Esbjerg (Denmark)

    2004-08-01

    Different simple stochastic models for failure related to pushover collapse are investigated. Next, a method is proposed to estimate the reliability of real offshore jacket structures. The method is based on the Model Correction Factor Method and can be used to very efficiently to estimate the reliability for total failure/collapse of jacket type platforms with wave in deck loads. A realistic example is evaluated and it is seen that it is possible to perform probabilistic reliability analysis for collapse of a jacket type platform using the model correction factor method. The total number of deterministic, complicated, non-linear (RONJA) analysis is typically as low as 10. Such reliability analyses are recommended to be used in practical applications, especially for cases with wave in deck load, where the traditional RSR analyses give poor measures of the structural reliability. (au)

  10. Direct methods of soil-structure interaction analysis for earthquake loadings (III)

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J. B.; Lee, S. R.; Kim, J. M.; Park, K. R.; Choi, J. S.; Oh, S. B. [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1995-06-15

    In this study, direct methods for seismic analysis of soil-structure interaction system have been studied. A computer program 'KIESSI-QK' has been developed based on the finite element technique coupled with infinite element formulation. A substructuring method isolating the displacement solution of near field soil region was adopted. The computer program developed was verified using a free-field site response problem. The post-correlation analysis for the forced vibration tests after backfill of the Hualien LSST project has been carried out. The seismic analyses for the Hualien and Lotung LSST structures have been also performed utilizing the developed computer program 'KIESSI-QK'.

  11. A case study demonstrating analysis of stormflows, concentrations, and loads of nutrients in highway runoff and swale discharge with the Stochastic Empirical Loading and Dilution Model (SELDM)

    Science.gov (United States)

    Granato, Gregory; Jones, Susan C.

    2015-01-01

    Decisionmakers need information about the quality and quantity of stormwater runoff, the risk for adverse effects of runoff on receiving waters, and the potential effectiveness of mitigation measures to reduce these risks. The Stochastic Empirical Loading and Dilution Model (SELDM) uses Monte Carlo methods to generate stormflows, concentrations, and loads from a highway site and an upstream basin to provide needed risk-based information. SELDM was designed to help inform water-management decisions for streams and lakes receiving runoff from a highway or other land-use site. The purpose of this paper is to provide a brief description of SELDM and a hypothetical case study demonstrating the type of risk-based information that SELDM can provide. Total nitrogen (TN) and total phosphorus (TP) were selected as example constituents because nutrients are a common concern throughout the Nation and data for receiving waters, highway runoff, and the performance of best management practices (BMPs) are readily available for these constituents. 

  12. A computational component analysis of dielectric relaxation and THz spectra of water/AOT reverse micelles with different water loading

    Science.gov (United States)

    Schmollngruber, Michael; Braun, Daniel; Steinhauser, Othmar

    2016-12-01

    In this computational study, we present molecular dynamics simulations of water/aerosol-OT/isooctane reverse micelles with different water loading. We compare these systems in terms of a detailed analysis of dielectric relaxation spectra and water librations in the THz region. The spectra are decomposed into contributions by molecular species and contributions from individual water solvation shells. Additionally, micellar tumbling motion is shown to have a profound influence on the observed dielectric relaxation spectra, if relaxation by internal reorganization and micellar tumbling occurs within similar time scales. A formalism to directly quantify the effect of micellar tumbling motion on a recorded dielectric spectrum is developed. Since micellar rotational diffusion obeys the laws of hydrodynamics, this method is applicable in an experimental context as well, only knowing the viscosity of the outside medium and the average volume of the reverse micelle.

  13. Validity of Simplified Analysis of Stability of Caison Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Andersen, Lars; Burcharth, Hans F.; Andersen, Thomas Lykke

    Excessive sliding and foundation failures are common failure modes for caisson breakwaters on rubble foundations. An accurate evaluation of these failure modes demands a dynamic analysis in the time domain, and due to the complexity of the material response, numerical solution methods must be app...

  14. Substructure method of soil-structure interaction analysis for earthquake loadings

    Energy Technology Data Exchange (ETDEWEB)

    Park, H. G.; Joe, Y. H. [Industrial Development Research Center, Univ. of Incheon, Incheon (Korea, Republic of)

    1997-07-15

    Substructure method has been preferably adopted for soil-structure interaction analysis because of its simplicity and economy in practical application. However, substructure method has some limitation in application and does not always give reliable results especially for embedded structures or layered soil conditions. The objective of this study to validate the reliability of the soil-structure interaction analysis results by the proposed substructure method using lumped-parameter model and suggest a method of seismic design of nuclear power plant structures with specific design conditions. In this study, theoretic background and modeling technique of soil-structure interaction phenomenon have been reviewed and an analysis technique based on substructure method using lumped-parameter model has been suggested. The practicality and reliability of the proposed method have been validated through the application of the method to the seismic analysis of the large-scale seismic test models. A technical guide for practical application and evaluation of the proposed method have been also provided through the various type parametric.

  15. SINGLE-SHELL TANK INTEGRITY PROJECT ANALYSIS OF RECORD-PRELIMINARY MODELING PLAN FOR THERMAL AND OPERATING LOADS

    Energy Technology Data Exchange (ETDEWEB)

    RAST RS; RINKER MW; BAPANAALLI SK; DEIBLER JE; GUZMAN-LEONG CE; JOHNSON KI; KARRI NK; PILLI SP; SANBORN SE

    2010-10-22

    This document is a Phase I deliverable for the Single-Shell Tank Analysis of Record effort. This document is not the Analysis of Record. The intent of this document is to guide the Phase II detailed modeling effort. Preliminary finite element models for each of the tank types were developed and different case studies were performed on one or more of these tank types. Case studies evaluated include thermal loading, waste level variation, the sensitivity of boundary effects (soil radial extent), excavation slope or run to rise ratio, soil stratigraphic (property and layer thickness) variation at different farm locations, and concrete material property variation and their degradation under thermal loads. The preliminary analysis document reviews and preliminary modeling analysis results are reported herein. In addition, this report provides recommendations for the next phase of the SST AOR project, SST detailed modeling. Efforts and results discussed in this report do not include seismic modeling as seismic modeling is covered by a separate report. The combined results of both static and seismic models are required to complete this effort. The SST AOR project supports the US Department of Energy's (DOE) Office of River Protection (ORP) mission for obtaining a better understanding of the structural integrity of Hanford's SSTs. The 149 SSTs, with six different geometries, have experienced a range of operating histories which would require a large number of unique analyses to fully characterize their individual structural integrity. Preliminary modeling evaluations were conducted to determine the number of analyses required for adequate bounding of each of the SST tank types in the Detailed Modeling Phase of the SST AOR Project. The preliminary modeling was conducted in conjunction with the Evaluation Criteria report, Johnson et al. (2010). Reviews of existing documents were conducted at the initial stage of preliminary modeling. These reviews guided the topics

  16. Study of concrete's behavior under 4-point bending load using Coda Wave Interferometry (CWI) analysis

    Science.gov (United States)

    Zhang, Y.; Abraham, O.; Chapeleau, X.; Cottineau, L.-M.; Tournat, V.; Le Duff, A.; Lascoup, B.; Durand, O.

    2013-01-01

    Coda Wave Interferometry (CWI) is an ultrasonic NDT method suitable for complex material such as concrete that can precisely measure small propagation velocity variation (10-2%). By measuring variation of propagation velocity in concrete caused by acoustoelasticity phenomena, CWI analysis can be used to monitor concrete's internal stress level. For the first time, CWI is used to measure propagation velocity variations due to a stress field in a concrete beam under four-points bending test, which contains simultaneously compressive and tensile stress. Embedded optical-fiber sensors, strain gauges are used in the experiment, in order to confirm and validate the CWI analysis result. Thermocouples are also embedded into concrete beams for monitoring internal temperature fluctuations.

  17. Load research and load estimation in electricity distribution

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A. [VTT Energy, Espoo (Finland). Energy Systems

    1996-12-31

    The topics introduced in this thesis are: the Finnish load research project, a simple form customer class load model, analysis of the origins of customers load distribution, a method for the estimation of the confidence interval of customer loads and Distribution Load Estimation (DLE) which utilises both the load models and measurements from distribution networks. The Finnish load research project started in 1983. The project was initially coordinated by the Association of Finnish Electric Utilities and 40 utilities joined the project. Now there are over 1000 customer hourly load recordings in a database. A simple form customer class load model is introduced. The model is designed to be practical for most utility applications and has been used by the Finnish utilities for several years. The only variable of the model is the customers annual energy consumption. The model gives the customers average hourly load and standard deviation for a selected month, day and hour. The statistical distribution of customer loads is studied and a model for customer electric load variation is developed. The model results in a lognormal distribution as an extreme case. Using the `simple form load model`, a method for estimating confidence intervals (confidence limits) of customer hourly load is developed. The two methods selected for final analysis are based on normal and lognormal distribution estimated in a simplified manner. The estimation of several cumulated customer class loads is also analysed. Customer class load estimation which combines the information from load models and distribution network load measurements is developed. This method, called Distribution Load Estimation (DLE), utilises information already available in the utilities databases and is thus easy to apply

  18. Deflection and Supporting Force Analysis of a Slender Beam under Combined Transverse and Tensile Axial Loads

    Science.gov (United States)

    2016-05-01

    supporting force analysis of a static pressure pipe that is to be used in the Defence Science and Technology Group Transonic Wind Tunnel test...Technology Group Transonic Wind Tunnel test facility. The static pressure pipe analysed herein was modelled as a slender propped cantilever beam...the Defence Science and Technology Group Transonic Wind Tunnel facility. A layout diagram of the static pressure pipe installation is shown in

  19. Static and Dynamic Stability Analysis of Distributed Energy Resources Components with Storage Devices and Loads for Smart Grids

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Groza, V.

    2011-01-01

    The distributed energy resources (DER) contains several technologies, such as diesel engines, small wind turbines, photovoltaic inverters, etc. The control of DER components with storage devices and (controllable) loads, such as batteries, capacitors, dump loads, are central to the concept of the...... are required under different operation modes and loads. The testing reporting here includes three modes of operation: stand alone, parallel/hybrid and grid connection.......The distributed energy resources (DER) contains several technologies, such as diesel engines, small wind turbines, photovoltaic inverters, etc. The control of DER components with storage devices and (controllable) loads, such as batteries, capacitors, dump loads, are central to the concept...

  20. Analysis of bonded anisotropic wedges with interface crack under anti-plane shear loading

    Institute of Scientific and Technical Information of China (English)

    M.GHADIRI; A.R.SHAHANI

    2014-01-01

    The antiplane stress analysis of two anisotropic finite wedges with arbitrary radii and apex angles that are bonded together along a common edge is investigated. The wedge radial boundaries can be subjected to displacement-displacement boundary condi-tions, and the circular boundary of the wedge is free from any traction. The new finite complex transforms are employed to solve the problem. These finite complex transforms have complex analogies to both kinds of standard finite Mellin transforms. The traction free condition on the crack faces is expressed as a singular integral equation by using the exact analytical method. The explicit terms for the strength of singularity are extracted, showing the dependence of the order of the stress singularity on the wedge angle, material constants, and boundary conditions. A numerical method is used for solving the resul-tant singular integral equations. The displacement boundary condition may be a general term of the Taylor series expansion for the displacement prescribed on the radial edge of the wedge. Thus, the analysis of every kind of displacement boundary conditions can be obtained by the achieved results from the foregoing general displacement boundary condition. The obtained stress intensity factors (SIFs) at the crack tips are plotted and compared with those obtained by the finite element analysis (FEA).

  1. Analysis of Plasma-Sprayed Thermal Barrier Coatings With Homogeneous and Heterogeneous Bond Coats Under Spatially Uniform Cyclic Thermal Loading

    Science.gov (United States)

    Arnold, Steven M.; Pindera, Marek-Jerzy; Aboudi, Jacob

    2003-01-01

    This report summarizes the results of a numerical investigation into the spallation mechanism in plasma-sprayed thermal barrier coatings observed under spatially-uniform cyclic thermal loading. The analysis focuses on the evolution of local stress and inelastic strain fields in the vicinity of the rough top/bond coat interface during thermal cycling, and how these fields are influenced by the presence of an oxide film and spatially uniform and graded distributions of alumina particles in the metallic bond coat aimed at reducing the top/bond coat thermal expansion mismatch. The impact of these factors on the potential growth of a local horizontal delamination at the rough interface's crest is included. The analysis is conducted using the Higher-Order Theory for Functionally Graded Materials with creep/relaxation constituent modeling capabilities. For two-phase bond coat microstructures, both the actual and homogenized properties are employed in the analysis. The results reveal the important contributions of both the normal and shear stress components to the delamination growth potential in the presence of an oxide film, and suggest mixed-mode crack propagation. The use of bond coats with uniform or graded microstructures is shown to increase the potential for delamination growth by increasing the magnitude of the crack-tip shear stress component.

  2. Strategy for solving a coupled problem of the electromagnetic load analysis and design optimization for local conducting structures to support the ITER blanket development

    Energy Technology Data Exchange (ETDEWEB)

    Rozov, Vladimir, E-mail: vladimir.rozov@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-lez-Durance (France); Belyakov, V.; Kukhtin, V.; Lamzin, E.; Mazul, I.; Sytchevsky, S. [D.V. Efremov Scientific Research Institute, 196641 St. Petersburg (Russian Federation)

    2014-11-15

    Highlights: • We present the way of modeling transient electro-magnetic loads on local conductive domains in the large magnetic system. • Simplification is achieved by decomposing of the problem, multi-scale integral-differential modeling and use of integral parameters. • The intrinsic scale of loads on a localized conductor with eddy is quantified through the load susceptibility tensor. • Solution is searched as response of a simple equivalent dynamic simulator, using control theory methods. • The concept is exemplified with multi-scenario assessment of EM eddy loads on ITER blanket modules. - Abstract: The complexity of the electromagnetic (EM) response of the tokamak structures is one of the key and design-driving issues for the ITER. We consider the specifics of the assessment of ponderomotive forces, acting on local components of a large electro-physical device during electromagnetic transients. A strategy and approach is proposed for the operative EM loads modeling and analysis that enables design optimization at early phases of development. The paper describes a method of principal simplification of the mathematical model, based on the analysis and exploiting specific features and peculiarities of the relevant technical problem, determined by the design and operation of the device and system under consideration. The application of the method for predictive EM loads analysis and corresponding numerical calculations are exemplified for the localized ITER blanket components — shield modules. The example demonstrates the efficiency of EM load analysis in complex electromagnetic systems via a set of simplified models with different scope, contents and level of detail.

  3. Analysis on the Load Carrying Mechanism Integrated as Heterogeneous Co-operative Manipulator in a Walking Wheelchair

    Science.gov (United States)

    Rajay Vedaraj, I. S.; Jain, Ritika; Rao, B. V. A.

    2014-07-01

    used for climbing stairs with three leg design and anlaysis were also done on the mechanism integrated to the system. Kinematics of the legs are analysed separately and the legs are designed to carry a maximum of 175kgs, which is sustained by the center leg and shared by the dual wing legs equally during the walking phase. In the proposed design, screwjack mechanism is used as the central leg to share the load and thus the analysis on the load sharing capability of the whole system is analysed and concluded in terms of failure modes.

  4. Thermal output analysis of a designed parabolic trough solar field for moderate temperature industrial load

    Directory of Open Access Journals (Sweden)

    Rizwan Masood

    2016-04-01

    Full Text Available This paper presents an overview of the Parabolic Trough Solar Collectors, which is a fastest growing technology amongst concentrated solar power technologies. It is largely being used in developed countries; mainly in steam power cycles for electricity generation but its use is not limited to electric power generation. This technology is also being used for many other applications like refrigeration and air-conditioning, desalination of sea water, pumping of irrigation water and many other heating applications for process industry. Though this technology is already being used in many developed countries but there is barely any development in Malaysia. There is thus need for assessment of this technology to explore the potential industrial applications, under local environmental conditions. In this article basic design and development considerations for a parabolic trough collector system have been discussed. This paper also includes a thermal output analysis of a designed parabolic trough solar field to provide the baseline information for industrial applications feasibility study. System Advisor Model (SAM has been used for this analysis, under environmental conditions of Ipoh, Malaysia. The results of simulation indicate that considerable amount of high temperature thermal energy can be obtained. The heat transfer fluid temperature reached up to 200 to 230oC, which can be used to operate an unfired boiler to produce steam or in some other industrial thermal application.

  5. Numerical Analysis on Failure Modes and Mechanisms of Mine Pillars under Shear Loading

    Directory of Open Access Journals (Sweden)

    Tianhui Ma

    2016-01-01

    Full Text Available Severe damage occurs frequently in mine pillars subjected to shear stresses. The empirical design charts or formulas for mine pillars are not applicable to orebodies under shear. In this paper, the failure process of pillars under shear stresses was investigated by numerical simulations using the rock failure process analysis (RFPA 2D software. The numerical simulation results indicate that the strength of mine pillars and the corresponding failure mode vary with different width-to-height ratios and dip angles. With increasing dip angle, stress concentration first occurs at the intersection between the pillar and the roof, leading to formation of microcracks. Damage gradually develops from the surface to the core of the pillar. The damage process is tracked with acoustic emission monitoring. The study in this paper can provide an effective means for understanding the failure mechanism, planning, and design of mine pillars.

  6. Statistical Analysis of the Progressive Failure Behavior for Fiber-Reinforced Polymer Composites under Tensile Loading

    Directory of Open Access Journals (Sweden)

    Fang Wang

    2014-01-01

    Full Text Available An analytical approach with the help of numerical simulations based on the equivalent constraint model (ECM was proposed to investigate the progressive failure behavior of symmetric fiber-reinforced composite laminates damaged by transverse ply cracking. A fracture criterion was developed to describe the initiation and propagation of the transverse ply cracking. This work was also concerned with a statistical distributions of the critical fracture toughness values with due consideration given to the scale size effect. The Monte Carlo simulation technique coupled with statistical analysis was applied to study the progressive cracking behaviors of composite structures, by considering the effects of lamina properties and lay-up configurations. The results deduced from the numerical procedure were in good agreement with the experimental results obtained for laminated composites formed by unidirectional fiber reinforced laminae with different orientations.

  7. CRITICAL ANALYSIS OF LOADING BY TECHNOLOGY RECONDITIONING, WITH APPLICATION TO REPAIR PIECES OF AUTO INDUSTRY

    Directory of Open Access Journals (Sweden)

    Gheorghe AMZA

    2015-05-01

    Full Text Available The problem of exploitation of diamond grinding wheels with metal coating for their grains including detonation ultra-dispersed diamonds to increase functional reliability to maintain the initial integrity of grains in the pressing and sintering of diamond-metal composites in the tool production is considered. One problem is that the presence of detonation ultra-dispersed diamonds in the grain metal coating of diamond powders not only improves the coating functional reliability in protection from destruction in the subsequent pressing and sintering in the production tool, but also resistance of such coating to the opening of the diamond cutting basis of the grains on the grinding wheel working surface that come into working contact with the material being processed. An analysis of the features of an effective exploitative destruction of detonation ultra-dispersed diamonds in the metal coating using electric current in the tool of the diamondspark grinding processes is presented.

  8. Contact Stress Analysis around Elliptical Bolt-loaded Hole in Orthotropic Plates

    Directory of Open Access Journals (Sweden)

    O. Aluko

    2012-12-01

    Full Text Available The practicality of changing the bolt shape from circular to elliptical under friction effects in order to reduce the contact stress distributions was analytically investigated. The analysis utilized the complex stress functions obtained from the assumed displacement expressions that satisfy the boundary conditions around the hole to determine the contact stresses. In the method of solution coulomb friction was used to determine the prescribed displacements at the boundary. The material properties of graphite/epoxy and carbon fiber reinforced plastics laminates were used in this investigation and the results compared with available literature. It was revealed that the stress distributions followed the same pattern in both geometries but with lower magnitude in elliptical shape and the reduction in stress distributions caused by changing the bolt shape from circular to elliptic depend on friction coefficient.

  9. Depletion Analysis of Modular High Temperature Gas-cooled Reactor Loaded with LEU/Thorium Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Sonat Sen; Gilles Youinou

    2013-02-01

    Thorium based fuel has been considered as an option to uranium-based fuel, based on considerations of resource utilization (Thorium is more widely available when compared to Uranium). The fertile isotope of Thorium (Th-232) can be converted to fissile isotope U-233 by neutron capture during the operation of a suitable nuclear reactor such as High Temperature Gas-cooled Reactor (HTGR). However, the fertile Thorium needs a fissile supporter to start and maintain the conversion process such as U-235 or Pu-239. This report presents the results of a study that analyzed the thorium utilization in a prismatic HTGR, namely Modular High Temperature Gas-Cooled Reactor (MHTGR) that was designed by General Atomics (GA). The collected for the modeling of this design come from Chapter 4 of MHTGR Preliminary Safety Information Document that GA sent to Department of Energy (DOE) on 1995. Both full core and unit cell models were used to perform this analysis using SCALE 6.1 and Serpent 1.1.18. Because of the long mean free paths (and migration lengths) of neutrons in HTRs, using a unit cell to represent a whole core can be non-trivial. The sizes of these cells were set to match the spectral index between unit cell and full core domains. It was found that for the purposes of this study an adjusted unit cell model is adequate. Discharge isotopics and one-group cross-sections were delivered to the transmutation analysis team. This report provides documentation for these calculations

  10. Dynamic Response Analysis of Storage Cask Lid Structure Subjected to Lateral Impact Load of Aircraft Engine Crash

    Energy Technology Data Exchange (ETDEWEB)

    Almomania, Belal; Kang, Hyun Gook [KAIST, Daejeon (Korea, Republic of); Lee, Sanghoon [Keimyung Univ., Daegu (Korea, Republic of)

    2015-10-15

    Several numerical methods and tests have been carried out to measure the capability of storage cask to withstand extreme impact loads. Testing methods are often constrained by cost, and difficulty in preparation for several impact conditions with different applied loads, and areas of impact. Instead, analytic method is an acceptable process that can easily apply different impact conditions for the evaluation of cask integrity. The aircraft engine impact is considered as one of the most critical impact accidents on the storage cask that significantly affects onto the lid closure system and may cause a considerable release of radioactive materials. This paper presents a method for evaluating the dynamic responses of one upper metal cask lid closure without impact limiters subjected to lateral impact of an aircraft engine with respect to variation of the impact velocity. An assessment method to predict damage response due to the lateral engine impact onto metal storage cask has been studied by using computer code LS-DYNA. The dynamic behavior of the lid movements was successfully calculated by utilizing a simplified finite element cask model, which showed a good agreement with the previous research. The simulation analyses results showed that no significant plastic deformation for bolts, lid, and the cask body. In this study, the lid opening and sliding displacements are considered as the major factors in initiating the leakage path. This analysis may be useful for evaluating the instantaneous leakage rates in a connection with the sliding and opening displacements between the lid and the flange to ensure that the radiological consequences caused by an aircraft engine crash accident during the storage phase are within the permissible level.

  11. Finite element analysis of different loading conditions for implant-supported overdentures supported by conventional or mini implants.

    Science.gov (United States)

    Solberg, K; Heinemann, F; Pellikaan, P; Keilig, L; Stark, H; Bourauel, C; Hasan, I

    2017-03-10

    The effect of implants' number on overdenture stability and stress distribution in edentulous mandible, implants and overdenture was numerically investigated for implant-supported overdentures. Three models were constructed. Overdentures were connected to implants by means of ball head abutments and rubber ring. In model 1, the overdenture was retained by two conventional implants; in model 2, by four conventional implants; and in model 3, by five mini implants. The overdenture was subjected to a symmetrical load at an angle of 20 degrees to the overdenture at the canine regions and vertically at the first molars. Four different loading conditions with two total forces (120, 300 N) were considered for the numerical analysis. The overdenture displacement was about 2.2 times higher when five mini implants were used rather than four conventional implants. The lowest stress in bone bed was observed with four conventional implants. Stresses in bone were reduced by 61% in model 2 and by 6% in model 3 in comparison to model 1. The highest stress was observed with five mini implants. Stresses in implants were reduced by 76% in model 2 and 89% increased in model 3 compared to model 1. The highest implant displacement was observed with five mini implants. Implant displacements were reduced by 29% in model 2, and increased by 273% in model 3 compared to model 1. Conventional implants proved better stability for overdenture than mini implants. Regardless the type and number of implants, the stress within the bone and implants are below the critical limits.

  12. Man-machine Integration Design and Analysis System (MIDAS) Task Loading Model (TLM) experimental and software detailed design report

    Science.gov (United States)

    Staveland, Lowell

    1994-01-01

    This is the experimental and software detailed design report for the prototype task loading model (TLM) developed as part of the man-machine integration design and analysis system (MIDAS), as implemented and tested in phase 6 of the Army-NASA Aircrew/Aircraft Integration (A3I) Program. The A3I program is an exploratory development effort to advance the capabilities and use of computational representations of human performance and behavior in the design, synthesis, and analysis of manned systems. The MIDAS TLM computationally models the demands designs impose on operators to aide engineers in the conceptual design of aircraft crewstations. This report describes TLM and the results of a series of experiments which were run this phase to test its capabilities as a predictive task demand modeling tool. Specifically, it includes discussions of: the inputs and outputs of TLM, the theories underlying it, the results of the test experiments, the use of the TLM as both stand alone tool and part of a complete human operator simulation, and a brief introduction to the TLM software design.

  13. Systematic review and meta-analysis of hepatitis C virus infection and HIV viral load: new insights into epidemiologic synergy

    Directory of Open Access Journals (Sweden)

    Nicholas Petersdorf

    2016-09-01

    Full Text Available Introduction: Hepatitis C virus (HCV and HIV infection frequently co-occur due to shared transmission routes. Co-infection is associated with higher HCV viral load (VL, but less is known about the effect of HCV infection on HIV VL and risk of onward transmission. Methods: We undertook a systematic review comparing 1 HIV VL among ART-naïve, HCV co-infected individuals versus HIV mono-infected individuals and 2 HIV VL among treated versus untreated HCV co-infected individuals. We performed a random-effects meta-analysis and quantified heterogeneity using the I2 statistic. We followed Cochrane Collaboration guidelines in conducting our review and PRISMA guidelines in reporting results. Results and discussion: We screened 3925 articles and identified 17 relevant publications. A meta-analysis found no evidence of increased HIV VL associated with HCV co-infection or between HIV VL and HCV treatment with pegylated interferon-alpha-2a/b and ribavirin. Conclusions: This finding is in contrast to the substantial increases in HIV VL observed with several other systemic infections. It presents opportunities to elucidate the biological pathways that underpin epidemiological synergy in HIV co-infections and may enable prediction of which co-infections are most important to epidemic control.

  14. Systematic review and meta-analysis of hepatitis C virus infection and HIV viral load: new insights into epidemiologic synergy

    Science.gov (United States)

    Petersdorf, Nicholas; Ross, Jennifer M; Weiss, Helen A; Barnabas, Ruanne V; Wasserheit, Judith N

    2016-01-01

    Introduction Hepatitis C virus (HCV) and HIV infection frequently co-occur due to shared transmission routes. Co-infection is associated with higher HCV viral load (VL), but less is known about the effect of HCV infection on HIV VL and risk of onward transmission. Methods We undertook a systematic review comparing 1) HIV VL among ART-naïve, HCV co-infected individuals versus HIV mono-infected individuals and 2) HIV VL among treated versus untreated HCV co-infected individuals. We performed a random-effects meta-analysis and quantified heterogeneity using the I2 statistic. We followed Cochrane Collaboration guidelines in conducting our review and PRISMA guidelines in reporting results. Results and discussion We screened 3925 articles and identified 17 relevant publications. A meta-analysis found no evidence of increased HIV VL associated with HCV co-infection or between HIV VL and HCV treatment with pegylated interferon-alpha-2a/b and ribavirin. Conclusions This finding is in contrast to the substantial increases in HIV VL observed with several other systemic infections. It presents opportunities to elucidate the biological pathways that underpin epidemiological synergy in HIV co-infections and may enable prediction of which co-infections are most important to epidemic control. PMID:27649908

  15. Ergonomic analysis in the manual transport of loads: a case study in a cement production company

    Directory of Open Access Journals (Sweden)

    Jarbas Rocha Martins

    2017-03-01

    Full Text Available This study aims to analyze the manual transport activity of 50kg bags in a cement production company by means of ergonomic work analysis (EWA, identifying environmental factors and loaders’ working conditions. In order for EWA to take place, photographic records, videos and interviews were performed. It covered aspects related to lifting, transportation and handling of cement bags, as well as observations of loaders’ posture while performing the activity. In this sense, both qualitative and quantitative aspects were taken into account, which were evidenced by the use of instruments for determining the concentration of agents in the environment. In addition, some management tools, such as the cause and effect diagram, and interviews conducted during the field research were used. It was found that the high rate of absenteeism in the activity is related to the strict control of productivity, the excessive lifting and manual transport of weights, and repetitive trunk flexion movements. The results shown by the EWA made it possible to propose preventive measures and some changes in the work environment.

  16. Numerical Analysis on Aerodynamic Behavior of a Hemispherical Structure under Different Wind Loading

    Directory of Open Access Journals (Sweden)

    R. Verma

    2016-04-01

    Full Text Available Light weight and adaptability in structures have attracted researchers towards the development of inflatable structures. These light weighted inflatable structures are used as emergency shelters, as a decoy and also as a permanent building. Earlier reports shows many cases in which these light weight structure have collapsed due to adverse wind conditions. This damage caused to these structures may be attributed to its poor wind resistance design conditions. Also, due to the uncertainties, there is limited and very few information representing the aerodynamic behaviour of the wind over hemispherical dome structures. An attempt is herewith made to find out the aerodynamic behaviour of the wind passing through a hemispherical shaped structure. CFD software FLUENT has been used to perform the analysis of a dome model in Indian wind conditions. Before study, the CFD code has been validated against experimental data available in literature. It is found that the realizable k-ε turbulent model shows good agreement with experimental data. The value of drag coefficient (Cd has been calculated by using frontal area of the structure and it is found out to be 0.32. The results with different wind conditions obtained by CFD shows that the increase in turbulent intensity in the flow field highly influences the drag force and it increase approximately 14% for a highly turbulent wind condition

  17. Implementation of three-phase transformer model in radial load-flow analysis

    Directory of Open Access Journals (Sweden)

    Mamdouh Abdel-Akher

    2013-03-01

    Full Text Available This paper presents an efficient approach for developing three-phase transformer admittance matrices in the radial power-flow analysis. The proposed transformer model overcomes the singularity problem of the nodal admittance submatrices of ungrounded transformer configurations. This has been achieved by applying symmetrical components modeling. The classical (6 × 6 transformer nodal admittance matrix written in phase components is converted to sequence components instead of the (3 × 3 admittance submatrices. In this model, the phase shifts accompanied with special transformer connections are included in the radial power-flow solution process without any convergence problems. The final model of the transformer is represented by a generalized power-flow equation written in phase components. The developed equation is applicable for all transformer connections. The transformer model is integrated into the radial power-flow and tested using the IEEE radial feeders. The results have shown that the developed transformer model is very efficient and the radial power-flow has robust convergence characteristics.

  18. Fracture load and failure analysis of zirconia single crowns veneered with pressed and layered ceramics after chewing simulation.

    Science.gov (United States)

    Stawarczyk, Bogna; Ozcan, Mutlu; Roos, Malgorzata; Trottmann, Albert; Hämmerle, Christoph H F

    2011-01-01

    This study determined the fracture load of zirconia crowns veneered with four overpressed and four layered ceramics after chewing simulation. The veneered zirconia crowns were cemented and subjected to chewing cycling. Subsequently, the specimens were loaded at an angle of 45° in a Universal Testing Machine to determine the fracture load. One-way ANOVA, followed by a post-hoc Scheffé test, t-test and Weibull statistic were performed. Overpressed crowns showed significantly lower fracture load (543-577 N) compared to layered ones (805-1067 N). No statistical difference was found between the fracture loads within the overpressed group. Within the layered groups, LV (1067 N) presented significantly higher results compared to LC (805 N). The mean values of all other groups were not significantly different. Single zirconia crowns veneered with overpressed ceramics exhibited lower fracture load than those of the layered ones after chewing simulation.

  19. Metric analysis of loading magnitudes at articular and non-articular weight-bearing surfaces in human calcaneus.

    Science.gov (United States)

    Mahato, Niladri Kumar; Murthy, S Sathiya Narayana

    2013-03-01

    The calcaneus is axially loaded at its articular interface with the talus. A large bulk of this load is transmitted to the ground across the non-articular tubercles at the plantar surface of the bone. A small part of the incumbent load sustained by the calcaneus is directed towards the forefoot at the calcaneo-cuboid junction. This study investigates the proportion of load distributed across the articular and non-articular surfaces of the calcaneus. The present study demonstrates strong and significant correlation between some of the load bearing variables and suggests the need for further investigations to understand the effect of angular aspects of axial loading on the calcaneus. Accounting for the relative distribution of weight across the articular and non-articular areas may enable us to appreciate the internal trabecular structure of the calcaneus in light of its clinical importance.

  20. Analysis of the Elastic Large Deflection Behavior for Metal Plates under Nonuniformly Distributed Lateral Pressure with In-Plane Loads

    Directory of Open Access Journals (Sweden)

    Jeom Kee Paik

    2012-01-01

    Full Text Available The Galerkin method is applied to analyze the elastic large deflection behavior of metal plates subject to a combination of in-plane loads such as biaxial loads, edge shear and biaxial inplane bending moments, and uniformly or nonuniformly distributed lateral pressure loads. The motive of the present study was initiated by the fact that metal plates of ships and ship-shaped offshore structures at sea are often subjected to non-uniformly distributed lateral pressure loads arising from cargo or water pressure, together with inplane axial loads or inplane bending moments, but the current practice of the maritime industry usually applies some simplified design methods assuming that the non-uniform pressure distribution in the plates can be replaced by an equivalence of uniform pressure distribution. Applied examples are presented, demonstrating that the current plate design methods of the maritime industry may be inappropriate when the non-uniformity of lateral pressure loads becomes more significant.

  1. Seismic analysis and evaluation of the base isolation system in AP1000 NI under SSE loading

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jianyun; Zhao, Chunfeng, E-mail: zhaowindy@126.com; Xu, Qiang; Yuan, Chenyang

    2014-10-15

    Graphical abstract: - Highlights: • The feasibility of base isolation technique in NI is evaluated. • A comparison of structural response highlighted the effectiveness of isolation system. • DAR was proposed to validate the effectiveness of base isolation under SSE. • Connection of pipes, seismic gap and fail safety system are also considered. - Abstract: Safety and integrity of NPP must be ensured during the plant life in any design conditions, particularly, in the event of a severe earthquake. Base isolation as a popular and powerful technology can drastically reduce the seismic response of the structure and prevent the structure from damage. The objective of this paper is to numerically investigate the dynamic response of the AP1000 Nuclear Island (NI) building with and without isolators under a typical safe shutdown earthquake (SSE). By the help of a sophisticated detailed three-dimensional finite element model of the Nuclear Island, the different design solutions are compared in terms of acceleration and relative displacement. The decreasing amplitude ratio (DAR) obtained in the calculations highlights the effectiveness of the isolation system in mitigating the seismic response of the nuclear island of AP1000. Acceleration floor response spectra (carried out from both isolated and non-isolated seismic analysis) are herein also presented and compared in order to validate the isolation technology effectiveness. The obtained numerical results highlight the drastic reduction of considered floor accelerations as the base isolation major effect. The connection of pipelines and design criteria of isolators presently recommended for the stability of isolated building are also validated and verified to highlight the feasibility and safety of the base isolation system. In addition, seismic gap, expansion joint and horizontal fail safe system are also recommended to apply in the isolated structure.

  2. Model Development and Loads Analysis of an Offshore Wind Turbine on a Tension Leg Platform with a Comparison to Other Floating Turbine Concepts: April 2009

    Energy Technology Data Exchange (ETDEWEB)

    Matha, D.

    2010-02-01

    This report presents results of the analysis of a 5-MW wind turbine located on a floating offshore tension leg platform (TLP) that was conducted using the fully coupled time-domain aero-hydro-servo-elastic design code FAST with AeroDyn and HydroDyn. The report also provides a description of the development process of the TLP model. The model has been verified via comparisons to frequency-domain calculations. Important differences have been identified between the frequency-domain and time-domain simulations, and have generated implications for the conceptual design process. An extensive loads and stability analysis for ultimate and fatigue loads according to the procedure of the IEC 61400-3 offshore wind turbine design standard was performed with the verified TLP model. This report compares the loads for the wind turbine on the TLP to those of an equivalent land-based turbine. Major instabilities for the TLP are identified and described.

  3. Modeling of the Critical-Current Behavior of Nb3Sn Subsized Cables Under Transverse Load Using 2D Finite Element Analysis and a Strain Scaling Law

    CERN Document Server

    Wang, T; Takayasu, M; Bordini, B

    2014-01-01

    The mechanisms causing the critical-current degradation of ITER-type Nb3Sn Cable-in-Conduit-Conductors have been studied in the past decade. One of the origins of the degradation of the performance is the Lorentz load during magnet operations. The strands within the cable subjected to the transverse loads locally experience larger strains than the ones caused by tensile loads. Results obtained with experiments on full size cables are limited due to their cost and difficulty so, to predict the degradations of a Nb3Sn CICC under transverse loads, empirical laws should be established. Strain scaling laws are available but have never been used to determine the behavior of strands under transverse load. We propose a new method, by which the critical-current behavior of a subsized cable under transverse loads is derived from the critical-current behavior under uni-axial strains. This method is based on the strain state of the Nb3Sn filaments obtained by finite element analysis (FEA). The FEA strain results are used...

  4. Use of Residential Smart Appliances for Peak-Load Shifting and Spinning Reserves Cost/Benefit Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, Chellury; Pratt, Robert G.; Srivastava, Viraj; Li, Shun

    2010-12-01

    In this report, we present the results of an analytical cost/benefit study of residential smart appliances from a utility/grid perspective in support of a joint stakeholder petition to the ENERGY STAR program within the Environmental Protection Agency (EPA) and Department of Energy (DOE). The goal of the petition is in part to provide appliance manufacturers incentives to hasten the production of smart appliances. The underlying hypothesis is that smart appliances can play a critical role in addressing some of the societal challenges, such as anthropogenic global warming, associated with increased electricity demand, and facilitate increased penetration of renewable sources of power. The appliances we consider include refrigerator/freezers, clothes washers, clothes dryers, room air-conditioners, and dishwashers. The petition requests the recognition that providing an appliance with smart grid capability, i.e., products that meet the definition of a smart appliance, is at least equivalent to a corresponding five percent in operational machine efficiencies. It is then expected that given sufficient incentives and value propositions, and suitable automation capabilities built into smart appliances, residential consumers will be adopting these smart appliances and will be willing participants in addressing the aforementioned societal challenges by more effectively managing their home electricity consumption. The analytical model we utilize in our cost/benefit analysis consists of a set of user-definable assumptions such as the definition of on-peak (hours of day, days of week, months of year), the expected percentage of normal consumer electricity consumption (also referred to as appliance loads) that can shifted from peak hours to off-peak hours, the average power rating of each appliance, etc. Based on these assumptions, we then formulate what the wholesale grid operating-cost savings, or benefits, would be if the smart capabilities of appliances were invoked, and

  5. Application of ANSYS in Structure Analysis of Loading Bridge%ANSYS在塔式起重机结构分析中的应用

    Institute of Scientific and Technical Information of China (English)

    陈斌

    2015-01-01

    Loading bridge is a kind of special mechanical and electrical equipment ,its structure is relatively complex,more and more workers begin to adopt the finite element method to analyze the structure of the loading bridge,which has been widely applied at present in the ANSYS finite element analysis software,can through the establishment of the finite element analysis model ,improve the test efficiency of loading bridge , so ANSYS software in the analysis of the structure of the loading bridge plays an important role.This paper discusses the composition and classification of loading bridge ,and then analyzes the functions and features of ANSYS software ,and finally discusses the application of ANSYS software in structure analysis of loading bridge.%塔式起重机是一种特殊的机电设备,其结构较为复杂,越来越多的工作人员开始采用有限元分析的方法对塔式起重机的结构进行分析。目前应用较为广泛的ANSYS有限元分析软件,可以通过有限元分析模型的建立,提升塔式起重机的检验效率,因此ANSYS软件在塔式起重机的结构分析中具有重要的作用。文章首先探讨塔式起重机的构成和分类,然后分析ANSYS软件的功能特点,最后探讨ANSYS软件在塔式起重机结构分析中的应用。

  6. [Analysis on nitrogen and phosphorus loading of non-point sources in Shiqiao river watershed based on L-THIA model].

    Science.gov (United States)

    Li, Kai; Zeng, Fan-Tang; Fang, Huai-Yang; Lin, Shu

    2013-11-01

    Based on the Long-term Hydrological Impact Assessment (L-THIA) model, the effect of land use and rainfall change on nitrogen and phosphorus loading of non-point sources in Shiqiao river watershed was analyzed. The parameters in L-THIA model were revised according to the data recorded in the scene of runoff plots, which were set up in the watershed. The results showed that the distribution of areas with high pollution load was mainly concentrated in agricultural land and urban land. Agricultural land was the biggest contributor to nitrogen and phosphorus load. From 1995 to 2010, the load of major pollutants, namely TN and TP, showed an obviously increasing trend with increase rates of 17.91% and 25.30%, respectively. With the urbanization in the watershed, urban land increased rapidly and its area proportion reached 43.94%. The contribution of urban land to nitrogen and phosphorus load was over 40% in 2010. This was the main reason why pollution load still increased obviously while the agricultural land decreased greatly in the past 15 years. The rainfall occurred in the watershed was mainly concentrated in the flood season, so the nitrogen and phosphorus load of the flood season was far higher than that of the non-flood season and the proportion accounting for the whole year was over 85%. Pearson regression analysis between pollution load and the frequency of different patterns of rainfall demonstrated that rainfall exceeding 20 mm in a day was the main rainfall type causing non-point source pollution.

  7. 负载均担并联系统模型及可靠性分析%Models and Reliability Analysis of Load-Sharing Parallel Systems

    Institute of Scientific and Technical Information of China (English)

    覃庆努; 魏学业; 吴小进; 白如雪

    2013-01-01

    The reliability of an actual load-sharing parallel system is greatly affected by total load of the system and load capacity of components. A failure rate variation model of components of unrepaired load-sharing parallel systems is established by analyzing the components’ load capacity. Through Markov process, the universal reliability model of load-sharing parallel systems is established. According to the failure rate variation model and the relations between total load of system and load capacity of components, the universal reliability model is classified into ideal load capacity model, maximum load capacity model, and critical load capacity model. The reliability of these three models is derived in this paper. The models and calculation results are verified via case study the reliability analysis of parallel systems with independent components and m/n:(F) voting system.%  针对实际中负载均担并联系统的可靠性受系统总负载和部件承载能力的影响,通过分析实际中部件的承载能力情况建立相应的部件失效率变化模型,利用马尔可夫过程建立负载均担不可修并联系统的通用可靠性模型。从失效率变化模型出发,根据总负载与部件承载能力的不同关系,将系统的通用可靠性模型细分为理想承载模型、最大承载模型和临界承载模型,并计算出各个模型下系统可靠度。以部件独立并联系统和m/n:(F)表决系统为例证,验证模型及计算结果的正确性。

  8. Prediction and validation of high frequency vibration repsonses of NASA Mars Pathfinder spacecraft due to acoustic launch load using statistical energy analysis

    Science.gov (United States)

    Hwang, H. J.

    2002-01-01

    Mid and high frequency structural responses of a spacecraft during the launch condition are mainly dominated by the intense acoustic pressure field over the exterior of the launch vehicle. The prediction of structural responses due to the acoustic launch load is therefore an important analysis for engineers and scientists to correctly define various dynamics specifications of the spacecraft.

  9. Iron load

    Directory of Open Access Journals (Sweden)

    Filippo Cassarà

    2013-03-01

    Full Text Available Recent research addressed the main role of hepcidin in the regulation of iron metabolism. However, while this mechanism could be relevant in causing iron load in Thalassemia Intermedia and Sickle-Cell Anemia, its role in Thalassemia Major (TM is marginal. This is mainly due to the high impact of transfusional requirement into the severe increase of body iron. Moreover, the damage of iron load may be worsened by infections, as HCV hepatitis, or liver and endocrinological damage. One of the most relevant associations was found between splenectomy and increase of risk for mortality due,probably, to more severe iron load. These issues suggest as morbidity and mortality of this group of patients they do not depend only by our ability in controlling heart damage but even in preventing or treating particular infections and complications. This finding is supported by the impairment of survival curves in patients with complications different from heart damage. However, because, during recent years different direct and indirect methods to detect iron overload in patients affected by secondary hemochromatosis have been implemented, our ability to maintain under control iron load is significantly improved. Anyway, the future in iron load management remains to be able to have an iron load map of our body for targeting chelation and other medical treatment according to the single organ damage.

  10. Analysis of axle and vehicle load properties through Bayesian networks based on weigh-in-motion data

    NARCIS (Netherlands)

    Morales Napoles, O.; Steenbergen, R.D.J.M.

    2014-01-01

    Weigh-in-Motion (WIM) systems are used, among other applications, in pavement and bridge reliability. The system measures quantities such as individual axle load, vehicular loads, vehicle speed, vehicle length and number ofaxles. Because ofthe nature ofúamc configuration, the quantities measured are

  11. Modelling nutrient fluxes from source to river load : a macroscopic analysis applied to the Rhine and Elbe basins

    NARCIS (Netherlands)

    Wit, de M.

    2000-01-01

    In many European rivers, including the major streams of the Rhine and Elbe basins, the nutrient load (N and P) still exceeds target levels. In this paper, a model is presented that describes the river nutrient load as a function of nutrient sources, runoff and lithology in the upstream basin. The mo

  12. Analysis of the phase control of the ITER ICRH antenna array. Influence on the load resilience and radiated power spectrum

    Science.gov (United States)

    Messiaen, A.; Swain, D.; Ongena, J.; Vervier, M.

    2015-12-01

    The paper analyses how the phasing of the ITER ICRH 24 strap array evolves from the power sources up to the strap currents of the antenna. The study of the phasing control and coherence through the feeding circuits with prematching and automatic matching and decoupling network is made by modeling starting from the TOPICA matrix of the antenna array for a low coupling plasma profile and for current drive phasing (worst case for mutual coupling effects). The main results of the analysis are: (i) the strap current amplitude is well controlled by the antinode Vmax amplitude of the feeding lines, (ii) the best toroidal phasing control is done by the adjustment of the mean phase of Vmax of each poloidal straps column, (iii) with well adjusted system the largest strap current phasing error is ±20°, (iv) the effect on load resilience remains well below the maximum affordable VSWR of the generators, (v) the effect on the radiated power spectrum versus k// computed by means of the coupling code ANTITER II remains small for the considered cases.

  13. Nonlinear Dynamics Modeling and Analysis of Torsional Spring-Loaded Antibacklash Gear with Time-Varying Meshing Stiffness and Friction

    Directory of Open Access Journals (Sweden)

    Zheng Yang

    2013-01-01

    Full Text Available Torsional spring-loaded antibacklash gear which can improve the transmission precision is widely used in many precision transmission fields. It is very important to investigate the dynamic characteristics of antibacklash gear. In the paper, applied force analysis is completed in detail. Then, defining the starting point of double-gear meshing as initial position, according to the meshing characteristic of antibacklash gear, single- or double-tooth meshing states of two gear pairs and the transformation relationship at any moment are determined. Based on this, a nonlinear model of antibacklash gear with time-varying friction and meshing stiffness is proposed. The influences of friction and variations of torsional spring stiffness, damping ratio and preload on dynamic transmission error (DTE are analyzed by numerical calculation and simulation, and the results show that antibacklash gear can increase the composite meshing stiffness; when the torsional spring stiffness is large enough, the oscillating components of the DTE (ODTE and the RMS of the DTE (RDTE trend to be a constant value; the variations of ODTE and RDTE are not significant, unless preload exceeds a certain value.

  14. A time-frequency analysis approach for condition monitoring of a wind turbine gearbox under varying load conditions

    Science.gov (United States)

    Antoniadou, I.; Manson, G.; Staszewski, W. J.; Barszcz, T.; Worden, K.

    2015-12-01

    This paper deals with the condition monitoring of wind turbine gearboxes under varying operating conditions. Generally, gearbox systems include nonlinearities so a simplified nonlinear gear model is developed, on which the time-frequency analysis method proposed is first applied for the easiest understanding of the challenges faced. The effect of varying loads is examined in the simulations and later on in real wind turbine gearbox experimental data. The Empirical Mode Decomposition (EMD) method is used to decompose the vibration signals into meaningful signal components associated with specific frequency bands of the signal. The mode mixing problem of the EMD is examined in the simulation part and the results in that part of the paper suggest that further research might be of interest in condition monitoring terms. For the amplitude-frequency demodulation of the signal components produced, the Hilbert Transform (HT) is used as a standard method. In addition, the Teager-Kaiser energy operator (TKEO), combined with an energy separation algorithm, is a recent alternative method, the performance of which is tested in the paper too. The results show that the TKEO approach is a promising alternative to the HT, since it can improve the estimation of the instantaneous spectral characteristics of the vibration data under certain conditions.

  15. Analysis of the phase control of the ITER ICRH antenna array. Influence on the load resilience and radiated power spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Messiaen, A., E-mail: a.messiaen@fz-juelich.de; Ongena, J.; Vervier, M. [Laboratory for Plasma Physics, ERM-KMS, TEC partner, Cycle, B1000-Brussels (Belgium); Swain, D. [US ITER Team, ORNL (United States)

    2015-12-10

    The paper analyses how the phasing of the ITER ICRH 24 strap array evolves from the power sources up to the strap currents of the antenna. The study of the phasing control and coherence through the feeding circuits with prematching and automatic matching and decoupling network is made by modeling starting from the TOPICA matrix of the antenna array for a low coupling plasma profile and for current drive phasing (worst case for mutual coupling effects). The main results of the analysis are: (i) the strap current amplitude is well controlled by the antinode V{sub max} amplitude of the feeding lines, (ii) the best toroidal phasing control is done by the adjustment of the mean phase of V{sub max} of each poloidal straps column, (iii) with well adjusted system the largest strap current phasing error is ±20°, (iv) the effect on load resilience remains well below the maximum affordable VSWR of the generators, (v) the effect on the radiated power spectrum versus k{sub //} computed by means of the coupling code ANTITER II remains small for the considered cases.

  16. Analysis of the phase control of the ITER ICRH antenna array. Influence on the load resilience and radiated power spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Messiaen, Andre [Ecole Royale Militaire, Brussels Belgium; Swain, David W [ORNL; Ongena, Jef [Ecole Royale Militaire, Brussels Belgium; Vervier, Michael [Ecole Royale Militaire, Brussels Belgium

    2015-01-01

    The paper analyses how the phasing of the ITER ICRH 24 strap array evolves from the power sources up to the strap currents of the antenna. The study of the phasing control and coherence through the feeding circuits with prematching and automatic matching and decoupling network is made by modeling starting from the TOPICA matrix of the antenna array for a low coupling plasma profile and for current drive phasing (worst case for mutual coupling effects). The main results of the analysis are: (i) the strap current amplitude is well controlled by the antinode V-max amplitude of the feeding lines, (ii) the best toroidal phasing control is done by the adjustment of the mean phase of V-max of each poloidal straps column, (iii) with well adjusted system the largest strap current phasing error is +/- 20 degrees, (iv) the effect on load resilience remains well below the maximum affordable VSWR of the generators, (v) the effect on the radiated power spectrum versus k//computed by means of the coupling code ANTITER II remains small for the considered cases. [GRAPHICS] .

  17. Evaluation of the botanical origin of commercial dry bee pollen load batches using pollen analysis: a proposal for technical standardization

    Directory of Open Access Journals (Sweden)

    Ortrud M. Barth

    2010-12-01

    Full Text Available High quality of bee pollen for commercial purpose is required. In order to attend the consumer with the best identification of the botanical and floral origin of the product, 25 bee pollen batches were investigated using two techniques of pollen grain preparation. The first started to identify pollen loads of different colors in two grams of each well mixed batch, and the second to identify pollen grains in a pool made of all the pollen loads comprised in two grams. The best result was obtained by this last technique, when a pollen grain suspension was dropped on a microscope slide and circa 500 pollen grains were counted per sample. This analysis resulted in the recognition of monofloral and bifloral pollen batches, while the use of the first technique resulted in all samples receiving a heterofloral diagnosis.É exigida alta qualidade para a comercialização de pólen apícola. A fim de atender o consumidor com a melhor identificação da origem botânica e floral do produto, 25 partidas de pólen apícola feram investigadas usande duas diferentes técnicas na preparação dos grãos de pólen. A primeira partiu da identificação das cargas polínicas contidas em dois gramas de cada partida bem misturada segundo suas cores. A segunda visava identificar os grãos de pólen de um agrupamento ("pool" de todas as cargas polínicas contidas em dois gramas de cada amostra. O melhor resultado foi obtido pela última técnica, quando uma suspensão de grãos de pólen era gotejada sobre uma lâmina de microscopia e cerca de 500 grãos de pólen eram centades por amostra. Esta análise resultou no reconhecimento de partidas monoflorais e biflorais de pólen apícola, enquanto que usando a primeira técnica, todas as amostras receberam a diagnose heterefloral.

  18. [Structure of allostatic load in railway workers].

    Science.gov (United States)

    Gorokhova, S G; Pfaf, V F; Muraseyeva, E V; Akhsanova, E R; Prigorovskaya, T S; At'kov, O Yu

    2016-01-01

    The authors studied allostatic load in railway workers, as an indicator of stress effect. Analysis covered biomarkers that form allostatic load index, and their ratio for variable allostatic load index levels. Moderate allostatic load appeared to prevail in the examinees group. Findings are that systolic and diastolic blood pressure, general cholesterol and hemoglobin make major contribution into allostatic load index. Comparison covered models of allostatic load index calculation for variable biomarkers sets.

  19. Analysis about Rooftop Garden Load Problem%屋顶花园荷载问题探析

    Institute of Scientific and Technical Information of China (English)

    李伟杰

    2011-01-01

    The roof garden is a kind of special form of roof greening, and roof load problem is the primary key to develop roof garden.This article, from two aspects of live load and static load, mainly expounds load source and classification of roof garden, analyzes the characteristics and standard of load.Reducing roof load should mainly start with decrease of planting matrix weight of static load, priority of afforestation plant, the setup scale number and location of landscape sketch and drainage facilities materials and so on.%屋顶花园是屋顶绿化的一种特殊形式,而屋面荷载问题则是发展屋顶花园的首要关键问题.本文主要从活荷载和静荷载两个方面阐述了屋顶花园的荷载来源及分类,分析了各类荷载的特点和标准.减少屋面荷载主要从减少静荷载的种植基质重量、优先绿化植物、景观小品的设置规模数量和位置以及排水设施材料等方面入手.

  20. Temporal analysis of E. coli, TSS and wastewater micropollutant loads from combined sewer overflows: implications for management.

    Science.gov (United States)

    Anne-Sophie, Madoux-Humery; Dorner, Sarah M; Sauvé, Sébastien; Aboulfadl, Khadija; Galarneau, Martine; Servais, Pierre; Prévost, Michèle

    2015-05-01

    A combined sewer overflow (CSO) outfall was monitored to assess the impact of temporal mass loads on the appropriateness of treatment options. Instantaneous loads (mass per s) varied by approximately three orders of magnitude during events (n = 9 in spring, summer and the fall) with no significant seasonal variations. The median fraction of total loads discharged with the first 25% of the total volume ranged from 28% (theophylline) to 40% (Total Suspended Solids (TSS)) and loads remained high for the duration of the events. E. coli and TSS loads originated primarily from wastewater (WW) (63% and 75%, respectively). However, a mix of stormwater (SW) and sewer deposit (SD) resuspension contributed from 73 to 95% for the first 50% of the volume discharged of total TSS loads for 2 events. The contribution of SD resuspension was not negligible for Wastewater Micropollutants (WWMPs), especially for carbamazepine. Sustained high loads over the course of CSOs highlight the need to revisit current CSO and SW management strategies that focus on the treatment of early discharge volumes.

  1. Details of Side Load Test Data and Analysis for a Truncated Ideal Contour Nozzle and a Parabolic Contour Nozzle

    Science.gov (United States)

    Ruf, Joseph H.; McDaniels, David M.; Brown, Andrew M.

    2010-01-01

    Two cold flow subscale nozzles were tested for side load characteristics during simulated nozzle start transients. The two test article contours were a truncated ideal and a parabolic. The current paper is an extension of a 2009 AIAA JPC paper on the test results for the same two nozzle test articles. The side load moments were measured with the strain tube approach in MSFC s Nozzle Test Facility. The processing techniques implemented to convert the strain gage signals into side load moment data are explained. Nozzle wall pressure profiles for separated nozzle flow at many NPRs are presented and discussed in detail. The effect of the test cell diffuser inlet on the parabolic nozzle s wall pressure profiles for separated flow is shown. The maximum measured side load moments for the two contours are compared. The truncated ideal contour s peak side load moment was 45% of that of the parabolic contour. The calculated side load moments, via mean-plus-three-standard-deviations at each nozzle pressure ratio, reproduced the characteristics and absolute values of measured maximums for both contours. The effect of facility vibration on the measured side load moments is quantified and the effect on uncertainty is calculated. The nozzle contour designs are discussed and the impact of a minor fabrication flaw in the nozzle contours is explained.

  2. Influence of loading cycle profile and frequency on a biomechanical parameter of a model of a balloon kyphoplasty-augmented lumbar spine segment: a finite element analysis study.

    Science.gov (United States)

    Li, Yuan; Lewis, Gladius

    2010-01-01

    For patients who are suffering debilitating and persistent pain due to vertebral compression fracture(s) and for whom conservative therapies have not provided relief, balloon kyphoplasty (BKP) is used as a surgical option. There are only a very few literature reports on the use of the finite element analysis (FEA) method to obtain biomechanical parameters of models of spine segments that include BKP augmentation at a given level. In each of these studies, the applied loading used was quasi-static. During normal activities of daily living, the patient's spine would be subject to dynamically-applied loading. Thus, the question of the influence of the characteristics of a dynamically-applied loading cycle on biomechanical parameters of a spine that includes BKP-augmented segment(s) is germane; however, a study of this issue is lacking. We investigated this issue in the present FEA work, with the spine segment model being the L1-L3 motion segment units (MSUs) (a segment that is commonly augmented using BKP) and prophylactic BKP simulated at L2. The dynamic load was the compressive load-versus-time cycle to which the L3-L4 MSU is subjected during gait. Four cases of the cycle were considered, corresponding to slow-, normal-, fast- and very fast-paced gait. The loading cycle was applied to the superior surface of L1 while the inferior surface of L3 was fully constrained. It was found that (1) the global mean von Mises stress during the loading cycle (σVMG), in each tissue in the model increased in going from a slow-paced gait cycle to a very fast-paced gait cycle; and (2) for the slow-paced gait cycle, with increase in frequency of the cycle, f (1 ≤ f ≤ 3 Hz), σVMG in each of these tissues increased. Potential uses of the present findings are identified.

  3. 浮式风机极限载荷与疲劳载荷对比分析%Comparison analysis about ultimate load and fatigue load of floating wind turbines

    Institute of Scientific and Technical Information of China (English)

    张友文; 王迎光

    2015-01-01

    According to the load cases in IEC61400-3, a 5 MW wind turbine developed by NREL will be used as a basic model for the research, and a FAST code will be applied in order to conduct the Aero-Hydro-Servo-Elastic coupled analysis of the wind turbine. For the short-term loads resulted from simulation in time domain, a Block-Maximum method coupled Gumbel distribution will be applied to predict the ultimate load of the wind turbine;The MLife software, the rain flow counting method, the linear cumulative damage law and the S-N curve as the background theory are used to calculate the fatigue load of the wind turbine. Under different working conditions, the floating wind turbine, monopile offshore wind turbine and onshore wind turbine’ s ultimate and fatigue loads are compared, and the effect factors of floating wind turbine ’ s dynamic response are discussed. The results show that for land-based wind turbines and monopile offshore wind turbines, wind is the main load source. But in terms of floating wind turbines, wave is the main load source;wind turbines’ design should be based on the specific environmental ( metocean) data to avoid resonation; within a certain range of assembly error, mass imbalance hardly has any impact on the loads.%根据IEC61400-3设定工况,采用NREL开发的5 MW风机基础模型,应用FAST,以Aero-Hydro-Servo-Elastic耦合仿真技术对风机进行研究。对时域仿真得到的短期载荷,应用分块极大值法联合Gumbel分布外推计算风机极限载荷;以雨流计数法、线性累积损伤理论和S-N曲线为理论基础应用MLife软件,计算风机疲劳载荷。对比分析不同工况下浮式风机、近海单桩风机和陆上风机的极限载荷与疲劳载荷,进而探讨影响浮式风机动态响应的因素。结果表明,对于陆上风机和近海单桩风机,风是其主要载荷来源;而波浪是浮式风机主要载荷来源。对风机进行设计要根据特定海域统计的海洋气候

  4. Steady-State Analysis of Parallel-Operated Self-Excited Induction Generators Supplying an Unbalanced Load

    Science.gov (United States)

    Radosavljević, Jordan; Klimenta, Dardan; Jevtić, Miroljub

    2012-07-01

    This paper proposed a multi-objective genetic algorithm (MOGA) based approach for determining the steady-state performance characteristics of three-phase self-excited induction generators (SEIGs) operating in parallel and supplying an unbalanced load. The symmetrical component theory is used for the transformation of a complex three-phase generators-capacitances-load system to a simple equivalent circuit. The MOGA has been employed for the determination of unknown variables by minimizing the impedance module of the equivalent circuit. Using this approach, effects of various parameters on the terminal voltage control characteristics are examined for two parallel SEIGs with C2C connection under a single phase load.

  5. Peak Load Regulation of Wind Power System Based on Wavelet Analysis%基于小波分析的风电系统负荷调峰

    Institute of Scientific and Technical Information of China (English)

    陈焕远; 刘新东; 佘彩绮

    2011-01-01

    针对风电系统负荷调峰问题,以减少调峰机组的爬坡出力次数与能源消耗为目的,提出了一种基于小波分析的负荷调峰方法.该方法采用近似对称光滑的紧支撑双正交小波db4(Daubechies函数)作为小波基,通过多分辨分析的Mallat算法对预测等效负荷进行2尺度分解,并将其中低频基础负荷分配给负荷调峰机组.仿真算例将该方法与未含小波分析的负荷调峰方法进行了对比,比较结果证明了其调峰性能优于后者.这表明该方法具有良好的调峰性能,能使调峰机组出力较为平缓,有效减轻对调峰机组的损耗和减少能源的消耗.%As to peak load regulation problem of wind power system, a peak load regulation method based on wavelet analysis is proposed in this paper to reduce the climbing power output times of regulation units and energy consumption.This method adopts the supported biorthogonal wavelet db4 (Daubechies function) with approximate symmetry smooth compactly as the wavelet bases, and uses the multiresolution analysis Mallat algorithm to decompose the predicted equivalent load to 2 scale. The basic load of the predicted equivalent load is distributed to the regulation unit. This method and another peak load regulation method without wavelet analysis are contrasted in the simulation example, and the comparative results prove that its peak load regulation performance is better than that of the latter, which indicates that this method has a good peak load regulation performance, can make the power output of regulation units more quietly, and effectively reduces the losses of regulation unit and energy consumption.

  6. Stress analysis in a non axisymmetric loaded reactor pressure vessel; Verificacao de tensoes em um vaso de pressao nuclear com carregamentos nao-axissimetricos

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Levi Barcelos; Assis, Gracia Menezes V. de [Coordenadoria para Projetos Especiais (COPESP), Sao Paulo, SP (Brazil); Miranda, Carlos Alexandre J.; Cruz, Julio Ricardo B.; Mattar Neto, Miguel [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1995-12-31

    In this work we intend to present the stress analysis of a PWR vessel under postulated concentrated loads. The vessel was modeled with Axisymmetric solid 4 nodes harmonic finite elements with the use of the ANSYS program, version 5.0. The bolts connecting the vessel flanges were modeled with beam elements. Some considerations were made to model the contact between the flanges. The perforated part of the vessel tori spherical head was modeled (with reduced properties due to its holes) to introduce its stiffness and loads but was not within the scope of this work. The loading consists of some usual ones, as pressure, dead weight, bolts preload, seismic load and some postulated ones as concentrated loads, over the vessel, modeled by Fourier Series. The results in the axisymmetric model are taken in terms of linearized stresses, obtained in some circumferential positions and for each position, in some sections along the vessel. Using the ASME Code (Section III, Division 1, Sub-section NB) the stresses are within the allowable limits. In order to draw some conclusions about stress linearization, the membrane plus bending stresses (Pl + Pb) are obtained and compared in some sections, using three different methods. (author) 4 refs., 15 figs., 7 tabs.

  7. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  8. Elastodynamic analysis at an interface of viscous fluid/thermoelastic micropolar honeycomb medium due to inclined load

    Institute of Scientific and Technical Information of China (English)

    Rajneesh Kumar; Rajani Rani Gupta

    2009-01-01

    In this paper, the effect of angle inclination at the interface of a viscous fluid and thermoelastic micropolar honeycomb solid due to inclined load is investigated. The inclined load is assumed to be a linear combination of normal load and tangential load. Laplace transform with respect to time variable and Fourier transform with respect to space variable are applied to solve the problem. Expressions of stresses, temperature distribution, and pressures in the transformed domain are obtained by introducing po-tential functions. The numerical inversion technique is used to obtain the solution in the physical domain. The frequency domain expressions for steady state are also obtained with appropriate change of variables. Graphic representations due to the response of different sources and changes of angle inclination are shown. Some particular cases are also discussed.

  9. Loading Conditions and Longitudinal Strength

    DEFF Research Database (Denmark)

    Sørensen, Herman

    1995-01-01

    Methods for the calculation of the lightweight of the ship.Loading conditions satisfying draught, trim and intact stability requirements and analysis of the corresponding stillwater longitudinal strength.......Methods for the calculation of the lightweight of the ship.Loading conditions satisfying draught, trim and intact stability requirements and analysis of the corresponding stillwater longitudinal strength....

  10. Stability Analysis of a Constant Power Load Serviced by a Buck Converter as the Source Impedance Varies

    Science.gov (United States)

    2012-09-01

    electric ships, being aware of the stability issues associated with direct current (DC)-DC and DC-alternating current (AC) power converters and... Electric vehicles FCV Fuel Cell Vehicle HEV Hybrid Electric Vehicle Hf Final Load Transfer Function Hf_vec Final Load Transfer Function...Voltage Law SL Source Inductance MEV More Electric Vehicle MVDC Medium Voltage DC xiv P Power OP Output Power Pof Final Power Level Poi

  11. An Higher Case Operation and Analysis of a Multiple Renewable Resources Connected To A Dc Load Through Dc Bus

    Directory of Open Access Journals (Sweden)

    G. Mahesh Kumar

    2014-08-01

    Full Text Available In our nation the usage of electricity is increasing day-by-day. According to that conserdations, the generated power from the non-renewable sources will not satisfy the demands properly. so for these purpose, by using multiple renewable sources, it will be very useful to some type of dc applications. The power produced from the individual renewable sources will not be satisfy the demand at all times. So by integration of a multiple renewable sources such as wind and solar a huge amount of power will be produced. These power will be coordinated to the ac grid or directly to dc consumers. For integration of renewable sources an aggregated model has to be proposed. In according to these operation BESS (battery energy storage systemis equipped with the system for maintaining the power balance. For obtaining the power balance the adaptive droop control technique has to be proposed and droop curves are evaluated. The droop characteristics are selected on the basis of the deviation between the optimized and real-time SOC of the BESS. In these paper, the operational analysis can be performed when real time soc is higher than the optimised soc and droop curves are plotted. Operational controls with in the micro grid [such as cost have to be optimized at the same time it will satisfy the demand] are designed to support the integration of wind and solar power. By these process micro grid real time supply and demand will be maintain in symmetry. The simulation results are to be developed in MATLAB SIMULINK process for renewable power generation and fast charging load connected to the dc bus, droop control based responses.

  12. Characterizing Wheel-Soil Interaction Loads Using Meshfree Finite Element Methods: A Sensitivity Analysis for Design Trade Studies

    Science.gov (United States)

    Contreras, Michael T.; Trease, Brian P.; Bojanowski, Cezary; Kulakx, Ronald F.

    2013-01-01

    A wheel experiencing sinkage and slippage events poses a high risk to planetary rover missions as evidenced by the mobility challenges endured by the Mars Exploration Rover (MER) project. Current wheel design practice utilizes loads derived from a series of events in the life cycle of the rover which do not include (1) failure metrics related to wheel sinkage and slippage and (2) performance trade-offs based on grouser placement/orientation. Wheel designs are rigorously tested experimentally through a variety of drive scenarios and simulated soil environments; however, a robust simulation capability is still in development due to myriad of complex interaction phenomena that contribute to wheel sinkage and slippage conditions such as soil composition, large deformation soil behavior, wheel geometry, nonlinear contact forces, terrain irregularity, etc. For the purposes of modeling wheel sinkage and slippage at an engineering scale, meshfree nite element approaches enable simulations that capture su cient detail of wheel-soil interaction while remaining computationally feasible. This study implements the JPL wheel-soil benchmark problem in the commercial code environment utilizing the large deformation modeling capability of Smooth Particle Hydrodynamics (SPH) meshfree methods. The nominal, benchmark wheel-soil interaction model that produces numerically stable and physically realistic results is presented and simulations are shown for both wheel traverse and wheel sinkage cases. A sensitivity analysis developing the capability and framework for future ight applications is conducted to illustrate the importance of perturbations to critical material properties and parameters. Implementation of the proposed soil-wheel interaction simulation capability and associated sensitivity framework has the potential to reduce experimentation cost and improve the early stage wheel design proce

  13. Load sensor

    NARCIS (Netherlands)

    Van den Ende, D.; Almeida, P.M.R.; Dingemans, T.J.; Van der Zwaag, S.

    2007-01-01

    The invention relates to a load sensor comprising a polymer matrix and a piezo-ceramic material such as PZT, em not bedded in the polymer matrix, which together form a compos not ite, wherein the polymer matrix is a liquid crystalline resin, and wherein the piezo-ceramic material is a PZT powder for

  14. Carbohydrate Loading.

    Science.gov (United States)

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  15. Effects of low glycaemic index/low glycaemic load vs. high glycaemic index/ high glycaemic load diets on overweight/obesity and associated risk factors in children and adolescents: a systematic review and meta-analysis.

    Science.gov (United States)

    Schwingshackl, Lukas; Hobl, Lisa Patricia; Hoffmann, Georg

    2015-08-25

    The objective of the present systematic review and meta-analysis was to synthesize the available literature data investigating the effects of low glycaemic index/low glycamic load dietary regimens on anthropometric parameters, blood lipid profiles, and indicators of glucose metabolism in children and adolescents. Literature search was performed using the electronic databases MEDLINE, EMBASE, and the Cochrane Central Register of trials with restrictions to randomized controlled trials, but no limitations concerning language and publication date. Parameters taken into account were: body weight, body mass index, z-score of body mass index, fat mass, fat-free mass, height, waist cicrumference, hip circumference, waist-to-hip ratio, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, diastolic and systolic blood pressure, fasting serum glucose, fasting serum insulin, HOMA-index, glycosylated haemoglobin, and C-reactive protein. Meta-analyses were performed for each parameter to assess pooled effect in terms of weighted mean differences between the post-intervention (or differences in means) of the low glycaemic index diets and the respective high glycaemic index counterparts. Data analysis was performed using the Review Manager 5.3. software. Nine studies enrolling 1.065 children or adolescents met the inclusion criteria. Compared to diets providing a high gylcaemic index, low glycaemic index protocols resulted in significantly more pronounced decreases in serum triglycerides [mean differences -15.14 mg/dl, 95%-CI (-26.26, -4.00)] and HOMA-index [mean difference -0.70, 95%-CI (-1.37, -0.04), fixed-effects model only]. Other parameters under investigation were not affected by either low or high glycaemic indices. The present systematic review and meta-analysis provides evidence of a beneficial effect of a low glycaemic index/load diet in children and adolescents being either overweight or obese. Regarding the limitations of this analysis, further studies

  16. Memory load effect in auditory-verbal short-term memory task: EEG fractal and spectral analysis.

    Science.gov (United States)

    Stokić, Miodrag; Milovanović, Dragan; Ljubisavljević, Miloš R; Nenadović, Vanja; Čukić, Milena

    2015-10-01

    The objective of this preliminary study was to quantify changes in complexity of EEG using fractal dimension (FD) alongside linear methods of spectral power, event-related spectral perturbations, coherence, and source localization of EEG generators for theta (4-7 Hz), alpha (8-12 Hz), and beta (13-23 Hz) frequency bands due to a memory load effect in an auditory-verbal short-term memory (AVSTM) task for words. We examined 20 healthy individuals using the Sternberg's paradigm with increasing memory load (three, five, and seven words). The stimuli were four-letter words. Artifact-free 5-s EEG segments during retention period were analyzed. The most significant finding was the increase in FD with the increase in memory load in temporal regions T3 and T4, and in parietal region Pz, while decrease in FD with increase in memory load was registered in frontal midline region Fz. Results point to increase in frontal midline (Fz) theta spectral power, decrease in alpha spectral power in parietal region-Pz, and increase in beta spectral power in T3 and T4 region with increase in memory load. Decrease in theta coherence within right hemisphere due to memory load was obtained. Alpha coherence increased in posterior regions with anterior decrease. Beta coherence increased in fronto-temporal regions. Source localization delineated theta activity increase in frontal midline region, alpha decrease in superior parietal region, and beta increase in superior temporal gyrus with increase in memory load. In conclusion, FD as a nonlinear measure may serve as a sensitive index for quantifying dynamical changes in EEG signals during AVSTM tasks.

  17. Effect of Degeneration on Fluid-Solid Interaction within Intervertebral Disc under Cyclic Loading – A Meta-Model Analysis of Finite Element Simulations

    Directory of Open Access Journals (Sweden)

    Mohammad eNikkhoo

    2015-01-01

    Full Text Available The risk of low back pain resulted from cyclic loadings is greater than that resulted from prolonged static postures. Disc degeneration results in degradation of disc solid structures and decrease of water contents, which is caused by activation of matrix digestive enzymes. The mechanical responses resulted from internal solid-fluid interactions of degenerative discs to cyclic loadings are not well studied yet. The fluid-solid interactions in discs can be evaluated by mathematical models, especially the poroelastic finite element models. We developed a robust disc poroelastic FE model to analyze the effect of degeneration on solid-fluid interactions within disc subjected to cyclic loadings at different loading frequencies. A backward analysis combined with in-vitro experiments were used to find the elastic modulus and hydraulic permeability of intact and enzyme-induced degenerated porcine discs. The results showed that the averaged peak-to-peak disc deformations during the in-vitro cyclic tests were well fitted with limited FE simulations and a quadratic response surface regression for both disc groups. The results showed that higher loading frequency increased the intradiscal pressure, decreased the total fluid loss, and slightly increased the maximum axial stress within solid matrix. Enzyme-induced degeneration decreased the intradiscal pressure and total fluid loss, and barely changed the maximum axial stress within solid matrix. The increase of intradiscal pressure and total fluid loss with loading frequency was less sensitive after the frequency elevated to 0.1 Hz for the enzyme-induced degenerated disc. Based on this study, it is found that enzyme-induced degeneration decreases energy attenuation capability of disc, but less change the strength of disc.

  18. Effects of load and maintenance duration on the time course of information encoding and retrieval in working memory: from perceptual analysis to post-categorization processes.

    Directory of Open Access Journals (Sweden)

    Diego ePinal

    2014-04-01

    Full Text Available Working memory (WM involves three cognitive events: information encoding, maintenance and retrieval; these are supported by brain activity in a network of frontal, parietal and temporal regions. Manipulation of WM load and duration of the maintenance period can modulate this activity. Although such modulations have been widely studied using the ERP technique, a precise description of the time course of brain activity during encoding and retrieval is still required. Here, we used this technique and principal component analysis to assess the time course of brain activity during encoding and retrieval in a delayed match to sample task. We also investigated the effects of memory load and duration of the maintenance period on ERP activity. Brain activity was similar during information encoding and retrieval and comprised six temporal factors, which closely matched the latency and scalp distribution of some ERP components: P1, N1, P2, N2, P300 and a slow wave. Changes in memory load modulated task performance and yielded variations in frontal lobe activation. Moreover, the P300 amplitude was smaller in the high than in the low load condition during encoding and retrieval. Conversely, the slow wave amplitude was higher in the high than in the low load condition during encoding, and the same was true for the N2 amplitude during retrieval. Thus, during encoding, memory load appears to modulate the processing resources for context updating and post-categorization processes, and during retrieval it modulates resources for stimulus classification and context updating. Besides, despite the lack of differences in task performance related to duration of the maintenance period, larger N2 amplitude and stronger activation of the left temporal lobe after long than after short maintenance periods were found during information retrieval. Thus, results regarding the duration of maintenance period were complex, and future work is required to test the time-based decay

  19. Experimental Analysis of Repaired Masonry Elements with Flax-FRCM and PBO-FRCM Composites Subjected to Axial Bending Loads

    Directory of Open Access Journals (Sweden)

    Oscar A. Cevallos

    2015-11-01

    Full Text Available In the construction industry, the use of natural fabrics as a reinforcement for cement-based composites has shown great potential. The use of these sustainable composites to provide strengthening or repair old masonry structures that exhibit structural problems mainly due to a poor tensile strength of the mortar/brick joints is revealed to be a promising area of research. One of the most significant load conditions affecting the mechanical response of masonry structures occurs when axial bending loads are applied on the resistant cross-section. In this study, three different types of masonry elements were built using clay bricks and a lime-based mortar. After 28 days, the samples were subjected to concentric and eccentric compressive loads. In order to produce significant bending effects, the compressive loads were applied with large eccentricity, and a sudden failure characterized the behavior of the unreinforced masonry (URM elements. The tested masonry specimens were repaired using fabric-reinforced cementitious matrix (FRCM composites produced using bi-directional flax and polyparaphenylene benzobisoxazole (PBO fabrics. The mechanical behavior of the URM and repaired samples was compared in terms of load-displacement and moment-curvature responses. Furthermore, the results achieved using flax-FRCM composites were compared with those of using PBO-FRCM composites.

  20. Load Analysis of Horse Head of Pumping units in Design%抽油机驴头设计中的载荷分析

    Institute of Scientific and Technical Information of China (English)

    李美求; 周思柱; 王宏丽

    2011-01-01

    通过对游梁抽油机驴头载荷分析,阐述了驴头现有设计中载荷选取存在的不足;鉴于有限宽度轴径油膜应力分布规律及绳轮机构受力分析方法,建立了合理的力学模型,推导出驴头和吊绳接触面载荷分布函数;运用有限元方法,分析了在两种不同分布载荷作用时驴头及相关部件设计的差异.实例计算及有限元分析表明,以余弦分布载荷计算与实际更为接近,确保了设计中的合理性.%The shortage of loading in design of horse head is indicated by analysis. Based on the distribution disciplinarian of Oil film stress of the limited width axis - diameter and mechanical analysis method of wheel to rope, the reasonable mechanical model is set up, the load distribution function on the interface of wheel to rope is deduced. When two different distribution of load is loaded, the difference in design of the horse head and the related components is given. By FEA, the cosine distribution of load is more reasonable and more credibility in during of design.