Shot loading platform analysis
International Nuclear Information System (INIS)
This document provides the wind/seismic analysis and evaluation for the shot loading platform. Hand calculations were used for the analysis. AISC and UBC load factors were used in this evaluation. The results show that the actual loads are under the allowable loads and all requirements are met
International Nuclear Information System (INIS)
This document presents the results from the analysis of the shot loading trainer (SLT). This device will be used to test the procedure for installing shot into the annulus of the Project W-320 shipping container. To ensure that the shot is installed uniformly around the container, vibrators will be used to settle the shot. The SLT was analyzed to ensure that it would not jeopardize worker safety during operation. The results from the static analysis of the SLT under deadweight and vibrator operating loads show that the stresses in the SLT are below code allowables. The results from the modal analysis show that the natural frequencies of the SLT are far below the operating frequencies of the vibrators, provided the SLT is mounted on pneumatic tires. The SLT was also analyzed for wind, seismic, deadweight, and moving/transporting loads. Analysis of the SLT is in accordance with SDC-4.1 for safety class 3 structures (DOE-RL 1993) and the American Institute of Steel Construction (AISC) Manual of Steel Construction (AISC 1989)
Analysis of Dynamic Flight Loads
Jansson, Natascha
2012-01-01
This thesis deals with the determination of loads on an aircraft struc- ture during flight. The focus is on flight conditions where the loads are significantly time-dependent. Analysis of flight loads is primarily motivated to ensure that structural failure is avoided. The ability to ac- curately determine the resulting structural loads which can occur during operation allows for a reduction of the safety margins in the structural design. Consequently it is then possible to decrease the aircr...
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.
Load Estimation from Natural input Modal Analysis
DEFF Research Database (Denmark)
Aenlle, Manuel López; Brincker, Rune; Canteli, Alfonso Fernández
2005-01-01
One application of Natural Input Modal Analysis consists in estimating the unknown load acting on structures such as wind loads, wave loads, traffic loads, etc. In this paper, a procedure to determine loading from a truncated modal model, as well as the results of an experimental testing programme...... estimation. In the experimental program a small structure subjected to vibration was used to estimate the loading from the measurements and the experimental modal space. The modal parameters were estimated by Natural Input Modal Analysis and the scaling factors of the mode shapes obtained by the mass change......, are presented. The method involves the inversion of the FRF matrix partly solving the numerical problems that appear because of the truncation of the modal space. However, the error in the load estimation depends on the degree of truncation of the modal space and on the accuracy of the modal parameter...
Analysis of a transient load measuring system
International Nuclear Information System (INIS)
An analysis of the performance of a load measuring system is presented. The load system was designed to measure the weight of a pressure vessel containing high pressure and temperature water. The uncertainty and frequency response of the system are quantified for both steady state and dynamic conditions as is the repeatability of the test rig. Computation of the mass flow exiting the system during explosive decompression of the system is also presented
Reliability analysis of rc containment structures under combined loads
International Nuclear Information System (INIS)
This paper discusses a reliability analysis method and load combination design criteria for reinforced concrete containment structures under combined loads. The probability based reliability analysis method is briefly described. For load combination design criteria, derivations of the load factors for accidental pressure due to a design basis accident and safe shutdown earthquake (SSE) for three target limit state probabilities are presented
Analysis of pile foundations under dynamic loads
International Nuclear Information System (INIS)
A method is presented for the analysis of pile foundations which are subjected to horizontal dynamic loads from earthquakes, airplane impact, gas explosion or other sources. The motion of the pile cap and the pile forces are computed. - The loads may be applied to the pile cap or directly to the piles (e.g. by earthquake wave motion). The soil may be stratified and is considered to be an elastic or visco-elastic medium. The piles are assumed vertical. The method makes use of an approximate fundamental solution for displacements caused by a dynamic point load in a layered visco-elastic medium. The approximation involves a discretization of the medium in the vertical direction. In horizontal directions the medium is treated by continuum theory. The soil medium supports each pile at about 10 to 20 nodes. A dynamic flexiblity matrix for the soil is derived which relates the elastic, damping and inertial forces of the soil to the displacements at each node. It includes effects of radiation damping. All piles are coupled through the soil flexibility matrix. The piles are modelled by beam elements. Transient response is computed using fast discrete Fourier transforms. The arrangement of the piles is arbitrary. However, simple and double symmetry can be accounted for by the computer program. When the pile arrangement is axisymmetric, the degrees of freedom can be reduced to only those of two piles per ring. The influence of the number of piles and the influence of the pile spacing on group stiffness and on pile forces is presented for two soil profiles. Dynamic effects on pile forces of a foundation for a reactor building are studied. They are significant when soils are soft. (orig.)
Rural Power System Load Forecast Based on Principal Component Analysis
Institute of Scientific and Technical Information of China (English)
Fang Jun-long; Xing Yu; Fu Yu; Xu Yang; Liu Guo-liang
2015-01-01
Power load forecasting accuracy related to the development of the power system. There were so many factors influencing the power load, but their effects were not the same and what factors played a leading role could not be determined empirically. Based on the analysis of the principal component, the paper forecasted the demands of power load with the method of the multivariate linear regression model prediction. Took the rural power grid load for example, the paper analyzed the impacts of different factors on power load, selected the forecast methods which were appropriate for using in this area, forecasted its 2014-2018 electricity load, and provided a reliable basis for grid planning.
Analysis of mechanical loads during yawing
International Nuclear Information System (INIS)
The yaw control, a major part of the wind turbine, is closely related to the efficiency of electric power production and the mechanical load. The yaw error, which results from the nacelle not being appropriately aligned in the wind direction, not only decreases the power output but also reduces the lifetime of the wind turbine as a result of large fatigue loads. However, the yawing rate cannot be increased indefinitely because of constraints on mechanical loads. This paper investigates the characteristics of an active yaw control system, the basic principle of the system, and mechanical loads around the yaw axis during yawing
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....
Analysis of aeroelastic loads and their contributions to fatigue damage
International Nuclear Information System (INIS)
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; negligible fatigue contributions are reported for loads with frequencies above 2 Hz
NIF ICCS network design and loading analysis
International Nuclear Information System (INIS)
The National Ignition Facility (NIF) is housed within a large facility about the size of two football fields. The Integrated Computer Control System (ICCS) is distributed throughout this facility and requires the integration of about 40,000 control points and over 500 video sources. This integration is provided by approximately 700 control computers distributed throughout the NIF facility and a network that provides the communication infrastructure. A main control room houses a set of seven computer consoles providing operator access and control of the various distributed front-end processors (FEPs). There are also remote workstations distributed within the facility that allow provide operator console functions while personnel are testing and troubleshooting throughout the facility. The operator workstations communicate with the FEPs which implement the localized control and monitoring functions. There are different types of FEPs for the various subsystems being controlled. This report describes the design of the NIF ICCS network and how it meets the traffic loads that will are expected and the requirements of the Sub-System Design Requirements (SSDR's). This document supersedes the earlier reports entitled Analysis of the National Ignition Facility Network, dated November 6, 1996 and The National Ignition Facility Digital Video and Control Network, dated July 9, 1996. For an overview of the ICCS, refer to the document NIF Integrated Computer Controls System Description (NIF-3738)
Load profiles analysis for electricity market
Radu Porumb; Petru Postolache; George Serițan; Ramona Vatu; Oana Ceaki
2013-01-01
In the wake of electric power system transition towards smart grids, and the adoption of the electric market schemes, electric utilities are facing the need of a better load profiles understanding for their customers. In this work, some key objectives were addresses, such as definition of the mathematical model for calculating the hourly energy specific, identification of the three target groups for users who have developed consumer profiles, definition of the two types of significant load an...
Fuel loading and homogeneity analysis of HFIR design fuel plates loaded with uranium silicide fuel
International Nuclear Information System (INIS)
Twelve nuclear reactor fuel plates were analyzed for fuel loading and fuel loading homogeneity by measuring the attenuation of a collimated X-ray beam as it passed through the plates. The plates were identical to those used by the High Flux Isotope Reactor (HFIR) but were loaded with uranium silicide rather than with HFIR's uranium oxide fuel. Systematic deviations from nominal fuel loading were observed as higher loading near the center of the plates and underloading near the radial edges. These deviations were within those allowed by HFIR specifications. The report begins with a brief background on the thermal-hydraulic uncertainty analysis for the Advanced Neutron Source (ANS) Reactor that motivated a statistical description of fuel loading and homogeneity. The body of the report addresses the homogeneity measurement techniques employed, the numerical correction required to account for a difference in fuel types, and the statistical analysis of the resulting data. This statistical analysis pertains to local variation in fuel loading, as well as to ''hot segment'' analysis of narrow axial regions along the plate and ''hot streak'' analysis, the cumulative effect of hot segment loading variation. The data for all twelve plates were compiled and divided into 20 regions for analysis, with each region represented by a mean and a standard deviation to report percent deviation from nominal fuel loading. The central regions of the plates showed mean values of about +3% deviation, while the edge regions showed mean values of about -7% deviation. The data within these regions roughly approximated random samplings from normal distributions, although the chi-square (χ2) test for goodness of fit to normal distributions was not satisfied
Load Specification and Seismic Analysis for ITER Tritium SDS
International Nuclear Information System (INIS)
Korea is supposed to design, fabricate, deliver and install the ITER tritium storage and delivery system (SDS). SDS is one of the major components of the tritium plant. It includes the fuel storage and delivery systems and the tritium loading station. The tritium loading station serves for receiving tritium from external facilities and supplying tritium to the fuel delivery system. Prior to unloading, calorimetric determinations of the amount of tritium contained in the tritium shipping containers are carried out. The storage system is composed of metal hydride beds to ensure safe storage of tritium inventories. To evaluate the integrity of SDS, load specifications and analyses for dominant load case should be conducted. This study includes a load specification and a structural analysis for SDS. For the load specification, every single load possible to occur in SDS was generated. Load combinations were made based on the characteristics of each single load and incident/accident scenarios. This structural analysis includes the modal analysis and the seismic analysis for the tritium SDS glove box. The dynamic characteristics of the glove box are obtained through the modal analysis. The seismic response results are calculated for the floor response spectra given
Design and analysis of a novel mechanical loading machine for dynamic in vivo axial loading
Macione, James; Nesbitt, Sterling; Pandit, Vaibhav; Kotha, Shiva
2012-02-01
This paper describes the construction of a loading machine for performing in vivo, dynamic mechanical loading of the rodent forearm. The loading machine utilizes a unique type of electromagnetic actuator with no mechanically resistive components (servotube), allowing highly accurate loads to be created. A regression analysis of the force created by the actuator with respect to the input voltage demonstrates high linear correlation (R2 = 1). When the linear correlation is used to create dynamic loading waveforms in the frequency (0.5-10 Hz) and load (1-50 N) range used for in vivo loading, less than 1% normalized root mean square error (NRMSE) is computed. Larger NRMSE is found at increased frequencies, with 5%-8% occurring at 40 Hz, and reasons are discussed. Amplifiers (strain gauge, linear voltage displacement transducer (LVDT), and load cell) are constructed, calibrated, and integrated, to allow well-resolved dynamic measurements to be recorded at each program cycle. Each of the amplifiers uses an active filter with cutoff frequency at the maximum in vivo loading frequencies (50 Hz) so that electronic noise generated by the servo drive and actuator are reduced. The LVDT and load cell amplifiers allow evaluation of stress-strain relationships to determine if in vivo bone damage is occurring. The strain gauge amplifier allows dynamic force to strain calibrations to occur for animals of different sex, age, and strain. Unique features are integrated into the loading system, including a weightless mode, which allows the limbs of anesthetized animals to be quickly positioned and removed. Although the device is constructed for in vivo axial bone loading, it can be used within constraints, as a general measurement instrument in a laboratory setting.
Phloem loading through plasmodesmata: a biophysical analysis
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...
FGM elastoplastic analysis under thermomechanical loading
International Nuclear Information System (INIS)
In this research, thick walled FGM spherical pressure vessels under internal pressure and temperature difference were studied. Material parameters were considered to vary as a power functions. In order to clarify the role of material parameters, several different materials with different parameters have been used. Different combinations of the internal pressure and temperature gradient loading were applied and their effects on the yield onset location, kinds of stresses and the role of temperature gradient, were studied. Linear kinematic hardening was supposed and the pressure vessel behavior under constant internal; pressure and cyclic temperature gradient, was obtained. -- Highlights: • Elastic solution of an FGM spherical pressure vessel under thermomechanical loading was obtained. • Yield onset under different thermomechanical loading and material properties were obtained. • Linear kinematic hardening was used and plastic strain and stress equations were developed. • Bree's interaction diagram was obtained for two different FGM pressure vessel
Load profiles analysis for electricity market
Directory of Open Access Journals (Sweden)
Radu Porumb
2014-04-01
Full Text Available In the wake of electric power system transition towards smart grids, and the adoption of the electric market schemes, electric utilities are facing the need of a better load profiles understanding for their customers. In this work, some key objectives were addresses, such as definition of the mathematical model for calculating the hourly energy specific, identification of the three target groups for users who have developed consumer profiles, definition of the two types of significant load and assessment of the impact of using consumer profiles on users.
Cognitive task load analysis : Allocating tasks and designing support
Neerincx, M.A.
2003-01-01
We present a method for Cognitive Task Analysis that guides the early stages of software development, aiming at an optimal cognitive load for operators of process control systems. The method is based on a practical theory of cognitive task load and support. In addition to the classical measure percentage time occupied, this theory distinguishes two load factors that affect cognitive task performance and mental effort: the level of information processing and the number of task-set switches. Re...
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.
Analysis of Loaded Substrate Integrated Waveguides and Attenuators
Xu, Ruo Feng; Farrall, A. J.; Young, Paul R.
2013-01-01
This letter provides an approximate analysis of a slotted substrate integrated waveguide with periodic loading elements using the transverse resonance technique. The technique is used to design a travelling wave attenuator whereby pin diodes are capacitively coupled to the waveguide slot. By changing the bias, and therefore loading resistance, a very constant, variable attenuation is produced over the waveguide band.
Transient/structural analysis of a combustor under explosive loads
Gregory, Peyton B.; Holland, Anne D.
1992-01-01
The 8-Foot High Temperature Tunnel (HTT) at NASA Langley Research Center is a combustion-driven blow-down wind tunnel. A major potential failure mode that was considered during the combustor redesign was the possibility of a deflagration and/or detonation in the combustor. If a main burner flame-out were to occur, then unburned fuel gases could accumulate and, if reignited, an explosion could occur. An analysis has been performed to determine the safe operating limits of the combustor under transient explosive loads. The failure criteria was defined and the failure mechanisms were determined for both peak pressures and differential pressure loadings. An overview of the gas dynamics analysis was given. A finite element model was constructed to evaluate 13 transient load cases. The sensitivity of the structure to the frequency content of the transient loading was assessed. In addition, two closed form dynamic analyses were conducted to verify the finite element analysis. It was determined that the differential pressure load or thrust load was the critical load mechanism and that the nozzle is the weak link in the combustor system.
Wavelet multiscale analysis of a power system load variance
Avdakovic, Samir; Nuhanovic, Amir; Kusljugic, Mirza
2013-01-01
Wavelet transform (WT) represents a very attractive mathematical area for just more than 15 years of its research in applications in electrical engineering. This is mainly due to its advantages over other processing techniques and signal analysis, which is reflected in the time-frequency analysis, and so it has an important application in the processing and analysis of time series. In this paper, for example, the analysis of the hourly load of a real power system over the past few yea...
A study on risk analysis for loading and un-loading accident
International Nuclear Information System (INIS)
Low Level Waste packages are transported from each Japanese nuclear power plants to Rokkasho-Mura by exclusive ship. These packages are contained in half-height 5 ton containers. The handling system for loading and unloading containers is composed of the 25 ton crane, the cell-guide system and transport trucks. These systems are mostly automated and under computer control. By design, the whole handling system should be highly protected from any accident. However unknown causes for accidents might be concealed in this handling system, because of complicated system interaction between computer control and human operation. The representative 25 ton bridge type crane was analyzed in this assessment. As the first step, causes of drop accidents were analyzed using design drawing of the crane and its system operation flow chart as inputs to the analysis. After analysis the protection methods were reviewed, and where necessary, revised in each step accident cause. Those results were rearranged by fault trees for each cause. To provide quantitative details of operational interactions, crane operators and safety supervisors were consulted. Based on their experience, a method to determine probabilities of basic events was tentatively adopted. According to this assessment, each protection method was clarified and some weak points of the loading and un-loading process were able to be identified. Figure 1 shows schematically the sequential steps in the method. As a result of this assessment, the PSA method (including fault trees, etc) was found to be adaptable for the loading and un-loading process (i.e. handling system) and to be effective in understanding the system characteristics. Further, using this PSA analysis method allows transport companies to review protection methods with 'Cost and Benefit' analysis concepts. (authors)
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.
Inverse Analysis of Distributed Load Using Strain Data
Nakamura, Toshiya; Igawa, Hirotaka
The operational stress data is quite useful in managing the structural integrity and airworthiness of an aircraft. Since the aerodynamic load (pressure) distributes continuously on the structure surface, identifying the load from finite number of measured strain data is not easy. Although this is an inverse problem, usually used is an empirical correlation between load and strain obtained through expensive ground tests. Some analytical studies have been conducted but simple mathematical expressions were assumed to approximate the pressure distribution. In the present study a more flexible approximation of continuous load distribution is proposed. The pressure distribution is identified based on finite number of strain data with using the conventional finite element method and pseudo-inverse matrix. Also an extension is made by coupling an aerodynamical restriction with the elastic equation. Numerical examples show that this extension improves the precision of the inverse analysis with very small number of strain data.
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.
Finite element analysis of impact loads on the femur
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
Objective:To investigate the stress distribution and fracture mechanism of proximal femur under impact loads. Methods:The image data of one male's femur were collected by the Lightspeed multi-lay spiral computed tomography.A 3D finite element model of the femur was established by employing the finite element software ANSYS,which mainly concentrated on the effects of the directions of the impact loads arising from intense movements and the parenchyma on the hip joint as well as those of the femur material properties on the distribution of the Mises equivalent stress in the femur after impact. Results:The numerical results about the effects of the angle δ of the impact loads to the anterior direction and the angle γ of the impact loads to the femur shaft on the bone fracture were given.The angle δ had larger effect on the stress distribution than the angle γ,which mainly represented the fracture of the upper femur including the femoral neck fracture when the posterolateral femur was impacted.This result was consistent with the clinical one.The parenchyma on the hip joint has relatively large relaxation effect on the impact loads. Conclusions:A 3D finite element analysis model of the femoral hip joint under dynamic loads is successfully established by using the impact dynamic theory.
Load-application devices: a comparative strain gauge analysis.
Nishioka, Renato Sussumu; de Vasconcellos, Luis Gustavo Oliveira; Jóias, Renata Pilli; Rode, Sigmar de Mello
2015-01-01
In view of the low loading values commonly employed in dentistry, a load-application device (LAD) was developed as option to the universal testing machine (UTM), using strain gauge analysis. The aim of this study was to develop a load-application device (LAD) and compare the LAD with the UTM apparatus under axial and non-axial loads. An external hexagonal implant was inserted into a polyurethane block and one EsthetiCone abutment was connected to the implant. A plastic prosthetic cylinder was screwed onto the abutment and a conical pattern crown was fabricated using acrylic resin. An impression was made and ten identical standard acrylic resin patterns were obtained from the crown impression, which were cast in nickel-chromium alloy (n=10). Four strain gauges were bonded diametrically around the implant. The specimens were subjected to central (C) and lateral (L) axial loads of 30 kgf, on both devices: G1: LAD/C; G2: LAD/L; G3: UTM/C; G4: UTM/L. The data (με) were statistically analyzed by repeated measures ANOVA and Tukey's test (p<0.05). No statistically significant difference was found between the UTM and LAD devices, regardless of the type of load. It was concluded that the LAD is a reliable alternative, which induces microstrains to implants similar to those obtained with the UTM. PMID:26200149
Engine System Loads Analysis Compared to Hot-Fire Data
Frady, Gregory P.; Jennings, John M.; Mims, Katherine; Brunty, Joseph; Christensen, Eric R.; McConnaughey, Paul R. (Technical Monitor)
2002-01-01
Early implementation of structural dynamics finite element analyses for calculation of design loads is considered common design practice for high volume manufacturing industries such as automotive and aeronautical industries. However with the rarity of rocket engine development programs starts, these tools are relatively new to the design of rocket engines. In the NASA MC-1 engine program, the focus was to reduce the cost-to-weight ratio. The techniques for structural dynamics analysis practices, were tailored in this program to meet both production and structural design goals. Perturbation of rocket engine design parameters resulted in a number of MC-1 load cycles necessary to characterize the impact due to mass and stiffness changes. Evolution of loads and load extraction methodologies, parametric considerations and a discussion of load path sensitivities are important during the design and integration of a new engine system. During the final stages of development, it is important to verify the results of an engine system model to determine the validity of the results. During the final stages of the MC-1 program, hot-fire test results were obtained and compared to the structural design loads calculated by the engine system model. These comparisons are presented in this paper.
Evaluation of condensation oscillation loads using spectral analysis techniques
International Nuclear Information System (INIS)
An experimental test program was started in the United States in 1978 to define and quantify the Condensation Oscillation (CO) phenomena in General Electric Mark I Suppression Chamber Systems. The program was funded by utilities with Mark I containments, and the results were included in a detailed load definition in the Mark I Containment Program Load Definition Report (LDR). The United States Nuclear Regulatory Commission (USNRC) has reviewed and approved the LDR CO load definition. Spectral analysis methods are employed to determine the significant load distributions and applied loading frequencies acting on the vent system during the CO phenomena. The case of a single input/output system is assumed. Test data obtained from full scale testing is utilized in this evaluation and consists of downcomer pressures and vent header hoop stress at the intersection of the downcomers. Spectral quantities investigated include auto-spectrum, cross-spectrum, ordinary coherence, and transfer functions. Transfer functions from the spectral analysis are evaluated against harmonic response functions from a finite element model of the vent system
Dynamic Load and Stress Analysis of a Crankshaft
Prof. N. G. Alvi; Ram.R.Wayzode; Dr. S. V. Deshmukh
2012-01-01
In this study a dynamic simulation was conducted on a crankshaft from a single cylinder four stroke engine. Finite element analysis was performed to obtain the variation of stress magnitude at critical locations. The pressure-volume diagram was used to calculate the load boundary condition in dynamic simulation model, and other simulation inputs were taken from the engine specification chart. The dynamic analysis was done analytically and was verified by...
Numerical Analysis of Vibrations of Structures under Moving Inertial Load
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 ...
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.
Numerical Analysis of Asphalt Pavements under Moving Wheel Loads
Institute of Scientific and Technical Information of China (English)
无
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.
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....
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.
Startup analysis for a high temperature gas loaded heat pipe
Sockol, P. M.
1973-01-01
A model for the rapid startup of a high-temperature gas-loaded heat pipe is presented. A two-dimensional diffusion analysis is used to determine the rate of energy transport by the vapor between the hot and cold zones of the pipe. The vapor transport rate is then incorporated in a simple thermal model of the startup of a radiation-cooled heat pipe. Numerical results for an argon-lithium system show that radial diffusion to the cold wall can produce large vapor flow rates during a rapid startup. The results also show that startup is not initiated until the vapor pressure p sub v in the hot zone reaches a precise value proportional to the initial gas pressure p sub i. Through proper choice of p sub i, startup can be delayed until p sub v is large enough to support a heat-transfer rate sufficient to overcome a thermal load on the heat pipe.
Finite element analysis of loaded structures at very high temperatures
Energy Technology Data Exchange (ETDEWEB)
Breitbach, G.
1989-05-01
At very high temperatures loaded metallic structures undergo creep deformations. The generated creep strains are connected with stress relaxations, stress redistributions and/or progressive deformations. In mainly load controlled situations the behaviour of the material can be described by a non-linear viscous flow law (Norton power play). A stress-deformation analysis of complex structures can be carried out by finite element codes in which the mentioned constitutive equation is implemented. The code PERMAS-VISCOUS was used to analyse the stress state of a notched tension bar and the deformation behaviour of a reformer tube of HTR under external pressure undergoing a creep collapse. The relation to experimental findings is also given. (orig./HP).
Finite element analysis of loaded structures at very high temperatures
International Nuclear Information System (INIS)
At very high temperatures loaded metallic structures undergo creep deformations. The generated creep strains are connected with stress relaxations, stress redistributions and/or progressive deformations. In mainly load controlled situations the behaviour of the material can be described by a non-linear viscous flow law (Norton power play). A stress-deformation analysis of complex structures can be carried out by finite element codes in which the mentioned constitutive equation is implemented. The code PERMAS-VISCOUS was used to analyse the stress state of a notched tension bar and the deformation behaviour of a reformer tube of HTR under external pressure undergoing a creep collapse. The relation to experimental findings is also given. (orig./HP)
Analysis concepts for large telescope structures under earthquake load
Koch, Franz
1997-03-01
The very large telescope (VLT) of ESO will be placed on Cerro Paranal in the Atacama desert in northern Chile. This site provides excellent conditions for astronomical observations. However, it is likely that important seismic activities occur. The telescope structure and its components have to resist the largest earthquakes expected during their lifetime. Therefore, design specifications and structural analyses have to take into account loads caused by such earthquakes. The present contribution shows some concepts and techniques in the assessment of earthquake resistant telescope design by the finite element method (FEM). After establishing the general design criteria and the geological and geotechnical characteristics of the site location, the seismic action can be defined. A description of various representations of the seismic action and the procedure to define the commonly used response spectrum are presented in more detail. A brief description of the response spectrum analysis method and of the result evaluation procedure follows. Additionally, some calculation concepts for parts of the entire telescope structure under seismic loads are provided. Finally, a response spectrum analysis of the entire VLT structure performed at ESO is presented to show a practical application of the analysis method and evaluation procedure mentioned above.
One-Dimensional Analysis of Full Load Draft Tube Surge
Chen, Changkun; Nicolet, Christophe; Yonezawa, Koichi; Farhat, Mohamed; Avellan, François; Tsujimoto, Yoshinobu
2008-01-01
One-dimensional stability analysis of a hydraulic system composed of a penstock, a runner, and a draft tube was carried out to determine the cause of the full load draft tube surge. It is assumed that the cavity volume at the runner exit is a function of the pressure at the vortex core evaluated from the instantaneous local pressure at the runner exit and an additional pressure decrease due to the centrifugal force on the swirling flow. It was found that the diffuser effect of the draft tube ...
Analysis of delamination growth in compressively loaded composite laminates
Tratt, Matthew D.
The present analytical and empirical study of composite structure delamination has attempted to predict the threshold stress for the initiation of delamination growth in compressively loaded composite laminates. The strain-energy release-rate distributions around circular delaminations are computed via MSC/NASTRAN analysis in conjunction with a virtual crack-opening technique. Static compression tests were conducted on specimens of graphite fiber-reinforced epoxy having circular delaminations of various sizes. Computed delamination growth threshold-stress prediction results were at substantial variance with the test data, but confirmed trends and gave qualitative insight into quasi-static delamination growth.
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.
Undrained loading and consolidation analysis for unsaturated soils
International Nuclear Information System (INIS)
In this paper, a computational procedure to calculate deformations of partly saturated soils due to air and water flow is presented. Undrained conditions can also be considered. State surfaces define the behaviour of soil under suction and mean stress changes. In undrained conditions, the analysis is performed by equating the volume changes of free air and water to the variations of volume and degree of saturation caused by changes in stresses and suction. If flow occurs, the analysis is carried out in two stages, uncoupling the transient flow problem from the stress - strain one. Both problems are strongly nonlinear. The formulation is applied to the consolidation of a partly saturated soil after a load application and to the study of infiltration with either free or imposed deformation on the boundary. (orig.)
Analysis of measurements from CAGR on-load instrumented stringers
International Nuclear Information System (INIS)
The initial fuel loadings of the Hinkley Point B and Hunterston B CAGRs included specially developed stringers containing instrumentation to make channel performance measurements. More recently the emphasis of the instrumented stringer programme has concentrated on developing a means of detecting and quantifying carbonaceous deposit on the fuel pins. An analysis route has been set-up to compare measured and calculated can temperatures and to calculate Stanton Number changes. Present analysis is dedicated towards gaining an increased understanding of the relationship between measurement and prediction in the prevailing non-depositing coolants. A series of experiments has been planned for Hinkley Point B in which several instrumented stringers containing many instrumented pins will be used to quantify deposition in a number of different coolant compositions so that a composition giving the optimum compromise between graphite corrosion and deposition can be identified. (author)
Further finite element structural analysis of FAST Load Assembly
International Nuclear Information System (INIS)
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
Structural integrity analysis of an INPP building under external loading
International Nuclear Information System (INIS)
After the terrorist attacks in New York and Washington D. C. using civil airplanes, the evaluation of civil airplane crashes into civil and NPP structures has become very important. The interceptions of many terrorists' communications reveal that the use of commandeered commercial aircraft is still a major part of their plans for destruction. Aircraft crash or other flying objects in the territory of the Ignalina Nuclear Power Plant (INPP) represents a concern to the plant. Aircraft traveling at high velocity have a destructive potential. The aircraft crash may damage the roof and walls of buildings, pipelines, electric motors, cases of power supplies, power cables of electricity transmission and other elements and systems, which are important for safety. Therefore, the evaluation of the structural response to an of aircraft crash is important and was selected for analysis. The structural integrity analysis due to the effects of an aircraft crash on an NPP building structure is the subject of this paper. The finite element method was used for the structural analysis of a typical Ignalina NPP building. The structural integrity analysis was performed for a portion of the ALS using the dynamic loading of an aircraft crash impact model. The computer code NEPTUNE was used for this analysis. The local effects caused by impact of the aircraft's engine on the building wall were evaluated independently by using an empirical formula. (authors)
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
The analysis of loading losses from tank trucks
Directory of Open Access Journals (Sweden)
Jovanović Ana P.
2006-01-01
Full Text Available The quantity of loading losses, which are the primary source of evaporative emissions from tank cars and trucks was analyzed in this paper. Loading losses occur as organic vapors in "empty" cargo tanks are displaced to the atmosphere by the liquid being loaded into the tanks. Emissions from loading petroleum liquid were estimated using three methods: the API (American Petroleum Institute method, the VDI (Verein Deutscher Ingenieure -Association of German Engineers method and the Yugoslav Standard JUS B.HO.531 method. The mass of evaporative losses from loading operations is a function of the following parameters: the method of loading the cargo, the physical and chemical characteristics of the cargo and the ambient temperature during loading. Evaporation losses from the loading of motor gasoline (MB-95, BMB-95, MB-98 and MB-86 and diesel fuels (D-2, Euro D-2 were calculated. Losses on a monthly and annual basis were presented for an assumed amount of loaded cargo. It was estimated that the highest loading losses occur in the summer period because of high ambient daily temperatures and in the period of higher transporting levels. It should be pointed out that the loading losses of diesel fuel calculated using an empirical coefficient according to JUS B.HO.531 are significantly higher in comparison with the loading losses calculated using emission factors from the EPA and the VDI method. The gasoline loading losses calculated using emission factors derived from the three methods are similar.
Analysis of carbon based materials under fusion relevant thermal loads
International Nuclear Information System (INIS)
how anisotropy can be tailored and on the strategies which were applied for the production of the investigated materials. Textures of fibers and microstructures of matrices were also described. Thermo-physical properties such as thermal conductivity and thermal expansion of some CFCs were studied for different materials' orientations. For the first time, some off-axis results of thermal conductivity and thermal expansion for fusion related CFCs are displayed. Room temperature bending and tensile loading of CFCs were performed and they allowed relating the microstructural findings to the anisotropic mechanical response. Fiber architecture of CFCs and interfacial shear strength between the fiber and the matrix appeared to be the main parameters which dictate the fracture mechanisms. In addition, the analysis of five batches of one CFC permitted to understand the difficulty of reproducing such advanced material. The differences in terms of needling process were related to the variations of the tensile properties in the various fibrous directions. Finally, fusion-relevant transient heat loads were simulated on the investigated CBMs within various high heat flux facilities, i.e. electron beam, ion beam and plasma gun. Erosion scenarios at different scales were compiled in relation to the CBM properties but also the type of the transient event. The locally preferential erosion and ejection of material from the surface of the CBM are comprehensively described as well as their implications. This ejection of hot particles from the CBM surface (so-called Brittle Destruction (BD) mechanism) was defined, explained and analyzed. An experimental thermal shock resistance criterion based on thermal-shock induced weight loss is presented. After analyzing the anisotropic response of CFCs to transient heat loads in their three orthotropic fiber directions, attempts to reduce BD were done by loading them under off-axis orientations. It partly succeeded and led to the observation of
Thermal–structural analysis of ITER triangular support for dominant load verification
Energy Technology Data Exchange (ETDEWEB)
Kim, Yu-Gyeong, E-mail: aspirany@hhi.co.kr [Hyundai Heavy Industries Co., Ltd., 1000, Bangeojinsunhwando-ro, Dong-gu, Ulsan (Korea, Republic of); Hwang, Jong-Hyun; Jung, Yung-Jin [Hyundai Heavy Industries Co., Ltd., 1000, Bangeojinsunhwando-ro, Dong-gu, Ulsan (Korea, Republic of); Kim, Hyun-Soo; Ahn, Hee-Jae [National Fusion Research Institute, 113 Gwahangno, Yuseong-gu, Daejeon-si (Korea, Republic of)
2014-12-15
Highlights: • The load combination method is introduced to thermal–structural analysis for contradictive loads occurred simultaneously. • The one-way coupling analysis also conducted for thermal–structural analysis and its validity is checked by comparing with the load combination. • The dominant load for triangular support bracket is determined as the baking condition. - Abstract: The triangular support is located on the lower inner shell of vacuum vessel of ITER, which should be designed to withstand various loads such as nuclear heat, coolant pressure and so on. The appropriateness of its design is evaluated under the dominant load that could represent the most conservative condition among the design loads. In order to decide the dominant load, a valid method for thermal–structural analysis is firstly verified considering contradictory behaviors between heat and structural loads. In this paper, two approaches; one-way coupling and load combination, are introduced for thermal–structural analysis. The one-way coupling is a method generally used but has a limit to apply on contradictory conditions. The load combination could give a proper solution since it evaluates each load independently and then adds up each result linearly. Based on the results of each case, structural analysis for another load case, baking condition with incident, is conducted to find out which load is dominant for triangular support. Consequently, it is found that the baking condition is the dominant load for triangular support bracket. The proposed load combination method gives a physically reasonable solution which can be used as a reference for checking the validity of other thermal–structural analysis. It is expected that these results could be applied for manufacturing design of the triangular support under various load conditions.
Thermal–structural analysis of ITER triangular support for dominant load verification
International Nuclear Information System (INIS)
Highlights: • The load combination method is introduced to thermal–structural analysis for contradictive loads occurred simultaneously. • The one-way coupling analysis also conducted for thermal–structural analysis and its validity is checked by comparing with the load combination. • The dominant load for triangular support bracket is determined as the baking condition. - Abstract: The triangular support is located on the lower inner shell of vacuum vessel of ITER, which should be designed to withstand various loads such as nuclear heat, coolant pressure and so on. The appropriateness of its design is evaluated under the dominant load that could represent the most conservative condition among the design loads. In order to decide the dominant load, a valid method for thermal–structural analysis is firstly verified considering contradictory behaviors between heat and structural loads. In this paper, two approaches; one-way coupling and load combination, are introduced for thermal–structural analysis. The one-way coupling is a method generally used but has a limit to apply on contradictory conditions. The load combination could give a proper solution since it evaluates each load independently and then adds up each result linearly. Based on the results of each case, structural analysis for another load case, baking condition with incident, is conducted to find out which load is dominant for triangular support. Consequently, it is found that the baking condition is the dominant load for triangular support bracket. The proposed load combination method gives a physically reasonable solution which can be used as a reference for checking the validity of other thermal–structural analysis. It is expected that these results could be applied for manufacturing design of the triangular support under various load conditions
On load paths and load bearing topology from finite element analysis
International Nuclear Information System (INIS)
Load paths can be mapped from vector plots of 'pointing stress vectors'. They define a path along which a component of load remains constant as it traverses the solution domain. In this paper the theory for the paths is first defined. Properties of the plots that enable a designer to interpret the structural behavior from the contours are then identified. Because stress is a second order tensor defined on an orthogonal set of axes, the vector plots define separate paths for load transfer in each direction of the set of axes. An algorithm is therefore presented that combines the vectors to define a topology to carry the loads. The algorithm is shown to straighten the paths reducing bending moments and removing stress concentration. Application to a bolted joint, a racing car body and a yacht hull demonstrate the usefulness of the plots.
THE ANALYSIS OF HEART FREQUENCY OF HORSES UNDER LOAD
Directory of Open Access Journals (Sweden)
Eva Mlyneková
2013-02-01
Full Text Available In our work we analysed the heart frequency of 11 warmblood horses on the load regulator of motion. The test lasted 3 weeks with gradual increase of load. The load was applied only in a step with gradual increase of time of load in up-sloping direction. The mean values of heart frequency of tested horses were within 61 beats/min. At the evaluation of maximum value of heart frequency we detected its twofold increase in comparison with mean values. The maximum rate of heart frequency under load was at the level of 147 beats/min. Detected values were not statistically significant which confirms that the load on tested horses was not causing any physiological changes.
Metatarsal Loading During Gait-A Musculoskeletal Analysis.
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. PMID:26719905
Concept of Hydrodynamic Load Analysis of Fixed Jacket Structure – An Overview of Horizontal Cylinder
Directory of Open Access Journals (Sweden)
Aliyu Baba
2014-04-01
Full Text Available This paper focuses on the analysis of hydrodynamic loads on fixed offshore structures (horizontal cylinder that are operating in shallow water and are often subjected to huge wave loading. For the purpose of this study, linear (Airy wave theory was adopted together with the application of (21 in the load computation. The loads for six different sea states were computed using spread sheet for the following values of time t = 0, T/4, T/2.
The Buckling Analysis of Axially Loaded Columns with Artificial Neural Networks
Ülker, Mehmet; CİVALEK, Ömer
2002-01-01
The determination of effective design values in structural analysis is important.Axially loaded columns are designed according to the their buckling load capacity. In this study, a multi-layer artificial neural network is trained to give critical load for axially loaded columns and various support conditions. Back-propagation training algorithms are used considering the circular, square, rectangular, and I cross-sections. The artificial neural network, with is trained for circular and rec...
Comparative analysis of design methods of transversally loaded diaphragms
Directory of Open Access Journals (Sweden)
Bonić Zoran
2015-01-01
Full Text Available Reinforced concrete diaphragms are in-built supporting structures constructed directly in the ground. They are intended for reception of lateral soil pressures, and due to the thickness-height ratio they belong to the group of deformable structures. The paper presents different design methods of transversally loaded diaphragms as well as constitutive soil models which can be used on this occasion. For comparison of the described methods, one example of design of reinforced-concrete diaphragm with the analysis of obtained results was done. The diaphragm is firstly treated using classical analytical methods, and then using the numerical methods based on the concept of problem discretization using finite differences method and the STRESS, TOWER and PLAXIS software. The goal of the paper is as accurate prediction of the diaphragm and surrounding soil behavior as possible, as well as finding of the relevant impacts required for the design. [Projekat Ministarstva nauke Republike Srbije, br. TR36028: Development and improvement of methods for analyses of soil - structure interaction based on theoretical and experimental research
Finite element analysis of tooth load distribution on P-110S conic threaded connections
International Nuclear Information System (INIS)
Based on elastic mechanics and by use of thick cylinder theory, this paper presents a finite element analysis model with interference fit and axial load on P-110S conic threaded connections and the tooth load distributions on contact threaded surfaces were investigated. A 2D finite element model with elastic-plastic axisymmetric contact threaded surfaces was established and the tooth load distributions on its thread teeth were analyzed under different interference fit and axial load. Results for the loads on every engaged tooth are obtained. These indicate that the load distribution on the engaged teeth is not uniform, with the maximum tooth load concentrated on the first three pairs or the farthest two pairs of engaged teeth from the pin end and the middle teeth only bear a very small load. Such results are identical to the practical situation and indicate that the finite element model proposed in this paper is reasonable.
Lei Jiang; Jiaming Li; Suhuai Luo; Sam West; Glenn Platt
2012-01-01
Energy signature analysis of power appliance is the core of nonintrusive load monitoring (NILM) where the detailed data of the appliances used in houses are obtained by analyzing changes in the voltage and current. This paper focuses on developing an automatic power load event detection and appliance classification based on machine learning. In power load event detection, the paper presents a new transient detection algorithm. By turn-on and turn-off transient waveforms analysis, it can accur...
Load flow analysis: Base cases, data, diagrams, and results
Energy Technology Data Exchange (ETDEWEB)
Portante, E.C.; Kavicky, J.A.; VanKuiken, J.C.; Peerenboom, J.P.
1997-10-01
This report describes how an electric utility system is modeled by using load flow techniques to establish a validated power flow case suitable for simulating and evaluating alternative system scenarios. Details of the load flow model are supported by additional technical and descriptive information intended to correlate modeled electrical system parameters with the corresponding physical equipment that makes up the system. Pictures and technical specifications of system equipment from the utility, public, or vendor are provided to support this association for many system components. The report summarizes the load flow model construction, simulation, and validation and describes the general capabilities of an information query system designed to access load flow parameters and other electrical system information.
Analysis of piping loads on shells of revolution
International Nuclear Information System (INIS)
The work of Bijaard as presented by Wichman, et al., Welding Research Council Bulletin 107 (1965), is widely used in industry to evaluate the effects of concentrated loads on cylinders and spheres. But many axially symmetric structures have configuration which preclude the use of this work. In such cases, the procedure given in this paper can greatly reduce the computational effort needed to obtain accurate stresses and deflections due to loads such as occur at piping connections. The paper provides a method of calculating the truncation error due to terminating the Fourier expansion of a loading at a given point. Also for various common loading situations, it provides points where the truncation error is zero. (Auth.)
Load displacement in grape harvesters: Discrete Element Analysis.
González Montellano, Carlos; Baguena Isiegas, Eva; Ramírez Gómez, Álvaro; Barreiro Elorza, Pilar
2012-01-01
Dynamic weighing of the hopper in grape harvesters is affected by a number of factors. One of them is the displacement of the load inside the hopper as a consequence of the terrain topography. In this work, the weight obtained by a load cell in a grape harvester has been analysed and quantified using the discrete element method (DEM). Different models have been developed considering different scenarios for the terrain.
Analysis of Load Test on Composite I-Girder Bridge
Huseynov, F.; Brownjohn, J. M. W.; O'Brien, Eugene J.; Hester, David
2016-01-01
This paper showcases the importance of field testing in efforts to deal with the deteriorating infrastructure. It demonstrates a load test performed on a healthy but aging composite reinforced concrete bridges in Exeter, UK. The bridge girders were instrumented with strain transducers and static strains were recorded while a four-axle, 32 tonne lorry remained stationary in a single lane. The results obtained from the field test were used to calculate transverse load distribution factors (DFs)...
Micromechanical stimulator for localized cell loading: fabrication and strain analysis
International Nuclear Information System (INIS)
Mechanical stimuli regulate cell structure and function during physiological processes. To understand the role of mechanical stimuli, engineered devices are developed to deliver controllable mechanical signals to cells cultured in vitro. Localized mechanical loading on selected cells are preferred when investigating intercellular communication. In this work, we fabricated and characterized a polydimethylsiloxane (PDMS) micro-device for applying controlled compressive/tensile loads to selected live cells. The device consists of nine circular PDMS membranes serving as the loading sites; the loading parameters at each site are individually controllable. The in-plane strain upon PDMS membrane deflection was experimentally characterized. The result showed that for a circular membrane with 500 µm in diameter and 60 µm thick, the radial strain from −6% (compressive) to 25% (tensile) can be achieved at the membrane center. This device allows localized cell loading with minimal fabrication/operation complexity and ease of scaling-up. It is expected to foster the development of high throughput mechanical loading systems for a broad array of cellular mechanobiological studies. (paper)
Evaluation of Load Analysis Methods for NASAs GIII Adaptive Compliant Trailing Edge Project
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.
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…
Use of fuzzy techniques for analysis of dynamic loads in power systems
Institute of Scientific and Technical Information of China (English)
无
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.
DEFF Research Database (Denmark)
Carmo, Carolina; Christensen, Toke Haunstrup
2016-01-01
temporality of the energy demand is needed. This paper contributes to this by focusing on the daily load profiles of energy demand for heating of Danish dwellings with heat pumps. Based on hourly recordings from 139 dwellings and employing cluster and regression analysis, the paper explores patterns...... (typologies) in daily heating load profiles and how these relate to socio-economic and technical characteristics of the included households. The study shows that the load profiles vary according to the external load conditions. Two main clusters were identified for both weekdays and weekends and across load...
A Universal Tare Load Prediction Algorithm for Strain-Gage Balance Calibration Data Analysis
Ulbrich, N.
2011-01-01
An algorithm is discussed that may be used to estimate tare loads of wind tunnel strain-gage balance calibration data. The algorithm was originally developed by R. Galway of IAR/NRC Canada and has been described in the literature for the iterative analysis technique. Basic ideas of Galway's algorithm, however, are universally applicable and work for both the iterative and the non-iterative analysis technique. A recent modification of Galway's algorithm is presented that improves the convergence behavior of the tare load prediction process if it is used in combination with the non-iterative analysis technique. The modified algorithm allows an analyst to use an alternate method for the calculation of intermediate non-linear tare load estimates whenever Galway's original approach does not lead to a convergence of the tare load iterations. It is also shown in detail how Galway's algorithm may be applied to the non-iterative analysis technique. Hand load data from the calibration of a six-component force balance is used to illustrate the application of the original and modified tare load prediction method. During the analysis of the data both the iterative and the non-iterative analysis technique were applied. Overall, predicted tare loads for combinations of the two tare load prediction methods and the two balance data analysis techniques showed excellent agreement as long as the tare load iterations converged. The modified algorithm, however, appears to have an advantage over the original algorithm when absolute voltage measurements of gage outputs are processed using the non-iterative analysis technique. In these situations only the modified algorithm converged because it uses an exact solution of the intermediate non-linear tare load estimate for the tare load iteration.
Limit load analysis of thick-walled concrete structures
International Nuclear Information System (INIS)
The paper illustrates the interaction of constitutive modeling and finite element solution techniques for limit load prediction of concrete structures. On the constitutive side, an engineering model of concrete fracture is developed in which the Mohr-Coulomb criterion is augmented by tension cut-off to describe incipient failure. Upon intersection with the stress path the failure surface collapses for brittle behaviour according to one of three softening rules, no-tension, no-cohesion, and no-friction. The stress transfer accompanying the energy dissipation during local failure is modelled by several fracture rules which are examined with regard to ultimate load prediction. On the numerical side the effect of finite element idealization is studied first as far as ultimate load convergence is concerned. Subsequently, incremental tangential and initial load techniques are compared together with the effect of step size. Limit load analyses of a thick-walled concrete ring and a lined concrete reactor closure conclude the paper with examples from practical engineering. (orig.)
Load-Aware Modeling and Analysis of Heterogeneous Cellular Networks
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...
International Nuclear Information System (INIS)
Thin shallow arches may become unstable under transverse loading if the built-up internal compressive forces reach a limiting value beyond which the structure undergoes a sudden large displacement towards a new stable configuration. This phenomenon could be both desirable (in toggle switches) and disastrous (collapse of a dome or truss). Hence, the so-called snap- or limit-load analysis becomes important as to which factors influence it to give guidelines in designing structures to behave favorably. By the introduction of functionally graded materials (FGMs) in recent years, and incorporating them into this phenomenon, interesting results can be obtained which can give structures with favorable instability properties. In this work, a thin shallow arch with a modulus that can be varied along the thickness or the arch length or both is considered. Based on the governing equations of the deflected arch, the snap load is obtained in a mixed analytical-numerical approach and a parameter study of the critical load is carried out. Several verifying and interesting examples are presented
Universal Power Quality Controller Modeling and Inverters Loading Analysis
Directory of Open Access Journals (Sweden)
F. Gharedaghi
2011-11-01
Full Text Available As much as nonlinear loads and power electronics devices are more applied in power distribution systems, the importance of power quality increases. This study proposes a Universal Power Quality Conditioner (UPQC with double-converter structure. The operation principle, the algorithm of compensation reference generation, and the control method are introduced. Computer simulation and many prototype experiments are carried out to verify the operation principle and investigate the compensation characteristics of UPQC for different power quality problems. It is verified that the UPQC can effectively compensate multiple different power quality interferences originated either from the load side or from the line side. The capacity of series and shunt inverters is calculated through loading calculations of these inverters applying phasor diagram to increase the design accuracy. The results of simulation in MATLAB/SIMULINK software show that the system operates correctly.
Study on fatigue analysis for operational load histories
International Nuclear Information System (INIS)
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.
Simulation analysis of turbine load step transient for nuclear power plant
International Nuclear Information System (INIS)
The CATIA2 code is used in the analysis of the turbine load from 20% step transient to 30% and from 30% step transient to 20% for the Qinshan phase-II 600 MW nuclear power plant. Analysis results proving: The reactor power control system has a capability of the automatic tracing load and steady reactor operation; The steam generator level control system, feedwater pump system and feedwater valve adjusting system have a capability following the load change, during the turbine load step transient +-10% of the nuclear power plant. All parameters work in a permitted range of the nuclear power plant normal operation, actuation protection does not present
Non linear dynamic analysis of piping systems under impulsive loadings
International Nuclear Information System (INIS)
The importance of piping systems in power industries and specially in nuclear power plants is well established. In view of safety requirements, the behaviour of these piping systems in case of faulted conditions must be studied. In particular, impulsive loadings like impacts on pipes or post rupture dynamics pipe behaviour are considered. The aim of this paper is to enlight the difficulties and features associated with such loadings and to present methods of solution using different finite elements codes. Two applications to real problems are presented
Finite element analysis of stemming loads on pipes
International Nuclear Information System (INIS)
A computational model has been developed for calculating the loads and displacements on a pipe placed in a hole which is subsequently filled with soil. A composite soil-pipe finite element model which employs fundamental material constants in its formalism is derived. The shear modulus of the soil, and the coefficient of friction at the pipe are the important constants to be specified. The calculated loads on the pipe are in agreement with experimental data for layered and unlayered stemming designs. As a result more economical designs of the pipe string can be realized
Analysis of thermal conductivity of polymeric nanocomposites under mechanical loading
Yu, Suyoung; Yang, Seunghwa; Cho, Maenghyo
2013-12-01
When the plastic deformation is applied to neat polymer, the polymer chains are aligned and the thermal conductivity of neat polymer increases linearly along the loading direction. However, the thermal conductivity change of nanocomposites consisting of polymer matrix and nanofillers during plastic deformation is not simple. The volume fraction and size of nanofillers scarcely affect the structural change of polymer chains during the plastic deformation. In this study, the structural change of polymeric materials according to the mechanical loading and its effect on the thermal transport properties are investigated through a molecular dynamics simulation. To investigate the effects of nanofiller, its volume fraction, and size on the thermal transport properties, the unit cells of neat amorphous nylon 6 and nanocomposites consisting of amorphous nylon 6 matrix and spherical silica particles are prepared. The molecular unit cells are uniaxially stretched by applying constant strain along the loading directions. Then, non-equilibrium molecular dynamics (NEMD) simulations are performed to estimate the thermal conductivities during plastic deformation. The alignment of polymer chains is analyzed by tracing the orientation correlation function of each polymer molecule and the free volume change during the mechanical loading is also analyzed.
Analysis of PWR cladding transient load under LOCA quench conditions
International Nuclear Information System (INIS)
LOCA is a classical design basis accident needed to be considered in all LWR safety analyses. The thermal shock induced by quench during LOCA may cause fracture in the claddings which could lead to core damage. Therefore it is necessary to study the cladding behavior during quench. This paper reports the results of LOCA quench experiments and simulations using the RANNS code for evaluating local mechanical and thermal states of axial load on the cladding. The experimental measurements suggest the rate of load gain decreases with an increasing of the ECR value due to the thicker zirconia layer which serves as a thermal barrier. In addition, the temperature-induced stress on the cladding along the axial direction appears uneven. Therefore, it is found that the LOCA simulation needs multiple elements in the axial direction for obtaining a fairly good prediction of the axial load gain. Finally, the RANNS simulation of the pellet center temperature is validated, and the RANNS code shows the capability in predicting the axial load generated during quench for ECR of lower or equal to 15%. (author)
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.
Nonlinear analysis of a reactor building for airplane impact loadings
International Nuclear Information System (INIS)
The purpose is to analyze the influence of material nonlinear behavior on the response of a reinforced concrete reactor building and on equipment response for airplane impact loadings. Two analyses are performed: first, the impact of a slow-flying commercial airplane (Boeing 707), then the impact of a fast flying military airplane (Phantom). (orig./HP)
Quantitative analysis of impact measurements using dynamic load cells
Directory of Open Access Journals (Sweden)
Brent J. Maranzano
2016-03-01
Full Text Available A mathematical model is used to estimate material properties from a short duration transient impact force measured by dropping spheres onto rectangular coupons fixed to a dynamic load cell. The contact stress between the dynamic load cell surface and the projectile are modeled using Hertzian contact mechanics. Due to the short impact time relative to the load cell dynamics, an additional Kelvin–Voigt element is included in the model to account for the finite response time of the piezoelectric crystal. Calculations with and without the Kelvin–Voigt element are compared to experimental data collected from combinations of polymeric spheres and polymeric and metallic surfaces. The results illustrate that the inclusion of the Kelvin–Voigt element qualitatively captures the post impact resonance and non-linear behavior of the load cell signal and quantitatively improves the estimation of the Young's elastic modulus and Poisson's ratio. Mathematically, the additional KV element couples one additional differential equation to the Hertzian spring-dashpot equation. The model can be numerically integrated in seconds using standard numerical techniques allowing for its use as a rapid technique for the estimation of material properties.
Analysis of load-bearing structure of a multi-storey office building in Idrija
Novak, Primož
2013-01-01
This thesis presents the design and static analysis of the load-bearing construction for the selected multi-storey reinforced concrete office building. The building is located in Idrija and consists of two parts, office building and hall, which are separated with dilatation. The thesis is focused on the Office building with vertical load-bearing structure made as a frame structure, consisting of columns and beams, which are interconnect with the solid reinforced concrete slabs. Load-bearing c...
Dynamic failure analysis on granite under uniaxial impact compressive load
Institute of Scientific and Technical Information of China (English)
Yue ZHAI; Junhai ZHAO; Guowei MA; Changming HU
2008-01-01
High strain-rate uniaxial compressive loading tests were produced in the modified split Hopkinson pres-sure bar (SHPB) with pulse shaper on granite samples. It was shown that the failure of the granite cylinder was typ-ical tensile splitting failure mode by sudden splitting parallel to the direction of uniaxial compressive loading at different strain rates. Besides, it was concluded that not only the strength of granite increased, but also the fragment size decreased and the fragment numbers increased with the increasing strain rate. To quantitatively analyze the failure phenomena, the numerical calculation based on a dynamic interacting sliding microcrack model was adopted to invest-igate the influence of microcrack with the different initial crack length, crack angle, crack space and friction coef-ficient on the macro-mechanical properties of granite under different strain rates. Accordingly, the strain-dependency of the compression strength and the fragmentation degree of granite was explained reasonably.
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.
Temporal analysis of the traffic loads on forest road networks
Grigolato S; Pellegrini M; Cavalli R
2013-01-01
The management of forest road networks is usually influenced by the traffic generated by wood transportation. In order to analyze the distribution and intensity of traffic generated by wood transportation in an Alpine region, the study considered a 21-year period with a total of 2 231 logging operations on a forest road network in a mountainous area. Most of the forest road network was affected by traffic load intensities generally of less than 500 t per year. The distribution of the traffic ...
Physiological analysis to quantify training load in badminton.
Majumdar, P; Khanna, G L; Malik, V; Sachdeva, S.; Arif, M.; Mandal, M.(Regional Centre for Accelerator-based Particle Physics (RECAPP), Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad, 211 019, Uttar Pradesh, India)
1997-01-01
OBJECTIVE: To estimate the training load of specific on court training regimens based on the magnitude of variation of heart rate-lactate response during specific training and to determine the magnitude of variation of biochemical parameters (urea, uric acid, and creatine phosphokinase (CPK)) 12 hours after the specific training programme so as to assess training stress. METHODS: The study was conducted on six national male badminton players. Maximum oxygen consumption (VO2), ventilation (VE)...
The first Superphenix fuel load reliability analysis and validation
International Nuclear Information System (INIS)
The excellent behavior of PHENIX driver fuel and the burnup values currently reached suggest that the first SUPERPHENIX fuel load will meet the design lifetime. However, to ensure the reliability of the entire load, all the parameters affecting fuel behavior in reactor must be analyzed. For that purpose, we have taken into account all the results of the examination and verifications during the fabrication process of the first load subassemblies. These data concern geometrical parameters or oxide composition as well as the cladding tube and plug weld soundness tests. The objective is to determine the actual dispersion of all the parameters to ensure the absence of failure due to fabrication defects with very high statistical confidence limits. The influence of all the parameters has been investigated for the situations which can occur during power-up, steady-state operation and transients. The fabrication quality allows us to demonstrate that in all cases good behavior criteria for fuel and structure will be maintained. This demonstration is based on calculation code results as well as on validation by specific experiments
Power analysis and simulation of a vehicle under combined loads
International Nuclear Information System (INIS)
Reducing fuel consumption in vehicles offers many obvious economic benefits, and also helps reduce air pollution emission levels. Mechanical engineers and automotive researches have continuously searched for ways to optimize fuel consumption in vehicles. This paper presented an analytical model of fuel consumption (AMFC) in an effort to coordinate the driving power and manage the overall fuel consumption for an internal combustion engine vehicle. The model calculated the different loads applied on the vehicle, such as road-slope, road-friction, wind-drag, accessories, and mechanical losses. It also solved the combustion equation of the engine under different working conditions including various fuel compositions, excess airs and air inlet temperatures. The model then determined the contribution of each load to signify the energy distribution and power flows of the vehicle. In order to assess the model's sensitivity to different loads, the following four simulations were conducted: flat-windless, flat-windy, sloppy-windless, sloppy-windy. The average fuel consumption for the four simulations was presented. The paper outlined the specification of the vehicle and environment as well as the simulation methodology. The model, algorithm, slope simulation, and drive strategy were presented. It was concluded that the power consumption significantly increased where the slope friction came into play and that the model has the potential to assist in vehicle energy management. 16 refs., 4 tabs., 14 figs
Analysis of sweeping heat loads on divertor plate materials
International Nuclear Information System (INIS)
The heat flux on the divertor plate of a fusion reactor is probably one of the most limiting constraints on its lifetime. The current heat flux profile on the outer divertor plate of a device like ITER is highly peaked with narrow profile. The peak heat flux can be as high as 30--40 MW/m2 with full width at half maximum (FWHM) is in the order of a few centimeters. Sweeping the separatrix along the divertor plate is one of the options proposed to reduce the thermomechanical effects of this highly peaked narrow profile distribution. The effectiveness of the sweeping process is investigated parametrically for various design values. The optimum sweeping parameters of a particular heat load will depend on the design of the divertor plate as well as on the profile of such a heat load. In general, moving a highly peaked heat load results in substantial reduction of the thermomechanical effects on the divertor plate. 3 refs., 8 figs
International Nuclear Information System (INIS)
A feasibility study was conducted for addition of consolidated fuel racks to an existing reinforced concrete spent fuel storage pool of a Mark I BWR plant. Nonlinear analysis of a detailed three-dimensional model of the fuel pool, considering cracking in concrete under gravity and thermal load conditions, showed that the pool has reserve capacities to carry the additional loads. (author)
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
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.
Design, Load Analysis and Optimization of Compound Epicyclic Gear Trains
Syed Ibrahim Dilawer
2013-01-01
- Gears in the Epicyclic gear trains are one of the most critical components in the mechanical power transmission system in which failure of one gear will affect the whole transmission system, thus it is very necessary to determine the causes of failure in an attempt to reduce them. The different modes of failure of gears and their possible remedies to avoid the failure are mentioned in J.R. Davis (2005) [17], Khurmi & Gupta (2006) [19], P. Kannaiah (2006) [18] [20] as bending failure (load f...
Characterising Turbulence Intensity for Fatigue Load Analysis of Wind Turbines
DEFF Research Database (Denmark)
Hansen, Kurt Schaldemose; Larsen, Gunner Chr.
2005-01-01
Turbulence in wind velocity presents a major factor for modern wind turbine design as cost reduction as are sort for the dynamic structures. Therefore this paper contains a parametrisation of the turbulence intensity at given sites, relevant for the calculation of fatigue loading of wind turbines....... The parameterisation is based on wind speed measurements extracted from the “Database on Wind Characteristics” (www.winddata.com). The parameterisation is based on the LogNormal distribution, which has proven to be suitable distribution to describe the turbulence intensity distribution....
Ultimate load analysis of pretensioned inverted T-beams with circular web openings
Institute of Scientific and Technical Information of China (English)
Hock Tian CHENG; Bashar S. MOHAMMED; Kamal Nasharuddin MUSTAPHA
2009-01-01
The provision of transverse openings in floor beams to facilitate the passage of utility pipes and service ducts not only results in a more systematic layout of pipes and ducts, it also translates into substantial economic savings in the construction of a multi-storey building. In this paper, ultimate load analysis of statically loaded simply supported pretensioned inverted T-beams with circular web openings is presented. Major findings relevant to ultimate load analysis of pretensioned beams with circular web openings are summarized. An attempt has been made to answer the frequently asked questions related to ultimate load analysis on multiple circular web open-ings. It has been shown that the analysis method for pretensioned beams with multiple large circular web openings can be further simplified without sacrificing rationality.
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.
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.
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.
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.
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.
Analysis Of Masonry Infilled RC Frame Structures Under Lateral Loading
Directory of Open Access Journals (Sweden)
Barnaure Mircea
2015-03-01
Full Text Available Partition walls are often made of masonry in Romania. Although they are usually considered non-structural elements in the case of reinforced concrete framed structures, the infill panels contribute significantly to the seismic behaviour of the building. Their impact is difficult to assess, mainly because the interaction between the bounding frame and the infill is an intricate issue. This paper analyses the structural behaviour of a masonry infilled reinforced concrete frame system subjected to in - plane loading. Three numerical models are proposed and their results are compared in terms of stiffness and strength of the structure. The role of the openings in the infill panel on the behaviour is analysed and discussed. The effect of gaps between the frame and the infill on the structural behaviour is also investigated. Comparisons are made with the in-force Romanian and European regulations provisions.
Theoretical analysis and applications on nano-block loaded rectangular ring.
Zhan, Shiping; Li, Hongjian; Cao, Guangtao; He, Zhihui; Li, Boxun; Xu, Hui
2014-10-01
We propose compact and switchable optical filters based on nano-block loaded rectangular rings, and investigate the selection property numerically and theoretically. A simple and convenient phase model is established for the theoretical analysis. The dependent factors, such as the number, size, and positions of the loaded blocks, are discussed in detail. It is found that a longer wavelength can be obtained without increasing the device dimension, and the selected wave is more sensitive to the length of the loaded blocks. The loading positions play key roles in the realization of separating the second-order modes. Finally, applications of this proposed structure are discussed simply. We find that the loaded filter device provides a more compact size than the unloaded one for the same properties, and a tunable plasmon induced transparency based switch effect is also achieved. These findings suggest potential applications in compact filters, tunable slow light devices, and sensor fields. PMID:25401254
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.
Fatigue Analysis of Load-Carrying Fillet Welds
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Tychsen, Jesper; Andersen, Jens Ulfkjær;
2006-01-01
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 is....... Using the test results, it is shown that the new definition of fatigue stress can be used for a wide range of DOB with a low standard deviation of the resulting SN curve....... 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 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...
Load carrying capacity analysis of materials for aluminium rims
Fajdiga, Matija; Čižman, Jure
2015-01-01
In this contribution we present an experimental simulation of the fatique strength of clamped aluminium rims. This is supported by numerical modelling using the Finite Element Method (FEM), which was used for stress-strain analysis of a model representing a clamped detail during bendings. The design and analysis of the model are made simultaneously on an integrated computer controlled test rig for testing the fatique strength of clamped parts subjected to bending. The simulation is evaluated ...
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.
Directory of Open Access Journals (Sweden)
Lei Jiang
2012-01-01
Full Text Available Energy signature analysis of power appliance is the core of nonintrusive load monitoring (NILM where the detailed data of the appliances used in houses are obtained by analyzing changes in the voltage and current. This paper focuses on developing an automatic power load event detection and appliance classification based on machine learning. In power load event detection, the paper presents a new transient detection algorithm. By turn-on and turn-off transient waveforms analysis, it can accurately detect the edge point when a device is switched on or switched off. The proposed load classification technique can identify different power appliances with improved recognition accuracy and computational speed. The load classification method is composed of two processes including frequency feature analysis and support vector machine. The experimental results indicated that the incorporation of the new edge detection and turn-on and turn-off transient signature analysis into NILM revealed more information than traditional NILM methods. The load classification method has achieved more than ninety percent recognition rate.
Stress analysis method for clearance-fit joints with bearing-bypass loads
Naik, R. A.; Crews, J. H., Jr.
1989-01-01
Within a multi-fastener joint, fastener holes may be subjected to the combined effects of bearing loads and loads that bypass the hole to be reacted elsewhere in the joint. The analysis of a joint subjected to search combined bearing and bypass loads is complicated by the usual clearance between the hole and the fastener. A simple analysis method for such clearance-fit joints subjected to bearing-bypass loading has been developed in the present study. It uses an inverse formulation with a linear elastic finite-element analysis. Conditions along the bolt-hole contact arc are specified by displacement constraint equations. The present method is simple to apply and can be implemented with most general purpose finite-element programs since it does not use complicated iterative-incremental procedures. The method was used to study the effects of bearing-bypass loading on bolt-hole contact angles and local stresses. In this study, a rigid, frictionless bolt was used with a plate having the properties of a quasi-isotropic graphite/epoxy laminate. Results showed that the contact angle as well as the peak stresses around the hole and their locations were strongly influenced by the ratio of bearing and bypass loads. For single contact, tension and compression bearing-bypass loading had opposite effects on the contact angle. For some compressive bearing-bypass loads, the hole tended to close on the fastener leading to dual contact. It was shown that dual contact reduces the stress concentration at the fastener and would, therefore, increase joint strength in compression. The results illustrate the general importance of accounting for bolt-hole clearance and contact to accurately compute local bolt-hole stresses for combined bearings and bypass loading.
QCT-based failure analysis of proximal femurs under various loading orientations.
Mirzaei, Majid; Keshavarzian, Maziyar; Alavi, Fatemeh; Amiri, Pegah; Samiezadeh, Saeid
2015-06-01
In this paper, the variations of the failure strength and pattern of human proximal femur with loading orientation were analysed using a novel quantitative computed tomography (QCT)-based linear finite element (FE) method. The QCT images of 4 fresh-frozen femurs were directly converted into voxel-based finite element models for the analyses of the failure loads and patterns. A new geometrical reference system was used for the alignment of the mechanical loads on the femoral head. A new method was used for recognition and assortment of the high-risk elements using a strain energy-based measure. The FE results were validated with the experimental results of the same specimens and the results of similar case studies reported in the literature. The validated models were used for the computational investigation of the failure loads and patterns under 15 different loading conditions. A consistent variation of the failure loads and patterns was found for the 60 different analysed cases. Finally, it was shown that the proposed procedure can be used as a reliable tool for the failure analysis of proximal femurs, e.g. identification of the relevant loading directions for specific failure patterns, or determination of the loading conditions under which the proximal femurs are failure-prone. PMID:25731689
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.
VISAR Unfold Analysis of Load Current in MagLIF Experiments
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.
Finite-element analysis of crack growth under monotonic and cyclic loading
Newman, J. C., Jr.
1977-01-01
An elastic-plastic (incremental) finite-element analysis, in conjunction with a crack-growth criterion, was used to study crack-growth behavior under monotonic and cyclic loading. The crack-growth criterion was based on crack-tip strain. Whenever the crack-tip strain equals or exceeds a critical strain value, the crack grows. The effects of element-mesh size, critical strain, strain hardening, and specimen type (tension or bending) on crack growth under monotonic loading were investigated. Crack growth under cyclic loading (constant amplitude and simple variable amplitude) were also studied. A combined hardening theory, which incorporates features of both isotropic and kinematic hardening under cyclic loading, was also developed for smooth yield surfaces and was used in the analysis.
Reliability testing and reliability analysis of the over-load protective relay
Institute of Scientific and Technical Information of China (English)
ZHAO Jing-ying; CHEN Hong-jian; LIU Guo-jin; ZHANG Yong; WU Pin-hua
2007-01-01
The over-load protective relay is widely used for motor protection. The reliability of the over-load protective relay directly affects the safe running of a motor. The reliability testing and reliability analysis of the over-load protective relay is an important way to improve the reliability of products. In this paper, the reliability test method of the over-load protective relay is studied, and the reliability tests of the typical products are carried out on a reliability tester developed by authors. In terms of the testing results, the reliability analysis is finished. The failure reasons are found and the measures are put forward to improve the reliability of the products.
Fatigue Damage Estimation in Existing Railway Steel Bridges by Detailed Loading History Analysis
Alessio Pipinato; Carlo Pellegrino; Claudio Modena
2012-01-01
Fatigue life estimation of metal historical bridges is a key issue for managing cost-effective decisions regarding rehabilitation or replacement of existing infrastructure. Because of increasing service loads and speeds, this type of assessment method is becoming relevant. Hence there is a need to estimate how long these structures could remain in service. In this paper a method to estimate fatigue damage in existing steel railway bridges by detailed loading history analysis is presented. The...
Honglin Xu; Taihe Shi; Zhi Zhang; Bin Shi
2014-01-01
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 e...
Nonlinear bending and collapse analysis of a poked cylinder and other point-loaded cylinders
Energy Technology Data Exchange (ETDEWEB)
Sobel, L.H.
1983-06-01
This paper analyzes the geometrically nonlinear bending and collapse behavior of an elastic, simply supported cylindrical shell subjected to an inward-directed point load applied at midlength. The large displacement analysis results for this thin (R/t = 638) poked cylinder were obtained from the STAGSC-1 finite element computer program. STAGSC-1 results are also presented for two other point-loaded shell problems: a pinched cylinder (R/t = 100), and a venetian blind (R/t = 250).
Analysis of Load Stress for Asphalt Pavement of Lean Concrete Base
Lijun, Suo; Xinwu, Wang
The study revealed that whether it is early distresses in asphalt pavement or not depends largely on working performance of base. In the field of asphalt pavement, it is widely accepted that lean concrete base, compared with the general semi-rigid base, has better working performance, such as high strength and good eroding resistance. Problem of early distresses in asphalt pavement, which caused by more traffic loadings, can be settled effectively when lean concrete is used in asphalt pavement. Traffic loading is important parameter used in the analysis of the new pavement design. However, few studies have done extensive and intensive research on the load stress for asphalt pavement of lean concrete base. Because of that, it is necessary to study the load stress for the asphalt pavement. In the paper, first of all, three-dimension finite element model of the asphalt pavement is created for the aim of doing mechanical analysis for the asphalt pavement. And then, the two main objectives of this study are investigated. One is analysis for load stress of lean concrete base, and the other is analysis for load stress of asphalt surface. The results show that load stress of lean concrete base decreases, decrease and increase with increase of base's thickness, surface's thickness and ratio of base's modulus to foundation's modulus respectively. So far as the asphalt surface is concerned, maximum shearing stress, which is caused by load, is evident in asphalt surface which is located in transverse contraction joint of lean concrete base of asphalt pavement. Maximum shearing stress decrease, decrease, decrease and increase respectively with increase of the surface's modulus, the surface's thickness, base's thickness and ratio of base's modulus to foundation's modulus.
Rajasekhar, K.; Dr.H.Sudarsana Rao; Dr. VAISHALI.G.GHORPADE
2012-01-01
Slurry Infiltrate Fibrous Concrete (SIFCON) is a new high performance and advanced material and can be considered as a special type of steel fiber reinforced concrete (SFRC). This paper describes the development of two – way slab model to predict the non-linear load-displacement behavior of SIFCON slab subjected to pressure loading. Slabs with 8%, 10% and 12% for different edge conditions have been modeled in Finite elements and verified with experimental values. The results of the analysis s...
Influence of Strain-rate Effects on the Analysis of Steel Sections under Blast Loads
KARLOS VASILEIOS; SOLOMOS George
2014-01-01
The response of structural steel components under explosive loading is numerically investigated. First the procedure for determining the pressure loads to be applied on a structure after an explosion is briefly described. The importance of the material model and its capability of including the high strain-rate effects in the numerical analysis is studied by comparing simulations by the FEM code EUROPLEXUS with published data of real blast experiments. These comparisons are made with respect t...
Methodology of demand forecast by market analysis of electric power and load curves
International Nuclear Information System (INIS)
A methodology for demand forecast of consumer classes and their aggregation is presented. An analysis of the actual attended market can be done by appropriate measures and load curves studies. The suppositions for the future market behaviour by consumer classes (industrial, residential, commercial, others) are shown, and the actions for optimise this market are foreseen, obtained by load curves modulations. The process of future demand determination is obtained by the appropriate aggregation of this segmented demands. (C.G.C.)
Semolič, Živa
2013-01-01
In the thesis an analysis and design of characteristic elements of the load-bearing structure for the selected multi-story building was undertaken. The building is located in Ljubljana and is a constituent of a building complex. Buildings are detached by expansion joints so one can be addressed separately. Load-bearing structure consists of monolithic reinforced concrete floor panels, reinforced concrete walls and reinforced concrete frames. The building was planned and designed according to ...
Nonlinear bending and collapse analysis of a poked cylinder and other point-loaded cylinders
International Nuclear Information System (INIS)
This paper analyzes the geometrically nonlinear bending and collapse behavior of an elastic, simply supported cylindrical shell subjected to an inward-directed point load applied at midlength. The large displacement analysis results for this thin (R/t = 638) poked cylinder were obtained from the STAGSC-1 finite element computer program. STAGSC-1 results are also presented for two other point-loaded shell problems: a pinched cylinder (R/t = 100), and a venetian blind (R/t = 250)
Directory of Open Access Journals (Sweden)
Yungang Zhan, Minxin Li
2013-07-01
Full Text Available Buckling of a cantilever steel pipe column under combined loads was studied through linear and nonlinear numerical analysis method. Firstly, linear buckling analysis of the cantilever column with linear-elastic material was used to select appropriate element type and element size for this problem. Then linear buckling and nonlinear buckling analyses for an imperfect cantilever column under different horizontal loads or displacements in the context of elasticity were performed to verify the ability of the linear buckling analysis to include large geometric changes. Thirdly, nonlinear analyses were carried out to examine the effect of plastification of material on the buckling limit loads for the imperfect cantilever column. Through these comparative studies, some aspects concerned with the numerical buckling analysis of structures such as columns were clarified.
Analysis of wind turbine blade behavior under static dual axis loads
Energy Technology Data Exchange (ETDEWEB)
Son, Byung Jik [Korea Univ., Seoul (Korea, Republic of); Huh, Yong Hak; Kim, Dong Jin; Kim, Jong Il [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)
2012-03-15
For the assessment of the performance of a wind turbine blade, a simulated loading test may be required. In this study, the blade behavior was investigated through numerical analysis using a dual axis loading test, closely simulating the real operation conditions. The blade structure for the 100 kw class wind turbine system was modeled using the finite element (FE) program ANSYS. The failure criteria and buckling analysis under dual axis loading were examined. The failure analysis, including fiber failure and inter fiber failure, was performed with Puck's failure criterion. As the dual axis load ratio increases, the relatively increased stress occurs at the trailing edge and skin surface 3300-3600mm away from the root. Furthermore, it is revealed that increasing the dual axis load ratio makes the location that is weakest against buckling move toward the root part. Thus, it is seen that the dual axis load test may be an essential requirement for the verification of blade performance.
International Nuclear Information System (INIS)
A model for the analysis of elbows in the elastic plastic field under dynamic loads has been described; it is based on an analysis of experimental and analytical data. A comparison has been made with experimental dynamic tests showing the influence of shakedown. It is shown that margins are present with respect to the conventional ASME III, analyses
The effect of loading time on flexible pavement dynamic response: a finite element analysis
Yin, Hao; Solaimanian, Mansour; Kumar, Tanmay; Stoffels, Shelley
2007-12-01
Dynamic response of asphalt concrete (AC) pavements under moving load is a key component for accurate prediction of flexible pavement performance. The time and temperature dependency of AC materials calls for utilizing advanced material characterization and mechanistic theories, such as viscoelasticity and stress/strain analysis. In layered elastic analysis, as implemented in the new Mechanistic-Empirical Pavement Design Guide (MEPDG), the time dependency is accounted for by calculating the loading times at different AC layer depths. In this study, the time effect on pavement response was evaluated by means of the concept of “pseudo temperature.” With the pavement temperature measured from instrumented thermocouples, the time and temperature dependency of AC materials was integrated into one single factor, termed “effective temperature.” Via this effective temperature, pavement responses under a transient load were predicted through finite element analysis. In the finite element model, viscoelastic behavior of AC materials was characterized through relaxation moduli, while the layers with unbound granular material were assumed to be in an elastic mode. The analysis was conducted for two different AC mixtures in a simplified flexible pavement structure at two different seasons. Finite element analysis results reveal that the loading time has a more pronounced impact on pavement response in the summer for both asphalt types. The results indicate that for reasonable prediction of dynamic response in flexible pavements, the effect of the depth-dependent loading time on pavement temperature should be considered.
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.
Friction Factors in Oil Wells through Analysis of Hook Load
Skarvøy, Christina Frengen
2014-01-01
As the easy oil and gas is gone, there is today a need for more complex wells in orderto extract the remaining hydrocarbons. Over recent decades, both inclination andlength of drilled wells have increased significantly. Analysis of the mechanical dragduring tripping is important to detect abnormal conditions in the well and could helpreducing the operational costs. This is also the most important reason for the need ofdetermining an exact friction factor. One way of revealing these restrictio...
Experimental and Numerical Analysis of Notched Composites Under Tension Loading
Aidi, Bilel; Case, Scott W.
2015-12-01
Experimental quasi-static tests were performed on center notched carbon fiber reinforced polymer (CFRP) composites having different stacking sequences made of G40-600/5245C prepreg. The three-dimensional Digital Image Correlation (DIC) technique was used during quasi-static tests conducted on quasi-isotropic notched samples to obtain the distribution of strains as a function of applied stress. A finite element model was built within Abaqus to predict the notched strength and the strain profiles for comparison with measured results. A user-material subroutine using the multi-continuum theory (MCT) as a failure initiation criterion and an energy-based damage evolution law as implemented by Autodesk Simulation Composite Analysis (ASCA) was used to conduct a quantitative comparison of strain components predicted by the analysis and obtained in the experiments. Good agreement between experimental data and numerical analyses results are observed. Modal analysis was carried out to investigate the effect of static damage on the dominant frequencies of the notched structure using the resulted degraded material elements. The first in-plane mode was found to be a good candidate for tracking the level of damage.
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
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.
A limit load analysis of RBMK-1500 reactor structures
International Nuclear Information System (INIS)
Presented is a mathematical model of Ignalina NPP facilities where the transported hermetic containers CASTOR RBMK will be located. Analysis of the mathematical model provides resultant stresses caused by free falling container with spent fuel. The result yield wall deflections and maximum stresses in the reinforcing bars of the structure, which maintains the integrity of these facilities of the Ignalina NPP. They indicate the excessive deflections of the walls and stresses in reinforcement in certain areas of the facilities. The ALGOR computer code is used for the calculation. (author). 3 figs., 6 refs
Analysis for Regression Model Behavior by Sampling Strategy for Annual Pollutant Load Estimation.
Park, Youn Shik; Engel, Bernie A
2015-11-01
Water quality data are typically collected less frequently than streamflow data due to the cost of collection and analysis, and therefore water quality data may need to be estimated for additional days. Regression models are applicable to interpolate water quality data associated with streamflow data and have come to be extensively used, requiring relatively small amounts of data. There is a need to evaluate how well the regression models represent pollutant loads from intermittent water quality data sets. Both the specific regression model and water quality data frequency are important factors in pollutant load estimation. In this study, nine regression models from the Load Estimator (LOADEST) and one regression model from the Web-based Load Interpolation Tool (LOADIN) were evaluated with subsampled water quality data sets from daily measured water quality data sets for N, P, and sediment. Each water quality parameter had different correlations with streamflow, and the subsampled water quality data sets had various proportions of storm samples. The behaviors of the regression models differed not only by water quality parameter but also by proportion of storm samples. The regression models from LOADEST provided accurate and precise annual sediment and P load estimates using the water quality data of 20 to 40% storm samples. LOADIN provided more accurate and precise annual N load estimates than LOADEST. In addition, the results indicate that avoidance of water quality data extrapolation and availability of water quality data from storm events were crucial in annual pollutant load estimation using pollutant regression models. PMID:26641336
Statistical Analysis of Baseline Load Models for Non-Residential Buildings
Energy Technology Data Exchange (ETDEWEB)
Coughlin, Katie; Piette, Mary Ann; Goldman, Charles; Kiliccote, Sila
2008-11-10
Policymakers are encouraging the development of standardized and consistent methods to quantify the electric load impacts of demand response programs. For load impacts, an essential part of the analysis is the estimation of the baseline load profile. In this paper, we present a statistical evaluation of the performance of several different models used to calculate baselines for commercial buildings participating in a demand response program in California. In our approach, we use the model to estimate baseline loads for a large set of proxy event days for which the actual load data are also available. Measures of the accuracy and bias of different models, the importance of weather effects, and the effect of applying morning adjustment factors (which use data from the day of the event to adjust the estimated baseline) are presented. Our results suggest that (1) the accuracy of baseline load models can be improved substantially by applying a morning adjustment, (2) the characterization of building loads by variability and weather sensitivity is a useful indicator of which types of baseline models will perform well, and (3) models that incorporate temperature either improve the accuracy of the model fit or do not change it.
Urban Saturated Power Load Analysis Based on a Novel Combined Forecasting Model
Directory of Open Access Journals (Sweden)
Huiru Zhao
2015-03-01
Full Text Available Analysis of urban saturated power loads is helpful to coordinate urban power grid construction and economic social development. There are two different kinds of forecasting models: the logistic curve model focuses on the growth law of the data itself, while the multi-dimensional forecasting model considers several influencing factors as the input variables. To improve forecasting performance, a novel combined forecasting model for saturated power load analysis was proposed in this paper, which combined the above two models. Meanwhile, the weights of these two models in the combined forecasting model were optimized by employing a fruit fly optimization algorithm. Using Hubei Province as the example, the effectiveness of the proposed combined forecasting model was verified, demonstrating a higher forecasting accuracy. The analysis result shows that the power load of Hubei Province will reach saturation in 2039, and the annual maximum power load will reach about 78,630 MW. The results obtained from this proposed hybrid urban saturated power load analysis model can serve as a reference for sustainable development for urban power grids, regional economies, and society at large.
A load factor based mean-variance analysis for fuel diversification
Energy Technology Data Exchange (ETDEWEB)
Gotham, Douglas; Preckel, Paul; Ruangpattana, Suriya [State Utility Forecasting Group, Purdue University, West Lafayette, IN (United States); Muthuraman, Kumar [McCombs School of Business, University of Texas, Austin, TX (United States); Rardin, Ronald [Department of Industrial Engineering, University of Arkansas, Fayetteville, AR (United States)
2009-03-15
Fuel diversification implies the selection of a mix of generation technologies for long-term electricity generation. The goal is to strike a good balance between reduced costs and reduced risk. The method of analysis that has been advocated and adopted for such studies is the mean-variance portfolio analysis pioneered by Markowitz (Markowitz, H., 1952. Portfolio selection. Journal of Finance 7(1) 77-91). However the standard mean-variance methodology, does not account for the ability of various fuels/technologies to adapt to varying loads. Such analysis often provides results that are easily dismissed by regulators and practitioners as unacceptable, since load cycles play critical roles in fuel selection. To account for such issues and still retain the convenience and elegance of the mean-variance approach, we propose a variant of the mean-variance analysis using the decomposition of the load into various types and utilizing the load factors of each load type. We also illustrate the approach using data for the state of Indiana and demonstrate the ability of the model in providing useful insights. (author)
Factors Affecting Pollutant Load Reduction with Uncertainty Analysis in Urban Stormwater BMP Systems
Park, D.
2015-12-01
This study incorporates uncertainty analysis into a model of the performance of stormwater best management practices (BMPs) to characterize the uncertainty in stormwater BMP effluent load that results from uncertainty in the BMP performance modeling in an urban stormwater system. Detention basins are used as BMPs in the urban stormwater systems, and the total suspended solids (TSS) are used as an urban nonpoint source pollutant in Los Angeles, CA. The k-C* model, which incorporates uncertainty analysis, is applied to the uncertainty of the stormwater effluent concentration in urban stormwater systems. This study presents a frequency analysis of the runoff volume and BMP overflows to characterize the uncertainty of BMP effluent loads, and the load frequency curve (LFC) is simulated with and without BMP conditions and verified using the observed TSS load. Finally, the effects of imperviousness, BMP volume, and BMP surface area are investigated using a reliability analysis. The results of this study can be used to determine the appropriate BMP size to achieve a specific watershed runoff pollutant load. The result of this evaluation method can support the adequate sizing of a BMP to meet the defined nonpoint source pollutant regulations. Acknowlegments This research was supported by a grant (14AWMP-B082564-01) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.
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.
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.
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.
A study for the replacement of blowdown loads analysis code of Korea standard nuclear plants
Energy Technology Data Exchange (ETDEWEB)
Yoo, B. T.; Hwang, S. T.; Choi, D. S.; Cho, C. S. [Korea Nuclear Fuel Company, Taejon (Korea, Republic of)
2002-10-01
The purpose of this study is to investigate the possibility to replace the CEFLASH-4B code used in the blowdown loads analysis of Korea Standard Nuclear Plants. Since the application of CEFLASH-4B is restricted after 2007 by U.S. Government, an alternative code to CEFLASH-4B is necessary. The SATAN-VI code was selected as an alternative choice to the CEFLASH-4B code since it was widely used in LOCA analyses to Westinghouse plants without any further charge. The SATAN-VI code was evaluated for the application to the blowdown loads analysis. With a few problems fixed and/or improved, SATAN-VI code is reasonably applicable to blowdown loads analysis in KSNP plants.
A study for the replacement of blowdown loads analysis code of Korea standard nuclear plants
International Nuclear Information System (INIS)
The purpose of this study is to investigate the possibility to replace the CEFLASH-4B code used in the blowdown loads analysis of Korea Standard Nuclear Plants. Since the application of CEFLASH-4B is restricted after 2007 by U.S. Government, an alternative code to CEFLASH-4B is necessary. The SATAN-VI code was selected as an alternative choice to the CEFLASH-4B code since it was widely used in LOCA analyses to Westinghouse plants without any further charge. The SATAN-VI code was evaluated for the application to the blowdown loads analysis. With a few problems fixed and/or improved, SATAN-VI code is reasonably applicable to blowdown loads analysis in KSNP plants
International Nuclear Information System (INIS)
Currently the ASME Boiler and Pressure Vessel Code is considering a simplified Static Analysis Method for seismic design of piping systems for incorporation into Appendix N of Section 3, Division 1, of the Code. This proposed method, called the Load Coefficient Method, uses coefficients, ranging from .4 to 1.0, times the peak value of the in-structure response spectra with a static analysis technique to evaluate the response of piping systems to seismic events. The coefficient used is a function of the pipe support spacing hence the frequency response of the system and in general, the greater the support spacing the lower the frequency, the lower the spectral response, hence the lower the coefficient. The results of the Load Coefficient Method static analyses have been compared to analyses using the Response Spectrum Modal Analysis Method. Reaction loads were also evaluated with one important modification, a minimum support reaction load as a function of nominal pipe diameter has been established. This assures that lightly loaded supports regardless of the analytical method used will be loaded to realistic values and eliminate the potential for under designed supports. With respect to the accelerations applicable to inline components, a factor of 0.9 times the Square Root of Sum of Square of horizontal floor spectra peaks was determined to envelop the horizontal accelerations and a coefficient of 1.2 was shown to envelop the vertical accelerations. Presented in this paper is the current form of the load coefficient method, a summarization of the results of the over 2,700 benchmark analysis of piping system segments which form the basis for the acceptance of the method, and an explanation of the use of the method
Simulation and Analysis of Wind Turbine Loads for Neutrally Stable Inflow Turbulence
Sim, C.; Manuel, L.; Basu, S.
2009-12-01
Efficient temporal resolution and spatial grids are important in simulation of the inflow turbulence for wind turbine loads analyses. There have not been many published studies that address optimal space-time resolution of generated inflow velocity fields in order to estimate accurate load statistics. This study investigates turbine extreme and fatigue load statistics for a utility-scale 5MW wind turbine with a hub-height of 90 m and a rotor diameter of 126 m. Load statistics, spectra, and time-frequency analysis representations are compared for various alternative space and time resolutions employed in inflow turbulence field simulation. Conclusions are drawn regarding adequate resolution in space of the inflow turbulence simulated on the rotor plane prior to extracting turbine load statistics. Similarly, conclusions are drawn with regard to what constitutes adequate temporal filtering to preserve turbine load statistics. This first study employs conventional Fourier-based spectral methods for stochastic simulation of velocity fields for a neutral atmospheric boundary layer. In the second part of this study, large-eddy simulation (LES) is employed with similar spatial and temporal resolution as in the earlier Fourier-based simulations to again establish turbine load statistics. A comparison of extreme and fatigue load statistics is presented for the two approaches used for inflow field generation. The use of LES-generated flows (enhanced in deficient high-frequency energy by the use of fractal interpolation) to establish turbine load statistics in this manner is computationally very expensive but the study is justified in order to evaluate the ability of LES to be used as an alternative to more common approaches. LES with fractal interpolation is shown to lead to accurate load statistics when compared with stochastic simulation. A more compelling reason for using LES in turbine load studies is the following: for stable boundary layers, it is not possible to
Wavelet Approach for Vibration Analysis of Fast Moving Load on a Viscoelastic Medium
Directory of Open Access Journals (Sweden)
Piotr Koziol
2010-01-01
Full Text Available This paper analyses theoretically the response of a solid for fast moving trains using models related to real situations: a load moving in a tunnel and a load moving on a surface. The mathematical model is described by Navier's elastodynamic equation of motion for the soil and Euler-Bernoulli equation for the beam with appropriate boundary conditions. Two modelling approaches are investigated: the model with half space under the beam and the model with finite thickness of supporting medium. The problem of singularities for displacements calculation is discussed in relation with boundary conditions and types of considered loads: harmonic and constant, point and distributed moving loads. The analysis in frequency-time and frequency-velocity domains is presented and discussed with regard to critical velocities.
Plastic limit load analysis for steam generator tubes with local wall-thinning
International Nuclear Information System (INIS)
This paper introduces the study of experimental and numerical analysis for plastic limit loads of Inconel 690 steam generators (SG) tubes with local wall-thinning defects. Meanwhile, the effect of the three dimensions of a local wall-thinning defect on the plastic limit load of SG tubes is analyzed. A test facility which can test both burst pressure and plastic limit load of SG tubes was established and SG tubes with 3 typical types of defects were tested by using the facility. A regularization method for local wall-thinning defect is proposed and the finite element method was used to analyze the plastic limit load of SG tubes with defects. Compared with the experimental results of SG tubes with real defects, the calculated values of plastic limit load for SG tubes with regularized defects are conservative. Based on finite element method, the effect of the three dimensions of local wall-thinning defects on plastic limit loads of defected Inconel 690 SG tubes has been got. The studied results show that the defect depth of a local wall-thinning defect is the main factor influencing the plastic limit load of SG tubes, on the other hand, both the longitudinal length and the circumferential length of a defect have effect on the plastic limit load of SG tubes. It is found that in some cases, when the longitudinal length and the circumferential angle of a local wall-thinning defect exceed some extent, the effect of the longitudinal length and the circumferential angle on plastic limit load can be ignored.
Analysis of waste storage tanks subjected to seismic loading
International Nuclear Information System (INIS)
At the Savannah River Site, High Activity Wastes are stored in carbon steel tanks that are within reinforced concrete vaults. These soil-embedded tank/vault structures are approximately 24m in diameter and 12m deep. Twenty-seven of these tanks required seismic analysis. The problem was reduced to a limited number of cases of soil-structure interaction and fluid-structure interaction problems. It was theorized that substantially reduced seismic input could be realized from soil structure interaction (SSI) but that it was also possible that tank-to-tank proximity could result in (re)amplification of the input. To determine the governing seismic input motion, the three dimensional SSI code, SASSI, was used. Also of concern was fluid response and tank behavior as a function of tank contents viscosity. Tank seismic analyses and studies have been based on low viscosity fluids (water) and the behavior is quite well understood. Typical wastes (salts, sludge), which are highly viscous, have not been the subject of studies to understand the effect of viscosity on seismic response. Conclusions based on this study provide insight into the quantification of the of seismic inputs for soil structure interaction for a 'soft' soil site and provides some conclusions for dealing with the viscosity variable. (author)
Dynamic ultimate load analysis using a finite difference method
International Nuclear Information System (INIS)
The method of numerical integration is explained on a one-degree-of-freedom system. A generalization to systems with several degrees of freedom is given. The conditions for numerical stability and for getting a sufficient approximation to the exact solution of the differential equations are dealt with. Not only a time discretization but also a geometric discretization is necessary. This may be anticipated by a lumped-mass dynamic model, or, with continuous bodies, it could be performed, e.g., by a mesh pattern of finite coordinate differences. Examples are given for the numerical treatment especially of beams and plates. Starting from the corresponding differential equations describing a process of wave propagation, the rotational inertia of single beam or plate elements as well as the transverse shear deformations are included. By this numerical method of dynamic analysis suitable for computer programming, point-by-point time-history solutions are obtained for deterministic excitations and for material properties, both varying arbitrarily with time and space. Applications for practical dynamic problems of nuclear structural design taking into account a defined material ductility are discussed. (orig./HP)
Stress analysis of a piping system under high-intensity shock loads
International Nuclear Information System (INIS)
This paper summarizes a methodology for the structural analysis of piping systems under high-impact shock loads, such as those predicted in naval codes. An equivalent spring-mass system is determined in such a way that, under the action of fictitious forces, its response reproduces well the naval specifications. Numerical analysis are performed using one FEM code. The stress analysis of an hypothetical piping system is then performed
Finite Element Analysis of Composite Hardened Walls Subjected to Blast Loads
Girum S. Urgessa
2009-01-01
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 ...
Response Analysis for Steel Reinforced Concrete Frame Structures under Earthquake Load
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...
Analysis of embedded waste storage tanks subjected to seismic loading
International Nuclear Information System (INIS)
At the Savannah River Site, High Activity Wastes are stored in carbon steel tanks that are within reinforced concrete vaults. These soil-embedded tank/vault structures are approximately 80 ft. in diameter and 40 ft. deep. The tanks were studied to determine the essentials of governing variables, to reduce the problem to the least number of governing cases to optimize analysis effort without introducing excessive conservatism. The problem reduced to a limited number of cases of soil-structure interaction and fluid (tank contents)-structure interaction problems. It was theorized that substantially reduced input would be realized from soil structure interaction (SSI) but that it was also possible that tank-to-tank proximity would result in (re)amplification of the input. To determine the governing seismic input motion, the three dimensional SSI code, SASSI, was used. Significant among the issues relative to waste tanks is the determination of fluid response and tank behavior as a function of tank contents viscosity. Tank seismic analyses and studies have been based on low viscosity fluids (water) and the behavior is quite well understood. Typical wastes (salts, sludge), which are highly viscous, have not been the subject of studies to understand the effect of viscosity on seismic response. The computer code DYNA3D was used to study how viscosity alters tank wall pressure distribution and tank base shear and overturning moments. A parallel hand calculation was performed using standard procedures. Conclusions based on this study provide insight into the quantification of the reduction of seismic inputs for soil structure interaction for a open-quotes softclose quotes soil site
A NASTRAN DMAP alter for linear buckling analysis under dynamic loading
Aiello, Robert A.; Grady, Joseph E.
1989-01-01
A modification to the NASTRAN solution sequence for transient analysis with direct time integration (COSMIC NASTRAN rigid format 9) was developed and incorporated into a DMAP alter. This DMAP alter calculates the buckling stability of a dynamically loaded structure, and is used to predict the onset of structural buckling under stress-wave loading conditions. The modified solution sequence incorporates the linear buckling analysis capability (rigid format 5) of NASTRAN into the existing Transient solution rigid format in such a way as to provide a time dependent eigensolution which is used to assess the buckling stability of the structure as it responds to the impulsive load. As a demonstration of the validity of this modified solution procedure, the dynamic buckling of a prismatic bar subjected to an impulsive longitudinal compression is analyzed and compared to the known theoretical solution. In addition, a dynamic buckling analysis is performed for the analytically less tractable problem of the localized dynamic buckling of an initially flawed composite laminate under transverse impact loading. The addition of this DMAP alter to the transient solution sequence in NASTRAN facilitates the computational prediction of both the time at which the onset of dynamic buckling occurs in an impulsively loaded structure, and the dynamic buckling mode shapes of that structure.
Validation of analysis methods for assessing flawed piping subjected to dynamic loading
International Nuclear Information System (INIS)
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
Fluctuation analysis of high frequency electric power load in the Czech Republic
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...
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.
Rus, Martin
2013-01-01
This thesis presents static analysis of load-bearing structure of a three storey office building in Ribnica according to Eurocode standard. The load-bearing structure is made of reinforced concrete and consists of smooth slabs on pillars that represent ceiling and roof structure, pillars and walls with openings. In the analysis of the load-bearing structure the influence of permanent and weigh down and also the impact of wind, snow and earthquake are considered. Detailed analysis of vertical ...
International Nuclear Information System (INIS)
Nuclear Power Plants (NPPs) have normal as well as emergency power supply systems. Both the power supply systems are to be reliable for proper operation of the plant. Diesel Generators (DGs) are the main on site power sources in Class III Emergency power supply system in the Nuclear Power Plants. Normally station auxiliary loads are fed by Class IV power supply system and during Class IV failure, essential safety and safety related loads are fed by Class III power supply system. The transfer of these loads from Class IV to Class III power supply is done through Emergency Transfer (EMTR) logic. For effective restoration of loads, EMTR logic has to be reliable. The EMTR scheme covers the sensing of under voltage on the 6.6 kV emergency bus, starting of DG on auto mode, tripping of motor loads and closing of DG circuit breaker and then sequential load pick up at high voltage and medium voltage levels. Both hardwired logic and PLC based logic are adopted for EMTR in NPPs. This paper discusses the reliability analysis carried out for hardwired EMTR logic by constructing fault tree using ISOGRAPH software. The target unavailability of EMTR system for plant safety is 10-4. It is shown that hardwired logic developed meets the target unavailability. (author)
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 k_{eff} margin varies from 0.05 to almost 0.3 Δk_{eff} 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.
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.
Impact location and load identification through inverse analysis with bounded uncertain measurements
International Nuclear Information System (INIS)
The growing demand for real-time damage assessment necessitates development of an efficient inverse analysis algorithm with consideration of practical issues such as uncertainty in measurement. A mathematical model-based inverse analysis scheme is proposed to identify impact locations and reconstruct impact load time history of a simply supported plate through multiple levels of analysis. The proximity of the impact location is first determined by the triangulation method and the impact location is then refined by minimization of an objective function through the particle swarm optimization method (PSO). Loss of data due to filtration is addressed in a further level by performing an interval analysis based on extreme measurement errors. The outcome of the analyses is a mean impact location, a load time history, and a range of likely deviations. The extreme deviation in impact location is shown by bounding lines, which form a rectangle. The deviation in load time history is also shown by upper and lower bounding sinusoidal curves. The results of the analyses indicate that the proposed method can effectively locate the impact point and reconstruct the load time history even with the existence of noise in the measured response. (paper)
Impact location and load identification through inverse analysis with bounded uncertain measurements
Ahmari, Saeed; Yang, Mijia
2013-08-01
The growing demand for real-time damage assessment necessitates development of an efficient inverse analysis algorithm with consideration of practical issues such as uncertainty in measurement. A mathematical model-based inverse analysis scheme is proposed to identify impact locations and reconstruct impact load time history of a simply supported plate through multiple levels of analysis. The proximity of the impact location is first determined by the triangulation method and the impact location is then refined by minimization of an objective function through the particle swarm optimization method (PSO). Loss of data due to filtration is addressed in a further level by performing an interval analysis based on extreme measurement errors. The outcome of the analyses is a mean impact location, a load time history, and a range of likely deviations. The extreme deviation in impact location is shown by bounding lines, which form a rectangle. The deviation in load time history is also shown by upper and lower bounding sinusoidal curves. The results of the analyses indicate that the proposed method can effectively locate the impact point and reconstruct the load time history even with the existence of noise in the measured response.
Large deflection analysis of cantilever beam under end point and distributed load
DEFF Research Database (Denmark)
Kimiaeifar, Amin; Tolou, N; Barari, Amin;
2014-01-01
distributed loads. Direct nonlinear solution by use of homotopy analysis method was implemented to drive the semi-exact solution of trajectory position of any point along the beam length. For the purpose of comparison, the deflections were calculated and compared to those of finite element method which was...
DEFF Research Database (Denmark)
Tsilipakos, O.; Pitilakis, A.; Yioultsis, T. V.; Papaioannou, S.; Vyrsokinos, K.; Kalavrouziotis, D.; Giannoulis, G.; Apostolopoulos, D.; Avramopoulos, H.; Tekin, T.; Baus, M.; Karl, M.; Hassan, K.; Weeber, J. C.; Markey, L.; Dereux, A.; Kumar, A.; Bozhevolnyi, S. I.; Pleros, N.; Kriezis, E. E.
2012-01-01
A comprehensive theoretical analysis of end-fire coupling between dielectric-loaded surface plasmon polariton and rib/wire silicon-on-insulator (SOI) waveguides is presented. Simulations are based on the 3-D vector finite element method. The geometrical parameters of the interface are varied in...
Zhang, Guangjian; Preacher, Kristopher J.; Luo, Shanhong
2010-01-01
This article is concerned with using the bootstrap to assign confidence intervals for rotated factor loadings and factor correlations in ordinary least squares exploratory factor analysis. Coverage performances of "SE"-based intervals, percentile intervals, bias-corrected percentile intervals, bias-corrected accelerated percentile intervals, and…
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.
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.
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.
Start point to savings - Better load demand analysis in commercial buildings
Energy Technology Data Exchange (ETDEWEB)
Abaravicius, Juozas; Pyrko, Jurek [Lund Univ., Dept of Energy Sciences (Sweden)
2007-07-01
Existing installations and energy systems in most commercial buildings could be used in a more efficient way to provide savings - both in terms of energy and load demand. The key for effective operation is a thorough and detailed analysis of energy use patterns that creates essential baseline for energy savings and the development of demand response (DR) strategies. The knowledge of energy demand variations is still very limited and the use of methods to analyse the load demand is rare. Many utilities have recently installed interval (hourly) metering even for smaller commercial users and households. This is a big step forward; however, experience shows that the data is being used only to a limited extent, mostly for billing purposes only. This paper reports about a study conducted with the objective of developing a detailed load demand analysis for commercial buildings. The study results should provide essential information for the formation and evaluation of future DR and energy efficiency strategies. This study was performed in collaboration with IKEA and E.ON and contributes to an ongoing IKEA energy efficiency programme. Two sample department stores in Sweden were selected and analysed within this project. The demand data analysis covers almost 3 years period, 2004-2006.This study contributes to new knowledge of energy use patterns (load demand) in commercial buildings. It proposes solutions of load-related problems, evaluates energy and load savings potential, identifies and analyses the needs, motives and barriers for participation in DR programmes. The study provides recommendations for ongoing and future efficiency and DR strategies and discusses the potential economic benefits from the DR measures.
Second-order FE Analysis of Axial Loaded Concrete Members According to Eurocode 2
Yosef Nezhad Arya, Nessa
2015-01-01
A nonlinear finite element analysis was performed for an axial loaded reinforced concrete column subjected to biaxial bending taking into account second-order effects. According to Eurocode there are two ways to take second-order effects into consideration: nonlinear FE analysis and hand calculation based on the simplified methods explained in Eurocode 2. Since simulating this kind of structures in ABAQUS is difficult, several simulations were made to find the correct model with satisfying ac...
Analysis of Cell Load Coupling for LTE Network Planning and Optimization
Siomina, Iana; Yuan, Di
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...
Stress load and durability analysis of railway vehicles using multibody approach
Directory of Open Access Journals (Sweden)
Nikolay LYSIKOV
2007-01-01
Full Text Available The present paper describes the CAE-based approach for durability analysis that is being implemented in Universal Mechanism software to predict the fatigue damage of parts of mechanical systems. The approach predicts fatigue strength of structural components of machines and mechanisms based on results of simulating their dynamics taking into account real working conditions. An application to the developedsoftware to a stress load and durability analysis is considered.
Comparative analysis of different methods of modelling of most loaded fuel pin in transients
International Nuclear Information System (INIS)
Different methods of modeling of most loaded fuel pin are presented at the work. Calculation studies are performed on example of accident related to WWER-1000 cluster rod ejection with using of spatial kinetic code DYN3D that uses nodal method to calculate distribution of neutron flux in the core. Three methods of modeling of most loaded fuel pin are considered - flux reconstruction in fuel macrocell, pin-by-pin calculation by using of DYN3D/DERAB package and by introducing of additional 'hot channel'. Obtained results of performed studies could be used for development of calculation kinetic models during preparing of safety analysis report (Authors)
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
coordinates is described, and the convected formulation of boundary elements is presented and used for illustrating the effect of 'high-speed' motion. Finally, a procedure for the coupling of a local finiteelement model with a boundary-element model of an exterior, or open, domain is described. The paper uses......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 in...
Analysis of installation and loading process for displacement piles by Discrete Element Model
Valentino, Francesca
2014-01-01
The present work investigates the influence of installation technology on the response of a single pile under axial load. Installation and loading process for both jacked and screw piles has been analysed through a Discrete Element Model (DEM) approach, by means of the commercial software Particle Flow Code 3D v3.0 (Itasca). The Thesis is subdivided in two main parts. Firstly, CPTs tests in calibration chamber available in literature have been used as the starting point for the analysis of fu...
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.
Wave load computation in direct strength analysis of semi-submersible platform structures
Institute of Scientific and Technical Information of China (English)
ZHANG Hai-bin; REN Hui-long; DAI Yang-shan; GE Fei
2004-01-01
A wave load computation approach in direct strength analysis of semi-submersible platform structures was presented in this paper. Considering the differences in shape of pontoon, column and beam, the combination of accumulative chord length cubic parameter spline theory and analytic method was adopted for generating the wet surface mesh of platform. The hydrodynamic coefficients of platform were calculated by the three-dimensional potential flow theory of the linear hydrodynamic problem for platform with low forward speed. The equation of platform motions was established and solved in frequency domain, and the responses of wave-induced loads on the platform can be obtained. With the interpolation method being utilized, the pressure loads on shell elements for finite element analysis (FEA) were converted from those on the hydrodynamic computation mesh, which pave the basis for FEA with commercial software.A computer program based on this method has been developed, and a calculation example of semi-submersible platform was illustrated.Analysis results show that this method is a satisfying approach of wave loads computation for this kind of platform.
International Nuclear Information System (INIS)
Full text: Transient dynamic analysis of 500 MWe PHWR nuclear containment has been carried out to evaluate the damage that may be caused due to aircraft impact of Boeing 707-320. A special three dimensional finite element analysis procedure has been developed for the double containment walls with an annulus gap in between outer containment wall (OCW) and inner containment wall (ICW). The case studies include the analyses of OCW single model and the combined model of OCW and ICW for impulsive load due to the aircraft impact. It is demonstrated that OCW would suffer local perforation with a peak local deformation of ∼94 mm without loss of the overall integrity. However, this first barrier cannot absorb the full impulsive load. Here after the local perforation of the first barrier OCW, the impulse load is transferred to the second barrier ICW in the combined model of OCW and ICW. In the analyses of the combined model, the ICW is subjected to lower impulse duration as the load is transferred after 0.195 sec due to the local perforation of OCW. This results in the local deformation of the ICW ∼66 mm. The analysis methodology evolved in the present work would be useful for studying the behaviour of double containment walls for aircraft impact with higher energies
Preliminary C3 Loading Analysis for Future High-Altitude Unmanned Aircraft in the NAS
Ho, Yan-Shek; Gheorghisor, Izabela; Box, Frank
2006-01-01
This document provides a preliminary assessment and summary of the command, control, and communications (C(sup 3)) loading requirements of a generic future high-altitude, long-endurance unmanned aircraft (UA) operating at in the National Airspace System. Two principal types of C(sup 3) traffic are considered in our analysis: communications links providing air traffic services (ATS) to the UA and its human pilot, and the command and control data links enabling the pilot to operate the UA remotely. we have quantified the loading requirements of both types of traffic for two different assumed levels of UA autonomy. Our results indicate that the potential use of UA-borne relays for the ATS links, and the degree of autonomy exercised by the UA during the departure and arrival phases of its flight, will be among the key drivers of C(sup 3) loading and bandwidth requirements.
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...... by the wind turbine standard IEC 61400-1. Finally, an approach for the assessment of the reliability of adhesive bonded composite stepped lap joints loaded in fatigue is presented. The introduced methodology can be applied in the same way to calculate the reliability level of wind turbine blade...
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.
Directory of Open Access Journals (Sweden)
K.RAJASEKHAR
2012-07-01
Full Text Available Slurry Infiltrate Fibrous Concrete (SIFCON is a new high performance and advanced material and can be considered as a special type of steel fiber reinforced concrete (SFRC. This paper describes the development of two – way slab model to predict the non-linear load-displacement behavior of SIFCON slab subjected to pressure loading. Slabs with 8%, 10% and 12% for different edge conditions have been modeled in Finite elements and verified with experimental values. The results of the analysis show that the SIFCON slabs with12% fibre volume fraction exhibit excellent performance in flexure among other slabs. The FEM results have agreed closely with the experimental deflection values for the loadings considered.
Energy Technology Data Exchange (ETDEWEB)
Huey, D.P. [Stress Engineering Services, Inc., Houston, TX (United States); Hair, J.D.; McLeod, K.B. [J.D. Hair & Associates, Inc., Tulsa, OK (United States)
1996-08-01
Pipelines installed by horizontal directional drilling (HDD) are subject to a combination of tension, blending, and external pressure. These installation loads, either individually or in combination, can be more severe than operational loads and may govern drilled path design or specification. This is particularly true as the state of the art in horizontal directional drilling is advanced to larger pipe diameters and longer drilled lengths. This paper presents methods for calculating installation loads, including pulling forces, and analyzing combined stresses in steel pipe during installation and operation. Pipe to soil frictional and fluidic drag forces are discussed. A method for analyzing the effect of bends on pulling force is presented. Methods of analysis are illustrated with example calculations. The paper results from work done under the sponsorship of the Pipeline Research Committee at the American Gas Association and is taken from an engineering design guide produced specifically for HDD pipeline installation. 10 refs., 5 figs.
Testing and Analysis of Composite Skin/Stringer Debonding Under Multi-Axial Loading
Krueger, Ronald; Cvitkovich, Michael K.; O'Brien, T. Kevin; Minguet, Pierre J.
2000-01-01
A consistent step-wise approach is presented to investigate the damage mechanism in composite bonded skin/stringer constructions under uniaxial and biaxial (in-plane/out-of-plane) loading conditions. The approach uses experiments to detect the failure mechanism, computational stress analysis to determine the location of first matrix cracking and computational fracture mechanics to investigate the potential for delamination growth. In a first step, tests were performed on specimens, which consisted of a tapered composite flange, representing a stringer or frame, bonded onto a composite skin. Tests were performed under monotonic loading conditions in tension, three-point bending, and combined tension/bending to evaluate the debonding mechanisms between the skin and the bonded stringer. For combined tension/bending testing, a unique servohydraulic load frame was used that was capable of applying both in-plane tension and out-of-plane bending loads simultaneously. Specimen edges were examined on the microscope to document the damage occurrence and to identify typical damage patterns. For all three load cases, observed failure initiated in the flange, near the flange tip, causing the flange to almost fully debond from skin. In a second step, a two dimensional plane-strain finite element model was developed to analyze the different test cases using a geometrically nonlinear solution. For all three loading conditions, computed principal stresses exceeded the transverse strength of the material in those areas of the flange where the matrix cracks had developed during the tests. In a third step, delaminations of various lengths were simulated in two locations where delaminations were observed during the tests. The analyses showed that at the loads corresponding to matrix ply crack initiation computed strain energy release rates exceeded the values obtained from a mixed mode failure criterion in one location, Hence. Unstable delamination propagation is likely to occur as
Sheppard, P S; Stevenson, J M; Graham, R B
2016-05-01
The objective of the present study was to determine if there is a sex-based difference in lifting technique across increasing-load conditions. Eleven male and 14 female participants (n = 25) with no previous history of low back disorder participated in the study. Participants completed freestyle, symmetric lifts of a box with handles from the floor to a table positioned at 50% of their height for five trials under three load conditions (10%, 20%, and 30% of their individual maximum isometric back strength). Joint kinematic data for the ankle, knee, hip, and lumbar and thoracic spine were collected using a two-camera Optotrak motion capture system. Joint angles were calculated using a three-dimensional Euler rotation sequence. Principal component analysis (PCA) and single component reconstruction were applied to assess differences in lifting technique across the entire waveforms. Thirty-two PCs were retained from the five joints and three axes in accordance with the 90% trace criterion. Repeated-measures ANOVA with a mixed design revealed no significant effect of sex for any of the PCs. This is contrary to previous research that used discrete points on the lifting curve to analyze sex-based differences, but agrees with more recent research using more complex analysis techniques. There was a significant effect of load on lifting technique for five PCs of the lower limb (PC1 of ankle flexion, knee flexion, and knee adduction, as well as PC2 and PC3 of hip flexion) (p < 0.005). However, there was no significant effect of load on the thoracic and lumbar spine. It was concluded that when load is standardized to individual back strength characteristics, males and females adopted a similar lifting technique. In addition, as load increased male and female participants changed their lifting technique in a similar manner. PMID:26851478
COMPARATIVE ANALYSIS OF MODELS OF RAILWAY LOADS C14 AND LM71 FOR GIRDER BRIDGES
Directory of Open Access Journals (Sweden)
V. Artomov
2014-01-01
Full Text Available Purpose. The article analyzes the railway load LM71 for the purpose of its application in national design projects of the railway girder bridges. Purpose of the article is harmonization of national design codes of enginnering structures with the European standards (Eurocodes. Methodology. Analytical calculation methods (influence lines, the matrix analysis and computer programming are used in the article. Findings. Deflected mode parameters of the railway bridges under the influence of loads C14 and LM71 have certain differences. The extent of these differences depends on length, material of drift structures and also on dynamic coefficients. These dependences should be considered in national design codes and in harmonized with Eurocodes standards. In the further researches relationships between load C14 and models SW, HSLM taking into account various dynamic effects and trains speedis planned to determine. Originality. The presented results, in particular deflected mode parameters (including loads with dynamic coefficients, obtained for the first time. Practical value. Results of research are used in National Annex to the National Standard of Ukraine NSTU-N B EN 1991-2:2010. Eurocode 1. Actions on structures. Part 2. Traffic loads on bridges (EN 1991-2:2003.
Naqui, J.; Su, L.; Mata, J.; Martín, F.
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.
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.
International Nuclear Information System (INIS)
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
International Nuclear Information System (INIS)
In the present paper a general time-dependent inelastic analysis procedure for three-dimensional bodies subjected to arbitrary time varying mechanical and thermal loads using these state variable theories is presented. For the purpose of illustrations, the problems of hollow spheres, cylinders and solid circular shafts subjected to various combinations of internal and external pressures, axial force (or constraint) and torque are analyzed using the proposed solution procedure. Various cyclic thermal and mechanical loading histories with rectangular or sawtooth type waves with or without hold-time are considered. Numerical results for these geometrical shapes for various such loading histories are presented using Hart's theory (Journal of Engineering Materials and Technology 1976). The calculations are performed for nickel in the temperature range of 250C to 4000C. For integrating forward in time, a method of solving a stiff system of ordinary differential equations is employed which corrects the step size and order of the method automatically. The limit loads for hollow spheres and cylinders are calculated using the proposed method and Hart's theory, and comparisons are made against the known theoretical results. The numerical results for other loading histories are discussed in the context of Hart's state variable type constitutive relations. The significance of phenomena such as strain rate sensitivity, Bauschinger's effect, crep recovery, history dependence and material softening with regard to these multiaxial problems are discussed in the context of Hart's theory
Development of CFD Analysis Methodology of Hydraulic Load Evaluation in POSRV Piping System
International Nuclear Information System (INIS)
APR1400 has been improved as an advanced light water reactor that adopts new technology's. One of major technologies is IRWST(In-containment Refueling Water Storage Tank) placed inside containment. In order to adjust the new technology when POSRV(Pilot Operated Safety Relief Valve) is opened, POSRV-IRWST linked line must be kept safe. Theoretical solution and experimental data are needed for structure integrity, but proven data are insufficient from the viewpoint of hydrodynamics. The hydrodynamic flow analysis and the thermodynamic behavior analysis should be performed by using CFD. The objective of this study is to develop the CFD analysis methodology of hydraulic load evaluation in IRWST piping system. This method is a basic hydraulic load evaluation in POSRV piping system. Also, this will help to analyze fluid-structural interface and to predict special phenomena. Therefore, that can be used as a basis to the most suitable design
Ricles, James M.
1990-01-01
The development and preliminary assessment of a method for dynamic structural analysis based on load-dependent Ritz vectors are presented. The vector basis is orthogonalized with respect to the mass and structural stiffness in order that the equations of motion can be uncoupled and efficient analysis of large space structure performed. A series of computer programs was developed based on the algorithm for generating the orthogonal load-dependent Ritz vectors. Transient dynamic analysis performed on the Space Station Freedom using the software was found to provide solutions that require a smaller number of vectors than the modal analysis method. Error norm based on the participation of the mass distribution of the structure and spatial distribution of structural loading, respectively, were developed in order to provide an indication of vector truncation. These norms are computed before the transient analysis is performed. An assessment of these norms through a convergence study of the structural response was performed. The results from this assessment indicate that the error norms can provide a means of judging the quality of the vector basis and accuracy of the transient dynamic solution.
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.
Analysis of 91.5 m high flare stack under dynamic loading
International Nuclear Information System (INIS)
Flare stacks are one of the major of civil engineering structures in the refineries. Several factors primarily the development of high strength materials, new design concepts and methods, introduction of new structural systems, improved construction method and the afford ability of modem efficient computing tools have significantly contributed to the continued development of tall structures in last few decades. Although 'Tall Structure' is a relative term, from structural engineering point of view, a Tall Structure can be defined as one whose structural design is governed primarily by the lateral load resisting systems. Simplified 2D analyses method and tools are generally not sufficient for the realistic prediction of the response of such systems that demand the 3D analysis. Because of the dynamic nature of the lateral loads (earthquake loading and wind loading) and requirement for 3D analysis, sophisticated computational tools and techniques are required. This paper is intended to study the behavior and structural system of 91.5 m (300 ft.) high flare stacks at global to component levels, interpretations of the results and finally the design. (author)
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.
Trend analysis of nutrient loadings in the South Saskatchewan River catchment
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
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.
The next generation analysis methodology for cracked pipe systems subjected to dynamic loads
International Nuclear Information System (INIS)
Evaluation procedures for cracked piping systems under dynamic loads, seismic and water hammer in particular, have evolved over the years from assuming an instantaneous brittle double-ended pipe break in the early years of the nuclear industry, to using peak load from a linear elastic analysis with elastic-plastic fracture mechanics over the past 10 years. With improvements in computing power and developments in the fracture mechanics analysis of cracked pipe, it is now possible, using work station computers, to perform nonlinear time-history cracked-pipe analyses that can predict, not only the maximum load, but an make reasonably accurate, but slightly conservative, predictions of the time to surface crack penetration, how far the crack may propagate around the circumference, and the crack opening history for leak rate, decompression, and jet-force calculations. This new analysis methodology, the so-called cracked-pipe element nonlinear FEA fracture analysis is currently being formulated and refined. The analytical methods and comparison with experimental cracked-pipe data, as well as some specific applications illustrating margins obtained by this methodology versus more traditional analyses will be summarized
Inverse thermoelastic analysis for thermal and mechanical loads identification using FBG data
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.
ANALYSIS OF A TIMBER LOADING SYSTEM WITH AID OF COMPUTER SIMULATION: A CASE STUDY
Sandoval Constantino Junior; Luiz Enéias Zanetti Cardoso; Larissa Lenharo Vendrametto
2016-01-01
The subject and problem focused on this work aim to point out the critical points and suggestions for improvements to a platform logistics of inventory warehouses loads an enterprise of the wood industry. This work aims to analyze existing bottlenecks, appointed by computer simulation, and propose improvements in order to optimize the current situation of the company. The study is based on analysis of data collected in the company through, sampling, computer simulation tools and literature...
Analysis of breaks in a non-equally load sharing system
Czech Academy of Sciences Publication Activity Database
Linka, A.; Volf, Petr; Tunák, M.
Bordeaux : University Victor Segalen, 2008, s. 99-101. ISSN N. [ALT'2008-- 2nd International Conference on Accelerated Life Testing. Bordeaux (FR), 09.06.2008-11.06.2008] R&D Projects: GA MŠk(CZ) 1M06047 Institutional research plan: CEZ:AV0Z10750506 Keywords : reliability analysis * load sharing system * breaking strength Subject RIV: BB - Applied Statistics, Operational Research
Traffic load of forest roads as a criterion for their categorization – GIS analysis
2007-01-01
The categorisation of forest roads can be based on several different criteria. In this paper, the outlines of the primary forest traffic infrastructure were divided according to the traffic load typical of long-distance transportation of timber. The survey was conducted in the management unit of Veprinačke šume, forest office of Opatija, forest administration of Buzet. This paper defines the methodology of forest roads categorisation using the GIS analysis, which should become a mandatory too...
Sequential design of decentralized load frequency controllers using μ synthesis and analysis
International Nuclear Information System (INIS)
A new systematic approach to design of sequential decentralized load frequency controllers for multi-area power systems based on μ synthesis and analysis is described. System uncertainties, practical constraints on control action and desired performance are included in the synthesis procedure. The robust performance in terms of the structured singular value is used as a measure of control performance. A four area power system example is presented, demonstrating the controllers' synthesis procedure and advantages of the proposed strategy
Analysis Of Load Match and Grid Interaction Indicators in NZEB with High-Resolution Data
Salom, Jaume
2014-01-01
A Net Zero Energy Building (Net ZEB) is succinctly described as a grid-connected building that generates as much energy as it uses over a year. The “Net Zero” balance is attained by applying energy conservation and efficiency measures and by incorporating renewable energy systems. The main objective of this report is to analyze the usefulness and relevance of proposed Load Match and Grid Interaction (LMGI) for Net Zero Energy Buildings. The methodology is based in the analysis of ...
Upper and lower bounds in limit analysis: adaptive meshing strategies and discontinuous loading
Muñoz Romero, José; Bonet Carbonell, Javier; Huerta, Antonio; Peraire Guitart, Jaume
2008-01-01
This is the pre-peer reviewed version of the following article: Muñoz, José J. [et al.]. Upper and lower bounds in limit analysis: adaptive meshing strategies and discontinuous loading. "International journal for numerical methods in engineering", Agost 2008, vol. 77, núm. 4, p. 471-501., which has been published in final form at http://www3.interscience.wiley.com/journal/121370765/abstract Peer Reviewed
STRESS ANALYSIS OF IC ENGINE PISTON FOR DIFFERENT MATERIAL AND PRESSURE LOAD USING FEA
Mr. Jadhav Vishal, Dr. R.K. Jain, Mr. Yogendra S.Chauhan
2016-01-01
This present work describes the stress distribution of two different aluminum alloys piston by using finite element method (FEM). The piston is designed for a single cylinder petrol engine using SOLIDWORKS 2013 software. The procedure for analytical design of two different aluminum alloy piston is described. Design is imported to ANSYS 15.0 software then static stress analysis is performed at different pressure load conditions on the piston. Results are presented and a comparison is made to f...
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.
Testing for Heterogeneous Factor Loadings Using Mixtures of Confirmatory Factor Analysis Models
Buzick, Heather M.
2010-01-01
The current study assessed the viability of mixture confirmatory factor analysis (CFA) for measurement invariance testing by evaluating the ability of mixture CFA models to identify differences in factor loadings across populations with identical mean structures. Using simulated data from a model with known parameters, convergence rates, parameter recovery, and the power of the likelihood-ratio test were investigated as impacted by sample size, latent class proportions, magnitude of factor lo...
Estill, Janne; Aubrière, Cindy; Egger, Matthias; Johnson, Leigh; Wood, Robin; Garone, Daniela; Gsponer, Thomas; Wandeler, Gilles; Boulle, Andrew; Davies, Mary-Ann; Hallett, Timothy B.; Keiser, Olivia
2012-01-01
In low-income settings, treatment failure is often identified using CD4 cell count monitoring. Consequently, patients remain on a failing regimen, resulting in a higher risk of transmission. We investigated the benefit of routine viral load monitoring for reducing HIV transmission.
International Nuclear Information System (INIS)
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
Simulation-Length Requirements in the Loads Analysis of Offshore Floating Wind Turbines: Preprint
Energy Technology Data Exchange (ETDEWEB)
Haid, L.; Stewart, G.; Jonkman, J.; Robertson, A.; Lackner, M.; Matha, D.
2013-06-01
The goal of this paper is to examine the appropriate length of a floating offshore wind turbine (FOWT) simulation - a fundamental question that needs to be answered to develop design requirements. To examine this issue, a loads analysis of an example FOWT was performed in FAST with varying simulation lengths. The offshore wind system used was the OC3-Hywind spar buoy, which was developed for use in the International Energy Agency Code Comparison Collaborative Project and supports NREL's offshore 5-megawatt baseline turbine. Realistic metocean data from the National Oceanic and Atmospheric Administration and repeated periodic wind files were used to excite the structure. The results of the analysis clearly show that loads do not increase for longer simulations. In regards to fatigue, a sensitivity analysis shows that the procedure used for counting half cycles is more important than the simulation length itself. Based on these results, neither the simulation length nor the periodic wind files affect response statistics and loads for FOWTs (at least for the spar studied here); a result in contrast to the offshore oil and gas industry, where running simulations of at least 3 hours in length is common practice.
International Nuclear Information System (INIS)
Three layouts have been considered for AHWR downcomer for codal qualification in order to ensure its structural integrity under normal and occasional loads. In addition to codal qualification a good piping layout should have less number of bends and weld joints in order to reduce the in-service inspection cost. Less number of bends will reduce the pressure drop in natural circulation and lesser number of weld joints will reduce the total time of in-service inspection that finally reduces the radiation dose to the workers. Conventional seismic design approach of piping with snubbers leads to high cost, maintenance and possible locking causing undue higher thermal stress during normal operation. New seismic supports in the form of Elasto-Plastic Damper (EPD) are the best suited for nuclear piping because of their simple design, low cost, passive nature and ease in installation. In this report the characteristics of EPD obtained from theory, finite element analysis and tests have been presented and comparison has also been made among the three. Analysis method and code qualification of AHWR downcomer piping considering the loadings due to normal operating and occasional loads such as earthquake have been discussed in detail. This report also explains the concept of single support and multi-support response spectrum analysis methods. The results obtained by using both types of supports i.e. conventional and EPD supports have been compared and use of EPD supports in AHWR downcomer pipe is recommended. (author)
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.
International Nuclear Information System (INIS)
Pressure Vessel Code, Section VIII, Division 2 and ASME STS-1. -- Highlights: • Fourier series is used to predict the load carrying capacity of cylindrical vessel. • Reliability approach used for analysis as against the deterministic approach. • Cylindrical pressure vessel is subjected to axial end load and external pressure. • Axisymmetric and asymmetric analysis carried out for imperfect pressure vessels. • Results are compared to the recommendations laid out in ASME B and PV Code
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.
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.
The design and analysis of single flank transmission error tester for loaded gears
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.
Analysis of the effects of rising temperature for embankments under seismic loads in cold regions
Institute of Scientific and Technical Information of China (English)
无
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.
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.
Applicability of soil-structure interaction analysis methods for earthquake loadings (III)
Energy Technology Data Exchange (ETDEWEB)
Chang, S. P.; Ko, H. M.; Kim, J. K.; Yoon, J. Y.; Chin, B. M.; Kim, M. S.; Kim, Y. S.; Yang, T. S.; Park, D. H. [Korea Electrical Engineering and Science Research Institute, Seoul (Korea, Republic of)
1995-06-15
The ultimate goals of this research are to cultivate the capability of accurate SSI analysis and to develop the effective soil-structure interaction analysis method and computer program by comparing analysis results obtained in Lotung/Hualien LSST project. In this research, computer analysis program using Hyper element for soil-structure interaction was developed to analyze on-going Hualien LSST forced vibration and seismic. Prediction analysis and post-prediction analysis for Hualien LSST forced vibration and seismic response were executed by developed program. Thus this report is mainly composed of two parts, One is the summary of theoretical background of Hyper element and the other is prediction analysis and post-prediction analysis results for Hualien LSST forced Vibration and seismic response tests executed by developed program. Also, material nonlinear soil modeling method was summarized for the further development of computer analysis program related to precise soil-structure interaction and relation method between Hyper element and generalized 3 dimensional finite element or generally loaded axisymmetric finite element was presented. It is confirmed that program using Hyper element is efficient and practical because it can consider nonhomogeniety easily and execute the analysis in short time by using horizontal analysis solution. The validity and efficiency of the program is verified by Hualien LSST forced vibration and seismic analysis results executed by developed program.
Applicability of soil-structure interaction analysis methods for earthquake loadings (III)
International Nuclear Information System (INIS)
The ultimate goals of this research are to cultivate the capability of accurate SSI analysis and to develop the effective soil-structure interaction analysis method and computer program by comparing analysis results obtained in Lotung/Hualien LSST project. In this research, computer analysis program using Hyper element for soil-structure interaction was developed to analyze on-going Hualien LSST forced vibration and seismic. Prediction analysis and post-prediction analysis for Hualien LSST forced vibration and seismic response were executed by developed program. Thus this report is mainly composed of two parts, One is the summary of theoretical background of Hyper element and the other is prediction analysis and post-prediction analysis results for Hualien LSST forced Vibration and seismic response tests executed by developed program. Also, material nonlinear soil modeling method was summarized for the further development of computer analysis program related to precise soil-structure interaction and relation method between Hyper element and generalized 3 dimensional finite element or generally loaded axisymmetric finite element was presented. It is confirmed that program using Hyper element is efficient and practical because it can consider nonhomogeniety easily and execute the analysis in short time by using horizontal analysis solution. The validity and efficiency of the program is verified by Hualien LSST forced vibration and seismic analysis results executed by developed program
Trends of Amphetamine Type Stimulants DTR Mass Load in Poznan Based on Wastewater Analysis.
Directory of Open Access Journals (Sweden)
Piotr Nowicki
2014-05-01
Full Text Available The aim of this study was to determine the monthly DTR mass load of amphetamine-type compounds in Poland as well as an investigation of cyclical behaviour by using time series analysis and especially trends analysis.Amphetamine, methamphetamine and MDMA (ecstasy were detected in wastewater samples collected from the main Wastewater Treatment Plant in the city of Poznan using liquid chromatography / tandem mass spectrometry (LC-MS-MS. Back-calculations used in the sewage epidemiology approach were applied to estimate the DTR mass load level of the drugs analyzed. Trends analysis was performed by fitting the data to a simple linear regression and then by using smoothing by means of a moving average (Mat lab 2013a. Trend analysis displays a steady tendency of increase or decrease throughout time series. When we plot the observation against time, we may notice that a straight line can describe the increase or decrease in the series as time goes on. Simple linear regression and method of last squares to estimate parameters of a straight-line model were used. Additionally, a lagged plot (autocorrelation plot was used to investigate an appearance of correlation between amphetamines throughout time.Trends analysis showed the slight increase in consumption of amphetamine and decreasing trend in case of ecstasy and methamphetamine within the investigated period. There is also visible, strong correlation between ecstasy and methamphetamine consumption which cannot be stated in case of amphetamine.Trends analysis is a very useful tool to analyse the increasing or decreasing tendency in consumption of illicit drugs based on the DTR mass load data.
Dynamics modeling and loads analysis of an offshore floating wind turbine
Jonkman, Jason Mark
The vast deepwater wind resource represents a potential to use offshore floating wind turbines to power much of the world with renewable energy. Many floating wind turbine concepts have been proposed, but dynamics models, which account for the wind inflow, aerodynamics, elasticity, and controls of the wind turbine, along with the incident waves, sea current, hydrodynamics, and platform and mooring dynamics of the floater, were needed to determine their technical and economic feasibility. This work presents the development of a comprehensive simulation tool for modeling the coupled dynamic response of offshore floating wind turbines, the verification of the simulation tool through model-to-model comparisons, and the application of the simulation tool to an integrated loads analysis for one of the promising system concepts. A fully coupled aero-hydro-servo-elastic simulation tool was developed with enough sophistication to address the limitations of previous frequency- and time-domain studies and to have the features required to perform loads analyses for a variety of wind turbine, support platform, and mooring system configurations. The simulation capability was tested using model-to-model comparisons. The favorable results of all of the verification exercises provided confidence to perform more thorough analyses. The simulation tool was then applied in a preliminary loads analysis of a wind turbine supported by a barge with catenary moorings. A barge platform was chosen because of its simplicity in design, fabrication, and installation. The loads analysis aimed to characterize the dynamic response and to identify potential loads and instabilities resulting from the dynamic couplings between the turbine and the floating barge in the presence of combined wind and wave excitation. The coupling between the wind turbine response and the barge-pitch motion, in particular, produced larger extreme loads in the floating turbine than experienced by an equivalent land
Computational analysis of damage and failure evolution in ceramic coatings under thermal loading
International Nuclear Information System (INIS)
Ceramic coatings on metallic substrates greatly improve the performance of various structures (gas turbines, aircraft engines, etc.) and also widen their functional applications, serving as thermal barriers and/or wear-resistant coatings. Ceramic coatings are characterized by randomness in distribution of pores, anisotropy of thermoelastic properties and their change with distance from a substrate. These factors, together with a mismatch in coefficients of thermal expansion of coatings and substrates, can cause damage evolution and failure initiation even under purely thermal loading in the absence of external mechanical loads. Microstructure of ceramic coatings greatly affects parameters of transition to macroscopic failure initiation and development. Damage evolution processes in ceramics can be studied using a numerical model based on ideas of continuum damage mechanics (CDM) developed in. This approach incorporates a thermodynamically based CDM-model of damage in alumina and an account for spatial randomness in material properties (initial porosity) linked with manufacturing of ceramic materials. It allows an adequate description of high-temperature loading and of size effect in alumina. This model is applied to analyses of damage evolution in alumina thermal barriers on a titan substrate under conditions of thermal loading by means of the original modeling scheme and advanced finite element analysis. The specific type of microstructure of alumina coatings is integrated into numerical modeling in terms of the random distribution of initial porosity. Two different levels of simulations are exploited: (a) macroscopic for analysis of general thermomechanical processes in the coating-substrate system under various conditions and (b) microscopic for analysis of local processes in the direct vicinity of pores in alumina. Effects of different types of microstructure (determined by modification of manufacturing processes for coatings) on damage evolution and quality of
DEFF Research Database (Denmark)
Lindblom, Erik Ulfson; Madsen, Henrik; Mikkelsen, Peter Steen
2007-01-01
In this paper two attempts to assess the uncertainty involved with model predictions of copper loads from stormwater systems are made. In the first attempt, the GLUE methodology is applied to derive model parameter sets that result in model outputs encompassing a significant number of 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...
International Nuclear Information System (INIS)
Numerical simulations of the macro-deformations of the sealing surfaces (gasketed junctures) of a PWR steel containment vessel's equipment hatch subjected to accident loadings have been performed. Results for the equipment hatch juncture indicate that the rotations of the hatch cover and penetration sleeve must be accounted for when performing leakage analysis because they can affect the compression of the gasket even though the gasket is in a pressure-seated configuration. Results from a leakage analysis indicated that excessive leakage can occur if the surface roughness is high and/or the compression set is high
Norwood, D. Scott; Shuart, Mark J.; Herakovich, Carl T.
1991-01-01
The present analysis of interlaminar stresses in unsymmetrically laminates plates gives attention to the linear elastic large-deflection response of square laminated composite plates subjected to either uniaxial tension or compression loading. The effects of Poisson-ratio and mutual-influence coefficient mismatching between adjacent layers is evaluated in both cross-ply and angle-ply, and symmetric and asymmetric laminates. A global/local analysis procedure is used to obtain improved free-edge depictions; the results obtained indicate that the out-of-plane deflections of the unsymmetric laminates reduce interlaminar shear stresses, while reducing interlaminar normal stresses in some laminates and increasing them in others.
Mohamed F. Zedan; Sami Al-Sanea; Abdulaziz Al-Mujahid; Zeyad Al-Suhaibani
2016-01-01
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 br...
2014-01-01
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 ...
Saeedi, Navid; Sab, Karam; Caron, Jean-François
2013-01-01
This paper deals with the analysis of long multilayered plates subjected to invariant loading along the longitudinal direction. By assuming that the strain field is independent of the longitudinal coordinate, the general form of the displacement field is obtained for a rectangular plate. It is shown that there are only four types of loading which can be applied at the longitudinal ends of the plate: traction, out-of-plane bending, torsion and in-plane bending. In addition to these loads, the ...
Analysis of Wind Power and Load Data at Multiple Time Scales
Energy Technology Data Exchange (ETDEWEB)
Coughlin, Katie; Eto, J.H.
2010-12-20
In this study we develop and apply new methods of data analysis for high resolution wind power and system load time series, to improve our understanding of how to characterize highly variable wind power output and the correlations between wind power and load. These methods are applied to wind and load data from the ERCOT region, and wind power output from the PJM and NYISO areas. We use a wavelet transform to apply mathematically well-defined operations of smoothing and differencing to the time series data. This approach produces a set of time series of the changes in wind power and load (or ?deltas?), over a range of times scales from a few seconds to approximately one hour. A number of statistical measures of these time series are calculated. We present sample distributions, and devise a method for fitting the empirical distribution shape in the tails. We also evaluate the degree of serial correlation, and linear correlation between wind and load. Our examination of the data shows clearly that the deltas do not follow a Gaussian shape; the distribution is exponential near the center and appears to follow a power law for larger fluctuations. Gaussian distributions are frequently used in modeling studies. These are likely to over-estimate the probability of small to moderate deviations. This in turn may lead to an over-estimation of the additional reserve requirement (hence the cost) for high penetration of wind. The Gaussian assumption provides no meaningful information about the real likelihood of large fluctuations. The possibility of a power law distribution is interesting because it suggests that the distribution shape for of wind power fluctuations may become independent of system size for large enough systems.
Resin-loaded papers: sampling and trace analysis using neutron activation and x-ray spectrography
International Nuclear Information System (INIS)
Resin-loaded papers, composed of approximately 50 weight percent cellulose and 50 weight percent resin, provide an ideal medium for sampling large volumes of solution, then determining the concentrated elements by either fluorescent x-ray spectrography or neutron activation. This combination of chemistry and spectrography offers a versatile quantitative approach to the determination of trace elements in the ppM-ppB range. Standards and unknowns are prepared by either multiple filtration of solutions through two or more papers to measure the collection efficiency or a radiotracer is added to the solution to serve as a collection monitor. Reagent and paper blanks are incorporated into the analytical procedure. Papers containing strong acid or base resins collect a wide range of ions. Specific ions are collected by either chemical processing of the solution prior to filtration through the resin-loaded paper or by the use of papers loaded with chelating resins having high specificity. Advantages of the resin-loaded paper approach prior to spectrography are: improved analytical accuracy as the standards and unknowns are present in similar matrices; sampling errors are reduced and sensitivity significantly increased by concentration of the elements from a large volume of solution; and x-ray and gamma-ray spectral interferences are greatly reduced compared to bulk analysis. Also standard papers can be reused and stored indefinitely for x-ray applications. Examples of published applications to a wide range of industrial, environmental, and health problems are summaized together with applications by the Bureau of Mines to metallurgical and mining problems. Potential applications of new ion exchange resins and reagent-loaded papers are also considered
Load following with Small Modular Reactors (SMR): A real options analysis
International Nuclear Information System (INIS)
Load following is the potential for a power plant to adjust its power output as demand and price for electricity fluctuates throughout the day. In nuclear power plants, this is done by inserting control rods into the reactor pressure vessel. This operation is very inefficient as nuclear power generation is composed almost entirely of fixed and sunk costs; therefore, lowering the power output doesn't significantly reduce generating costs and the plant is thermo-mechanical stressed. A more efficient solution is to maintain the primary circuit at full power and to use the excess power for cogeneration. This paper assesses the technical-economic feasibility of this approach when applied to Small Modular Reactors (SMR) with two cogeneration technologies: algae-biofuel and desalinisation. Multiple SMR are of particular interest due to the fractional nature of their power output. The result shows that the power required by an algae-biofuel plant is not sufficient to justify the load following approach, whereas it is in the case of desalination. The successive economic analysis, based on the real options approach, demonstrates the economic viability of the desalination in several scenarios. In conclusion, the coupling of SMR with a desalination plant is a realistic solution to perform efficient load following. - Highlights: • Nuclear power plants (NPP) are required to operate in load following mode. • Small modular reactors (SMR) are NPP suitable for cogeneration purposes. • SMR can use cogeneration options to perform the load following. • The paper assesses two cogeneration options: microalgae and desalination. • SMR plus Desalination is suitable from both a technical and economic perspective
Effect of axial loads on implant-supported partial fixed prostheses by strain gauge analysis
Directory of Open Access Journals (Sweden)
Luis Gustavo Oliveira de Vasconcellos
2011-12-01
Full Text Available OBJECTIVES: The present study used strain gauge analysis to perform an in vitro evaluation of the effect of axial loading on 3 elements of implant-supported partial fixed prostheses, varying the type of prosthetic cylinder and the loading points. MATERIAL AND METHODS: Three internal hexagon implants were linearly embedded in a polyurethane block. Microunit abutments were connected to the implants applying a torque of 20 Ncm, and prefabricated Co-Cr cylinders and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n=5. Four strain gauges (SG were bonded onto the surface of the block tangentially to the implants, SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments with a 10 Ncm torque and an axial load of 30 kg was applied at five predetermined points (A, B, C, D, E. The data obtained from the strain gauge analyses were analyzed statistically by RM ANOVA and Tukey's test, with a level of significance of p<0.05. RESULTS: There was a significant difference for the loading point (p=0.0001, with point B generating the smallest microdeformation (239.49 µε and point D the highest (442.77 µε. No significant difference was found for the cylinder type (p=0.748. CONCLUSIONS: It was concluded that the type of cylinder did not affect in the magnitude of microdeformation, but the axial loading location influenced this magnitude.
Test and analysis on impact characteristics evaluation of nuclear fuel packaging loaded on vehicle
International Nuclear Information System (INIS)
The characteristics of impact to transport containers were clarified by collision test and analysis in the case of small packagings, such as UO2 powder transport containers, that are loaded in plural numbers and by theoretical analysis using a spring-mass model of particles model in the case of large packagings, such as the new fuel assembly, that can be handled singly and independently. Principal characteristics are as follows: (1) The crush impact acceleration of containers is about 1/10 approx. 1/3 of 9-m free drop acceleration; (2) the crush impact loading of containers is observed to be smaller than 9-m free drop loading due to the secured buffer absorption. Therefore the crush impact deformation of containers is smaller than the 9-m free drop deformation. Finally, it has been proved that the UO2 powder container is safe at 50 km/h collision in the way of transportation with buffer after confirming the safety of the container by the drop test prescribed in technical standards (regulations). 10 figures, 2 tables
Analysis of transient state in HTS tapes under ripple DC load current
International Nuclear Information System (INIS)
The paper concerns the analysis of transient state (quench transition) in HTS tapes loaded with the current having DC component together with a ripple component. Two shapes of the ripple were taken into account: sinusoidal and triangular. Very often HTS tape connected to a power electronic current supply (i.e. superconducting coil for SMES) that delivers DC current with ripples and it needs to be examined under such conditions. Additionally, measurements of electrical (and thermal) parameters under such ripple excitation is useful to tape characterization in broad range of load currents. The results presented in the paper were obtained using test bench which contains programmable DC supply and National Instruments data acquisition system. Voltage drops and load currents were measured vs. time. Analysis of measured parameters as a function of the current was used to tape description with quench dynamics taken into account. Results of measurements were also used to comparison with the results of numerical modelling based on FEM. Presented provisional results show possibility to use results of measurements in transient state to prepare inverse models of superconductors and their detailed numerical modelling.
Analysis of transient state in HTS tapes under ripple DC load current
Stepien, M.; Grzesik, B.
2014-05-01
The paper concerns the analysis of transient state (quench transition) in HTS tapes loaded with the current having DC component together with a ripple component. Two shapes of the ripple were taken into account: sinusoidal and triangular. Very often HTS tape connected to a power electronic current supply (i.e. superconducting coil for SMES) that delivers DC current with ripples and it needs to be examined under such conditions. Additionally, measurements of electrical (and thermal) parameters under such ripple excitation is useful to tape characterization in broad range of load currents. The results presented in the paper were obtained using test bench which contains programmable DC supply and National Instruments data acquisition system. Voltage drops and load currents were measured vs. time. Analysis of measured parameters as a function of the current was used to tape description with quench dynamics taken into account. Results of measurements were also used to comparison with the results of numerical modelling based on FEM. Presented provisional results show possibility to use results of measurements in transient state to prepare inverse models of superconductors and their detailed numerical modelling.
An Efficient SDN Load Balancing Scheme Based on Variance Analysis for Massive Mobile Users
Directory of Open Access Journals (Sweden)
Hong Zhong
2015-01-01
Full Text Available In a traditional network, server load balancing is used to satisfy the demand for high data volumes. The technique requires large capital investment while offering poor scalability and flexibility, which difficultly supports highly dynamic workload demands from massive mobile users. To solve these problems, this paper analyses the principle of software-defined networking (SDN and presents a new probabilistic method of load balancing based on variance analysis. The method can be used to dynamically manage traffic flows for supporting massive mobile users in SDN networks. The paper proposes a solution using the OpenFlow virtual switching technology instead of the traditional hardware switching technology. A SDN controller monitors data traffic of each port by means of variance analysis and provides a probability-based selection algorithm to redirect traffic dynamically with the OpenFlow technology. Compared with the existing load balancing methods which were designed to support traditional networks, this solution has lower cost, higher reliability, and greater scalability which satisfy the needs of mobile users.
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%.
Directory of Open Access Journals (Sweden)
M. Gowtha Muneswara Rao
2014-05-01
Full Text Available The present research work deals with the micromechanical analysis of fiber reinforced composites with orthotropic fibers under fiber directional tensile loading and transverse directional tensile loading using three-dimensional finite element method. The problem is modeled in ANSYS software and the FE model is validated with bench mark results. Longitudinal Young's modulus and transverse Young's modulus corresponding Poisson's ratios are predicted. Fiber reinforced composite materials are now an important class of an engineering materials. They offer outstanding mechanical properties, unique flexibility in design capabilities, and ease of fabrication. Additional advantages include light weight and corrosion resistance, impact resistance, and excellent fatigue strength. Today fiber composites are routinely used in such diverse applications as automobiles, aircraft, space vehicles, offshore structures, containers and piping, sporting goods, electronics, and appliances.
Directory of Open Access Journals (Sweden)
Assaf Ya'akobovitz
2011-01-01
Full Text Available Following the recent progress in integrating single-wall carbon nanotubes (SWCNTs into silicon-based micro-electromechanical systems (MEMS, new modeling tools are needed to predict their behavior under different loads, including thermal, electrical and mechanical. In the present study, the mechanical behavior of SWCNTs under thermoelectrical loading is analyzed using a large deflection geometrically nonlinear string model. The effect of the resistive heating was found to have a substantial influence on the SWCNTs behavior, including significant enhancement of the strain (up to the millistrains range and buckling due to the thermal expansion. The effect of local buckling sites was also studied and was found to enhance the local strain. The theoretical and numerical results obtained in the present study demonstrate the importance of resistive heating in the analysis of SWCNTs and provide an additional insight into the unique mechanics of suspended SWCNTs.
Status of the ITER full-tungsten divertor shaping and heat load distribution analysis
International Nuclear Information System (INIS)
In September 2011, the ITER Organization (IO) proposed to begin operation with a full-tungsten (W) armoured divertor, with the objective of taking a decision on the final target material (carbon fibre composite or W) by the end of 2013. This period of 2 years would enable the development of a full-W divertor design compatible with nuclear operations, the investigation of further several physics R and D aspects associated with the use of W targets and the completion of technology qualification. Beginning with a brief overview of the reference heat load specifications which have been defined for the full-W engineering activity, this paper will report on the current status of the ITER divertor shaping and will summarize the results of related three-dimensional heat load distribution analysis performed as part of the design validation. (paper)
Performance Analysis of Superstrate Loaded Patch Antenna and Abstain from Environmental Effects
Directory of Open Access Journals (Sweden)
R.K.Yadav
2011-08-01
Full Text Available Present paper demonstrates, the effect of superstrate loading of different constant on the performance behavior of square patch antenna. The optimum design parameters of the antenna are selected to achieve the compact dimensions as well as the best possible characteristics such as high radiation efficiency, high gain, directivity and bandwidth. The proposed antenna structure is fed with50 ohms coaxial cable for impedance matching. HFSS simulation tool has been used for the analysis,which offers multiple state-of the-art solver technologies, each based on the finite element method. The obtained results reveal that superstrate loading do not change only the resonance frequency but also affects the other parameters; gain, directivity and bandwidth. In particular, the resonance frequency lowers and shift in resonant frequency increases with the dielectric constant of superstrates. In addition, it has also been observed that return loss and VSWR increases, however bandwidth and directivity decreases with the dielectric constant of superstrates.
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.
Cyclic Loading of Growing Tissue in a Bioreactor: Mathematical Model and Asymptotic Analysis
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.
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
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.
Cavitation erosion prediction based on analysis of flow dynamics and impact load spectra
International Nuclear Information System (INIS)
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
Stress analysis of the KSTAR vacuum vessel under thermal and electromagnetic loads
International Nuclear Information System (INIS)
One of the principal components of the KSTAR(Korea Superconducting Tokamak Advanced Research) tokamak structure is the vacuum vessel, which acts as the high vacuum boundary for the plasma and also provides the structural support for internal components. Hyundai Heavy Industries Inc. has performed the engineering design of the vacuum vessel. Here the overall configuration of the KSTAR vacuum vessel was briefly described and then the design methodology and the analysis results were presented. The vacuum vessel consists of double walls, several ports, leaf spring style supports. Double walls are separated by reinforcing ribs and filled with baking/shielding water. The overall external dimensions of the main body are 3.39 m high, 1.11 m inner radius, 2.99 m outer radius, and made of SA240-316LN. The vacuum vessel was designed to be capable of achieving the base pressure of 1x10-8 Torr, and also to be structurally capable of sustaining the vacuum pressure, the electromagnetic and thermal loads during plasma disruption and bakeout, respectively. The vacuum vessel will be baked out maximum 150 .deg. C by hot pressurized water through the channels formed between double walls and the reinforcing ribs. A 3-D temperature distribution and the resulting thermal loads in the vessel were calculated during bakeout. It was found that the vacuum vessel and its supports were structurally rigid based on the thermal stress analysis. The maximum electromagnetic loads on the vacuum vessel induced by eddy and halo currents resulting from the engineering plasma radial and vertical disruption scenarios have been estimated. The stress analyses have been performed based on these electromagnetic loads and the resulting stresses at the critical locations of the vacuum vessel were within the allowable stresses
Stress analysis of 500 MWe PHWR calandria non-radial nozzles for external loadings
International Nuclear Information System (INIS)
The 500 MWe Pressurised Heavy Water Reactor (PHWR) calandria is a stainless steel horizontal cylindrical vessel which houses the core of the reactor. It has a number of vertical non-radial nozzles which locate shut down, reactivity control and over pressure relief safety devices. The calandria is designed, fabricated and inspected as per ASME Boiler and Pressure Vessel Code class one component stringent requirements. Model studies of this equipment is carried out to know the stress concentration factors for various thermal and seismic loads transferred through these nozzles. In this experiment nozzles lying in one quadrant of calandria are simulated on a 1:3.2 size model and six types of forces are applied on each nozzle. Total 136 numbers of 3 element strain rosettes have been used in this experiment. The strain data are collected through a 100 channel data recording system and stresses on prototype calandria are predicted for various load cases with the help of a BASIC language rosette analysis program implemented on the microprocessor system of the data logger. The interaction effect between various nozzles is also studied. Comparisons have been made between present experimental results and simplified analytical design calculation (based on Bijlaard's method) along with finite element analysis results of a selected group of 3 nozzles. It is shown that local stresses near an opening decay within a short distance from root of the nozzle and interaction effect on neighbouring nozzles surrounding a loaded nozzles is small. The stress concentration factor data generated can be used by the designer to calculate peak and local stresses on the calandria shell-nozzle junctions of various reactivity devices for all six kinds of nominal thermal and seismic loads. (author). 3 refs., tabs., figs
Mattila, M K
1985-01-01
One requirement for successful occupational health care is reliable information on occupational hazards. The aim of this study was to develop a simple, standardised method for workplace investigations for use in occupational health care. The theoretical framework of the method comprises the stress-strain model, the hazard-danger model, and risk behaviour theory. The new method, termed job load and hazard analysis, includes four stages: identification of hazards, their evaluation, conclusions ...
TRBUCKL - A NASTRAN DMAP ALTER FOR LINEAR BUCKLING ANALYSIS UNDER DYNAMIC LOADING
Aiello, R. A.
1994-01-01
Delaminations near the outer surface of a laminate are susceptible to local buckling and buckling-induced delamination propagation when the laminate is subjected to transverse impact loading. This results in a loss of stiffness and strength. TRBUCKL is an unique dynamic delamination buckling and delamination propagation analysis capability that can be incorporated into the structural analysis program, NASTRAN. This capability will aid engineers in the design of structures incorporating composite laminates. The capability consists of: (1) a modification of the direct time integration solution sequence which provides a new analysis algorithm that can be used to predict delamination buckling in a laminate subjected to dynamic loading; and (2) a new method of modeling the composite laminate using plate bending elements and multipoint constraints. The capability now exists to predict the time at which the onset of dynamic delamination buckling occurs, the dynamic buckling mode shape, and the dynamic delamination strain energy release rate. A procedure file for NASTRAN, TRBUCKL predicts both impact induced buckling in composite laminates with initial delaminations and the strain energy release rate due to extension of the delamination. In addition, the file is useful in calculating the dynamic delamination strain energy release rate for a composite laminate under impact loading. This procedure simplifies the simulation of progressive crack extension. TRBUCKL has been incorporated into COSMIC NASTRAN. TRBUCKL is a DMAP Alter for NASTRAN. It is intended for use only with the COSMIC NASTRAN Direct Transient Analysis (RF 9) solution sequence. The program is available as a listing only. TRBUCKL was developed in 1987.
International Nuclear Information System (INIS)
Oskarshamn 1 is the oldest nuclear plant in operation in Sweden. It was designed and erected at the end of the 1960's. During the last five years an extensive upgrading process of the power plant has been carried out. Within the frame of one of these upgrading projects the outer and inner Main Steam Isolation Valves (MSN) have been replaced. As a consequence of these replacements it was necessary to make an overhaul investigation of the basic general concept regarding pipe rupture descriptions and rupture locations, in order to attain a design of the pipe whip restraints in accordance with requirements of modern standards. In this paper two application examples regarding finite element analysis of concrete containment structures under accident loading conditions are presented. Each example includes a brief introduction of the problem and the object of the commission. The finite element model and the structural response analysis are described and the results are discussed. The application examples are: 1. Non-linear structural analysis of a reinforced concrete culvert affected by internal over-pressurization and impulse load effects of pipe rupture reactions. 2. Non-linear thermal stress analysis around a steel penetration of a reactor containment
International Nuclear Information System (INIS)
Highlights: • Phenomenological uncertainty analysis has been applied to level 2 PSA. • The methodology provides an alternative to simple deterministic analyses and sensitivity studies. • A realistic evaluation provides a more complete characterization of risks. • Uncertain parameters of MAAP code for the early containment failure were identified. - Abstract: This paper illustrates an application of a severe accident analysis code, MAAP, to the uncertainty evaluation of early containment failure scenarios employed in the containment event tree (CET) model of a reference plant. An uncertainty analysis of containment pressure behavior during severe accidents has been performed for an optimum assessment of an early containment failure model. The present application is mainly focused on determining an estimate of the containment building pressure load caused by severe accident sequences of a nuclear power plant. Key modeling parameters and phenomenological models employed for the present uncertainty analysis are closely related to the in-vessel hydrogen generation, direct containment heating, and gas combustion. The basic approach of this methodology is to (1) develop severe accident scenarios for which containment pressure loads should be performed based on a level 2 PSA, (2) identify severe accident phenomena relevant to an early containment failure, (3) identify the MAAP input parameters, sensitivity coefficients, and modeling options that describe or influence the early containment failure phenomena, (4) prescribe the likelihood descriptions of the potential range of these parameters, and (5) evaluate the code predictions using a number of random combinations of parameter inputs sampled from the likelihood distributions
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
Genetic algorithm optimisation of load cell geometry by finite element analysis
Robinson, Gordon M.
1995-01-01
The objective of the work described in this thesis was to numerically model the influence of end-loading conditions on column strain gauge load cells and to develop the model into a program for optimising the geometry of column load cells. It is shown that, for most practical loading conditions, load celis with large numbers of equispaced strain gauges are only sensitive to the axisymmetric components of contact stress distribution. The problem of cylindrical load celis subject to frictio...
Stress Analysis of Laminated Composite Cylinders Under Non-Axisymmetric Loading
Energy Technology Data Exchange (ETDEWEB)
Starbuck, J.M.
1999-10-26
The use of thick-walled composite cylinders in structural applications has seen tremendous growth over the last decade. Applications include pressure vessels, flywheels, drive shafts, spoolable tubing, and production risers. In these applications, the geometry of a composite cylinder is axisymmetric but in many cases the applied loads are non-axisymmetric and more rigorous analytical tools are required for an accurate stress analysis. A closed-form solution is presented for determining the layer-by-layer stresses, strains, and displacements and first-ply failure in laminated composite cylinders subjected to non-axisymmetric loads. The applied loads include internal and external pressure, axial force, torque, axial bending moment, uniform temperature change, rotational velocity, and interference fits. The formulation is based on the theory of anisotropic elasticity and a state of generalized plane deformation along the axis of the composite cylinder. Parametric design trade studies can be easily and quickly computed using this closed-form solution. A computer program that was developed for performing the numerical calculations is described and results from specific case studies are presented.
Reliability analysis of the bulk cargo loading system including dependent components
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.
Markov chain modelling of reliability analysis and prediction under mixed mode loading
Singh, Salvinder; Abdullah, Shahrum; Nik Mohamed, Nik Abdullah; Mohd Noorani, Mohd Salmi
2015-03-01
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.
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.
The analysis of increments of internal damage to wheat grain affected by dynamic loading
International Nuclear Information System (INIS)
An analysis of internal damage increase was performed for samples of winter and spring wheat, for damage caused by dynamic loading. The internal damage increase was determined separately for every kernel, on the basis of its damage status before and after loading. The internal damage status (endosperm cracks) was assessed by means of a damage index calculated on the basis of results of damage identification within the fields of a square grid superimposed on the X-ray image of a kernel analysed. Increase in the mean damage index for a grain sample was adopted as a measure of the vulnerability of the grain sample to damage caused by the load applied. Quantitative and qualitative analyses were performed for the status of damage of the grain samples of the varieties under study. Especially interesting conclusions were formulated analysing the 'damage balance' of the grain samples. The methods used in the study can be applied also in other laboratory studies on damage to cereal grain or to the seeds of certain crop plants, e.g., when studying the effects of the successive stages of their destruction. (author). 3 refs, 6 figs, 1 tab
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.
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
Seismic analysis of new fuel assembly loading machine for China experimental fast reactor
International Nuclear Information System (INIS)
New fuel assembly loading machine of China Experiment Fast Reactor is a kind of kinetic equipment with very complex structure. Many of its motional and driving components can not be simulated exactly by finite element model (FEM). A simplified FEM analysis method was introduced in the paper, and the main frame of the equipment was simulated by a simplified FEM model. Response spectrum analysis method was used to obtain the acceleration response of the main components of the equipment under seismic condition. Theoretical analysis method was used to calculate the stresses of the main connecting bolts, and these bolts were evaluated based the regulations of nuclear codes to ensure the structure integrity of the equipment. (authors)
Space station electrical power distribution analysis using a load flow approach
Emanuel, Ervin M.
1987-01-01
The space station's electrical power system will evolve and grow in a manner much similar to the present terrestrial electrical power system utilities. The initial baseline reference configuration will contain more than 50 nodes or busses, inverters, transformers, overcurrent protection devices, distribution lines, solar arrays, and/or solar dynamic power generating sources. The system is designed to manage and distribute 75 KW of power single phase or three phase at 20 KHz, and grow to a level of 300 KW steady state, and must be capable of operating at a peak of 450 KW for 5 to 10 min. In order to plan far into the future and keep pace with load growth, a load flow power system analysis approach must be developed and utilized. This method is a well known energy assessment and management tool that is widely used throughout the Electrical Power Utility Industry. The results of a comprehensive evaluation and assessment of an Electrical Distribution System Analysis Program (EDSA) is discussed. Its potential use as an analysis and design tool for the 20 KHz space station electrical power system is addressed.
Reliability analysis and prediction of mixed mode load using Markov Chain Model
International Nuclear Information System (INIS)
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
Integrated Vehicle Ground Vibration Testing in Support of Launch Vehicle Loads and Controls Analysis
Askins, Bruce R.; Davis, Susan R.; Salyer, Blaine H.; Tuma, Margaret L.
2008-01-01
All structural systems possess a basic set of physical characteristics unique to that system. These unique physical characteristics include items such as mass distribution and damping. When specified, they allow engineers to understand and predict how a structural system behaves under given loading conditions and different methods of control. These physical properties of launch vehicles may be predicted by analysis or measured by certain types of tests. Generally, these properties are predicted by analysis during the design phase of a launch vehicle and then verified by testing before the vehicle becomes operational. A ground vibration test (GVT) is intended to measure by test the fundamental dynamic characteristics of launch vehicles during various phases of flight. During the series of tests, properties such as natural frequencies, mode shapes, and transfer functions are measured directly. These data will then be used to calibrate loads and control systems analysis models for verifying analyses of the launch vehicle. NASA manned launch vehicles have undergone ground vibration testing leading to the development of successful launch vehicles. A GVT was not performed on the inaugural launch of the unmanned Delta III which was lost during launch. Subsequent analyses indicated had a GVT been performed, it would have identified instability issues avoiding loss of the vehicle. This discussion will address GVT planning, set-up, execution and analyses, for the Saturn and Shuttle programs, and will also focus on the current and on-going planning for the Ares I and V Integrated Vehicle Ground Vibration Test (IVGVT).
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.
Reliability analysis and prediction of mixed mode load using Markov Chain Model
Nikabdullah, N.; Singh, S. S. K.; Alebrahim, R.; Azizi, M. A.; K, Elwaleed A.; Noorani, M. S. M.
2014-06-01
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.
Analysis of the CRBRP part-load conditions using SSC/MINET
International Nuclear Information System (INIS)
The Super System Code (SSC), coupled with the MINET (Momentum Integral Network) Code, was used to determine the plausibility of these postulated plant conditions, particularly with regard to whether the heat exchangers have sufficient heat transfer area for these conditions to prevail. The SSC/MINET representation of the Clinch River Plant used for the part load study is shown. SSC was used to analyze the reactor, the primary loop, and most of the intermediate loop. MINET was used for the rest of the CRBRP system. The analysis relies primarily on energy balances (SSC), an established package of heat transfer correlations (SSC and MINET), and two steady state momentum integral network solvers
Wind loads analysis at the anchorages of the Talavera de la Reina cable stayed bridge
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L. Rosa
2014-06-01
Full Text Available This paper describes wind tunnel tests performed on wind tunnel models of the Talavera de la Reina cable stayed bridge. The work describes the aeroelastic model construction and it is focused on the evaluation and analysis of the mean and peak wind loads at the tower foundation and the cable anchorages since these data can be very useful by the bridge manufacturer as a support for the bridge design. The work is part of a complete wind tunnel study carried out to analyze the aeroelastic stability of the bridge.
Analysis of piles in residual soil from granite considering residual loads
da Fonseca, AV; dos Santos, JA; Esteves, EC; F. Massad
2007-01-01
The paper deals with the analysis of static loading tests carried out in 3 different types of piles: bored piles with temporary casing, continuous flight auger, CFA, piles (bored and CFA piles with circular section - nominal diameter Ø600 mm) and driven piles (with square section - width 350 mm). These piles were installed in the CEFEUP/ISC2 experimental site, located in the Campus of the Faculty of Engineering of the University of Porto (Portugal), in a contact zone between the gneissic rock...
Analysis of DESY-Flash LLRF Measurements for the ILC Heavy Beam Loading Test
Energy Technology Data Exchange (ETDEWEB)
Cancelo, Gustavo; Chase, Brian; Davidsaver, Michael; /Fermilab; Carwardine, J.; /Argonne; Simrock, Stefan; Ayvazyan, Valeri; Grecki, Mariusz; /DESY; Matsumoto, Toshihiro; Michizono, Shinichiro; /KEK, Tsukuba
2009-06-01
In September 2008 the DESY-FLASH accelerator was run with up to 550, 3 nano-coulomb bunches at 5 Hz repetition rate. This test is part of a longer-term study aimed at validating ILC parameters by operation as close as possible to ILC beam currents and RF gradients. The present paper reports on the analysis that has been done in order to understand the RF control system performance during this test. Actual klystron power requirements and beam stability are evaluated with heavy beam loading conditions. Results include suggested improvements for upcoming tests in 2009.
Comparative analysis of pulse shape discrimination methods in a 6Li loaded plastic scintillator
International Nuclear Information System (INIS)
Three algorithms for discriminating between fast neutrons, thermal neutrons and gamma rays in a 6Li 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
FE analysis of unstiffened and stiffened corrugated panels subjected to blast loading
International Nuclear Information System (INIS)
This paper presents the results of a dynamic analysis on unstiffened and stiffened corrugated panels subjected to hydrocarbon explosion. A parametric study is also conducted on simplified models of the stiffened corrugated panels considering the effect of stiffeners on the compressive flange under different loading levels. The 1/2 symmetry of corrugated panels is modeled. This numerical study is performed using NX Nastran version 7.5. The unstiffened panel produces localized buckling at the center of corrugation and large permanent deformation by increasing the peak pressure. The stiffened panels suppress the structural response, and the vee stiffeners are structurally more effective than the round ones
Analysis of DESY-Flash LLRF Measurements for the ILC Heavy Beam Loading Test
International Nuclear Information System (INIS)
In September 2008 the DESY-FLASH accelerator was run with up to 550, 3 nano-coulomb bunches at 5 Hz repetition rate. This test is part of a longer-term study aimed at validating ILC parameters by operation as close as possible to ILC beam currents and RF gradients. The present paper reports on the analysis that has been done in order to understand the RF control system performance during this test. Actual klystron power requirements and beam stability are evaluated with heavy beam loading conditions. Results include suggested improvements for upcoming tests in 2009.
Meshless Analysis of Laminated Composite and Sandwich Plates Subjected to Various Types of Loads
Singh, Jeeoot; Singh, Sandeep; Shukla, K. K.
2014-03-01
The bending analysis of laminated composite and sandwich plates using different radial basis functions and higher-order shear deformation theory is presented. This meshfree technique is insensitive to spatial dimension and considers only a cloud of nodes (centers) for the spatial discretization of both the problem domain and the boundary. Numerical results for simply supported isotropic, symmetric cross-ply composite and sandwich plate are presented. The results are compared with other available results. It is observed that convergence of the polynomial function is faster as compared to other radial basis functions, whereas Gaussian function takes the least solution time. The effect of various types of loadings on sandwich plate is presented.
Considerations concerning the analysis of NPP structures subjected to blast loading
International Nuclear Information System (INIS)
Basic features of the loads induced on structures by air blasts are described in IAEA Design Guide NS-G-1.5 (2003) in terms of a normalized distance that takes into account the amount and type of explosive charge. The guide presents charts that allow the determination of the peak value of the incident pressure, the total impulse of the positive phase and other relevant design parameters, which are generally used for design or verification purposes of sensitive nuclear structures. For the determination of the resulting actions on structures subjected to a specified blast event, the load-time functions induced by the incident pressure wave must next be evaluated, as discussed for example by Kinney and Graham. The authors note that a number of models are available for such purpose, such as Zaslavskii et al., which lead to different predictions and raise the issue of model uncertainty in this problem. In this paper, the uncertainties expected in the various stages of the process are examined in connection with the analysis of the air vent stack of a NPP presently under design. The spatial and temporal pressure distributions induced at the site by the blast were determined by means of a finite element model that simulates the shock wave propagation considering the topographical features of the site and the main structures of the NPP. The numerically determined pressures are compared with the IAEA design guide recommendations. Next, the loads induced in the air vent stack by the shock wave as well as the dynamic response of the stack are determined employing several models. The validity of commonly accepted assumptions in the determination of the response of structures to blast loading is finally discussed
Mechanical analysis of the EC upper launcher with respect to electromagnetic loads
Energy Technology Data Exchange (ETDEWEB)
Vaccaro, A. [Forschungszentrum Karlsruhe, Association FZK-Euratom, Institute for Material Research I, D-76021 Karlsruhe (Germany)], E-mail: Alessandro.Vaccaro@imf.fzk.de; Kleefeldt, K.; Spaeh, P.; Strauss, D. [Forschungszentrum Karlsruhe, Association FZK-Euratom, Institute for Material Research I, D-76021 Karlsruhe (Germany)
2009-06-15
The design of the EC upper launcher for ITER approaches maturity and thus it needs to be qualified with respect to the critical loads. One major source of critical loads are eddy currents, which are induced in the structure during plasma instabilities, of which the most severe conditions may happen during a vertical displacement event (VDE) followed by a fast current quench. High mechanical loads are then acting on the front end of the cantilevered launcher structure as a consequence of the interaction between the static toroidal field and the eddy currents. The EC upper launcher has a length of about 6 m and the nominal gap to the neighbouring components is 20 mm. The targeted limit for the launcher displacements is 10 mm, when accounting for tolerances in manufacturing, positioning and thermal displacement. The conceptual design of the launcher is at risk to miss this requirement, thus different configurations of the main frame are considered and analysed. Especially, the cross-section of the single wall segment has been varied to identify the most efficient strategy for increasing the stiffness of the structure. For this purpose, the mechanical loads from an upward VDE (linear current decay from 15 to 0 MA within 40 ms) are used as input to a finite element analysis with the ANSYS software tool. The displacement at the free plasma facing end of the launcher is calculated and analyzed. Its main component is in toroidal direction and the effort of mitigation is concentrated primarily on the bottom-wall. The approach satisfies the limitations given by the space requests of the mm-wave system which is to be integrated into the port plug.
The effect of meteorological data on atmospheric pressure loading corrections in VLBI data analysis
Balidakis, Kyriakos; Glaser, Susanne; Karbon, Maria; Soja, Benedikt; Nilsson, Tobias; Lu, Cuixian; Anderson, James; Liu, Li; Andres Mora-Diaz, Julian; Raposo-Pulido, Virginia; Xu, Minghui; Heinkelmann, Robert; Schuh, Harald
2015-04-01
Earth's crustal deformation is a manifestation of numerous geophysical processes, which entail the atmosphere and ocean general circulation and tidal attraction, climate change, and the hydrological circle. The present study deals with the elastic deformations induced by atmospheric pressure variations. At geodetic sites, APL (Atmospheric Pressure Loading) results in displacements covering a wide range of temporal scales which is undesirable when rigorous geodetic/geophysical analysis is intended. Hence, it is of paramount importance that the APL signal are removed at the observation level in the space geodetic data analysis. In this study, elastic non-tidal components of loading displacements were calculated in the local topocentric frame for all VLBI (Very Long Baseline Interferometry) stations with respect to the center-of-figure of the solid Earth surface and the center-of-mass of the total Earth system. The response of the Earth to the load variation at the surface was computed by convolving Farrell Green's function with the homogenized in situ surface pressure observations (in the time span 1979-2014) after the subtraction of the reference pressure and the S1, S2 and S3 thermal tidal signals. The reference pressure was calculated through a hypsometric adjustment of the absolute pressure level determined from World Meteorological Organization stations in the vicinity of each VLBI observatory. The tidal contribution was calculated following the 2010 International Earth Rotation and Reference Systems Service conventions. Afterwards, this approach was implemented into the VLBI software VieVS@GFZ and the entirety of available VLBI sessions was analyzed. We rationalize our new approach on the basis that the potential error budget is substantially reduced, since several common errors are not applicable in our approach, e.g. those due to the finite resolution of NWM (Numerical Weather Models), the accuracy of the orography model necessary for adjusting the former as
Analysis of the role of PCNA-DNA contacts during clamp loading
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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
International Nuclear Information System (INIS)
To investigate relevance of the definition of the reference stress to estimate J and C* for surface crack problems, this paper compares FE J and C* results for surface cracked pipes with those estimated according to the reference stress approach using various definitions of the reference stress. Pipes with part circumferential inner surface crack and finite internal axial crack are considered, subject to internal pressure and global bending. The crack depth and aspect ratio are systematically varied. The reference stress is defined in four different ways using (I) the local limit load, (II) the global limit load, (III) the global limit load determined from the FE limit analysis, and (IV) the optimised reference load. It is found that the reference stress based on the local limit load gives overall excessively conservative estimates of J and C*. Use of the global limit load clearly reduces the conservatism, compared to that of the local limit load, although it can provide sometimes non-conservative estimates of J and C*. The use of the FE global limit load gives overall non-conservative estimates of J and C*. The reference stress based on the optimised reference load gives overall accurate estimates of J and C*, compared to other definitions of the reference stress. Based on the present finding, general guidance on the choice of the reference stress for surface crack problems is given
RF-thermal-structural-RF coupled analysis on a travelling wave disk-loaded accelerating structure
International Nuclear Information System (INIS)
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. (authors)
Uncertainty analysis on simple mass balance model to calculate critical loads for soil acidity
International Nuclear Information System (INIS)
Simple mass balance equations (SMBE) of critical acid loads (CAL) in forest soil were developed to assess potential risks of air pollutants to ecosystems. However, to apply SMBE reliably at large scales, SMBE must be tested for adequacy and uncertainty. Our goal was to provide a detailed analysis of uncertainty in SMBE so that sound strategies for scaling up CAL estimates to the national scale could be developed. Specifically, we wanted to quantify CAL uncertainty under natural variability in 17 model parameters, and determine their relative contributions in predicting CAL. Results indicated that uncertainty in CAL came primarily from components of base cation weathering (BCw; 49%) and acid neutralizing capacity (46%), whereas the most critical parameters were BCw base rate (62%), soil depth (20%), and soil temperature (11%). Thus, improvements in estimates of these factors are crucial to reducing uncertainty and successfully scaling up SMBE for national assessments of CAL. - A comprehensive uncertainty analysis, with advanced techniques and full list and full value ranges of all individual parameters, was used to examine a simple mass balance model and address questions of error partition and uncertainty reduction in critical acid load estimates that were not fully answered by previous studies
OPTIMAL PLACEMENT OF DSTATCOM AND LOAD FLOW ANALYSIS OF RADIAL DISTRIBUTION NETWORKS
Directory of Open Access Journals (Sweden)
M.MANOHARA
2012-06-01
Full Text Available This paper presents the modeling of shunt Distribution FACT device in load flow analysis for the steady state voltage compensation and loss minimizations. For this purpose, Distribution STATCOM (D-STATCOM isconsidered as shunt compensator. An accurate model for this device is derived to use in load flow analysis. The rating of this device as well as direction of reactive power injection required to compensate voltage to the desired value (1 p.u are derived and discussed analytically and mathematically using phasor diagrams. Sinceperformance of D-STATCOM varies when it reach to the maximum capacity, modeling of this compensator in the maximum rating of reactive power injection are derived and discussed. The validity of proposed model for fixed compensation and compensation for fixed voltage is examined using MATLAB coding for two IEEE standard distribution systems consisting of 33 and 69 nodes respectively. The best location of D-STATCOM using Rate of under Voltage Mitigation node (RUVMN in the distribution network is determined.
Leclère, Quentin; Ablitzer, Frédéric; Pézerat, Charles
2015-09-01
The paper aims to combine two objectives of the Force Analysis Technique (FAT): vibration source identification and material characterization from the same set of measurement. Initially, the FAT was developed for external load location and identification. It consists in injecting measured vibration displacements in the discretized equation of motion. Two developments exist: FAT and CFAT (Corrected Force Analysis Technique) where two finite difference schemes are used. Recently, the FAT was adapted for the identification of elastic and damping properties in a structure. The principal interests are that the identification is local and allows mapping of material characteristics, the identification can be made at all frequencies, especially in medium and high frequency domains. The paper recalls the development of FAT and CFAT on beams and plates and how it can be possible to extract material characteristics in areas where no external loads are applied. Experimental validations are shown on an aluminum plate with arbitrary boundary conditions, excited by a point force and where a piece of foam is glued on a sub-surface of the plate. Contactless measurements were made using a scanning laser vibrometer. The results of FAT and CFAT are compared and discussed for material property identifications in the regions with and without foam. The excitation force identification is finally made by using the identified material properties. CFAT gives excellent results comparable to a direct measurement obtained by a piezoelectric sensor. The relevance of the corrected scheme is then underlined for both source identification and material characterization from the same measurements.
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.)
Numerical Analysis on Protecting Performance of Layered Arch Structures Subjected to Blast Loading
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Dong Yongxiang
2009-03-01
Full Text Available Dynamic responses of layered arch structure composed of different materials subjected to blast loading are analysed by numerical simulation. The deflection, the particle velocity and the particle acceleration of the arch inwall and stress curves versus time are obtained comparing properties of blast resistance of different arch structures with the same amount of charge. The results show that the arch structure composed of foam concrete-SFRC-steel has good blast resistance. furthermore, the dynamic performance of the foam concrete-SFRC-steel composite structures is studied with different amount of charge. Additionally, coupling relationship of blast resistance and explosion charge is analysed. Comparison of numerical results with experimental results, show that they are in good agreement. This numerical analysis may provide important guidance for blastresistant design and analysis of underground structures.Defence Science Journal, 2009, 59(2, pp.131-136, DOI:http://dx.doi.org/10.14429/dsj.59.1500
Wang, L. F.; Lin, Y. Z.; Higo, T.
2002-04-01
In order to obtain high luminosity and energy efficiency in future linear colliders, most designs for e + and e - collisions in the TeV range will use multi-bunch operation. Therefore, the study of higher order modes excited by previous bunches in the train becomes very important for the optimal design of the accelerator components. Many designs have used tapered disk-loaded waveguides for acceleration. Various numerical methods have been used for the modal analysis of the structure. In this paper, a high-precision eigenmode-computation analysis based on a variational method will be discussed. It allows for rounding the edge of a disk hole without any approximation in shape treatment and calculates the exactly synchronous modes. It converges much faster than the mesh-based computer code SUPERFISH. Good agreement was observed between the results of the variational method and those of other methods.
Wang, L F; Higo, T
2002-01-01
In order to obtain high luminosity and energy efficiency in future linear colliders, most designs for e sup + and e sup - collisions in the TeV range will use multi-bunch operation. Therefore, the study of higher order modes excited by previous bunches in the train becomes very important for the optimal design of the accelerator components. Many designs have used tapered disk-loaded waveguides for acceleration. Various numerical methods have been used for the modal analysis of the structure. In this paper, a high-precision Eigenmode-computation analysis based on a variational method will be discussed. It allows for rounding the edge of a disk hole without any approximation in shape treatment and calculates the exactly synchronous modes. It converges much faster than the mesh-based computer code SUPERFISH. Good agreement was observed between the results of the variational method and those of other methods.
Coupled Loads Analysis of the Modified NASA Barge Pegasus and Space Launch System Hardware
Knight, J. Brent
2015-01-01
A Coupled Loads Analysis (CLA) has been performed for barge transport of Space Launch System hardware on the recently modified NASA barge Pegasus. The barge re-design was facilitated with detailed finite element analyses by the ARMY Corps of Engineers - Marine Design Center. The Finite Element Model (FEM) utilized in the design was also used in the subject CLA. The Pegasus FEM and CLA results are presented as well as a comparison of the analysis process to that of a payload being transported to space via the Space Shuttle. Discussion of the dynamic forcing functions is included as well. The process of performing a dynamic CLA of NASA hardware during marine transport is thought to be a first and can likely support minimization of undue conservatism.
Analysis and behaviour of FRP-confined short concrete columns subjected to eccentric loading
Institute of Scientific and Technical Information of China (English)
无
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.
Shakedown and ratchetting under tension-torsion loadings: analysis and experiments
International Nuclear Information System (INIS)
Structural design analyses are conducted with the aim of verifying the exclusion of ratchetting. To this end it is important to make a clear distinction between the shakedown range and the ratchetting range. The performed experiment comprised a hollow tension specimen which was subjected to alternating axial forces, superimposed with constant moments. First, a series of uniaxial tests has been carried out in order to calibrate a bounded kinematic hardening rule. The load parameters have been selected on the basis of previous shakedown analyses with the PERMAS code using a kinematic hardening material model. It is shown that this shakedown analysis gives reasonable agreement between the experimental and the numerical results. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis
Shakedown and ratchetting under tension-torsion loadings: analysis and experiments
Energy Technology Data Exchange (ETDEWEB)
Heitzer, M. E-mail: m.heitzer@fz-juelich.de; Staat, M.; Reiners, H.; Schubert, F
2003-10-01
Structural design analyses are conducted with the aim of verifying the exclusion of ratchetting. To this end it is important to make a clear distinction between the shakedown range and the ratchetting range. The performed experiment comprised a hollow tension specimen which was subjected to alternating axial forces, superimposed with constant moments. First, a series of uniaxial tests has been carried out in order to calibrate a bounded kinematic hardening rule. The load parameters have been selected on the basis of previous shakedown analyses with the PERMAS code using a kinematic hardening material model. It is shown that this shakedown analysis gives reasonable agreement between the experimental and the numerical results. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis.
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.
Lovejoy, Andrew E.; Hilburger, Mark W.
2013-01-01
This document outlines a Modeling and Analysis Plan (MAP) to be followed by the SBKF analysts. It includes instructions on modeling and analysis formulation and execution, model verification and validation, identifying sources of error and uncertainty, and documentation. The goal of this MAP is to provide a standardized procedure that ensures uniformity and quality of the results produced by the project and corresponding documentation.
International Nuclear Information System (INIS)
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
Energy Technology Data Exchange (ETDEWEB)
Kennedy, R.P.; Campbell, R.D.; Narver, R.B.
1978-05-01
The objective of this study is to demonstrate that for structures subjected to short duration load time histories, the dynamically computed stress obtained from linear elastic analysis should be permitted to significantly exceed code specified stress limits (e.g., ASME code limits) which are applicable for static loads. An approximate two-dimensional model of the Mark I vent header subjected to pool swell impact load is used for this demonstration. A series of nonlinear static and dynamic analyses are performed until collapse is calculated for both static and dynamic application of the load. The static collapse load is compared to the static load corresponding to an elastically calculated code specified stress limit and the static reserve margin against collapse, R/sub S/, is defined for this stress limit. Similarly, the dynamic reserve margin against collapse, R/sub D/, is defined by the ratio of the dynamic collapse load to the dynamic load corresponding to the same elastically calculated stress limit.
International Nuclear Information System (INIS)
The objective of this study is to demonstrate that for structures subjected to short duration load time histories, the dynamically computed stress obtained from linear elastic analysis should be permitted to significantly exceed code specified stress limits (e.g., ASME code limits) which are applicable for static loads. An approximate two-dimensional model of the Mark I vent header subjected to pool swell impact load is used for this demonstration. A series of nonlinear static and dynamic analyses are performed until collapse is calculated for both static and dynamic application of the load. The static collapse load is compared to the static load corresponding to an elastically calculated code specified stress limit and the static reserve margin against collapse, R/sub S/, is defined for this stress limit. Similarly, the dynamic reserve margin against collapse, R/sub D/, is defined by the ratio of the dynamic collapse load to the dynamic load corresponding to the same elastically calculated stress limit
Fatigue analysis of corroded pipelines subjected to pressure and temperature loadings
International Nuclear Information System (INIS)
In this paper a methodology for the fatigue analysis of pipelines containing corrosion defects is proposed. This methodology is based on the nominal stresses from a Global Analysis using a one-dimensional Finite Element (FE) model of the pipeline together with the application of stress concentration factors (SCFs). As the stresses may exceed the yielding limit in the corrosion defects, the methodology also adopts a strain-life approach (ε–N method) which is capable of producing less conservative fatigue lives than the stress-based methods. In addition the proposed methodology is applied in the assessment of the fatigue life of an onshore-hot pipeline containing corrosion pits and patches. Five corrosion pits and five corrosion patches with different sizes are considered. The corrosion defects are situated on the external surface of the pipeline base material. The SCFs are calculated using solid FE models and the fatigue analyses are performed for an out-of-phase/non-proportional (NP) biaxial stresses related to the combined loading (internal pressure and temperature) variations caused by an intermittent operation with hot heavy oil (start-up and shut-down). The results show that for buried pipelines subjected to cyclic combined loadings of internal pressure and temperature fatigue may become an important failure mode when corroded pipeline segments are left in operation without being replaced. -- Highlights: • An ε–N methodology for the fatigue life assessment of corroded pipelines is proposed. • The methodology includes: global analysis, stress amplification, and strain life calculation. • Different-size corrosion patches and pits on the external surface of the pipeline were analyzed. • It's shown that fatigue is a concern when corroded pipeline segments operate for many years
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%.
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.
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.
Structural Load Analysis of a Wind Turbine under Pitch Actuator and Controller Faults
International Nuclear Information System (INIS)
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
User`s Guide for the NREL Force and Loads Analysis Program. Version 2.2
Energy Technology Data Exchange (ETDEWEB)
Wright, A D
1992-08-01
The following report gives the reader an overview of and instructions on the proper use of the National Renewable Energy Laboratory Force and Loads Analysis Program (FLAP, version 2.2). It is intended as a tool for prediction of rotor and blade loads and response for two- or three-bladed rigid hub wind turbines. The effects of turbulence are accounted for. The objectives of the report are to give an overview of the code and also show the methods of data input and correct code execution steps in order to model an example two-bladed rigid hub turbine. A large portion of the discussion (Sections 6.0, 7.0, and 8.0) is devoted to the subject of inputting and running the code for wind turbulence effects. The ability to include turbulent wind effects is perhaps the biggest change in the code since the release of FLAP version 2.01 in 1988. This report is intended to be a user`s guide. It does not contain a theoretical discussion on equations of motion, assumptions, underlying theory, etc. It is intended to be used in conjunction with Wright, Buhl, and Thresher (1988).
Preliminary analysis of a large 1600 MWe PWR core loaded with 30% MOX fuel
International Nuclear Information System (INIS)
The paper presents a full-core 3-D analysis of the performances of a large 1600 MWe PWR core, loaded with 30% MOX fuel, in accordance with the European Utility Requirements (EUR). These requirements state that the European next generation power plants have to be designed capable to use MOX (UO2 - PuO2) fuel assemblies up to 50% of the core, together with UO2 fuel assemblies. The use of MOX assemblies has a significant impact on key physic parameters and on safety. A lot of studies have been carried out in the past to explore the feasibility of plutonium recycling strategies by loading LWR reactors with MOX fuel. Many of these works were based on lattice codes, in order to perform detailed analyses of the neutronic characteristics of MOX assemblies. With the aim to take into account their interaction with surrounding UO2 fuel elements, and the global effects on the core at operational conditions, an integrated approach making use of a 3-D core simulation is required. In this light, the present study adopts the state-of-art numerical models CASMO-5 and SIMULATE-3 to analyze the behavior of the core fueled with 30% MOX and to compare it with that of a large PWR reference core, fueled with UO2. (author)
Institute of Scientific and Technical Information of China (English)
Changguo Wang; Huifeng Tan; Xingwen Du
2009-01-01
This paper extends Le van's work to the case of nonlinear problem and the complicated configuration. The wrinkling stress distribution and the pressure effects are also included in our analysis. Pseudo-beam method is presented based on the inflatable beam theory to model the inflatable structures as a set of inflatable beam elements with a pre-stressed state. In this method, the discretized nonlinear equations are given based upon the virtual work principle with a 3-node Timoshenko's beam model. Finite element simulation is performed by using a 3-node BEAM189 element incorporating ANSYS nonlinear program. The pressure effect is equivalent included in our method by modifying beam element cross-section parameters related to pressure. A benchmark example, the bending case of an inflatable cantilever beam, is performed to verify the accuracy of our pro-posed method. The comparisons reveal that the numerical results obtained with our method are close to open published analytical and membrane finite element results. The method is then used to evaluate the whole buckling and the load-carrying characteristics of an inflatable support frame subjected to a compression force. The wrinkling stress and region characteristics are also shown in the end. This method gives better convergence characteristics, and requires much less computation time. It is very effective to deal with the whole load-carrying ability analytical problems for large scale inflatable structures with complex configuration.
Structural Load Analysis of a Wind Turbine under Pitch Actuator and Controller Faults
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.
Analysis of concrete targets with different kinds of reinforcements subjected to blast loading
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.
Norwood, D. S.; Shuart, Mark J.; Herakovich, Carl T.
1991-01-01
An analytical study of interlaminar stresses in unsymmetrically laminated plates is presented. The study examines the linear elastic, large deflection response of square laminated composite plates subjected to uniform thermal loading. Both cross-ply and angle-ply, symmetric and unsymmetric, laminates are examined to evaluate the effects of mismatch between adjacent layers in elastic constants and coefficients of thermal expansion. A geometrically nonlinear kinematic description is used to predict the large out-of-plane (transverse) deflections. The nonlinear, three-dimensional boundary value problems are formulated from elasticity theory and approximate solutions are determined using the finite element method. A global/local analysis procedure is used to obtain improved free edge stress predictions. For the laminates and loading conditions considered, the results indicate that the out-of-plane deflections of the unsymmetric laminates reduce interlaminar shear stresses. These deflections also reduce interlaminar normal stresses in some laminates and increase these stresses for others. The results indicate that as the out-of-plane deflections become large, the differences in interlaminar stress predictions between linear and nonlinear theory can become quite large.
Analysis of drain pumping system for nuclear power plants under transient turbine loads
International Nuclear Information System (INIS)
Many nuclear stations do not incorporate deaerators in their feedwater heating systems. To attain high turbine cycle performance without a deaerator, a drain pumping system is widely used for returning hot drains from the high-pressure heaters to the feedwater system. With a greatly increased feedwater flow for nuclear units, together with the drain pumping system being moved to a higher extraction point, the heater--drain tank system will be subject to a rapid pressure decay under turbine load rejections. In addition, the drain pump suction flow reduces considerably, thereby increasing the suction pipe resident time. It is these critical changes in operating conditions that should receive careful consideration in drain pumping system design. An analytical approach is presented for determining drain tank pressure decay, drain pump suction pressure decay, and transient behavior of the heater--drain tank system based on analysis of closed feedwater heater performance and the varying feedwater temperature entering the heater under turbine load rejections. The emphasis is placed on adequate and optimum design of a drain pumping system, including a discussion of some design criteria to be followed, as well as sizing of the pressure equalizer between heater and drain tank. All mathematical equations required for determining the design parameters are derived. Finally, some example calculations are given to illustrate the application of the developed analytical approach to system design
Ximénez, Carmen
2016-01-01
This article extends previous research on the recovery of weak factor loadings in confirmatory factor analysis (CFA) 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 c...
International Nuclear Information System (INIS)
Background: Synchrotron Radiation X-ray fluorescence analysis is an advanced method of quantitative elemental analysis. It is a scientific platform for life science, material science, and environmental science. Purpose: In this present study, the drug loading behavior of dendrimers nano-vectors was investigated by using the method of Synchrotron Radiation X-ray fluorescence analysis. Methods: The copper (Ⅱ) ions were loaded into acetyl-modified generation 5(G5) PAMAM dendrimers. We monitored and imaged the distribution of copper in A549 cell by Shanghai Synchrotron Radiation Facility (SSRF) to observe the cellular uptake of copper-dendrimers conjugates. Results: The results of hard X-ray fluorescence mapping showed a stronger fluorescence of Cu in the cells treated with G5-Ac-Cu than that of control. Conclusions: This investigation provided a method of using synchrotron radiation X-ray fluorescence analysis to study the drug loading behavior of dendrimers. (authors)
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.
Sammer, G
1998-05-01
In the investigation of heart rate and heart rate variability, the discrimination between mental workload, physical activity and respiration is known to be methodologically difficult. At most, heart rate variability measures are more likely to be coarse-grained measures with variability confounded by heart rate. Moreover, the spectral analysis of heart rate variability shows broad-band frequency characteristics, pointing towards non-stationarity or non-linearity. From this it is suggested to focus on non-linear dynamic analyses that are variance-insensitive. The experimental section of the paper focuses on the estimation of two non-linear measures for both heartbeat dynamics and respiration, the correlation dimension indicating complexity and the Lyapunov exponents indicating predictability. The results indicate that the complexity of heart dynamics is related to the type of task and that the predictability of heart dynamics is related to the amount of load. PMID:9613233
Stoll, Frederick; Gurdal, Zafer; Starnes, James H., Jr.
1991-01-01
A method was developed for the geometrically nonlinear analysis of the static response of thin-walled stiffened composite structures loaded in uniaxial or biaxial compression. The method is applicable to arbitrary prismatic configurations composed of linked plate strips, such as stiffened panels and thin-walled columns. The longitudinal ends of the structure are assumed to be simply supported, and geometric shape imperfections can be modeled. The method can predict the nonlinear phenomena of postbuckling strength and imperfection sensitivity which are exhibited by some buckling-dominated structures. The method is computer-based and is semi-analytic in nature, making it computationally economical in comparison to finite element methods. The method uses a perturbation approach based on the use of a series of buckling mode shapes to represent displacement contributions associated with nonlinear response. Displacement contributions which are of second order in the model amplitudes are incorported in addition to the buckling mode shapes. The principle of virtual work is applied using a finite basis of buckling modes, and terms through the third order in the model amplitudes are retained. A set of cubic nonlinear algebraic equations are obtained, from which approximate equilibrium solutions are determined. Buckling mode shapes for the general class of structure are obtained using the VIPASA analysis code within the PASCO stiffened-panel design code. Thus, subject to some additional restrictions in loading and plate anisotropy, structures which can be modeled with respect to buckling behavior by VIPASA can be analyzed with respect to nonlinear response using the new method. Results obtained using the method are compared with both experimental and analytical results in the literature. The configurations investigated include several different unstiffened and blade-stiffening panel configurations, featuring both homogeneous, isotropic materials, and laminated composite
An Analysis of Mongolian Culture-Loaded Words and Their Translation Strategies
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…
Structural analysis of the ITER vacuum vessel from disruption loading with halo asymmetry
International Nuclear Information System (INIS)
Static structural analyses of the ITER vacuum vessel were performed with toroidally asymmetric disruption loads. Asymmetric halo current conditions were assumed to modify symmetric disruption loads which resulted in net lateral loading on the vacuum vessel torus. Structural analyses with the asymmetric loading indicated significantly higher vessel stress and blanket support forces than with symmetric disruption loads. A recent change in the vessel support design which provided toroidal constraints at each mid port was found to be effective in reducing torus lateral movement and vessel stress
Mayer, John P.; Hamer, Harold A.
1961-01-01
Power spectral densities of normal load factor have been obtained for two service operational training flights of a Republic F-84G airplane and three service operational training flights of a North American F-86A airplane in order to indicate the load-factor frequency content and possible uses of power spectral methods in analyzing maneuver load data. It was determined that the maneuvering load-factor time histories appeared to be described by a truncated normal distribution. The power spectral densities obtained were relatively level at frequencies below 0.03 cycle per second and varied inversely with approximately the cube of the frequency at the higher frequencies. In general, the frequency content was very low above 0.2 cycle per second. The load-factor peak distributions were estimated fairly well from the spectrum analysis. In addition, peak load data obtained during service operations of fighter-type airplanes with flight time totaling about 24,000 hours were examined and appeared to agree reasonably well with the type of equations obtained from spectrum peak-load distributions.
The Analysis of the Effect of Coolant Channel Width on Fuel Loading of the RSG-GAS Core
International Nuclear Information System (INIS)
The RGS-GAS using uranium silicide fuel, plate type and 250 g U of loading is planned to increase the fuel loading to 300 g U even to 400 g U. The silicide fuel has advantages when increase the fuel loading in the same volume. Because of that case, it is necessary to analyze the effect of coolant channel width on fuel loading of the RSG-GAS core. Analyzing the effect the work which done is to generate cell and core calculation using WIMSD/4 and Batan-2DIFF codes. The WIMSD/4 code is used to generate cross section of core material and Batan-2DIFF is used to calculate the effective multiplication factor. The model that used in this calculation there are three kind of fuel loading namely, 250 g U, 300 g U and 400 g U. The coolant channel width is simulated from 1.75 mm to 2.55 mm. From that fuel loadings, it is analyzed which coolant channel width gave the best effective multiplication factor. From result of analysis showed that the best effective multiplication factor is on the coolant channel width of 2.55 mm for third of fuel loadings. (author)
Analysis of changes in bone cement damping factor and its effect on bone load
Directory of Open Access Journals (Sweden)
P. Postawa
2007-07-01
Full Text Available Purpose: The article presents the results of simulations and material-related investigations for bone cement used for alloplasty of hip joint. Mechanical properties of bone cements are of key importance for a successful surgery and further use of the joint as well as its behaviour during complex load which appears during patient’s walk.Design/methodology/approach: One of the methods of thermal analysis for polymeric materials has been used for investigations. DMTA method is based on the analysis of the signal (reaction from the deformed material under particular conditions, at the changeable ambient temperature as well as frequency and amplitude of vibrations. DMTA thermograms give information on change in storage modulus E’ and the mechanical loss factor tgδ, which is responsible for dissipation of energy during deformation.Findings: During simulation investigations ADINA engineering environment has been used; it enabled, at the assumed boundary and initial conditions, to assess the stress which appears in individual cross-sections of the analysed bone and the implant fixed by means of bone cement. During the analysis the cross-sections have been presented and the values of the stress which appears in individual zones have been determined.Research limitations/implications: Due to high complexity, only the results of simulation software have been used, clinic trials will be possible not before thorough check and analysis of the obtained results.Practical implications: Practical application of the results of the investigations described in this paper will be possible after long and comprehensive clinical trials.Originality/value: Original value of this paper are the results of tests since such an analysis has never been conducted by scientific environment working on this subject.
An analysis on the load balancing strategies in wavelength-routed optical networks
Liu, Kai; Fu, Minglei; Le, Zichun
2008-11-01
Routing and wavelength assignment (RWA) is one of the key issues in the wavelength-routed optical networks. Although some RWA algorithms have been well performed to meet the need of certain networks requirement, they usually neglect the performance of the whole networks, especially the load balancing of the whole networks. This is quite likely to lead to some links bearing excessive ligthpaths and traffic load, while other links being at an idle state. In this paper, the load distribution vector ( LDV ) is introduced to describe the links load of the networks firstly. Then by means of minimizing the LDV of the networks, the load balancing of the whole networks is tried to improve. Based on this, a heuristic load balancing (HLB) strategy is presented. Moreover, a novel RWA algorithm adopting the heuristic load balancing strategy is developed, as well as two other RWA algorithms adopting other load balancing strategies. At last, the simulations of the three RWA algorithms with different load balancing strategies are done for comparison on the basis of both the regular topology and the irregular topology networks. The simulation results show that the key performance parameters such as the average variance of links, the maximum link load and the number of established lightpath are improved by means of our novel RWA algorithm with the heuristic load balancing strategy.
Matsuura, Akihiro; Irimajiri, Mami; Matsuzaki, Kunihiro; Hiraguri, Yuko; Nakanowatari, Toshihiko; Yamazaki, Atusi; Hodate, Koichi
2013-01-01
The aim of this study was to establish a method for estimating loading capacity for Japanese native horses by gait analysis using an accelerometer. Six mares of Japanese native horses were used. The acceleration of each horse was recorded during walking and trotting along a straight course at a sampling frequency of 200 Hz. Each horse performed 12 tests: one test with a loaded weight of 80 kg (First 80 kg) followed by 10 tests with random loaded weights between 85 kg and 130 kg and a final test with a loaded weight of 80 kg again. The time series of acceleration was subjected to fast Fourier transformation, and the autocorrelation coefficient was calculated. The first two peaks of the autocorrelation were defined as symmetry and regularity of the gait. At trot, symmetries in the 100, 110, and 125 kg tests were significantly lower than that in First 80 kg (P < 0.05, by analysis of covariance and Sidak's test). These results imply that the maximum permissible load weight is less than 100 kg, which is 29% of the body weight of Japanese native horses. Our method is a widely applicable and welfare-friendly method for estimating maximum permissible load weights of horses. PMID:23302086
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. PMID:27041006
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.
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.
Ding, Xuanming; Zhang, Ting; Li, Ping; Cheng, Ke
2016-02-01
This paper aims to present a theoretical method to study the bearing performance of vertically loaded large-diameter pipe pile groups. The interactions between group piles result in different bearing performance of both a single pile and pile groups. Considering the pile group effect and the skin friction from both outer and inner soils, an analytical solution is developed to calculate the settlement and axial force in large-diameter pipe pile groups. The analytical solution was verified by centrifuge and field testing results. An extensive parametric analysis was performed to study the bearing performance of the pipe pile groups. The results reveal that the axial forces in group piles are not the same. The larger the distance from central pile, the larger the axial force. The axial force in the central pile is the smallest, while that in corner piles is the largest. The axial force on the top of the corner piles decreases while that in the central pile increases with increasing of pile spacing and decreasing of pile length. The axial force in side piles varies little with the variations of pile spacing, pile length, and shear modulus of the soil and is approximately equal to the average load shared by one pile. For a pile group, the larger the pile length is, the larger the influence radius is. As a result, the pile group effect is more apparent for a larger pile length. The settlement of pile groups decreases with increasing of the pile number in the group and the shear modulus of the underlying soil.
Xu, Chang
2016-04-01
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.
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.
Tuma, Margaret L.; Davis, Susan R.; Askins, Bruce R.; Salyer, Blaine H.
2008-01-01
The National Aeronautics and Space Administration (NASA) Ares Projects Office (APO) is continuing to make progress toward the final design of the Ares I crew launch vehicle and Ares V cargo launch vehicle. Ares I and V will form the space launch capabilities necessary to fulfill NASA's exploration strategy of sending human beings to the Moon, Mars, and beyond. As with all new space vehicles there will be a number of tests to ensure the design can be Human Rated. One of these is the Integrated Vehicle Ground Vibration Test (IVGVT) that will be measuring responses of the Ares I as a system. All structural systems possess a basic set of physical characteristics unique to that system. These unique characteristics include items such as mass distribution, frequency and damping. When specified, they allow engineers to understand and predict how a structural system like the Ares I launch vehicle behaves under given loading conditions. These physical properties of launch vehicles may be predicted by analysis or measured through certain types of tests. Generally, these properties are predicted by analysis during the design phase of a launch vehicle and then verified through testing before the vehicle is Human Rated. The IVGVT is intended to measure by test the fundamental dynamic characteristics of Ares I during various phases of operational/flight. This testing includes excitations of the vehicle in lateral, longitudinal, and torsional directions at vehicle configurations representing different trajectory points. During the series of tests, properties such as natural frequencies, mode shapes, and transfer functions are measured directly. These data will then be used to calibrate loads and Guidance, Navigation, and Controls (GN&C) analysis models for verifying analyses of Ares I. NASA launch vehicles from Saturn to Shuttle have undergone Ground Vibration Tests (GVTs) leading to successful launch vehicles. A GVT was not performed on the unmanned Delta III. This vehicle was
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.
Pineda, Evan J.; Waas, Anthony M.; Berdnarcyk, Brett A.; Arnold, Steven M.; Collier, Craig S.
2009-01-01
This preliminary report demonstrates the capabilities of the recently developed software implementation that links the Generalized Method of Cells to explicit finite element analysis by extending a previous development which tied the generalized method of cells to implicit finite elements. The multiscale framework, which uses explicit finite elements at the global-scale and the generalized method of cells at the microscale is detailed. This implementation is suitable for both dynamic mechanics problems and static problems exhibiting drastic and sudden changes in material properties, which often encounter convergence issues with commercial implicit solvers. Progressive failure analysis of stiffened and un-stiffened fiber-reinforced laminates subjected to normal blast pressure loads was performed and is used to demonstrate the capabilities of this framework. The focus of this report is to document the development of the software implementation; thus, no comparison between the results of the models and experimental data is drawn. However, the validity of the results are assessed qualitatively through the observation of failure paths, stress contours, and the distribution of system energies.
A Finite Element Analysis of Bearing Resistance of Timber Loaded through a Steel Plate
Directory of Open Access Journals (Sweden)
Leijten A.J.M.
2012-01-01
Full Text Available Decrease projected length of bolts due to bending deformation in timber joints compresses the steel washers onto timber member and increases lateral resistance of the joints. As this lateral strength increase primarily depend on bearing characteristics of timber beneath the steel washers, a finite element analysis was performed to predict their bearing-embedment behavior. A 3-D finite element model consisting of 8-node solid and contact pair elements was developed using ANSYS assuming an anisotropic plasticity model for timber and an elastic-perfectly plastic model for the washers. Material constants for both steel washer and timber member were obtained from previous test data. The results of the analysis were in good agreement with the experimental load-embedment curves as well as the analytical curves obtained in a previous study based on a rigid-body-spring-model. The same approach was also used to evaluate the effective bearing length (under uniform compression of a 50 mm depth timber block partially compressed.
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.
Fractal analysis of damage detected in concrete structural elements under loading
Energy Technology Data Exchange (ETDEWEB)
Carpinteri, A. [Politecnico di Torino, Department of Structural Engineering and Geotechnics, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)], E-mail: alberto.carpinteri@polito.it; Lacidogna, G.; Niccolini, G. [Politecnico di Torino, Department of Structural Engineering and Geotechnics, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)
2009-11-30
In Civil Engineering materials subjected to stress or strain states a quantitative evaluation of damage is of great importance due to the critical character of this phenomenon, which at a certain point suddenly turns into a catastrophic failure. An effective damage assessment criterion is represented by the statistical analysis of the amplitude distribution of acoustic emission (AE) signals emerging from the growing microcracks. The amplitudes of such signals are distributed according to the Gutenberg-Richter (GR) law and characterised through the b-value which decreases systematically with damage growth. On the other hand, the damage process is also characterised by the progressive coalescence of microcracks to form fracture surfaces. Geometrically the fractal dimension D of the damaged domain is expected to decrease from an initial value comprised between 2 and 3 towards a final value nearly equal to 2. The b-value and the fractal analysis, are here applied to two case studies of concrete specimens loaded up to failure, and the obtained results are compared and discussed. In particular, we emphasize that a single fractal dimension does not adequately describe a crack network, since two damaged domains with the same fractal dimension could have significantly different properties.
Cheng, Yung-Chang; Lin, Deng-Huei; Jiang, Cho-Pei; Lee, Shyh-Yuan
2015-01-01
The main aim of this article was to introduce the application of a uniform design for experimental methods to drop the micromotion of a novel ITI dental implant model under the dynamic loads. Combining the characteristics of the traditional ITI and Nano-Tite implants, a new implant with concave holes has been constructed. Compared to the traditional ITI dental implant model, the micromotion of the new dental implant model was significantly reduced by explicit dynamic finite element analysis. From uniform design of experiments, the dynamic finite element analysis method was applied to caluculated the maximum micromotion of the full model. Finally, the chief design in all the experiment simulations which cause the minimum micromotion is picked as the advanced model of the design. Related to the original design, which was associated with a micromotion of 45.11 μm, the micromotion of the improved version was 31.37 μm, for an improvement rate of 30.5%. PMID:26406049
International Nuclear Information System (INIS)
Aim: The main objective of the study was to analyze the structure of data contained in the archives exported from a tomotherapy treatment planning system. An additional aim was to create an application equipped with a user-friendly interface to enable automatic reading of files and data analysis, also using external algorithms. Analyses had to include image registration, dose deformation and summation. Materials and methods: Files from the archive exported from the tomotherapy treatment planning system (TPS) were analyzed. Two programs were used to analyze the information contained in the archive files: XML Viewer by Mind Fusion Limited and H x D hex editor by Mael Hora. To create an application enabling loading and analyzing the data, Matlab by MathWorks, version R2009b, was used. Results: Archive exported from the TPS is a directory with several files. It contains three types of data: .xml, .img and .sin. Tools available in Matlab offer great opportunities for analysis and transformation of loaded information. Proposed application automates the loading of necessary information and simplifies data handling. Furthermore, the application is equipped with a graphical user interface (GUI). The main application window contains buttons for opening the archives and analyzing the loaded data. Conclusion: The analysis of data contained in the archive exported from the tomotherapy treatment planning system allowed to determine the way and place of saving information of our interest, such as tomography images, structure sets and dose distributions. This enabled us to develop and optimize methods of loading and analyzing this information. (authors)
International Nuclear Information System (INIS)
Highlights: • The interactive mechanism between system and PHEVs is presented. • The charging load self-management without sacrificing user requirements is proposed. • The charging load self-management is coupled to system operation risk analysis. • The charging load self-management can reduce the extra risk brought by PHEVs. • The charging load self-management can shift charging power to the time with low risk. - Abstract: Many jurisdictions around the world are supporting the adoption of electric vehicles through incentives and the deployment of a charging infrastructure to reduce greenhouse gas emissions. Plug-in hybrid electric vehicles (PHEVs), with offer mature technology and stable performance, are expected to gain an increasingly larger share of the consumer market. The aggregated effect on power grid due to large-scale penetration of PHEVs needs to be analyzed. Nighttime-charging which typically characterizes PHEVs is helpful in filling the nocturnal load valley, but random charging of large PHEV fleets at night may result in new load peaks and valleys. Active response strategy is a potentially effective solution to mitigate the additional risks brought by the integration of PHEVs. This paper proposes a power system operation risk analysis framework in which charging load self-management is used to control system operation risk. We describe an interactive mechanism between the system and PHEVs in conjunction with a smart charging model is to simulate the time series power consumption of PHEVs. The charging load is managed with adjusting the state transition boundaries and without violating the users’ desired charging constraints. The load curtailment caused by voltage or power flow violation after outages is determined by controlling charging power. At the same time, the system risk is maintained under an acceptable level through charging load self-management. The proposed method is implemented using the Roy Billinton Test System (RBTS) and
Analysis and Load Testing of Two Steel Through Truss Bridges in Indiana
Malone, Brian Joseph; Heffron, Mark A.; Ramirez, J.A.; White, Donald W.
1996-01-01
Results of the load tests of two steel through truss bridges were used to evaluate the assumptions used by BARS for the rating of this type of bridge. Based on the results from this study it is recommended that the Indiana Department of Transportation use the load distribution factors in the 1994 LRFD Specifications in the rating of these bridges. This will imply replacing the load distribution factors currently in BARS. The implementation of the new distribution factors will result in a l...
Analysis of Metal Plate Connected Wood Truss Assemblies under Out-of-Plane Loads
Mohamadzadeh, Milad
2014-01-01
In 2012, falls from elevation in construction industry represented 36% of the total fatalities. The Occupational Safety and Health Administration requires workers to use fall protection systems where workers are 6 feet or more above a lower level. Anchors for fall protection systems attached to roof trusses may cause out-of-plane loading on these structures. Metal plate connected wood trusses (MPCWT) are not designed to carry out-of-plane loads and MPCWT performance under these loads are not ...
Plato (power load analysis tool) - a module of west wall monitoring system
International Nuclear Information System (INIS)
The mandate of the WEST (W Environment for Steady-state Tokamak) project, is to upgrade the medium- sized superconducting Tokamak, Tore Supra in a major scale. One of it's objectives, is to also act as a test-bed for ITER divertor components, to be procured and used in ITER. WEST would be installing actively cooled Tungsten divertor elements, like the ones to be used in ITER. These components would be tested under two experimental scenarios: high power (Ip = 0.8MA, lasting 30s with 15MW injected power) and high fluence (Ip = 0.6 MA, lasting 1000s with 12 MW injected power). Heat load on the divertor target will range from a few MW/m2 up to 20 MW/m2 depending on the X point location and the heat flux decay length. The tungsten Plasma Facing Components (PFCs) are less tolerant to overheating than their Carbon counterparts and prevention of their burnout is a major concern. It is in this context that the Wall Monitoring System (WMS) - a software framework aimed at monitoring the health of the Wall components, was conceived. WMS has been divided into three parts: a) a pre-discharge power load analysis tool to check compatibility between plasma scenario and PFC's operational limits in terms of heat flux b) a real-time system during discharge, to take into account all necessary measurements involved in the PFCs protection c) a set of analysis tools that would be used post-discharge, that would access WEST database and compare predicted and experimental results. This paper presents an overview of PLATo - the pre-pulse module of WMS that has been recently developed under IPR-IRFM research collaboration. PLAto has two major components - one that produces heat flux information of the PFCS and the other that produces energy graphs depending on shot profile defined by time variant magnetic equilibrium and injected power profiles. Preliminary results will be presented based on foreseen WEST plasma reference scenarios. (author)
Institute of Scientific and Technical Information of China (English)
ZHANG Gui-bao; CHEN Jun; WANG Amber
2008-01-01
During stamping process,the material properties,process design parameters and production environments inevitably have variation and noisy factors,which possibly affect the sheet metal forInability and the deformation of the die structure.After gaining a success in applying sheet metal forming numerical simulation analysis to get the forming loads during stamping process,a methodology of die structure analysis based on sheet metal forming simulation was proposed and validated by experiments.Based on these results,the effect related with initial blank thickness,blank holder force,blank positioning error and die alignment error variations to a DP600 hyperbolic bottomed cup drawing die's forming loads (especially unbalanced loads),and deformation and stress was studied numerically.The influence level of these variations to the die's forming loads,deformation and stress was disclosed.The findings can guide die design,die tryout and process control for high-strength steel (HSS) stamping with increased forming load and decreased sheet metal formability.
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.
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.
Paaver, Urve; Heinämäki, Jyrki; Kassamakov, Ivan; Hæggström, Edward; Ylitalo, Tuomo; Nolvi, Anton; Kozlova, Jekaterina; Laidmäe, Ivo; Kogermann, Karin; Veski, Peep
2014-02-28
We showed that scanning white light interferometry (SWLI) can provide nanometer depth resolution in 3D topographic analysis of electrospun drug-loaded nanofibrous mats without sample preparation. The method permits rapidly investigating geometric properties (e.g. fiber diameter, orientation and morphology) and surface topography of drug-loaded nanofibers and nanomats. Electrospun nanofibers of a model drug, piroxicam (PRX), and hydroxypropyl methylcellulose (HPMC) were imaged. Scanning electron microscopy (SEM) served as a reference method. SWLI 3D images featuring 29 nm by 29 nm active pixel size were obtained of a 55 μm × 40 μm area. The thickness of the drug-loaded non-woven nanomats was uniform, ranging from 2.0 μm to 3.0 μm (SWLI), and independent of the ratio between HPMC and PRX. The average diameters (n=100, SEM) for drug-loaded nanofibers were 387 ± 125 nm (HPMC and PRX 1:1), 407 ± 144 nm (HPMC and PRX 1:2), and 290 ± 100 nm (HPMC and PRX 1:4). We found advantages and limitations in both techniques. SWLI permits rapid non-contacting and non-destructive characterization of layer orientation, layer thickness, porosity, and surface morphology of electrospun drug-loaded nanofibers and nanomats. Such analysis is important because the surface topography affects the performance of nanomats in pharmaceutical and biomedical applications. PMID:24378328
Finite Element Analysis of Ultimate Load Capacity of Slender Concrete-Filled Steel Composite Columns
Directory of Open Access Journals (Sweden)
Alireza Bahrami
2011-01-01
Full Text Available Ultimate load capacity of slender concrete-filled steel composite columns is investigated in this paper. Nonlinear analyses are done by the use of finite element software, LUSAS, to study the ultimate axial load behaviour of the columns. Verification of the finite element modelling is done by comparing the result with the corresponding experimental result reported by other researchers. Analyses are carried out to assess different shapes and number of cold-formed steel sheeting stiffeners with various thicknesses of cold-formed steel sheets and their effects on the behaviour and ultimate axial load capacity of the columns. The results are presented in the form of axial load-normalized axial shortening plots. It is demonstrated that the ultimate axial load capacity of the slender concrete-filled steel composite columns can be accurately predicted by proposed finite element modelling. Obtained results from the study show that various thicknesses of cold-formed steel sheets, and different shapes and number of stiffeners influence the ultimate axial load capacity and behaviour of the columns. Also, the ultimate axial load capacity of the columns is improved by increase of number of stiffeners. Moreover, increase of thickness of cold-formed steel sheet enhances the ultimate axial load capacity.
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.
Structural analysis of the ITER Vacuum Vessel regarding 2012 ITER Project-Level Loads
International Nuclear Information System (INIS)
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
Analysis for the loads on I-sparger in IRWST following POSRV open/closure
International Nuclear Information System (INIS)
Following POSRV actuation in KNGR (Korean Next Generation Reactor), the water, air, and steam in PSRV discharge line are released into IRWST. After POSRV closure, the water in IRWST enter the POSRV discharge line. The thermo-hydraulic loads on I-Sparger generated due to these phenomena are classified into the thrust load due to water discharge from PSRV discharge line, the pressure load induced by the oscillation of air bubbles in IRWST, and the impact load generated by the collision in the entered water with the elbow of PSRV discharge line. The thrust load was evalued by the methodology of ANSI/ANS 58.2, the pressure load was analyzed using the shape function for the pressure distribution in IRWST, the impact load was calculated by the simple evaluated equation for water hammer. After the I-Sparger performance test by KAERI is conducted, the methodology to evaluate the loads on I-Sparger will be verified and modified comparing the results in this paper with the test results
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.
Kameo, Yoshitaka; Ootao, Yoshihiro; Ishihara, Masayuki
2016-04-01
Trabecula, an anatomical unit of the cancellous bone, is a porous material that consists of a lamellar bone matrix and interstitial fluid in a lacuno-canalicular porosity. The flow of interstitial fluid caused by deformation of the bone matrix is believed to initiate a mechanical response in osteocytes for bone remodeling. In order to clarify the effect of the lamellar structure of the bone matrix--i.e., variations in material properties--on the fluid flow stimuli to osteocytes embedded in trabeculae, we investigated the mechanical behavior of an individual trabecula subjected to cyclic loading based on poroelasticity. We focused on variations in the trabecular permeability and developed an analytical solution containing both transient and steady-state responses for interstitial fluid pressure in a single trabecular model represented by a multilayered two-dimensional poroelastic slab. Based on the obtained solution, we calculated the pressure and seepage velocity of the interstitial fluid in lacuno-canalicular porosity, within the single trabecula, under various permeability distributions. Poroelastic analysis showed that a heterogeneous distribution of permeability produces remarkable variations in the fluid pressure and seepage velocity in the cross section of the individual trabecula, and suggests that fluid flow stimuli to osteocytes are mostly governed by the value of permeability in the neighborhood of the trabecular surfaces if there is no difference in the average permeability in a single trabecula. PMID:26081726
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.
Transient Analysis of Lumped Circuit Networks Loaded Thin Wires By DGTD Method
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.
Dynamical analysis of multi-layered anisotropic cylindrical panels under thermal load
International Nuclear Information System (INIS)
The increased use of composite materials in aerospace and mechanical engineering structures is due to their high stiffness and strength-to-weight ratio. Studies involving the thermoelastic behavior of composite plates and shells have received great attention in recent years. Thermoelastic problems of reinforced rectangular panels was investigated by Birman. In this paper the static response of isotropic reinforced panels in non-uniform thermal field is discussed. An exact three-dimensional thermoelasticity solution for a cross-ply cylindrical panel has been obtained by Huang and Tauchert using the power series method. Three-dimensional thermal stress analysis of laminated panels have been studied by Saha and Pabitra. Analytical three-dimensional thermoelasticity solutions are presented for static problems of simply supported sandwich panels and cylindrical shells subjected to mechanical load and temperature gradient with constant intensity at inner or outer surfaces by Scott and Noor. Thermoelasticity solution of multilayer anisotropic shells was studied by Shvets and Flyachok. In this paper , the complete system of basic equations of linear dynamic theory of thermal stresses in multilayer shells is developed with the allowance for transverse anisotropy of the material for each layer. In this paper the governing differential equations of motion in term of displacements for each layer of cylindrical panel are solved by enforcing continuity conditions and using Galerkin finite element method. Refs. 5 (author)
Analysis of pressure distributions on combinations of cylinders due to the effect of wind loading
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.
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.
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.
Static Analysis of Transversely Loaded Isotropic and Orthotropic Plates with Central Cutout
Kalita, K.; Halder, S.
2014-10-01
Plate structures are an integral part of engineering and construction industry. Taking into consideration various design and functional aspects, openings are provided in these plates for access and maintenance. The presence of cutout creates stress concentration, which eventually reduces the mechanical strength of the structure and in extreme cases may lead to its failure. Therefore it is of immense practical importance to investigate these stress concentrations. In this work the deflection and induced stresses for isotropic plate and orthotropic plate with central circular and square cutout under transverse loading is studied with the help of Finite Element Method (FEM). The variation in deflection and stresses with change in d/W and b/W ratio for steel (isotropic material) as compared to e-glass/epoxy (orthotropic material) is studied. Dependence of the deflection and Stress Concentration Factor (SCF) on cutout geometry and size is also observed. The effect of orienting the square cutout with positive X-baseline is also studied. Four different boundary conditions are considered. The results so obtained are critically examined and presented in graphical form. A popular finite element package, ANSYS has been used for the analysis.
Energy Technology Data Exchange (ETDEWEB)
Scheffler, D. (Bergakademie Freiberg (Germany). Inst. fuer Bergbau); Neumann, R. (Bergakademie Freiberg (Germany). Inst. fuer Bergbau)
1993-08-01
The present paper gives a survey of the research project on the subject ''Prognosis of the cutting resistance of rocks'', which is being carried out at the Institute of Mining of the Technical University Mining Academy of Freiberg at the request of the TAKRAF Lauchhammer Company in Leipzig. It is stressed in the introduction that a thorough knowledge of the specific cutting resistance of rocks is already necessary in the preliminary stage of technological drafts of mining systems. In addition to the essential fundamentals for the definition and calculation of specific cutting resistances, various aspects of the systematic research methods applied in laboratory analyses as well as in cutting resistance and load analyses on site, which make a prognosis of the cutting resistances possible, are discussed. Examples of measurement analyses on excavating equipment illustrate the significant test results obtained. Special tests include inter alia the analysis of individual components of the cutting resistance as well as the development of a simulation programme for the purpose of calculating the drive rating functions and assessing the dynamic reactions of the excavating machine. At the same time, the laboratory equipment used for these analyses also serves as an instructive and effective means of training students in this field of research. (orig.)
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.
Askari, Ayman
Structural failures by fracture in oil and petroleum industries can have severe consequences both in term of loss of life and of economics. This severity will increase in the future as the size and complexity of installations increase. Industry must be constantly vigilant in learning from past failures and in studying the possible effects of changes in technology on fracture risks. The combination of the effects of fabrication and operation, and of corrosive surroundings has not been clearly understood or analyzed. For structures in oil and petroleum industries, this complex interaction contributes to brittle fracture. In this research, the most common type of this combination is discussed and analyzed. The structure consists of a welded thick wall pressure vessel subject to primary loading and exposed to hydrogen at elevated temperature. To be more practical, a real case of a crack in a thick wall, welded pressure vessel under high hydrogen partial pressure and moderate temperature is selected from a petroleum refinery. This research establishes a procedure to deal with the complex interaction of issues associated with material processing and corrosive atmosphere that are active in this process. It also establishes a formal procedure to predict the active life of a structure that has a crack and is exposed to a hydrogen-enriched atmosphere. To achieve that there are five major steps to be carried out in this work: (1) Welding process simulation. (2) Post Weld Heat Treatment (PWHT) simulation. (3) Material property degradation due to hydrogen embrittlement. (4) Stress analysis of the cracked specimen. (5) Fitness for purpose analysis.
Safety analysis of dual purpose metal cask subjected to impulsive loads due to aircraft engine crash
International Nuclear Information System (INIS)
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 and seismic tests subjected to strong earthquake motions. 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. 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 research (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 developed
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)
无
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.
YATKIN Sinan; GERBOLES Michel
2012-01-01
The PM mass loss due to EDXRF analysis of PM 10 loaded filters was investigated in this study. The mass loss was gravimetrically evaluated on collocated filters analyzed both by EDXRF under vacuum condition and by Ion Chromatography. Then, this comparison was repeated with a gaseous mixture of air and Helium (He) instead of evacuating the measurements chamber of the EDXRF spectrometer. It was shown that EDXRF analysis under vacuum medium leads to mass loss of water soluble ions ...
International Nuclear Information System (INIS)
Predictions of crack arrest behaviour are performed for a cracked reactor pressure vessel under both thermal and pressure loading. The object is to compare static and dynamic calculations. The dynamic calculations are made using an explicit finite-element technique where crack growth is simulated by gradual nodal release. Three different load cases and the effect of different velocity dependence on the crack-propagation toughness are studied. It is found that for the analysed cases the static analysis is slightly conservative, thus justifying its use for these problems. (author)
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
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.
Tests and matching analysis of a load resilient ICRH antenna on TEXTOR
International Nuclear Information System (INIS)
Due to rearrangement of the diagnostic positions resulting from the dynamic ergodic divertor installation on TEXTOR, a new antenna pair has been recently installed. This antenna has been designed to test the load resilient 'conjugate-T' (CT) mode of operation. The paper describes the calibration of the system and shows from impedance matrix measurements that the load resilience can be maintained in presence of the mutual coupling between the pair. The practical tuning procedure to obtain the load resilience of the system is also described
Rate-Optimal Multiuser Scheduling with Reduced Feedback Load and Analysis of Delay Effects
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Alouini Mohamed-Slim
2006-01-01
Full Text Available We propose a feedback algorithm for wireless networks that always collects feedback from the user with the best channel conditions and has a significant reduction in feedback load compared to full feedback. The algorithm is based on a carrier-to-noise threshold, and closed-form expressions for the feedback load as well as the threshold value that minimizes the feedback load have been found. We analyze two delay scenarios. The first scenario is where the scheduling decision is based on outdated channel estimates, and the second scenario is where both the scheduling decision and the adaptive modulation are based on outdated channel estimates.
Transient Three-Dimensional Startup Side Load Analysis of a Regeneratively Cooled Nozzle
Wang, Ten-See
2008-01-01
The objective of this effort is to develop a computational methodology to capture the startup side load physics and to anchor the computed aerodynamic side loads with the available data from a regeneratively cooled, high-aspect-ratio nozzle, hot-fired at sea level. The computational methodology is based on an unstructured-grid, pressure-based, reacting flow computational fluid dynamics and heat transfer formulation, a transient 5 s inlet history based on an engine system simulation, and a wall temperature distribution to reflect the effect of regenerative cooling. To understand the effect of regenerative wall cooling, two transient computations were performed using the boundary conditions of adiabatic and cooled walls, respectively. The results show that three types of shock evolution are responsible for side loads: generation of combustion wave; transitions among free-shock separation, restricted-shock separation, and simultaneous free-shock and restricted shock separations; along with the pulsation of shocks across the lip, although the combustion wave is commonly eliminated with the sparklers during actual test. The test measured two side load events: a secondary and lower side load, followed by a primary and peak side load. Results from both wall boundary conditions captured the free-shock separation to restricted-shock separation transition with computed side loads matching the measured secondary side load. For the primary side load, the cooled wall transient produced restricted-shock pulsation across the nozzle lip with peak side load matching that of the test, while the adiabatic wall transient captured shock transitions and free-shock pulsation across the lip with computed peak side load 50% lower than that of the measurement. The computed dominant pulsation frequency of the cooled wall nozzle agrees with that of a separate test, while that of the adiabatic wall nozzle is more than 50% lower than that of the measurement. The computed teepee-like formation
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
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.
Zhan, Yu; Liu, Changsheng; Zhang, Fengpeng; Qiu, Zhaoguo
2016-07-01
The laser ultrasonic generation of Rayleigh surface wave and longitudinal wave in an elastic plate is studied by experiment and finite element method. In order to eliminate the measurement error and the time delay of the experimental system, the linear fitting method of experimental data is applied. The finite element analysis software ABAQUS is used to simulate the propagation of Rayleigh surface wave and longitudinal wave caused by laser excitation on a sheet metal sample surface. The equivalent load method is proposed and applied. The pulsed laser is equivalent to the surface load in time and space domain to meet the Gaussian profile. The relationship between the physical parameters of the laser and the load is established by the correction factor. The numerical solution is in good agreement with the experimental result. The simple and effective numerical and experimental methods for laser ultrasonic measurement of the elastic constants are demonstrated. PMID:27079489
International Nuclear Information System (INIS)
In the course of the gradual safety upgrading of the VVER-440 NPP Paks, the loading capacity of the civil structures due to earthquake loading superposed by operational conditions was analyzed. Based on a three-dimensional detailed finite-element model, several dynamic analyses were performed in the frequency domain for the main building complex of each of the four nuclear units. At first, the bearing capacity of the as-built structure was evaluated, followed by additional calculations considering required and optimized upgrading measures. An additional requirement was that implementation of the upgrading steel elements had to be executed during operation. The effectiveness of different upgrading options for the structures and systems, as well as the implementation feasibility of the upgrading measures and seismic safety, were investigated. For the essential retrofit concept, the mathematical model was updated and the final dynamic response and bearing capacity calculations performed. The excitation was defined by a site-specific design spectrum, with a maximum acceleration of 0.25 g for the horizontal and 0.23 g for the vertical direction. Furthermore, a wide range of soil parameters and the liquefaction effect was considered. The maximum forces and stresses were calculated for the load cases, dead weight, snow loads (NOL), and seismic excitation. In accordance to the specified criteria made for NPP PAKS, the extraordinary loading of earthquake was super-positioned with the other load cases in a realistic manner. The stress results were evaluated by the specific acceptance criteria defined for the seismic requalification of the Paks NPP. As a result of the analysis and the provided upgrading measures, the civil structure is now capable to withstand a horizontal and vertical seismic loading equivalent to the above excitation level. (authors)
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.
Analysis of an adhesively bonded single lap joint subjected to eccentric loading
DEFF Research Database (Denmark)
Anyfantis, Konstantinos; Tsouvalis, N. G.
2013-01-01
A new experimental test is proposed, which allows the contribution of Mode I, II and III fracture modes to the failure of the adhesive layer of bonded joints aiming at achieving the realistic conditions often occurring during loading of practical joints. The main objective of this test 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......, which correspond to Mode I, II and III loading and fracture. These tests were designed so that the metal substrates do not enter plasticity and the adhesive achieves a mode mixity ratio between Mode II and Mode III not lower than 0.5. The experiments were simulated in a 3-dimensional finite element...
Analysis of Laminated Architectural Glazing Subjected to Wind Load and Windborne Debris Impact
Shetty, Mahesh S; Dharani, Lokeswarappa R.; Daniel S. Stutts
2012-01-01
During windstorms and hurricanes, architectural glazing is subjected to wind loading and windborne debris impact. Wind-borne debris is categorized into two types. One is small hard missile like roof gravel and the other is large soft missile representing the lumber from wood-framed buildings. Laminated architectural glazing (LAG) is the commonly used glazing in buildings where impact resistance is needed. The prefailure stress response of the LAG due to the combined loading due to wind and wi...
Assaf Ya'akobovitz; Slava Krylov; Yael Hanein
2011-01-01
Following the recent progress in integrating single-wall carbon nanotubes (SWCNTs) into silicon-based micro-electromechanical systems (MEMS), new modeling tools are needed to predict their behavior under different loads, including thermal, electrical and mechanical. In the present study, the mechanical behavior of SWCNTs under thermoelectrical loading is analyzed using a large deflection geometrically nonlinear string model. The effect of the resistive heating was found to have a substantial ...
Kim, Dong-Seok; Kim, Dae-Gon; Park, Chan-Jin; Cho, Lee-Ra
2009-01-01
STATEMENT OF PROBLEM Despite an improved bone reactions of Mg-incorporated implants in the animals, little yet has been carried out by the experimental investigations in functional loading conditions. PURPOSE This study investigated the clinical and histologic parameters of osseointegrated Mg-incorporated implants in early loading conditions. MATERIAL AND METHODS A total of 36 solid screw implants (diameter 3.75 mm, length 10 mm) were placed in the mandibles of 6 beagle dogs. Test groups incl...
Numerical analysis of prestressed reinforced concrete beam subjected to blast loading
International Nuclear Information System (INIS)
Highlights: • Numerical study of prestressed RC beam against blast loadings by using LS-DYNA. • Numerical model is calibrated with testing results available. • The prestress is pre-applied on the RC beam in an analytical approach. • Parametric studies on prestress, concrete compressive strength and blast load. • Blast resistance performance of prestressed beam is identified. - Abstract: Prestressing technique has been widely used in civilian and military constructions. The prestressed reinforced concrete (RC) structural components such as beams and columns usually outperform the non-prestressed RC components because prestressing not only increases the structural stiffness and load carrying capacity, but also has higher crack resistance than non-prestressed component. As a result, it usually leads to light structures. The investigation of non-prestressed RC components subjected to blast loadings has been reported in the literature. However, the study on the blast-resistant capacity of prestressed RC components is very limited. In this study, the dynamic response of a simply-supported prestressed RC beam with rectangular section under blast loadings is numerically investigated by using finite element codes LS-DYNA. The prestress is pre-applied on the RC beam in an analytical approach. The reliability of the numerical model is calibrated with testing results available in the literature. With the calibrated model, numerical simulations on four groups of prestressed RC beams to blast loadings are carried out to investigate the influences of prestressing level and concreted compressive strength on beam blast loading resistance capacity. The structural responses such as mid-span maximum deflection, residual deflection, cracking, stress of rebars and shear stress of concrete near the supports are extracted from the numerical results. The effectiveness of prestressing on blast-resistant capacity of RC beam is demonstrated through comparing the results with the
A numerical analysis of empty and foam-filled aluminium conical tubes under oblique impact loading
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.
Finite Element Analysis of Ultimate Load Capacity of Slender Concrete-Filled Steel Composite Columns
Alireza Bahrami; Wan Hamidon Wan Badaruzzaman; Siti Aminah Osman
2011-01-01
Ultimate load capacity of slender concrete-filled steel composite columns is investigated in this paper. Nonlinear analyses are done by the use of finite element software, LUSAS, to study the ultimate axial load behaviour of the columns. Verification of the finite element modelling is done by comparing the result with the corresponding experimental result reported by other researchers. Analyses are carried out to assess different shapes and number of cold-formed steel sheeting stiffeners with...
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.
Qingwen Li; Lan Qiao; Gautam Dasgupta; Siwei Ma; Liping Wang; Jianghui Dong
2015-01-01
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 vi...
Transient three-dimensional startup side load analysis of a regeneratively cooled nozzle
Wang, Ten-See
2009-07-01
The objective of this effort is to develop a computational methodology to capture the side load physics and to anchor the computed aerodynamic side loads with the available data by simulating the startup transient of a regeneratively cooled, high-aspect-ratio nozzle, hot-fired at sea level. The computational methodology is based on an unstructured-grid, pressure-based, reacting flow computational fluid dynamics and heat transfer formulation, and a transient inlet history based on an engine system simulation. Emphases were put on the effects of regenerative cooling on shock formation inside the nozzle, and ramp rate on side load reduction. The results show that three types of asymmetric shock physics incur strong side loads: the generation of combustion wave, shock transitions, and shock pulsations across the nozzle lip, albeit the combustion wave can be avoided with sparklers during hot-firing. Results from both regenerative cooled and adiabatic wall boundary conditions capture the early shock transitions with corresponding side loads matching the measured secondary side load. It is theorized that the first transition from free-shock separation to restricted-shock separation is caused by the Coanda effect. After which the regeneratively cooled wall enhances the Coanda effect such that the supersonic jet stays attached, while the hot adiabatic wall fights off the Coanda effect, and the supersonic jet becomes detached most of the time. As a result, the computed peak side load and dominant frequency due to shock pulsation across the nozzle lip associated with the regeneratively cooled wall boundary condition match those of the test, while those associated with the adiabatic wall boundary condition are much too low. Moreover, shorter ramp time results show that higher ramp rate has the potential in reducing the nozzle side loads.
ANALYSIS OF FAILURE IN WOVEN CARBON/EPOXY LAMINATES UNDER QUASI-STATIC AND IMPACT LOADING
Harding, J.; Li, Y
1991-01-01
A finite element method is used to determine the tensile stress concentration factors and the interlaminar shear stresses close to a failed ply in a woven carbon reinforced epoxy laminate under tensile loading. Ply failure is modelled by a reduction in stiffness in the loading direction. Different reductions in stiffness, representing either matrix break-up or fibre tow fracture are studied and the redistributed stress system, for the case where delamination follows initial ply failure, is al...
Rajen Pudur; Sarsing Gao
2016-01-01
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 sinu...
An Analysis of Load Imbalance in Scale-out Data Serving
Novakovic, Stanko; Daglis, Alexandros; Bugnion, Edouard; Falsafi, Babak; Grot, Boris
2016-01-01
Despite the natural parallelism across lookups, performance of distributed key-value stores is often limited due to load imbalance induced by heavy skew in the popularity distribution of the dataset. To avoid violating service level objectives expressed in terms of tail latency, systems tend to keep server utilization low and organize the data in micro-shards, which in turn provides units of migration and replication for the purpose of load balancing. These techniques reduce the skew, but inc...
Transient Two-Dimensional Analysis of Side Load in Liquid Rocket Engine Nozzles
Wang, Ten-See
2004-01-01
Two-dimensional planar and axisymmetric numerical investigations on the nozzle start-up side load physics were performed. The objective of this study is to develop a computational methodology to identify nozzle side load physics using simplified two-dimensional geometries, in order to come up with a computational strategy to eventually predict the three-dimensional side loads. The computational methodology is based on a multidimensional, finite-volume, viscous, chemically reacting, unstructured-grid, and pressure-based computational fluid dynamics formulation, and a transient inlet condition based on an engine system modeling. The side load physics captured in the low aspect-ratio, two-dimensional planar nozzle include the Coanda effect, afterburning wave, and the associated lip free-shock oscillation. Results of parametric studies indicate that equivalence ratio, combustion and ramp rate affect the side load physics. The side load physics inferred in the high aspect-ratio, axisymmetric nozzle study include the afterburning wave; transition from free-shock to restricted-shock separation, reverting back to free-shock separation, and transforming to restricted-shock separation again; and lip restricted-shock oscillation. The Mach disk loci and wall pressure history studies reconfirm that combustion and the associated thermodynamic properties affect the formation and duration of the asymmetric flow.
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.
Analysis of loads and fluid-structure interactions in a condensation pool
Energy Technology Data Exchange (ETDEWEB)
Timperi, A.; Paettikangas, T.; Niemi, J. [VTT, Technical Research Centre of Finland (Finland)
2007-04-15
A simplified direct contact condensation model was implemented into the Volume of Fluid model of the Fluent CFD code. Transient three-dimensional test runs for the POOLEX experiments, where steam is blown into a water pool were performed. The model was found to provide too small condensation rate for steam when compared to experiments. In addition, the calculated back and forth oscillation of the steam water interface was much smaller than in the experiments. The model was found to be numerically quite robust. The discrepancies of the simulation, such as the too small condensation rate, could be to some extent cured by making improvements into the condensation model. As an alternative estimation method of thermohydraulic loads in condensation pools, the SILA code based on potential flow theory, was taken into use. SILA solves the pressure distribution caused by oscillating bubbles in a pool, and is easier to use and more flexible than Method of Images studied earlier. SILA has been modified for pools without an inner cylinder and test simulations for the POOLEX water pool were performed. The MpCCI FSI coupling software employs an explicit coupling scheme, which results in numerical instability in the case of the POOLEX facility. In order to improve stability, ways for implementing an implicit coupling scheme with MpCCI were examined. It was found that such a scheme is difficult to achieve without access to the source codes. An implicit coupling scheme is expected to be available with MpCCI in forthcoming years. A method was developed which can be used for analysing two-way FSI problems realistically by using only one-way coupling of CFD and structural analysis codes. In the method, the mass of the fluid is accounted for in the structural motion by adding the fluid to the structural model as an acoustic medium. Validity of the method was examined with promising results mathematically by an order of magnitude analysis and by comparing numerical results with a full
Analysis of the stress-strain state of New Exchequer combined damat static loads
Directory of Open Access Journals (Sweden)
Sainov Mikhail Petrovich
Full Text Available In the article the authors analyze numerical modeling results of the stress-strain state of a combined dam created by construction of a higher rockfill dam with a reinforced concrete face behind the downstream face of the concrete dam. The analysis was conducted on the example of the design of 150 meter high New Exchequer dam (USA. Numerical modeling was conducted with consideration of non-linearity of soils deformation as well as non-linear behavior of the interaction “concrete - soil”, “concrete - concrete”. The analysis showed that though in a combined dam the concrete part gets additional displacements and settlements, its stress state remains favorable without appearance of tensile stresses and opening of the contact “concrete - rock”. This is explained by the fact that on the top the concrete dam is weightened by the reservoir hydrostatic pressure. The role of rockfill lateral pressure on the concrete dam stress state is small. There may be expected sliding of soil in relation to the concrete dam downstream face due to the loss of its shear strength. Besides, decompaction of the contact "soil - concrete" may occur, as earthfill will have considerable displacements in the direction from the concrete dam. Due to this fact the loads from the earthfill weight do not actually transfer to the concrete dam. The most critical zone in the combined dam is the interface of the reinforced concrete face with the concrete dam. Under the action of the hydrostatic pressure the earth-fill under the face will have considerable settlements and displacements, because soil slides in relation to the concrete dam downstream face. This results in considerable openings (10 cm and shear displacements (50 сm in the perimeter joint. The results of the numerical modeling are confirmed by the presence of seepage in New Exchequer dam, which led to the necessity of its repair. Large displacements do not allow using traditional sealing like copper water stops
Analysis of loads and fluid-structure interactions in a condensation pool
International Nuclear Information System (INIS)
A simplified direct contact condensation model was implemented into the Volume of Fluid model of the Fluent CFD code. Transient three-dimensional test runs for the POOLEX experiments, where steam is blown into a water pool were performed. The model was found to provide too small condensation rate for steam when compared to experiments. In addition, the calculated back and forth oscillation of the steam water interface was much smaller than in the experiments. The model was found to be numerically quite robust. The discrepancies of the simulation, such as the too small condensation rate, could be to some extent cured by making improvements into the condensation model. As an alternative estimation method of thermohydraulic loads in condensation pools, the SILA code based on potential flow theory, was taken into use. SILA solves the pressure distribution caused by oscillating bubbles in a pool, and is easier to use and more flexible than Method of Images studied earlier. SILA has been modified for pools without an inner cylinder and test simulations for the POOLEX water pool were performed. The MpCCI FSI coupling software employs an explicit coupling scheme, which results in numerical instability in the case of the POOLEX facility. In order to improve stability, ways for implementing an implicit coupling scheme with MpCCI were examined. It was found that such a scheme is difficult to achieve without access to the source codes. An implicit coupling scheme is expected to be available with MpCCI in forthcoming years. A method was developed which can be used for analysing two-way FSI problems realistically by using only one-way coupling of CFD and structural analysis codes. In the method, the mass of the fluid is accounted for in the structural motion by adding the fluid to the structural model as an acoustic medium. Validity of the method was examined with promising results mathematically by an order of magnitude analysis and by comparing numerical results with a full
Limit load analysis for local wall-thinning steam generator tubes
International Nuclear Information System (INIS)
Steam generator(SG) tubes form approximately 80% of pressure boundary of the reactor primary coolant[1]. During the past 40 years, a large number of operating PWPs have experienced degradation due to local wall-thinning of SG tubes, which was caused by corrosion or squeezing of tubes at support plate or tubesheet intersections or other reasons. This paper introduced the study of experiment and numerical analyses for plastic limit loads of local wall-thinning SG tubes. The effect of the dimension of local wall-thinning on plastic limit load was analyzed. The main contents in this paper were summarized as follows: 1 Experiment equipment which could test not only bursting pressure but also plastic limit load was built. Two kinds of local wall-thinning shapes were respectively made on SG tubes. One kind of local wall-thinning shape was rectangle-like flaw, which was used to simulate local wall-thinning caused by squeezing of tubes at support plate. The other kind of local wall-thinning shape was arc-like flaw, which was used to simulate local wall-thinning caused by corrosion. Different size local wall-thinning SG tubes of these two kinds of shape were test by using the equipment. 2 Regularization method for local wall-thinning defect was provided based on experimental and finite element method. 3 The effect order of local wall-thinning configuration on plastic limit load was studied. It was found that: Except defect thickness, the longitudinal length and circumferential length of SGT defect can also influence the plastic limit load; When the longitudinal length of SGT defect exceeded 6 mm, the effect of longitudinal length on plastic limit load can be ignored; When the circumferential angle of defect exceed 45 degree, the effect of circumferential angle on plastic limit load can be ignored. (authors)
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.
Cascade failure analysis of power grid using new load distribution law and node removal rule
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.
Calculation and characteristics analysis of blade pitch loads for large scale wind turbines
Institute of Scientific and Technical Information of China (English)
无
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.
Ignition Prediction of Pressed HMX based on Hotspot Analysis Under Shock Pulse Loading
Kim, Seokpum; Miller, Christopher; Horie, Yasuyuki; Molek, Christopher; Welle, Eric; Zhou, Min
The ignition behavior of pressed HMX under shock pulse loading with a flyer is analyzed using a cohesive finite element method (CFEM) which accounts for large deformation, microcracking, frictional heating, and thermal conduction. The simulations account for the controlled loading of thin-flyer shock experiments with flyer velocities between 1.7 and 4.0 km/s. The study focuses on the computational prediction of ignition threshold using James criterion which involves loading intensity and energy imparted to the material. The predicted thresholds are in good agreement with measurements from shock experiments. In particular, it is found that grain size significantly affects the ignition sensitivity of the materials, with smaller sizes leading to lower energy thresholds required for ignition. In addition, significant stress attenuation is observed in high intensity pulse loading as compared to low intensity pulse loading, which affects density of hotspot distribution. The microstructure-performance relations obtained can be used to design explosives with tailored attributes and safety envelopes.
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.
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.
Stability analysis of shallow tunnels subjected to eccentric loads by a boundary element method
Directory of Open Access Journals (Sweden)
Mehdi Panji
2016-08-01
Full Text Available In this paper, stress behavior of shallow tunnels under simultaneous non-uniform surface traction and symmetric gravity loading was studied using a direct boundary element method (BEM. The existing full-plane elastostatic fundamental solutions to displacement and stress fields were used and implemented in a developed algorithm. The cross-section of the tunnel was considered in circular, square, and horseshoe shapes and the lateral coefficient of the domain was assumed as unit quantity. Double-node procedure of the BEM was applied at the corners to improve the model including sudden traction changes. The results showed that the method used was a powerful tool for modeling underground openings under various external as well as internal loads. Eccentric loads significantly influenced the stress pattern of the surrounding tunnel. The achievements can be practically used in completing and modifying regulations for stability investigation of shallow tunnels.
Partially Loaded Cavity Analysis by Using the 2-D FDTD Method
International Nuclear Information System (INIS)
A compact two-dimensional (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 inhomogeneous cylindrical cavity and a cubic cavity loaded with dielectric post, are presented to validate the utility and efficiency of the proposed method. (cross-disciplinary physics and related areas of science and technology)
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.
Diffusion and bulk flow in phloem loading - a theoretical analysis of the polymer trap mechanism
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...
Vibration Analysis of a Simply Supported Beam Traversed by Uniform Distributed Moving Load
Institute of Scientific and Technical Information of China (English)
Yu YANG; Nian-guan TENG; Yian-feng TENG
2004-01-01
Considering the engineering background of some transportation system like maglev, vertical vibration of the simply supported beam is investigated. The length of the vehicle is assumed to be longer than the beam span. The model of moving distributed load with constant speed is established .The beam can be taken as Euler-Bernoulli beam model and the right side of the control equation is simplified by using a moving status function. Duhamel integral and mode superposition method is used to solve the dynamic behavior of the beam. In this aspect deflection and acceleration are included. The results of different parameters such as the span of beam, velocity of load and ratio vehicle-Beam masses are compared. All results show that the dynamic response of the beam is tied up with these factors: the frequency of the beam, the moving frequency of the load and the ratio of vehicle-beam mass.
Numerical analysis of high strain rate failure of electro-magnetically loaded steel sheets
Erice, Borja; Mohr, Dirk
2015-09-01
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.
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.
Koutromanos, Ioannis
2011-01-01
Masonry-infilled reinforced concrete (RC) frames constitute a significant part of the building inventory in earthquake-prone regions around the world. The development of accurate analysis tools and of retrofit techniques is important for enhancing the seismic safety of older construction of this type. Most of the existing analytical approaches have either adopted simplified models with limited predictive capabilities or been restricted to the monotonic loading regime. Additionally, many of th...
Desing analysis and development of a nacelle main load frame for a 500 kW wind turbin
Pehlivan, Selim Ahmet
2012-01-01
Wind energy is gaining increasing momentum over the last two decades. Wind energy business is one of the most attractive in renewable energy sectors. While several wind turbine designs are available in the industry, developing a wind turbine for continuous commercial electricity production is one of the challenging engineering problems in todays world. This work involves design, analysis and development of a nacelle main load frame for a 500kw wind turbine as part of the national wind turbine...
Czech Academy of Sciences Publication Activity Database
Vilhelm, J.; Rudajev, Vladimír; Lokajíček, Tomáš; Veverka, Ján
2008-01-01
Roč. 41, č. 5 (2008), s. 695-714. ISSN 0723-2632 R&D Projects: GA ČR GA205/04/0088; GA ČR GA205/06/0906 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z30460519 Keywords : rock sample * ultrasonic emission * cracks nucleation * autocorrelation analysis * laboratory loading Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.589, year: 2008
Analysis and design of load-bearing structure of a multi-residential building in Novo mesto
Kocman, Luka
2013-01-01
This thesis presents the analysis and design of load-bearing elements of reinforced concrete supporting structure of the multi-residential building in the village Podbreznik in Novo mesto. The supporting structure is made of full interfloor plates, roof plate and the unconnected and connected walls with or without openings. Two dimensioned supporting elements, namely the ceiling panel in the 1st floor and the wall with openings on the circumference of building, are analyzed in detail. The ana...
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.
Finite element dynamic analysis of finite beams on a bilinear foundation under a moving load
Castro Jorge, P.; Pinto da Costa, A.; Simões, F. M. F.
2015-06-01
The present paper is concerned with the behaviour of finite elastic beams, acted by a moving transverse concentrated load, interacting with elastic foundations of different stiffnesses in compression and in tension. Using finite element analyses, the displacement amplitudes and the critical velocities of the load on a UIC-60 rail are computed and their dependence with respect to the difference between the foundation's moduli in compression and in tension is evaluated. The limit case of a tensionless foundation is as well analyzed. The numerical algorithm relies on the internal force vectors and tangent stiffness matrices computed exactly with automatic symbolic manipulation.
Effect of kraft dead load on recovery boiler performance: a theoretical analysis
Energy Technology Data Exchange (ETDEWEB)
Blackwell, B.; MacCallum, C.
1987-07-01
Reduced liquor dead load decreases fireside deposit formation in recovery boilers. Reduced dead load also increases temperatures in the lower furnace, providing many advantages, including decreased total reduced sulphur emissions and a higher reduction efficiency. Boiler thermal efficiency is improved. It was estimated that by applying a process based on partial evaporation of white liquor, the capacity of one Babcock and Wilcox boiler could be increased by about 7%. A portion of this increase could be achieved by other process measures directed at increasing the causticizing and reduction efficiency. 19 refs., 1 tab.
S. Tauqeer ul Islam Rizvi; Lin-shu He; Da-jun Xu
2015-01-01
The objective of the paper is to compute the optimal burn-out conditions and control requirements that would result in maximum down-range/cross-range performance of a waverider type hypersonic boost-glide (HBG) vehicle within the medium and intermediate ranges, and compare its performance with the performances of wing-body and lifting-body vehicles vis-à-vis the g-load and the integrated heat load experienced by vehicles for the medium-sized launch vehicle under study. Trajectory optimization...
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
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.
Single and multi degree of freedom analysis of steel beams under blast loading
International Nuclear Information System (INIS)
Highlights: ► Experimentally tested beams under blast are analyzed using SDOF and MDOF models. ► SDOF model adequately captures the time dependant deformations and internal forces. ► Constant DIF based on a low strain rate leads to conservative estimate of the DIF. ► The responses of the test beams are governed by the first mode of vibration. - Abstract: This paper presents detailed analysis of the results of field tests on 13 full scale wide flange steel beams subjected to blast loads generated by the detonation of up to 250 kg of ANFO explosive. The experimental results are analyzed using an equivalent Single-Degree-of-Freedom (SDOF) model of a beam, which includes material nonlinearity and strain rate effects. To account for strain rate effect on beam stiffness and strength, its full moment-curvature response is determined by dividing its cross-section into a number of layers and a strain rate-dependent stress-strain relationship, based on the Cowper–Symonds strain rate model, is used to capture the nonlinear stress distribution over the section. To determine the effects of higher modes of vibration and the variation of beam mechanical properties along its length on its dynamic response, the test beams are also analyzed using a Multi-Degree-of-Freedom (MDOF) model involving beam finite elements. Each element has two nodes and three degrees of freedom and is again divided into a number of layers to capture the strain rate effect and nonlinear stress distribution over its depth. The predicted displacements and strains by the two models are compared with the corresponding experimental data and the results show that for the given beams, the time-dependant deformations, internal forces, and moments can be adequately predicted by either model because the first mode of vibration is found to dominate their response; however, the use of a constant strain rate through the so-called Dynamic Increase Factor (DIF) can lead to highly conservative estimate of the
Elrod, David; Christensen, Eric; Brown, Andrew
2011-01-01
At NASA/MSFC, Structural Dynamics personnel continue to perform advanced analysis for the turbomachinery in the J2X Rocket Engine, which is under consideration for the new Space Launch System. One of the most challenging analyses in the program is predicting turbine blade structural capability. Resonance was predicted by modal analysis, so comprehensive forced response analyses using high fidelity cyclic symmetric finite element models were initiated as required. Analysis methodologies up to this point have assumed the flow field could be fully described by a sector, so the loading on every blade would be identical as it travelled through it. However, in the J2X the CFD flow field varied over the 360 deg of a revolution because of the flow speeds and tortuous axial path. MSFC therefore developed a complex procedure using Nastran Dmap's and Matlab scripts to apply this circumferentially varying loading onto the cyclically symmetric structural models to produce accurate dynamic stresses for every blade on the disk. This procedure is coupled with static, spin, and thermal loading to produce high cycle fatigue safety factors resulting in much more accurate analytical assessments of the blades.
Navarro-Zafra, J.; Curiel-Sosa, J. L.; Serna Moreno, M. C.
2016-04-01
A three-dimensional structural integrity analysis using the eXtended Finite Element Method (XFEM) is considered for simulating the crack behaviour of a chopped fibre-glass-reinforced polyester (CGRP) cruciform specimen subjected to a quasi-static tensile biaxial loading. This is the first time this problem is accomplished for computing the stress intensity factors (SIFs) produced in the biaxially loaded area of the cruciform specimen. A static crack analysis for the calculation of the mixed-mode SIFs is carried out. SIFs are calculated for infinite plates under biaxial loading as well as for the CGRP cruciform specimens in order to review the possible edge effects. A ratio relating the side of the central zone of the cruciform and the crack length is proposed. Additionally, the initiation and evolution of a three-dimensional crack are successfully simulated. Specific challenges such as the 3D crack initiation, based on a principal stress criterion, and its front propagation, in perpendicular to the principal stress direction, are conveniently addressed. No initial crack location is pre-defined and an unique crack is developed. Finally, computational outputs are compared with theoretical and experimental results validating the analysis.
Load flow solution with induction motor
Pichai Aree
2006-01-01
The classical constant-power load model is usually employed for load flow analysis. Since the actual loads of power systems mostly have nonlinear voltage-dependent characteristics, integration of nonlinear load models into load flow algorithm is essential to get better and accurate results of load flow analysis. In this paper, the conventional load flow algorithm is modified to incorporate the nonlinear model of induction motor load. The algorithm efficiency of the modified load flow has been...
International Nuclear Information System (INIS)
Risk management in the electric power industry involves measuring the risk for all instruments owned by a company. The value of many of these instruments depends directly on electricity prices. In theory, the wholesale price in a real-time market should reflect the short-run marginal cost. However, most markets are not perfectly competitive, therefore by understanding the degree of correlation between price and physical drivers, electric traders and consumers can manage their risk more effectively and efficiently. Market data from two power-pool architectures, both pre-2003 ISO-NE and Australia's NEM, have been studied. The dynamic character of electricity price is mean-reverting, and consists of intra-day and weekly variations, seasonal fluctuations, and instant jumps. Parts of them are affected by load demands. Hourly signals on both price and load are divided into deterministic and random components with a discrete Fourier transform algorithm. Next, the real-time price-load relationship for periodic and random signals is examined. In addition, time-varying volatility models are constructed on random price and random load with the GARCH model, and the correlation between them analysed. Volatility plays a critical role on evaluating option pricing and risk management. (author)
Action Analysis for Ice, Wind and Electro Dynamic Loads in Spans with Arbitrary Wire Layout
Sergey, I.; Y. Bladyko; Y. Panamarenka; B. Tsemekhman; Tarasov, V.
2014-01-01
The paper considers problems pertaining to design of electrical power transmission line spans and switchgears with flexible conductors with due account of wind, ice and electro-dynamic loads. Impact evaluation assesses an influence of inter-phase insulating spacers on maximum rapprochement and tensile of flexible conductors at their electro-dynamic interaction.
Action Analysis for Ice, Wind and Electro Dynamic Loads in Spans with Arbitrary Wire Layout
Directory of Open Access Journals (Sweden)
I. Sergey
2014-09-01
Full Text Available The paper considers problems pertaining to design of electrical power transmission line spans and switchgears with flexible conductors with due account of wind, ice and electro-dynamic loads. Impact evaluation assesses an influence of inter-phase insulating spacers on maximum rapprochement and tensile of flexible conductors at their electro-dynamic interaction.
Performance optimum analysis and load matching of an energy selective electron heat engine
International Nuclear Information System (INIS)
A new model of the energy selective electron (ESE) heat engine with a variable bias voltage resulting from a variable load resistance is established. Analytical expressions for the power output and efficiency of the system are derived, based on the Fermi–Dirac distribution of electrons. The general performance characteristics of the system are revealed. The effects of the energy level of the central position of the filter, chemical potential, and load resistance on the performance of the system are discussed in detail. It is found that as long as the position of the filter is suitably designed, the maximum electric current may be obtained at zero load. The optimal values of two important parameters, the energy level of the central position of the filter and chemical potential or load resistance, are calculated for differently operating states, and consequently, two important criteria on the parametric optimum design are obtained. These results obtained here may provide some guidance for the optimum design of ESE heat engines. -- Highlights: ► A new model of the energy selective electron heat engine is established. ► The maximum power output and electric current are calculated under different conditions. ► The effects of two key parameters on the performance of the system are discussed. ► The general performance characteristics of the system are revealed. ► Two important criteria of the parametric optimum design are obtained.
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
This paper deals with loop connections loaded in tension. Such connections; also known as U-bar joints, are frequently used in practice to establish continuity between precast deck elements in steel–concrete composite bridges. The tensile strength of a loop connection may either be governed by...
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…
Residual dent in locally loaded foam core sandwich structures – Analysis and use for NDI
Koissin, Vitaly; Shipsha, Andrey
2008-01-01
This paper addresses the residual denting in the face sheet and corresponding core damage in a locally loaded flat sandwich structure with foam core. The problem is analytically considered in the context of elastic bending of the face sheet accompanied by non-linear deformation of the crushed foam c
Kim, Seong-un; Lim, Sung-man; Kim, Eun-ae; Yang, Il-ho
2016-01-01
This study is for the implication of editorial design in science textbooks which are designed for student-centered instruction, when the elements of the editorial design are different, we focus on how the students' eye movement and cognitive load change. For this, we produced a new book for 5th grade students in elementary school that is modified…
Analysis of the influence of the loading applied during the cooling phase of WPS tests
International Nuclear Information System (INIS)
The Reactor Pressure Vessel is an essential component liable to limit the life duration of PWR's. Its behaviour in service is limited in time due to the embrittling effects of irradiation. The safety analyses made at the European level study the behaviour of defects in the vessel subject to loading resulting from thermal transients. These analyses do not take into account the effect of load history/warm pre-stressing (WPS) of the defects, which is observed in a wide range of experimental studies. The non-consideration of the beneficial effect of this physical phenomenon has two major consequences: - a poor knowledge of the real margins associated with the transients to which the vessel is subjected, - an economical penalty due to large under-estimation of the life duration of the vessel. This paper presents the results of our WPS tests performed on a CT specimen manufactured with 18MND5 steel with different types of loading during the cooling phase applied as follow: case 1: constant force value maintained case 2: constant crack mouth opening displacement maintained during cooling phase case 3: oscillating force value decreasing case 4: oscillating force value maintained. WPS effect is observed in the cases 1, 3 and 4 and failure occurs during the crossing of the transition curve in the case 2 because of the monotone increase of the force due to CMOD maintained. Case 3 and 4 show that WPS effect is fundamentally an effect of the loading history. (orig.)
Fracture analysis of concrete under dynamic loading on the basis of the cohesive crack model
International Nuclear Information System (INIS)
The mechanical relationship between motions and input forces of nodes along cohesive crack surfaces are investigated by using the substructure technique in order to develop a numerical method for fracture of concrete under dynamic loading. An outline of the computational procedure of the method using the relationships is demonstrated. (author)
Analysis of inter-fragmentary movement as a function of musculoskeletal loading conditions in sheep.
Duda, G N; Eckert-Hübner, K; Sokiranski, R; Kreutner, A; Miller, R; Claes, L
1998-03-01
It is well accepted that inter-fragmentary movement influences the fracture healing process. Small axial movement can stimulate callus formation whereas larger shear movement delays the healing process. It is, therefore, essential for optimal fracture healing to minimize shear and to control axial movement. Unfortunately, the complex gap movements are mostly unknown under the large variety of clinical as well as experimental conditions of fracture fixation. To further understand the complex interactions of musculoskeletal loading and inter-fragmentary movements in bones and to reduce the need for animal experiments, a three-dimensional (3D) musculoskeletal model of the left hind limb of a sheep was developed. From 3D ground reaction forces and inverse dynamics, resultant joint loading was determined over a gait cycle. Muscle and joint contact forces were derived from an optimization routine and internal loads in the tibia and metatarsus from beam theory. Finally, inter-fragmentary movements were calculated from the bony loading condition and experimentally determined stiffness matrices of monolateral AISF external fixator constructs. Both the joint contact forces at the hip and gap movement of a mid-shaft tibial fracture agree with in vivo data reported in the literature. The bones proved to be mainly axially loaded with slightly increasing shear forces toward their ends. The results suggest that inter-fragmentary movement of metatarsal fractures is fairly independent of the fracture location whereas the movement increases in proximal tibial fractures compared to those in the distal and diaphyseal tibia. Considerable shear movement was found for all locations and external fixator mountings. However, shear movement could be minimized with a cranio-lateral rather than a cranio-medial shift from the cranial fixator plane. PMID:9645534
Reliability Analysis of Traditional and Ballistic Bench Press Exercises at Different Loads.
García-Ramos, Amador; Padial, Paulino; García-Ramos, Miguel; Conde-Pipó, Javier; Argüelles-Cienfuegos, Javier; Štirn, Igor; Feriche, Belén
2015-09-29
The purpose of this study was to determine test-retest reliability for peak barbell velocity (Vpeak) during the bench press (BP) and bench press throw (BPT) exercises for loads corresponding to 20-70% of one-repetition maximum (1RM). Thirty physically active collegiate men conducted four evaluations after a preliminary BP 1RM determination (1RM·bw-1 = 1.02 ± 0.16 kg·kg-1). In counterbalanced order, participants performed two sessions of the BP in one week and two sessions of the BPT in another week. Recovery time between sessions within the same week was 48 hours and recovery time between sessions of different weeks was 120 hours. On each day of evaluation the individual load-velocity relationship at each tenth percentile (20-70% of 1RM) in a Smith machine for the BP or BPT was determined. Participants performed three attempts per load, but only the best repetition (highest Vpeak), registered by a linear position transducer, was analysed. The BPT resulted in a significantly lower coefficient of variation (CV) for the whole load-velocity relationship, compared to the BP (2.48% vs. 3.22%; p = 0.040). Test-retest intraclass correlation coefficients (ICCs) ranged from r = 0.94-0.85 for the BPT and r = 0.91-0.71 for the BP (p < 0.001). The reduction in the biological within-subject variation in BPT exercise could be promoted by the braking phase that obligatorily occurs during a BP executed with light or moderate loads. Therefore, we recommend the BPT exercise for a most accurate assessment of upper-body velocity. PMID:26557190
International Nuclear Information System (INIS)
The static method for the evaluation of the limit loads of a perfectly elasto-plastic structure is presented. Using the static theorem of Limit Analysis and the Finite Element Method, a lower bound for the colapso load can be obtained through a linear programming problem. This formulation if then applied to symmetrically loaded shells of revolution and some numerical results of limit loads in nozzles are also presented. (Author)
International Nuclear Information System (INIS)
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
Peloquin, John M; Elliott, Dawn M
2016-04-01
Cracks in fibrous soft tissue, such as intervertebral disc annulus fibrosus and knee meniscus, cause pain and compromise joint mechanics. A crack concentrates stress at its tip, making further failure and crack extension (fracture) more likely. Ex vivo mechanical testing is an important tool for studying the loading conditions required for crack extension, but prior work has shown that it is difficult to reproduce crack extension. Most prior work used edge crack specimens in uniaxial tension, with the crack 90° to the edge of the specimen. This configuration does not necessarily represent the loading conditions that cause in vivo crack extension. To find a potentially better choice for experiments aiming to reproduce crack extension, we used finite element analysis to compare, in factorial combination, (1) center crack vs. edge crack location, (2) biaxial vs. uniaxial loading, and (3) crack-fiber angles ranging from 0° to 90°. The simulated material was annulus fibrosus fibrocartilage with a single fiber family. We hypothesized that one of the simulated test cases would produce a stronger stress concentration than the commonly used uniaxially loaded 90° crack-fiber angle edge crack case. Stress concentrations were compared between cases in terms of fiber-parallel stress (representing risk of fiber rupture), fiber-perpendicular stress (representing risk of matrix rupture), and fiber shear stress (representing risk of fiber sliding). Fiber-perpendicular stress and fiber shear stress concentrations were greatest in edge crack specimens (of any crack-fiber angle) and center crack specimens with a 90° crack-fiber angle. However, unless the crack is parallel to the fiber direction, these stress components alone are insufficient to cause crack opening and extension. Fiber-parallel stress concentrations were greatest in center crack specimens with a 45° crack-fiber angle, either biaxially or uniaxially loaded. We therefore recommend that the 45° center crack case be
Directory of Open Access Journals (Sweden)
Cardozo A.C.
2004-01-01
Full Text Available The aim of the present study was to assess the spectral behavior of the erector spinae muscle during isometric contractions performed before and after a dynamic manual load-lifting test carried out by the trunk in order to determine the capacity of muscle to perform this task. Nine healthy female students participated in the experiment. Their average age, height, and body mass (± SD were 20 ± 1 years, 1.6 ± 0.03 m, and 53 ± 4 kg, respectively. The development of muscle fatigue was assessed by spectral analysis (median frequency and root mean square with time. The test consisted of repeated bending movements from the trunk, starting from a 45º angle of flexion, with the application of approximately 15, 25 and 50% of maximum individual load, to the stand up position. The protocol used proved to be more reliable with loads exceeding 50% of the maximum for the identification of muscle fatigue by electromyography as a function of time. Most of the volunteers showed an increase in root mean square versus time on both the right (N = 7 and the left (N = 6 side, indicating a tendency to become fatigued. With respect to the changes in median frequency of the electromyographic signal, the loads used in this study had no significant effect on either the right or the left side of the erector spinae muscle at this frequency, suggesting that a higher amount and percentage of loads would produce more substantial results in the study of isotonic contractions.
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
Shepherd, Micah R; Fahnline, John B; Dare, Tyler P; Hambric, Stephen A; Campbell, Robert L
2015-11-01
Many structural acoustics problems involve a vibrating structure in a heavy fluid. However, obtaining fluid-loaded natural frequencies and damping experimentally can be difficult and expensive. This paper presents a hybrid experimental-numerical approach to determine the heavy-fluid-loaded resonance frequencies and damping of a structure from in-air measurements. The approach combines in-air experimentally obtained mode shapes with simulated in-water acoustic resistance and reactance matrices computed using boundary element (BE) analysis. The procedure relies on accurate estimates of the mass-normalized, in vacuo mode shapes using singular value decomposition and rational fraction polynomial fitting, which are then used as basis modes for the in-water BE analysis. The method is validated on a 4.445 cm (1.75 in.) thick nickel-aluminum-bronze rectangular plate by comparing natural frequencies and damping obtained using the hybrid approach to equivalent data obtained from actual in-water measurements. Good agreement is shown for the fluid-loaded natural frequencies and one-third octave loss factors. Finally, the limitations of the hybrid approach are examined. PMID:26627781
International Nuclear Information System (INIS)
The Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE) suite of programs can be used to organize and standardize in an electronic format information from probabilistic risk assessments or individual plant examinations. The Models and Results Database (MAR-D) program of the SAPHIRE suite serves as the repository for probabilistic risk assessment and individual plant examination data and information. This report demonstrates by examples the common electronic and manual methods used to load these types of data. It is not a stand alone document but references documents that contribute information relative to the data loading process. This document provides a more detailed discussion and instructions for using SAPHIRE 5.0 only when enough information on a specific topic is not provided by another available source
International Nuclear Information System (INIS)
Flow time analysis is a powerful concept to analyze the flow time of any arriving customer in any system at any instant. A load management mechanism can be employed very effectively in any queueing system by utilizing a system which provides probability of dual service rate. In this paper, we develop and demonstrate the flow and service processes transition diagram to determine the flow time of a customer in a load management late arrival state dependent finite discrete time queueing system with dual service rate where customers are hypo geometrically distributed. We compute the probability mass function of each starting state and total probability mass function. The obtained analytical results are validated with simulation results for varying values of arrival and service probabilities. (author)
Thermodynamic analysis of load-leveling hyper energy converting and utilization system
International Nuclear Information System (INIS)
Load-leveling hyper energy converting and utilization system (LHECUS) is a hybrid cycle which utilizes ammonia-water mixture as the working fluid in a combined power generation and refrigeration cycle. The power generation cycle functions as a Kalina cycle and an absorption refrigeration cycle is combined with it as a bottoming cycle. LHECUS is designed to utilize the waste heat from industry to produce cooling and power simultaneously. The refrigeration effect can be either transported to end-use sectors by means of a solution transportation absorption chiller (STA) as solution concentration difference or stored for demand load leveling. This paper shows a simulation of the LHECUS cycle. A computer model was written to balance the cycle and key parameters for optimizing the cycle were identified
ANALYSIS OF A DATABASE REPLICATION ALGORITHM UNDER LOAD SHARING IN NETWORKS
Directory of Open Access Journals (Sweden)
SANJAY KUMAR YADAV
2016-02-01
Full Text Available Recently, (PDDRA a Pre-fetching based dynamic data replication algorithm has been published. In our previous work, modifications to the algorithm have been suggested to minimize the delay in data replication. In this paper, a simulation framework is presented and results are obtained to estimate the throughput and average delay. The overall network is divided into two parts as local and global networks. The data requests are generated only at the local nodes. However, the service can be obtained form both local and global servers. In our previous work it has been found that the throughput and average delay heavily depends on buffer capacity of sever node and if server load is below 80% then, nearly 100% throughput is possible with very small average delay. In this paper, we have shown that shown the delay can be further minimized by sharing the load among servers, still throughput remains nearly 100 percent.
Quantitative damage and detwinning analysis of nanotwinned copper foil under cyclic loading
International Nuclear Information System (INIS)
High-purity Cu samples containing parallel columns of highly aligned nanotwins with median spacing of ∼25 nm were subjected to tension–compression cyclic loading by a high-throughput cyclic testing method. The methodology utilizes gradients in surface strain amplitude of a vibrating cantilever: one along the beam axis, with decreasing strain from the fixed to the free end of the beam, and the other through the foil thickness with decreasing strain from the surface to the neutral axis. Systematic microstructural investigations indicate that nanotwins are not stable under cyclic loading and that the applied strain amplitude has a strong influence on the resulting twin structure. In the highly stressed regions the detwinning process produces a twin free microstructure, allowing for subsequent extrusion and crack formation, and introduces fatal defects into structural parts
Aerothermal loads analysis for high speed flow over a quilted surface configuration
Olsen, G. C.; Smith, R. E.
1984-08-01
Attention is given to hypersonic laminar flow over a quilted surface configuration that simulates an array of Space Shuttle Thermal Protection System panels bowed in a spherical shape as a result of thermal gradient through the panel thickness. Pressure and heating loads to the surface are determined. The flow field over the configuration was mathematically modeled by means of time-dependent, three-dimensional conservation of mass, momentum, and energy equations. A boundary mapping technique was then used to obtain a rectangular, parallel piped computational domain, and an explicit MacCormack (1972) explicit time-split predictor corrector finite difference algorithm was used to obtain steady state solutions. Total integrated heating loads vary linearly with bowed height when this value does not exceed the local boundary layer thickness.
Lyle, Karen H.
2015-01-01
Acceptance of new spacecraft structural architectures and concepts requires validated design methods to minimize the expense involved with technology demonstration via flight-testing. Hypersonic Inflatable Aerodynamic Decelerator (HIAD) architectures are attractive for spacecraft deceleration because they are lightweight, store compactly, and utilize the atmosphere to decelerate a spacecraft during entry. However, designers are hesitant to include these inflatable approaches for large payloads or spacecraft because of the lack of flight validation. This publication summarizes results comparing analytical results with test data for two concepts subjected to representative entry, static loading. The level of agreement and ability to predict the load distribution is considered sufficient to enable analytical predictions to be used in the design process.
Energy Technology Data Exchange (ETDEWEB)
2014-09-01
This brochure addresses gaps in actionable knowledge that can 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. This brochure should be used to make these decisions so systems can operate more energy efficiently; upfront capital costs will also decrease. This information can also be used to drive changes in negotiations about PPL energy demands. It should enable brokers and tenants to agree about lower PPL capacities. Owner-occupied buildings will also benefit. Overestimating PPL capacity leads designers to oversize electrical infrastructure and cooling systems.
Experimental analysis of a t-stub component subjected to impact loading
Barata, Pedro; Santiago, Aldina; Rodrigues, João Paulo C.; Rigueiro, Constança
2014-01-01
After the accidents occurred during the first decade of this millennium, such as the World Trade Center (2001), London (2005) and Madrid (2004), special attention was given to the study of robust structures subjected to different accidental loads. The World Trade Center attack highlighted troublesome weakness in connections, which exhibited poor performance caused by brittle failure. Structural details played a very significant behavioural role when the structure is subjected to impulsive loa...
The effect of load imbalances on the performance of Monte Carlo algorithms in LWR analysis
International Nuclear Information System (INIS)
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
A computer analysis of heating and cooling loads for different types of building
Stritih, Uroš; Muhič, Simon; Novak, Peter
2015-01-01
This paper presents simulations of heating and cooling loads for different types of building with the TRNSYS programme package. We present seven different building types and four different weather conditions in the European Union. Altogether we made 28 simulations and the results for an office building are shown in this paper. Prispevek prikazuje simulacije ogrevalnih in hladilnih obremenitev za različne tipe stavb s programskim paketom TRNSYS. Prikazujemo sedem različnih tipov stavb in št...
Daniel S. Stutts; Dharani, Lokeswarappa R.; Shetty, Mahesh S; Jun Wei
2013-01-01
Wind loading and windborne debris (missile) impact are the two primary mechanisms that result in window glazing damage during hurricanes. Wind-borne debris is categorized into two types: small hard missiles; such as roof gravel; and large soft missiles representing lumber from wood-framed buildings. Laminated architectural glazing (LAG) may be used in buildings where impact resistance is needed. The glass plies in LAG undergo internal damage before total failure. The bulk of the published wor...
Finite element analysis of composite tubes with integral ends subjected to bending loads
Adams, Michael B.
1995-01-01
An analytical investigation was perfonned to study the effect of applied bending loads on laminated composite tubes. Elasticity-based linear models were developed using finite element software to predict stresses within the individual plies of the tubes. The tubes under investigation were graphite/epoxy laminated composites with a stacking sequence of [0/-45/+45/90/90/+45/ -45/0] X 2 (Sixteen plies per tube). End pieces of isotropic titanium were integrally constructed with bon...
Design of a bed load and driftwood filtering dam, analysis of the phenomena and hydraulic design
Schleiss, Anton; Speerli, J.; Pfammatter, Roger; Bianco-Riccioz, Manuella; Bianco, Philippe; De Cesare, Giovanni
2014-01-01
Flood protection often calls on to the realization of retention works for bed load as well as wood and debris flow. Certain relatively recent arrangements did not perform according to their intended function, what shows the complexity of the design and the implementation of such works. Adaptations were necessary to reach the security objectives. The design of a retention dam for solid materials and floating driftwood requires the consideration of numerous hydraulic and material transport proc...
Design of the overhead bridge crane beam and strenght analysis for given loads
Armán Morales, Sergio
2012-01-01
The main aim of the project is: for given loads, analyse and design (analytically and with Catia software) different beams for an overhead crane. For this purpose, it will be study the theory of cranes and structures calculation and from this theory I will design an algorithm that allows finding the necessary beam from de European standard metallic beam list. After obtaining the analytical and the software (Catia) results for each beam, it will be compare the results between them and presente...
Directory of Open Access Journals (Sweden)
S. Tauqeer ul Islam Rizvi
2015-12-01
Full Text Available The objective of the paper is to compute the optimal burn-out conditions and control requirements that would result in maximum down-range/cross-range performance of a waverider type hypersonic boost-glide (HBG vehicle within the medium and intermediate ranges, and compare its performance with the performances of wing-body and lifting-body vehicles vis-à-vis the g-load and the integrated heat load experienced by vehicles for the medium-sized launch vehicle under study. Trajectory optimization studies were carried out by considering the heat rate and dynamic pressure constraints. The trajectory optimization problem is modeled as a nonlinear, multiphase, constraint optimal control problem and is solved using a hp-adaptive pseudospectral method. Detail modeling aspects of mass, aerodynamics and aerothermodynamics for the launch and glide vehicles have been discussed. It was found that the optimal burn-out angles for waverider and wing-body configurations are approximately 5° and 14.8°, respectively, for maximum down-range performance under the constraint heat rate environment. The down-range and cross-range performance of HBG waverider configuration is nearly 1.3 and 2 times that of wing-body configuration respectively. The integrated heat load experienced by the HBG waverider was found to be approximately an order of magnitude higher than that of a lifting-body configuration and 5 times that of a wing-body configuration. The footprints and corresponding heat loads and control requirements for the three types of glide vehicles are discussed for the medium range launch vehicle under consideration.
International Nuclear Information System (INIS)
A variety of power generation complementary can reduce the large power fluctuation in the electrical power system caused by large-scale new energy power connected into grid. The quick power generation such as hydropower, gas power, and fuel power are the most suitable complementary power. However, they are very short in China; meanwhile the coal-fired power with slow rate of power change is dominant. Consequently, the coal-fired power has to increase its load change range and speed so as to undertake the job of power complementation in the electric power system. This paper proposes a method to improve the load change capacity for the water cooled power plants through controlling the cooling water flow. Then the CCWCS (condenser cooling water control system) is put forward to execute this method on the premise of unit safety. CCWCS can also reduce the coal consumption in steady turbine load conditions. Based on the modeling of condenser, variable speed pump for the condenser cooling water and the characteristics of turbine power output to condenser pressure, the paper presents the relationship between the cooling water flow and turbine power output. Finally, a case study on a 600,000 kW unit proves the feasibility of our idea. - Highlights: • Altering condenser pressure can fast and effectively change steam turbine's load. • Keep condensers under the optimum pressure can save more energy. • It is obligatory to keep the condenser pressure within safe boundary in any time. • We design an automatic system to put our above idea into practice
Numerical analysis of singly curved shallow composite panels under three-point bend load
Guedes, RM; Alcides Sa
2008-01-01
The experimental methodology to test curved panels under three-point bend (3PB) load is assessed. The problem arises when mechanical and strength characterization of pipe material systems is required. Test specimens cut out from pipe samples oriented in the tangential direction were used to measure hoop modulus and strength. In this procedure singly curved beams with the same radius as the pipe are obtained. The present assessment was made using three different approaches: Finite Element Meth...
Stress-strain analysis of specimens subjected to tensile loading during moisture uptake
Angelos Mintzas; Rui Miranda Guedes; Andrey Aniskevich
2015-01-01
Abstract: A robust and efficient numerical method for the calculation of the internal stress state that develops within structures subjected to mechanical and steady state or transient hygroscopic loading conditions, has been developed. The method encompasses a layer by layer approach whereby the structure is discretised into plies with different material properties corresponding to thedifferent ply moisture content. The proposed method has been validated against finite element solutions, and...
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)
无
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...
Stiffness Analysis of Nail-Plate Joints Subjected to Short-Term Loads
DEFF Research Database (Denmark)
Nielsen, Jacob
In Denmark it has been old tradition to use timber in all kinds of structures. In particular, timber has been widely used for the load-bearing structures in roofs, waals, and floors. Today timber is used for structures as roof trusses and floor joists almost only. Timber structures are made with ...... requires a hydraulic pressing tool to embed the nails into the wood. Only joints with a nail-plate of the latter type will be analysed in this thesis....
Reliability Analysis of Traditional and Ballistic Bench Press Exercises at Different Loads
Directory of Open Access Journals (Sweden)
García-Ramos Amador
2015-09-01
Full Text Available The purpose of this study was to determine test–retest reliability for peak barbell velocity (Vpeak during the bench press (BP and bench press throw (BPT exercises for loads corresponding to 20–70% of one-repetition maximum (1RM. Thirty physically active collegiate men conducted four evaluations after a preliminary BP 1RM determination (1RM·bw-1 = 1.02 ± 0.16 kg·kg-1. In counterbalanced order, participants performed two sessions of the BP in one week and two sessions of the BPT in another week. Recovery time between sessions within the same week was 48 hours and recovery time between sessions of different weeks was 120 hours. On each day of evaluation the individual load-velocity relationship at each tenth percentile (20–70% of 1RM in a Smith machine for the BP or BPT was determined. Participants performed three attempts per load, but only the best repetition (highest Vpeak, registered by a linear position transducer, was analysed. The BPT resulted in a significantly lower coefficient of variation (CV for the whole load–velocity relationship, compared to the BP (2.48% vs. 3.22%; p = 0.040. Test–retest intraclass correlation coefficients (ICCs ranged from r = 0.94-0.85 for the BPT and r = 0.91-0.71 for the BP (p < 0.001. The reduction in the biological within-subject variation in BPT exercise could be promoted by the braking phase that obligatorily occurs during a BP executed with light or moderate loads. Therefore, we recommend the BPT exercise for a most accurate assessment of upper-body velocity.
Nonlinear analysis for a reinforced concrete frame structure under extreme loads
Catalin BACIU; Marin LUPOAE
2012-01-01
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. Ev...
MODELING AND ANALYSIS OF DISTRIBUTION LOAD CURRENTS PRODUCED BY AN AD JUSTABLE SPEED DRIVE HEAT PUMP
Hoffman, Stephen Paul
1993-01-01
A number of demand side management techniques have been proposed for the efficient use of electric power in the commercial and residential sector. The adjustable speed drive heat pump is a technology which has the prospect of decreasing power demands for space heating. This design has the advantage over conventional designs of higher efficiency and, potentially, reduction of peak power demand. Its main disadvantage is higher cost. Further, it has the disadvantage that it produces a load curre...
Rekha Parashar; Shashikant,
2015-01-01
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 re...
Helland, Torunn Husevåg
2015-01-01
This thesis concerns the stability of diode bridge rectifier-loaded synchronous generators characterized by large values of synchronous, transient and subtransient reactances in the d- and q-axis, with the possibility of connecting a battery-bank. The synchronous reactances are in the range 2.5-5.5pu. The electrical system studied is installed in two tug-ships using two different types of generators, with different ranges of generator reactances and performance. One of the tugships studie...
Jiří Witzany; Radek Zigler
2016-01-01
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 cra...
International Nuclear Information System (INIS)
In this report, further investigations of the model concept for radionuclide transport in stream, developed in the SKB report TR-05-03 is presented. Especially three issues have been the focus of the model investigations. The first issue was to investigate the influence of assumed channel geometry on the simulation results. The second issue was to reconsider the applicability of the equation for the bed-load transport in the stream model, and finally the last issue was to investigate how the model discretisation will influence the simulation results. The simulations showed that there were relatively small differences in results when applying different cross-sections in the model. The inclusion of the exact shape of the cross-section in the model is therefore not crucial, however, if cross-sectional data exist, the overall shape of the cross-section should be used in the model formulation. This could e.g. be accomplished by using measured values of the stream width and depth in the middle of the stream and by assuming a triangular shape. The bed-load transport was in this study determined for different sediment characteristics which can be used as an order of magnitude estimation if no exact determinations of the bed-load are available. The difference in the calculated bed-load transport for the different materials was, however, found to be limited. The investigation of model discretisation showed that a fine model discretisation to account for numerical effects is probably not important for the performed simulations. However, it can be necessary for being able to account for different conditions along a stream. For example, the application of mean slopes instead of individual values in the different stream reaches can result in very different predicted concentrations
Stochastic analysis of wind loaded light-frame low-rise buildings using simplified models
Czech Academy of Sciences Publication Activity Database
Fischer, Cyril; Kasal, Bohumil
Vol. 9. Portland, OR : Bender , Donald A, 2006 - ( Bender , D.; Gromala, D.; Rosowsky, D.). s. 1-8 [Conference on timber engineering -WCTE 2006 /9./. 06.08.2006-10.08.2006, Portland, OR] R&D Projects: GA ČR(CZ) GP103/03/P080 Institutional research plan: CEZ:AV0Z20710524 Keywords : timber structures * wind loading * simplified model Subject RIV: JM - Building Engineering
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.
The safety analysis concept of welded components under cyclic loads using fracture mechanics method
Al-Mukhtar, Ahmed
2010-01-01
Fracture Mechanics process of Welded Joint is a very vast research area and has many possibilities for solution and prediction. Although the fatigue strength (FAT) and stress intensity factor (SIF) solutions are reported in several handbooks and recommendations, these values are available only for a small number of specimens, components, loading and welding geometries. The available solutions are not always adequate for particular engineering applications. Moreover, the reliable solutions of ...
Fangping Liu; Jianting Zhou
2016-01-01
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 equation...
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.
Thermal hydraulic analysis of thorium fuel assemblies loaded with annular seed pins
International Nuclear Information System (INIS)
Thermal hydraulic characteristics of thorium-based fuel assemblies loaded with annular seed pins have been analyzed using MATRAA combined with MATRA, and compared with those of the existing thorium-based assemblies. MATRA and MATRAA showed good agreements for the pressure drops at the internal subchannels. The pressure drop generally increased in the cases of the assemblies loaded with annular seed pins due to the larger wetted perimeter, but an exception existed. In the inner subchannels of the seed pins, mass fluxes were high due to the grid form losses in the outer subchannels. About 43% of the heat generated from the seed pin flowed into the inner subchannel and the rest into the outer subchannel, which implies the inner to outer wall heat flux ratio was approximately 1.2. The maximum temperatures of the annular seed pins were slightly above 500 qC. The MDNBRs of the assemblies loaded with annular seed pins were higher than those of the existing assemblies. Due to the fact that interchannel mixing cannot occur in the inner subchannels, temperatures and enthalpies were higher in the inner subchannels
Analysis of Load Management in LTE%LTE中负荷管理功能分析
Institute of Scientific and Technical Information of China (English)
王毅
2011-01-01
负荷管理功能是LTE的E-UTRAN系统中RRM的一个重要组成部分.通过分析LTE系统中eNB负荷过载的场景,引出负荷管理功能的必要性,并进一步分析了负荷参量表示及负荷管理功能的主要处理内容,对于移动通信系统负荷管理功能及其他RRM功能的设计、实现具有很强的指导意义.%Load management is main function of RRM in LTE E-UTRAN system. On the basis of analyzing the scene of eNB overload in LTE, the necessity of load management is introduced, the measure parameter and design of load management are described. It is important to instruct the architecture design and realization of function of mobile communication system and its RRM function.
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.
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.
Load Flow and Short Circuit Analysis of the Class III Power System of HANARO
International Nuclear Information System (INIS)
The planning, design, and operation of electric power system require engineering studies to assist in the evaluation of the system performance, reliability, safety and economics. The Class III power of HANARO supplies power for not only HANARO but also RIPF and IMEF. The starting current of most ac motors is five to ten times normal full load current. The loads of the Class III power are connected in consecutive orders at an interval for 10 seconds to avoid excessive voltage drop. This technical report deals with the load flow study and motor starting study for the Class III power of HANARO using ETAP(Electrical Transient Analyzer Program) to verify the capacity of the diesel generator. Short-circuit studies are done to determine the magnitude of the prospective currents flowing throughout the power system at various time intervals after a fault occurs. Short-circuit studies can be performed at the planning stage in order to help finalize the system layout, determine voltage levels, and size cables, transformers, and conductors. From this study, we verify the short circuit current capacity of air circuit breaker(ACB) and automatic transfer switch(ATS) of the Class III power
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.
Directory of Open Access Journals (Sweden)
Daniel S. Stutts
2013-05-01
Full Text Available Wind loading and windborne debris (missile impact are the two primary mechanisms that result in window glazing damage during hurricanes. Wind-borne debris is categorized into two types: small hard missiles; such as roof gravel; and large soft missiles representing lumber from wood-framed buildings. Laminated architectural glazing (LAG may be used in buildings where impact resistance is needed. The glass plies in LAG undergo internal damage before total failure. The bulk of the published work on this topic either deals with the stress and dynamic analyses of undamaged LAG or the total failure of LAG. The pre-failure damage response of LAG due to the combination of wind loading and windborne debris impact is studied. A continuum damage mechanics (CDM based constitutive model is developed and implemented via an axisymmetric finite element code to study the failure and damage behavior of laminated architectural glazing subjected to combined loading of wind and windborne debris impact. The effect of geometric and material properties on the damage pattern is studied parametrically.
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.
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
A PERFORMANCE ANALYSIS OF LOAD BALANCED DEFLECTION ROUTING WITH PRIORITY SCHEDULING IN OBS NETWORKS
Directory of Open Access Journals (Sweden)
V.KAVITHA
2013-04-01
Full Text Available Burst contention is one of the major problems in optical burst switching networks. When two or more bursts request for same output wavelength channel at the same time, contention may occur. Deflection routing is one of the methods used to resolve contention in optical Network, where one of the contending burst is deflected to alternate path rather than primary path to reach the destination. Deflected path does not consider the load balancing at the router that leads loss of bursts. This paper introduces a new method of contention resolution Load Balanced Deflection Routing (LBDR where the load balancing is done at the router by which the least congested path is selected as alternate path to deflect the congested burst. The reservation scheduled for a deflected burst can be exempted by non deflected burst by preemptive priority scheduling. By simulation results, we show that our proposed scheme (LBDR outperforms Contention based Limited Deflection Routing (CLDR in terms of throughput and packet delivery ratio with less delay.
International Nuclear Information System (INIS)
The package used to transport radioactive spent fuel, which is called by flask, must maintain the structural integrity for the requirements of hypothetical accident conditions, the 1.6 m free drop impact. These requirements for the flask design should be verified through test or finite element analysis to confirm the regulatory guide. In this paper, three dimensional impact analysis using ABAQUS/Explicit code under the 1.6 m free drop impact condition for the flask loaded in protective device is performed to simulate real operating situation of that. In the FE-analysis, symmetric analysis model of the flask loaded in protective device in used and reduced integration 3D solid element is applied. The 1.6 m free drop impact condition in simulated as initial impact velocity, 5.6 m/s. As the results, maximum stress intensity on each part of the flask and maximum deformation of the lead radiation shield of the flask is calculated and the structural intensity of the flask is evaluated
International Nuclear Information System (INIS)
The main objective of this thesis is the fatigue behavior of concrete under high-cycle compressive loadings. Current knowledge about fatigue behavior of concrete is still incomplete. This concerns especially the process of fatigue which is preceding the fatigue failure. The leak of knowledge about fatigue behavior is opposed to the steady growing importance of this topic within the practice in civil engineering. Therefore, within this thesis a systematic and comprehensive investigation of the process of fatigue itself was done. This contributes to the better understanding of the progression of damage and the corresponding processes within the material. The experimental investigation consisted mainly of experiments with constant amplitude loadings in compression with cylindrical specimen made of normal strength concrete. Two differed load levels were used which resulted in numbers of cycles to failure of 106 and 107 as well as 103 and 104. The experiments were done in combination with different types of nondestructive and destructive testing methods like strain measuring, deformation of surface, ultrasonic signals, acoustic emissions, optical microscopy and also scattering electron microscopy. To access some parameters of influence in relation to the fatigue behavior additional creep tests and also several tests with different scales of specimen were done. The fatigue process of concrete is determined as an evolution of damage that starts from the beginning of the loading process. This evolution has manifold and different influences on the different material properties of concrete. In this relation a major finding was that fatigue related damage leads to a transformation of the complete stress-strain-relationship. This relationship is also subjected to an evolution process. Due to the authors observations it could not be determined that the investigated changes in macroscopic material behavior are caused by a development of micro cracks within the material structure
International Nuclear Information System (INIS)
In the framework of the activities concerning the safety of nuclear power plants (NPP) in Middle- and East Europe among others the behaviour of the reactor cavity bottom ceiling of a NPP of type WWER-1000 impinged by impact loads due to the postulated failure of the lower head of the reactor pressure vessel (RPV-LH) caused by an assumed core melt accident has been investigated. For the investigations of the structure dynamical behaviour of the reactor cavity ceiling the AUTODYN-Code was used. This code is using an explicit solver and is suitable particularly for the simulation of impact problems. For the investigations on the load bearing capacity of the cavity ceiling an axisymmetric Finite Element (FE) model of both the RPV-LH made of steel and the reactor cavity ceiling with detailed consideration of the reinforcement in the concrete was generated. The effects of the rebars were simulated by shell elements with adequate cross-sections based on the number of rebars. To represent the load and temperature dependent deformation of the heated RPV-LH during the impact phase the FE-model has steel layers of different temperature dependent material properties representing the assumed temperature distribution over the wall thickness at postulated failure. The assumed molten core material located above the inner surface of the RPV-LH is taken into account by adjusting the density of the lower head. In the dynamic calculations the internal pressure conditions at the time of failure and consequently the impact velocity were varied. The calculations show the damage of the concrete and the strains in the reinforcement were assessed by adequate failure criteria. (authors)
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.
Public policy analysis of energy efficiency and load management in changing electricity businesses
International Nuclear Information System (INIS)
The focus of this paper is (1) the potential effectiveness of the reform of the electricity industry on promoting energy efficiency and load management, and (2) the potential effectiveness of new mechanisms for promoting energy efficiency and load management. Many countries are initiating reforms of their power sectors to stimulate private investment, increase operation and management efficiencies, and lower the cost of power. These countries are unbundling vertically integrated utilities into distinct generation, transmission, distribution and retail supply companies; introducing commercial management principles to government-owned monopolies; and in many cases transferring operation or ownership to private companies. Electric industry restructuring may force regulators and policy makers to re-examine existing mechanisms for promoting load management and energy efficiency. In some cases, electric industry restructuring replaces the long-standing relationship between a single monopoly provider and protected customer franchise with a new set of relationships among retail electricity suppliers and customers who may now be free to choose suppliers. In these types of situations, markets, not government regulators and utility monopolies, are seen as determining future energy production and consumption decisions. However, it is uncertain whether this type of restructuring will overcome important market barriers to energy efficiency that limit markets for energy-efficient products and services from functioning effectively. As a result of these barriers, a large, untapped potential for cost-effective energy-efficiency investments exists. Supporters of public policies argue that energy-efficiency programs are an appropriate government strategy to capture economic efficiencies that the market cannot secure unassisted
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
Analysis of EV Charging Load Based on Household Driving Data in California
Liu, Jiarui
2015-01-01
We analyzed a detailed set of over 1000 daily driving traces of GPS-equipped residential vehicles in South California and combined them with the features of four Plug-in Hybrid Electric Vehicle (PHEV) models in order to develop a test data set for PHEV related studies in the field of smart grid. The four PHEV models that were studied are Chevrolet Volt, Honda Accord Plug-in, Ford Fusion Energi, and Toyota Prius Plug-in. The per-PHEV state-of-charge (SoC) traces, the per-PHEV charging load tra...
Static deflection analysis of non prismatic multilayer p-NEMS cantilevers under electrical load
Pavithra, M.; Muruganand, S.
2016-04-01
Deflection of Euler-Bernoulli non prismatic multilayer piezoelectric nano electromechanical (p-NEMS) cantilever beams have been studied theoretically for various profiles of p-NEMS cantilevers by applying the electrical load. This problem has been answered by applying the boundary conditions derived by simple polynomials. This method is applied for various profiles like rectangular and trapezoidal by varying the thickness of the piezoelectric layer as well as the material. The obtained results provide the better deflection for trapezoidal profile with ZnO piezo electric layer of suitable nano cantilevers for nano scale applications.
DYNA3D Finite Element Analysis of Steam Explosion Loads on a Pedestal Wall Design
Energy Technology Data Exchange (ETDEWEB)
Noble, C R
2007-01-18
The objective of this brief report is to document the ESBWR pedestal wall finite element analyses that were performed as a quick turnaround effort in July 2005 at Lawrence Livermore National Laboratory and describe the assumptions and failure criteria used for these analyses [Ref 4]. The analyses described within are for the pedestal wall design that included an internal steel liner. The goal of the finite element analyses was to assist in determining the load carrying capacity of the ESBWR pedestal wall subjected to an impulsive pressure generated by a steam explosion.
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. PMID:25965455
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).
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, and is...... not easy to use nor easy installable. During the course of 2015 a library will be released with proper build, install and usage documentation. The version that is included in this repository was extensively used within the INDUFLAP project....
Analysis of the stress and reability of the ceramic head under oblique load
Czech Academy of Sciences Publication Activity Database
Fuis, Vladimír
Čejkovice: Faculty of Physical Education and Sport , Charles University, 2002 - (Jelen, K.; Kušová, S.; Chalupová, M.; Otáhal, J.), s. 193-195 ISBN 80-86317-23-4. [Biomechanics of man 2002. Čejkovice (CZ), 12.11.2002-15.11.2002] R&D Projects: GA ČR GA101/01/0974 Keywords : hip joint endoprosthesis * oblique loading * computational modelling Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass