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.