scholarly journals Sensitivity Analysis of a Nuclear Reactor System Finite Element Model

2018 ◽  
Author(s):  
Gregory A. Banyay ◽  
Stephen D. Smith ◽  
Jason S. Young
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Surrogate Model ◽  
Computational Design ◽  
Element Model ◽  
Sensitivity Analyses ◽  
Physical Parameters ◽  
Loading Conditions ◽  
Pressurized Water

The structures associated with the nuclear steam supply system (NSSS) of a pressurized water reactor (PWR) warrant evaluation of various non-stationary loading conditions which could occur over the life of a nuclear power plant. These loading conditions include those associated with a loss of coolant accident and seismic event. The dynamic structural system is represented by a finite element model consisting of significant epistemic and aleatory uncertainties in the physical parameters. To provide an enhanced understanding of the influence of these uncertainties on model results, a sensitivity analysis is performed. This work demonstrates the construction of a computational design of experiment which runs the finite element model a sufficient number of times to train and verify a unique aggregate surrogate model. Adaptive sampling is employed in order to reduce the overall computational burden. The surrogate model is then used to perform both global and local sensitivity analyses.

scholarly journals Sensitivity Analysis of the Influence of Structural Parameters on Dynamic Behaviour of Highly Redundant Cable-Stayed Bridges

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
B. Asgari ◽  
S. A. Osman ◽  
A. Adnan
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Structural Parameters ◽  
Element Model ◽  
Structural Behavior ◽  
Model Tuning ◽  
The Finite Element Model ◽  
Cable Stayed Bridges

The model tuning through sensitivity analysis is a prominent procedure to assess the structural behavior and dynamic characteristics of cable-stayed bridges. Most of the previous sensitivity-based model tuning methods are automatic iterative processes; however, the results of recent studies show that the most reasonable results are achievable by applying the manual methods to update the analytical model of cable-stayed bridges. This paper presents a model updating algorithm for highly redundant cable-stayed bridges that can be used as an iterative manual procedure. The updating parameters are selected through the sensitivity analysis which helps to better understand the structural behavior of the bridge. The finite element model of Tatara Bridge is considered for the numerical studies. The results of the simulations indicate the efficiency and applicability of the presented manual tuning method for updating the finite element model of cable-stayed bridges. The new aspects regarding effective material and structural parameters and model tuning procedure presented in this paper will be useful for analyzing and model updating of cable-stayed bridges.

Updating Finite Element Model of Combined Structures on the Basis of Dynamic Test Results

1996 ◽  
Author(s):  
Chen Xin ◽  
Qin Ye ◽  
Yuan Xiguang ◽  
Zhang Ping ◽  
Sun Jian
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Test Data ◽  
Dynamic Test ◽  
Element Model ◽  
Physical Parameters ◽  
Structural Joint ◽  
Combined Structure ◽  
Joint Parameters ◽  
Two Stages

Abstract According to the real situation, a new method of updating the finite element model (FEM) of a combined structure step by step is proposed in this paper. It is assumed that there are two types of error when establishing the FEMs. One of them results from the simplifications, in fact, it is severe for complicated structures, which usually assume many simplifications; the other is from the process of identifying structural joint parameters. For this reason, it is recommended that the FEM should be established in two stages. At the first stage, the local physical parameters relating with the simplifications are corrected by using the dynamic test data of the corresponding substructures. Then, the structural joint parameters that link the substructures are corrected by the dynamic test data of the combined structure as a whole. The updating formula is presented and proved, and its algorithm is also described. And the experimental results show that the efficiency and accuracy of the proposed method are quite satisfactory.

Comparison of femur strain under different loading scenarios: Experimental testing

2020 ◽  
Vol 235 (1) ◽  
pp. 17-27
Author(s):  
Ievgen Levadnyi ◽  
Jan Awrejcewicz ◽  
Yan Zhang ◽  
Yaodong Gu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain Distribution ◽  
Element Model ◽  
Surface Strain ◽  
Image Correlation ◽  
Loading Conditions ◽  
Bone Implant ◽  
Bone Stiffness

Bone fracture, formation and adaptation are related to mechanical strains in bone. Assessing bone stiffness and strain distribution under different loading conditions may help predict diseases and improve surgical results by determining the best conditions for long-term functioning of bone-implant systems. In this study, an experimentally wide range of loading conditions (56) was used to cover the directional range spanned by the hip joint force. Loads for different stance configurations were applied to composite femurs and assessed in a material testing machine. The experimental analysis provides a better understanding of the influence of the bone inclination angle in the frontal and sagittal planes on strain distribution and stiffness. The results show that the surface strain magnitude and stiffness vary significantly under different loading conditions. For the axial compression, maximal bending is observed at the mid-shaft, and bone stiffness is also maximal. The increased inclination leads to decreased stiffness and increased magnitude of maximum strain at the distal end of the femur. For comparative analysis of results, a three-dimensional, finite element model of the femur was used. To validate the finite element model, strain gauges and digital image correlation system were employed. During validation of the model, regression analysis indicated robust agreement between the measured and predicted strains, with high correlation coefficient and low root-mean-square error of the estimate. The results of stiffnesses obtained from multi-loading conditions experiments were qualitatively compared with results obtained from a finite element analysis of the validated model of femur with the same multi-loading conditions. When the obtained numerical results are qualitatively compared with experimental ones, similarities can be noted. The developed finite element model of femur may be used as a promising tool to estimate proximal femur strength and identify the best conditions for long-term functioning of the bone-implant system in future study.

Multi-Fidelity Surrogate Model-Assisted Fatigue Analysis of Welded Joints

2020 ◽  
Author(s):  
Lili Zhang ◽  
Tingli Xie ◽  
Jiexiang Hu ◽  
Ping Jiang ◽  
Jasuk Koo ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Stress Distribution ◽  
Finite Element Model ◽  
Surrogate Model ◽  
Element Model ◽  
Leg Length ◽  
Verification Method ◽  
Leave One Out ◽  
The Finite Element Model

Abstract In this study, an additive scaling function based multi-fidelity (ASF-MF) surrogate model is constructed to fast predict fatigue life as well as the stress distribution for the welded single lap joint. The influence of leg length, leg height, the width of the specimen and load in the fatigue test are taken into consideration. In the construction of the MF surrogate model, the finite element model that is calibrated with the experiment is chosen as the high-fidelity (HF) model. While the finite element model that is not calibrated with the experiment is considered as the low-fidelity (LF) model, aiming to capture the trend of the HF model. The Leave-one-out (LOO) verification method is utilized to compare the prediction performance of the ASF-MF surrogate model with that of the single-fidelity Kriging surrogate model. Results show that the ASF-MF surrogate model can better predict the fatigue life as well as the stress distribution.

Numerical investigation into the effect of ballast properties on buckling of continuously welded rail (CWR)

2020 ◽  
pp. 095440972096579
Author(s):  
Fatemeh Khatibi ◽  
Morteza Esmaeili ◽  
Saeed Mohammadzadeh
Keyword(s):  
Finite Element ◽  
Discrete Element Method ◽  
Finite Element Model ◽  
Field Data ◽  
Friction Angle ◽  
Element Model ◽  
Sensitivity Analyses ◽  
Track Stiffness ◽  
Dem Analysis ◽  
Continuously Welded Rail

In this paper, the effect of ballast properties including ballast depth, shoulder width, shoulder height, inter particle friction angle and ballast porosity on track buckling capacity are investigated numerically using discrete element method (DEM) analysis. First, a Single Tie Push Test (STPT) is simulated using DEM and the results are validated with field data. Then a sensitivity analyses is carried out. To investigate the effect of ballast properties on buckling capacity, the STPT responses according to the DEM analysis are introduced as a lateral track stiffness into a finite element model of continuously welded rail track, and a thermal buckling simulation is performed. The results show a significant effect of ballast porosity on buckling temperature.

The Finite Element Method: A Tool to Evaluate Shear Bond Strength of Dental Bracket

2014 ◽  
Vol 984-985 ◽  
pp. 431-437
Author(s):  
Vijaykumar Hiremath ◽  
Girija Bidarimath ◽  
Basavaraj Endigeri
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Model ◽  
Testing Machine ◽  
Three Dimensional ◽  
Element Model ◽  
Loading Conditions ◽  
Acceptable Error ◽  
Three Dimensional Finite Element ◽  
Element Method

In this paper finite element model of steel dental bracket is generated along with bonding agent, enamel & stress analysis is carried out on the bracket for different loading conditions. Three dimensional finite element model developed are constrained with boundary condition that resembles to the reality. The Vonmisses stress is recorded for each loading conditions and compared with experimental results. The experimental work for 60 samples were carried out on Universal testing machine at material testing laboratory, Basaveshwar Engineering College, Bagalkot. It is found from FEM results that the shear bonding strength for different loadings from 60 N to 80 N varies from 7.276 N/mm2 to 9.7N/mm2, which are closer to experimental values with acceptable error. The study reveals that Finite Element Method can be used as a strong tool to analyze the dental bracket and study different parameters to improve its performance and to avoid time and cost required for experimentation.

scholarly journals A Circuit Model for CMOS Hall Cells Performance Evaluation including Temperature Effects

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Maria-Alexandra Paun ◽  
Jean-Michel Sallese ◽  
Maher Kayal
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Circuit Model ◽  
Physical Parameters ◽  
Geometrical Parameters ◽  
Voltage Sensitivity ◽  
Behavior Simulation ◽  
Different Shapes ◽  
Lumped Circuit Model

In order to provide the information on their Hall voltage, sensitivity, and drift with temperature, a new simpler lumped circuit model for the evaluation of various Hall cells has been developed. In this sense, the finite element model proposed by the authors in this paper contains both geometrical parameters (dimensions of the cells) and physical parameters such as the mobility, conductivity, Hall factor, carrier concentration, and the temperature influence on them. Therefore, a scalable finite element model in Cadence, for behavior simulation in circuit environment of CMOS Hall effect devices, with different shapes and technologies assessing their performance, has been elaborated.

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