A Method to Determine the Boundary Conditions of the Finite Element Model of a Slender Beam Using Measured Modal Parameters

1996 ◽  
Vol 118 (3) ◽  
pp. 474-478 ◽  
Author(s):  
Wang Fengquan ◽  
Chen Shiyu
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Interpolation Method ◽  
Element Model ◽  
Accurate Method ◽  
Modal Parameters ◽  
Computation Method ◽  
Modal Parameter ◽  
The Finite Element Model

In this paper, a method used to determine the boundary conditions of the Finite Element Model of a slender beam with measured structure modal parameters is presented. On deriving the method, the finite element model theory for dynamic calculating is used. Combined with the modal parameters from experiment, an FEM-modal parameter equation to determine the boundary conditions is put forward. For solving the equation, three methods are given. The first is the accurate method. The second is the full mode computation method by means of generalized inverse matrix. The third is the interpolation method of frequency. A numerical simulation with computer is given and the results of calculation fully verify the effectiveness of the method offered and also verify that the accuracy of the method is satisfying. Finally, an applied example is given and the results of calculation fully verify the effectiveness of the method offered.

The Method of Modal Parameters to Determine the Boundary Condition of Finite Element Model

1991 ◽  
Author(s):  
Chen Shiyu ◽  
Wang Fengquan
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Finite Element Model ◽  
Interpolation Method ◽  
Element Model ◽  
Accurate Method ◽  
Modal Parameters ◽  
Computation Method ◽  
Modal Parameter ◽  
The Third

Abstract In this paper, a method used to determine the boundary condition of Finite Element Model with structure modal parameters is presented. On deriving the method, the theory of Finite Element Model for dynamic calculating is used. Combined with the modal parameters got from experiment, a FEM-Modal Parameter equation to determine the boundary condition is put forward. For solving the equation, three methods are given. The first is the accurate method. The second is the full mode computation method by means of generlized inverse matrix. The third is the interpolation method of frequency. An applied example is given and the results of calculation fully verify the effectiveness of the method offered.

Dynamic Behavior of Electronic Module Spring Clips, Retention Bar, and Backplane Connector: Modeling and Testing

2009 ◽  
Author(s):  
Kenneth P. Vandevoordt ◽  
Michael Feng
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Element Model ◽  
Guidance System ◽  
Printed Wiring Board ◽  
Wiring Board ◽  
Electrical Components ◽  
Hardware Test ◽  
The Finite Element Model

Electronic modules for a guidance system are mounted in a rack with spring clips resisting motion normal to the printed wiring board (PWB) and an aluminum bar with an elastomer pad keeping the module connected to a backplane. The elastomer pad also resists motion normal to the board. The proper boundary conditions for the spring clips, retention bar, and connector are needed in a finite element model in order to evaluate the shock and vibration transmitted to the module’s electrical components. The finite element model of the module was assembled, and an actual module was tested under random vibration and a 1g sine sweep. The printed wiring board elastic modulus was artificially set higher in the FEM than a measured value to account for the stiffening effect of board components which were omitted from the model. By also choosing the proper boundary conditions to represent the spring clips, retention bars, and backplane connection, the finite element model was able to match the first and second mode frequencies from the hardware test results.

scholarly journals Applied theory of bending vibration of the piezoelectric and piezomagnetic bimorph

2020 ◽  
Vol 10 (03) ◽  
pp. 2050007
Author(s):  
Do Thanh Binh ◽  
V. A. Chebanenko ◽  
Le Van Duong ◽  
E. Kirillova ◽  
Pham Manh Thang ◽  
...  
Keyword(s):  
Finite Element ◽  
Variational Principle ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Element Model ◽  
Applied Theory ◽  
Bending Vibration ◽  
Steady Vibrations ◽  
The Finite Element Model

Based on the variational principle, equations and boundary conditions for transverse steady vibrations of a bimorph consisting of a piezoelectric and piezomagnetic layers are obtained. The results of calculations of natural frequencies are compared with the finite element model of the device in ACELAN.

Modal Analysis and Experimental Analysis of Dynamic Characteristics of Linear Rolling Guide

2012 ◽  
Vol 482-484 ◽  
pp. 2360-2364
Author(s):  
Xiao Peng Li ◽  
Hao Guo ◽  
Jing Nian Liu ◽  
Ya Li Liu
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Experimental Analysis ◽  
Dynamic Performance ◽  
Element Model ◽  
Cnc Machine ◽  
Element Analysis ◽  
Rolling Guide ◽  
The Finite Element Model

The finite element model of the liner rolling guide of the CNC machine tool is established. Then the natural frequencies and the corresponding vibration modes of the liner rolling guide (LRG) are obtained by analyzing the finite element model (FEM) of the linear rolling guide in two different boundary conditions. By comparing the modal characters of the two states it is proved that the movable joint and bolted interfaces of the rail have certain effects on the dynamic performance of linear rolling guide. Besides, the liner rolling guide also have been tested dynamically, obtaining the modal parameters of the rail guide; finally, the validity of finite element model and the effect of boundary conditions on the interface of the linear rolling guide are verified by comparing the finite element analysis of frequency and experimental analysis of frequency

Factors Influencing Natural Frequencies in a Prestressed Concrete Panel for Damage Detection

2014 ◽  
Vol 69 (3) ◽  
Author(s):  
L. D. Goh ◽  
A. A. Rahman ◽  
N. Bakhary ◽  
B. H. Ahmad
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Detection ◽  
Prestressed Concrete ◽  
Natural Frequencies ◽  
Element Model ◽  
Modal Parameters ◽  
Actual Structure ◽  
Modal Test ◽  
The Finite Element Model

Modal parameters such as natural frequencies, mode shapes, and damping ratios are widely used as damage indicators in the field of vibration-based damage detection. These modal parameters can be easily obtained by conducting the modal test on the actual structure or from the finite element model. However, many publications are focusing only on the relationship between the modal parameters and the changes in structural properties for damage detection. There are a limited number of publications discussing on the factors that may affect the modal parameters for damage detection. Hence, this paper provides a study on the level of influence of several factors on the natural frequencies of a prestressed concrete panel. The factors that are considered in this study are the size of element used in the numerical model, the dimension of the structural element, and the prestressing force applied in the prestressed concrete panel. The natural frequencies computed from the finite element model are also verified with the actual measured natural frequencies that are determined through the modal test conducted in the laboratory. 

scholarly journals Experimental Studies on Finite Element Model Updating for a Heated Beam-Like Structure

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Kaipeng Sun ◽  
Yonghui Zhao ◽  
Haiyan Hu
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Model Updating ◽  
Element Model ◽  
Modal Parameters ◽  
Finite Element Model Updating ◽  
Time Varying ◽  
The Finite Element Model

An experimental study was made for the identification procedure of time-varying modal parameters and the finite element model updating technique of a beam-like thermal structure in both steady and unsteady high temperature environments. An improved time-varying autoregressive method was proposed first to extract the instantaneous natural frequencies of the structure in the unsteady high temperature environment. Based on the identified modal parameters, then, a finite element model for the structure was updated by using Kriging meta-model and optimization-based finite-element model updating method. The temperature-dependent parameters to be updated were expressed as low-order polynomials of temperature increase, and the finite element model updating problem was solved by updating several coefficients of the polynomials. The experimental results demonstrated the effectiveness of the time-varying modal parameter identification method and showed that the instantaneous natural frequencies of the updated model well tracked the trends of the measured values with high accuracy.

Study on a Modifying Method of Finite Element Model for Analyzing the Shaft Rotation System

2012 ◽  
Vol 268-270 ◽  
pp. 1049-1052
Author(s):  
Xu Xing Jin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Modal Testing ◽  
Computation Method ◽  
Shaft Rotation ◽  
Rotation System ◽  
The Finite Element Model ◽  
Element Method

Finite element method is an important computation method for analyzing the shaft rotation system of machine tools. However, due to the structural complexity of the shaft rotation system, the result error between the finite element method and the modal testing is often large. Such error results from the difference between the finite element model and the actual system. In the present study, a finite element model of the shaft rotation system is firstly established, an experiment of modal testing is also carried out to verify the results of mathematical model. Based on the comparison of the error, then the finite element model is modified by means of optimization methods. Finally, the Campbell diagram and the critical speed diagram are calculated, and the optimization values of the stiffness of bearings are obtained. The research results indicate that this method of verifying model is accurate and efficient.

scholarly journals Modal Parameter Identification and Numerical Simulation for Self-anchored Suspension Bridges Based on Ambient Vibration

2018 ◽  
Vol 38 ◽  
pp. 03033
Author(s):  
Bing Liu ◽  
Li Guo Sun
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Suspension Bridge ◽  
Element Model ◽  
Ambient Vibration ◽  
Vibration Velocity ◽  
Suspension Bridges ◽  
Laser Vibrometer ◽  
Modal Parameter ◽  
The Finite Element Model

This paper chooses the Nanjing-Hangzhou high speed overbridge, a self-anchored suspension bridge, as the research target, trying to identify the dynamic characteristic parameters of the bridge by using the peak-picking method to analyze the velocity response data under ambient excitation collected by 7 vibration pickup sensors set on the bridge deck. The ABAQUS is used to set up a three-dimensional finite element model for the full bridge and amends the finite element model of the suspension bridge based on the identified modal parameter, and suspender force picked by the PDV100 laser vibrometer. The study shows that the modal parameter can well be identified by analyzing the bridge vibration velocity collected by 7 survey points. The identified modal parameter and measured suspender force can be used as the basis of the amendment of the finite element model of the suspension bridge. The amended model can truthfully reflect the structural physical features and it can also be the benchmark model for the long-term health monitoring and condition assessment of the bridge.

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.

Biodynamics of Human Thorax With Body Armors Subject to Bullet Impact

2001 ◽  
Author(s):  
Y. W. Kwon ◽  
J. A. Lobuono
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Body Armor ◽  
Projectile Impact ◽  
Human Thorax ◽  
Trachea And Bronchi ◽  
Armor System ◽  
The Finite Element Model

Abstract The objective of this study is to develop a finite element model of the human thorax with a protective body armor system so that the model can adequately determine the thorax’s biodynamical response from a projectile impact. The finite element model of the human thorax consists of the thoracic skeleton, heart, lungs, major arteries, major veins, trachea, and bronchi. The finite element model of the human thorax is validated by comparing the model’s results to experimental data obtained from cadavers wearing a protective body armor system undergoing a projectile impact.

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