scholarly journals Statistics of the Von Mises Stress Response For Structures Subjected To Random Excitations

1998 ◽  
Vol 5 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Mu-Tsang Chen ◽  
Ronald Harichandran

Finite element-based random vibration analysis is increasingly used in computer aided engineering software for computing statistics (e.g., root-mean-square value) of structural responses such as displacements, stresses and strains. However, these statistics can often be computed only for Cartesian responses. For the design of metal structures, a failure criterion based on an equivalent stress response, commonly known as the von Mises stress, is more appropriate and often used. This paper presents an approach for computing the statistics of the von Mises stress response for structures subjected to random excitations. Random vibration analysis is first performed to compute covariance matrices of Cartesian stress responses. Monte Carlo simulation is then used to perform scatter and failure analyses using the von Mises stress response.

2013 ◽  
Vol 455 ◽  
pp. 310-313
Author(s):  
Er Ming He ◽  
Ge Liang Yin ◽  
Ya Qi Hu

In order to study the random vibration responses of satellite-borne equipment, the finite element model of satellite-borne equipment was established and its random vibration analysis was performed by ANSYS. The results showed that the stress of key part was too large to meet the strength requirement. The structural design was modified based on the stress analysis results. At the cost of adding 1.03% weight, we find the fundamental frequency of the modified model is increased by 14% and the maximum 1˰σ von Mises stress is decreased by 30%, which verify the correctness of the modification method. This analysis and modification method also can be applied to modify other satellite-borne equipments to shorten the development period and reduce the design cost.


2013 ◽  
Vol 423-426 ◽  
pp. 1501-1505 ◽  
Author(s):  
Teng Han ◽  
Xiao Qi He ◽  
Yun Fei En

Finite element simulation method of random vibration analysis was used for hermetically metal sealing. According to the results of the random vibration analysis and the theory of fatigue fracture mechanics, the hermetically metal sealing on the PCB plate cracking damage mechanism was analyzed. The danger point of the Von Mises stress was obtained, and the Von Mises stress - time history data was accessed through inverse Fourier transformation. And rain flow count method was used to calculate Von Mises stress-time history data of cycle count. The linear cumulative damage theory and the material S-N curve were used to calculate the fatigue life of Hermetically metal sealing.


Author(s):  
Mu-Tsang Chen

Abstract Random vibration analysis (RVA) of structural systems is a rapidly growing branch of engineering mechanics. The theory of random vibration is central to the analysis and design of structures in a variety of engineering fields. In recent years, RVA in conjunction with finite element methods has been available in several commercial computer-aided-engineering software, such as ANSYS, NASTRAN, etc. The finite element-based RVA is being widely adopted for computing stochastic responses, such as displacements, stresses and strains in terms of statistical quantities, i.e., root-mean-square responses. However, these statistical responses from RVA are limited to Cartesian responses which depend on the coordinate system of use. In structural design, a failure criterion using distortion energy known as the von Mises theory is more appropriate and of interest in this paper. The statistics of von Mises stress can not be obtained in terms of the statistics of Cartesian stresses. Simulation-based von Mises stress responses corresponding to a covariance matrix of Cartesian stresses are used to perform scatter and failure analyses. Based on a sufficient number of stress samples, a probability distribution of von Mises stress response may be obtained. Given a specified design criterion, statistical moments of safety margin as well as a safety index can be computed. In addition, a required design strength corresponding to a desired probability of failure can be provided in this study.


ICTE 2015 ◽  
2015 ◽  
Author(s):  
Hanfei Guo ◽  
Xiaoxue Liu ◽  
Wei Tong ◽  
Youwei Zhang ◽  
Yanlei Zhang

2017 ◽  
Vol 400 ◽  
pp. 481-507 ◽  
Author(s):  
Yanbin Li ◽  
Sameer B. Mulani ◽  
Rakesh K. Kapania ◽  
Qingguo Fei ◽  
Shaoqing Wu

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