Variable Stiffness Design and Multiobjective Crashworthiness Optimization for Collision Post of Subway Cab Cars

Wei Guo,Ping Xu,Jie Xing,Zhaofeng Yi,Chengxing Yang,Hui Zhao

doi:10.3390/machines9110246

Wei Guo, Ping Xu + Show 4 more

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https://doi.org/10.3390/machines9110246

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Abstract

This paper proposes a variable stiffness collision post (VSCP) structure based on a uniform stiffness collision post (USCP) structure and performs stiffness matching optimization for VSCPs. A collision post structure assembled in a subway front-end frame can maintain the living space and absorb a certain amount of the kinetic energy of an impact. The experiment was applied on USCP, and the finite element model was verified experimentally. To investigate the effects of the stiffness parameters of VSCP on the specific energy absorption response (SEA_VSCP) and the area of intrusion response (S_In), response surface models fitted from design of experiment were adopted with the finite element model. In addition, a multiobjective optimization design was realized by using the global response search method and a Pareto frontier sequence was generated, which was based on the developed response surface model. It was found that the optimal value of SEA_VSCP and S_In responses cannot be achieved at the same time. Finally, a grey relational analysis is propounded to attain a desirable balance between SEA_VSCP and S_In from the Pareto frontier sequence under constraints of the peak crash force of VSCP and energy absorption of the front-end of cab car. The optimization result shows that the crashworthiness of VSCP is better than that of USCP.

Highlights

Variable stiffness design is realized by varying the thickness of each part of the collision post
The results reveal that full quadratic models are proposed and the corresponding polynomial functions for SEA_VSCP and S_In are attached in Appendix A: Polynomial functions of SEA_VSCP and S_In
The optimal solution is found by the gray relational analysis method, which can strike the desired balance between SEA_VSCP and S_In

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The rapid development of subway traffic has led to an increase in subway vehicle collision accidents, which will inevitably cause serious casualties and property losses [1,2]. The study of railway vehicle passive safety technologies has become a new hot topic [3,4]. Thin-walled structures have been widely used as energy absorption devices due to their low masses and high energy absorption efficiencies. There are many research results demonstrating the excellent crashworthiness performance of thin-walled structures [5,6,7,8,9]

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