Crashworthiness optimization of front rail structure using macro element method and evolutionary algorithm

In this paper, the research on crashworthiness optimization of thin-walled structures is presented. The model of "S"-shaped frame subjected to complex crush load is analyzed. The objective of the study is to determine the optimal dimensions of the space frame cross section so as to achieve the maximal energy absorption of the structure and to fulfill the design requirements related to the crushing force value and the geometry relationship. The Visual Crash Studio (VCS) software, based on the macro element methodology, is used to simulate the response of a thin-walled beam during the impact and to determine crashworthy parameters. The results present a very good correlation with the finite element calculations but can be obtained in a much shorter time. The VCS software was coupled to evolutionary algorithm developed to determine the best solution. The optimization procedures revealed the necessity of a new design criterion related to maximal bending moments in the structure. This formulation enabled to obtain very good results after short processing on a PC computer. The proposed approach may be successfully used at early stages of the crashworthiness analysis.