Crushing analysis under multiple impact loading cases for novel tailored-property multi-wall tubes

Abstract

Multi-wall profile as one of the most widely approaches can enhance the crashworthiness properties in thin-walled tubular structures. In actual application process as energy absorbers, there may be a variety of circumstances including axial crushing and lateral crushing. However, the crashworthiness in the multi-wall tubular structure considering both axial crushing and lateral crushing circumstances has rarely been evaluated in the existing literature. In the study, a new tailored-property multi-wall thin-walled structure (TMTS) is put forward to increase the ultimate strength of this material in the region of corner to accommodate two conditions including lateral and axial crushing conditions. Finite element models verified from experiments were established in PAM-CRASH to analyse the crashworthiness performance for this structure. Under lateral and axial crushing, it was revealed that TMTSs exhibited obvious superiority to the corresponding traditional structures. It was concluded that wall thickness, tailoring length and other geometry parameters could effectively influence the crushing performance of the TMTSs. In addition, the progressive deformation mode could be exhibited by the well-designed TMTSs under axial impact. Furthermore, the theoretical model of the TMTS was proposed according to the Super-folding Element Theory. Theoretical analysis is consistent with simulation results, which proves that the deformation formula and the analytical model are all correct. Finally, according to the multi-objective optimisation method, the thicknesses of tailored and non-tailored regions of the TMTS were reasonably configured to further enhance crashworthiness. The research results provide good guidance and theoretical support for the development of novel lightweight energy-absorbing structures under various loading circumstances.