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.

摘要

多壁型材作为最广泛的方法之一可以增强薄壁管状结构的耐撞性。在作为吸能器的实际应用过程中，可能会出现轴向破碎和横向破碎等多种情况。然而，在现有文献中很少评估考虑轴向破碎和横向破碎情况的多壁管状结构的耐撞性。在研究中，提出了一种新的量身定制的多壁薄壁结构（TMTS），以增加该材料在拐角区域的极限强度，以适应横向和轴向破碎两种条件。在PAM-CRASH中建立了实验验证的有限元模型，分析了该结构的耐撞性能。在横向和轴向破碎下，TMTSs表现出明显优于相应的传统结构。得出的结论是，壁厚、剪裁长度和其他几何参数可以有效地影响 TMTS 的破碎性能。此外，设计良好的 TMTS 在轴向冲击下可以表现出渐进变形模式。此外，根据超折叠元理论提出了TMTS的理论模型。理论分析与仿真结果一致，证明变形公式和解析模型都是正确的。最后，根据多目标优化方法，合理配置TMTS的剪裁区域和非剪裁区域的厚度，进一步提高耐撞性。