Crashworthiness analysis and optimisation of a multi-level bionic multi-cell tube under axial dynamic impact

In this study, a multi-level bionic multi-cell tube (MBMT-n) is proposed, inspired by the horsetail's cross-sectional structure, and the multi-cell tube shape and distribution characteristics of bamboo vascular bundles. A systematic crashworthiness analysis of MBMT-n under axial dynamic impact was conducted using LS-DYNA. The findings indicate that MBMT-n can enhance crashworthiness while maintaining the same mass. Additionally, the impact of wall thickness and bionic unit cell's length–width ratio was investigated. Furthermore, a theoretical prediction model for mean crushing force (MCF) was established using the simplified super-folding unit theory. Lastly, to further enhance the structure's crashworthiness, multi-objective optimisation of MBMT-3 was performed using the NSGA-II algorithm. The several optimal structures were subsequently identified under various peak crushing force (PCF). This study offers a novel approach to the design of energy-absorbing structures.