Parametric and multi-objective optimization analysis of cactus stem-inspired bionic multi-cell tubes for enhanced crashworthiness

This study extends our previous research on the cactus stem-inspired bionic multi-cell tube (CSBMT) by conducting a deeper investigation aimed at further enhancing its crashworthiness performance. Finite element analysis (FEA) was employed to investigate the energy absorption performance of CSBMT under varying geometric parameters, including the number of corners ( N ), inner diameter ( D i ), and outer angle ( β ). Additional analyses examined the influence of oblique loading (0°-30°) and gradient wall thickness distributions ( n = 0.2-5.0). The results indicate that increasing N and D i significantly improves the specific energy absorption (SEA), while a larger β and smaller n enhance load uniformity and deformation stability. Compared with the baseline configuration, the optimal design achieved a 74.9 % improvement in SEA. Compared with 16 classical thin-walled energy-absorbing structures, the CSBMT exhibited superior energy absorption and load-bearing capacity under 20° oblique loading. Furthermore, a multi-objective structural optimization of the CSBMT was performed using the Non-dominated Sorting Genetic Algorithm II (NSGA-II), and a compromise solution was identified based on the minimum distance criterion. The optimized structure exhibited a well-balanced performance between energy absorption efficiency and peak load control. The findings provide valuable insights for the design of bio-inspired energy-absorbing structures in crashworthiness applications. • Extended study of cactus stem-inspired bionic multi-cell tube for crashworthiness. • Parametric study on corner number, inner diameter, and outer angle. • Gradient and oblique effects additionally examined for completeness. • Multi-objective optimization via RSM and NSGA-II framework. • Optimized design improved SEA and reduced PCF simultaneously.