Crashworthiness analysis of novel bidirectional gradient hierarchical double tubes inspired by the leaf tissue

Inspired by the cross-sectional view of leaf tissue, a bidirectional gradient hierarchical double tube (BGHDT) was proposed and its crashworthiness performance was investigated by finite element simulation. The results indicate that the proposed BGHDT has better energy absorption capacity than the conventional hexagon tube under the same mass condition. The folding wavelength of BGHDT is shorter than that of conventional hexagonal tubes, resulting in a larger number of folds. Compared with conventional hexagon tubes, the energy absorption of BGHDT with 3rd hierarchical level increases by 139.39% and its peak crush force (PCF) decreases by 16.29% at the same mass. Finally, the effects of wall thickness and the number of connecting units on the crashworthiness performance of BGHDT are systematically studied.