Crashworthiness analysis of bio-inspired fractal petal-like multi-cell tubes with Fibonacci spiral section under axial crushing

Bio-inspired structures and materials have gained significant attention in protective structures due to their excellent energy absorption (EA) and lightweight properties. In this study, a novel bio-inspired petal multi-cell tube (BPMT) is developed with inspirations from the Fibonacci spiral structure observed in living organisms. Finite element (FE) models of BPMT with different cross-sectional configurations are established and validated through quasi-static axial crushing tests. The crushing performance of the BPMT with different hierarchical orders, wall thicknesses and inner diameters are numerically investigated. The results show that the highest specific EA (SEA) rose by 45% through the increase of hierarchical order and by 49% through the decrease of inner diameters. Moreover, the distribution of wall thickness in the BPMT plays a crucial role in EA during the crushing process. In addition, compared with other typical multi-cell tubes, a maximum increase of 22% in the SEA of BPMTs is obtained, indicating BPMT's superiority as an energy absorber. The findings of this study provide an effective guide for the design of multi-cell tubes with high EA efficiency.