On the crashworthiness of bio-inspired hexagonal prismatic tubes under axial compression

Bio-inspired conception is prevailing in structure design due to its mechanical promotion. In this study, crashworthiness analyses of twelve patterns of hexagonal prismatic tubes were numerically investigated by means of Finite Element method, including original hexagonal tube (OHT), full triangular hexagonal tube (FTHT), internal clone hexagonal tube (ICHT), double filled hexagonal tube (DFHT) and their reinforced hierarchical structures. Key crashworthiness indexes of different structures were compared with each other in detail. Corresponding formulas to predict the mechanical performance were derived representatively. As confirmed by both theoretical solutions and numerical results, the energy absorption capacities and deformation modes of the bio-inspired hexagonal prismatic tubes are superior to those of the original ones. Although they contribute substantially to the improvement of energy absorption ability, the different reinforcement ways show their different merits. Self-similar hierarchical designs can greatly increase the stability of the axial collapse process. While the lattice enhancement designs show higher SEA. All achievements in this study provide significant guidelines in the reinforcement design of lightweight structures.