A bionic tree-liked fractal structure as energy absorber under axial loading

•A bionic tree-liked fractal method is introduced to design an energy absorber with high crashworthiness.•The theoretical model is developed to predict the energy absorption of the tree-liked fractal structure.•The fractal coefficient and wall thickness have significant effect on energy absorption.•The 3rd order tree-liked fractal structure has higher energy absorption than typical multi-cell structure.