Investigation of lateral crushing behaviors of hierarchical quadrangular thin-walled tubular structures

Energy absorbing efficiency of thin-walled tubular structures is restricted by the folding of the ultra-thin walls, depressing the mean crushing force (MCF) of the tubular structure. Hierarchical topology increases the energy absorbing ability of tubular structure notably without increasing the weight. In an effort to reveal this advantage, hierarchical quadrangular tubes (HQTs) are proposed in this paper. These proposed structures have multi-cellular structure and sandwich cellular walls. During the crushing, two deformation stages, including crushing of the side walls and compression of the short vertical ribs in the horizontal sandwich walls, were observed in the experiments. The latter greatly increases the MCF of thin-walled quadrangular tubes (TQTs). Based on three typical folding elements and two energy absorbing mechanisms, the MCF can be consistently predicted. According to the research, extraordinary energy absorption can be achieved through hierarchical topology design.