Crushing analysis of square gradient hierarchical multicellular tubes

Inspired by tree fractals, a novel square gradient hierarchical multicellular tube (SGHMT) is proposed, and a finite element (FE) model of the structure is constructed using Abaqus/Explicit. The accuracy of the FE numerical model was verified using experiments, and the energy absorption characteristics of the structure under axial impact were analyzed. The results show that the high-level SGHMTs have higher energy absorption capacity and impact force efficiency (CFE) compared with the low-level SGHMTs for both the same wall thickness and the same mass, and crashworthiness is greatly improved. The energy absorption (EA) and CFE of SGHMT-3 are 11.39 and 4.47 times higher than those of SGHMT-0 under the same wall thickness condition, respectively. The EA and CFE of SGHMT-3 are 2.15 and 2.28 times higher than those of SGHMT-0, respectively, under the same mass condition. On this basis, further geometrical parameter analysis was carried out, and it was found that the structural parameters (wall thickness, hierarchy, and shape scale factor gamma 1, gamma 2) had a significant effect on the crashworthiness of the square gradient hierarchical multicellular tubes. Finally, a comparative study with other multicellular tubes was carried out to demonstrate the superiority of the proposed square gradient hierarchical multicellular tubes compared with other multicellular tubes.