Crushing behavior of biomimetic hierarchical multi-cell thin-walled tubes under multi-angle loading

This paper proposes a set of biomimetic hierarchical multi-cell thin-walled structures (BHM). The internal structure of the proposed BHM tubes is constructed based on the micro-structure of bamboo and traditional multi-cell thin-walled structures (TMT). The crashworthiness performance of the proposed structures with different cross-sectional configurations under multi-angle loads was numerically studied. The anti-collision performance of BHM and TMT under multi-angle crushing loads was comparatively studied through finite element simulation. In addition, the TOPSIS method was used to select the optimal cross-sectional configuration of the biomimetic thin-walled tube. The results show that compared with TMT, BHM exhibits excellent crash- worthiness under small-angle collisions, and this advantage begins to decline as the collision angle increases. Among different types of BHM, the hexagonal BHM and the balanced configuration of BHM can effectively improve the energy absorption capacity and load stability of the structure, and quadrilateral BHM provides a reference for reducing the peak crushing force. The optimal cross-sectional configuration obtained by the TOPSIS method is the hexagonal bio-hierarchical multi-walled tube with a balanced configuration. Finally, a comparative analysis with other hierarchical multi-cell tubes reported in the literature confirms that the crashworthiness performance of BHM exceeds existing designs. Theoretical derivation of the mean crushing force was conducted for the proposed tubes, and the theoretical predictions of MCF are in good agreement with the numerical results. The results of this study provide effective guidance for using the biomimetic method with a bamboo-like micro cross-sectional morphology to design multi-cell energy absorbers with high energy absorption efficiency.