Axial crashworthiness performance of bionic multi-cell tubes with variable thickness

Thin-walled and bionic structures have been widely used in automotive and railway industries, as they present superior mechanical performance under axial loading. As an integration of these two concepts, bionic multi-cell tubes could be an outstanding candidatee. This research proposes novel variable thickness bionic multi-cell tubes (VTBMTs) inspired by pine cones and bamboo. The baseline computer VTBMTs model is validated using existing physical experiments. Initial peak force (IPF), crushing force efficiency (CFE) and specific energy absorption (SEA) of VTBMTs are assessed and compared with those of circular tubes to investigate the influence of cross-sectional shape and thickness on energy absorption characteristics. A multiobjective optimisation method is employed to improve crashworthiness performance further. Optimal results demonstrate that the VTBMTs achieve a 35.96% lower IPF, a 125.86% higher CFE, and an 11.72% higher SEA than the original tube, suggesting that VTBMTs can be used as a promising energy absorption structure.