Axial compression of multi-cell hexagonal tubes with novel hierarchical architectures: Numerical and theoretical analyses

Abstract

The architecture of hierarchy is extensively used in the construction of energy absorbers due to its super mechanical performance. Two new types of hierarchical multi-cell hexagonal tubes were constructed in this study based on different hierarchical architectures. Numerical models of both two types of tubes were developed and employed to study their crashworthiness under axial compression. It is found that the peak crushing force (PCF) of the proposed tubes is smaller than that of single hexagonal tubes with the same mass, demonstrating the merit of hierarchical tubes to minimize sudden injury. The mean crushing force (MCF), energy absorption (EA) and specific energy absorption (SEA) of the proposed tubes increase with the increase of wall thickness and hierarchical order. The SEA of the 3rd order is up to over 200% that of single hexagonal tubes with the same mass. In addition, the second type of proposed hierarchical tubes with hierarchical cells relatively uniformly distributed in the tubes display slightly greater SEA than the first type of proposed hierarchical tubes with hierarchical cells along the edges. Theoretical model for the first type of hierarchical tubes was further developed and verified. The theoretical analysis and numerical simulation agree well.