Aluminum hierarchical tubular structure inspired by skeletal muscle tissues: Quasi-static and low-velocity impact testing

This paper investigates experimentally and numerically the protective capability of skeletal muscle-inspired hierarchical tubular (MHT) structures made of aluminum under both quasi-static and dynamic impact conditions. In the quasi-static compression tests, structures with higher hierarchical order were more deformable and had lower contact force. Dynamic impact tests were conducted for the first time on MHT specimens of three different hierarchical orders using a drop tower facility. The results indicated a significant reduction in both the maximum and mean contact forces on the protected body when shielded by the second- and third-order MHT structures. This suggested that increasing the hierarchical order of the structure effectively enhanced impact protection capability. Numerical models were developed using ABAQUS/Explicit to accurately reproduce the deformation process and force-time functions of the dynamic impact scenarios. A parametric study found that the impact resistance performance of the MHT structures was robust against various impact velocities and masses.