Dynamic response of muscle-inspired hierarchical tubular structure under lateral shock loading

Muscle-inspired hierarchical tubular (MHT) structures have demonstrated exceptional potential for lightweight protective applications owing to their remarkable energy dissipation capacity, yet their behavior under high-velocity lateral impact remains insufficiently investigated. This study systematically examines the dynamic response of MHT structures under lateral impact loading through integrated experimental and numerical approaches. Specimens with three hierarchical levels, fabricated from 6061 aluminum alloy, were subjected to high-velocity foam projectile impacts using a single-stage light-gas gun system. A corresponding finite element model was developed, and the numerical predictions agree well with the experimental observations. The results reveal a clear trade-off that the 1st-order MHT exhibits higher stiffness and lower deformation but suffers from severe impact reactions and projectile damage. In contrast, higher-order MHTs develop more extensive impact-side deformation, prolong projectile-target interaction, and establish a front-to-rear gradient of decreasing deformation. Multi-level configurations effectively reduce peak acceleration and contact force through sequential activation of substructures, leading to attenuated force transmission. Furthermore, with increasing impact velocity, the energy absorption distribution shifts from the outer to the inner layers, demonstrating the adaptability of MHTs to diverse impact velocity scenarios. By adjusting the wall thickness, the mass distribution of the 3rd-order MHT is tuned to achieve distinct energy absorption characteristics, providing guidance for tailoring structural parameters to diverse engineering demands. These findings provide valuable insights for the design of lightweight protective structures under lateral impact. • The dynamic response of muscle-inspired hierarchical tubular (MHT) structures under lateral impact loading was investigated both experimentally and numerically. • The influence of structural hierarchy on deformation evolution, impact mitigation behavior and energy absorption capability is revealed. • Mass distribution designs are evaluated and compared for superior structural performance.