Conch shell–inspired thin-walled structure with enhanced energy absorption and impact resistance

This study presents a conch shell–inspired thin-walled structure as a novel lightweight energy absorber for automotive crash box applications. The bio-inspired design aims to enhance both energy absorption efficiency and impact resistance. Comparative experimental and numerical investigations were conducted against a conventional square tube with identical wall thickness and mass. Quasi-static axial compression tests revealed a stable progressive collapse mode and significantly improved crashworthiness. Finite element models, validated by experimental results, were further employed to evaluate key performance indicators, including specific energy absorption (SEA), crushing force efficiency (CFE), and undulation of load-carrying capacity (ULC). Without increasing mass or manufacturing complexity, the bio-inspired structure achieved 1.93 and 2.20 times higher SEA and CFE than the square tube, respectively, while the ULC was reduced by 18.5%. Parametric analyses demonstrated that the proposed structure maintains stable SEA and deformation controllability at large height-to-width ratios. Moreover, a theoretical model based on the super-folding element theory accurately predicts the mean crushing force. Low-velocity impact tests further confirmed its superior dynamic energy absorption and impact resistance. Overall, the conch shell–inspired design demonstrates strong potential for developing lightweight, high-performance crashworthy components for automotive safety systems.