Crashworthiness performance of lightweight crash box by lattice metamaterials

Crash boxes are vital components in automotive safety systems, designed to absorb impact energy during collisions and protect vehicle occupants. Thin-walled structures with intricate geometries are commonly employed in crash box designs due to their lightweight nature and high energy absorption efficiency. Among these, concave structures have demonstrated superior crashworthiness compared to conventional thin-walled configurations. In this study, a crash box featuring a concave structure is designed and manufactured with consideration of practical manufacturing constraints. Its crushing behaviour is investigated under both quasi-static and dynamic loading conditions. The performance of the proposed design is benchmarked against a commercially available crash box. Results show that while both designs achieve comparable total energy absorption, the proposed crash box exhibits twice the specific energy absorption, indicating a significantly lighter structure. Furthermore, the influence of impact initiators is examined, highlighting their critical role in enhancing crash box performance.