Hierarchical Deformation Mechanisms and Energy Absorption in Bioinspired Thin-Walled Structures.

Lightweight, hierarchical thin-walled tubes are essential in aerospace and transportation for their exceptional impact resistance and energy absorption capabilities. This study applies bionic design principles to revolutionize traditional thin-walled tube structures, enhancing their energy absorption performance. Inspired by natural models-spider webs, beetle elytra, cuttlebone, and spiral wood fibers-integrated bionic hierarchical thin-walled tubes (IBHTTs) with diverse bionic structural and material combinations are developed using additive manufacturing. Mechanical tests and simulations demonstrated distinct deformation behaviors and significant performance enhancements. An IBHTT incorporating spider web, beetle elytra, and cuttlebone-inspired designs achieved a 129.7% increase in absorbed energy (EA) and a 21.8% improvement in specific energy absorption(SEA) compared to conventional tubes. Introducing spiral wood fiber-inspired features further improved toughness under compression and impact, with helical formations enabling mutual squeezing and self-twisting, resulting in a 397.5% increase in absorbed energy and a 67.0% boost in specific energy absorption. Furthermore, IBHTTs with adjustable helical angles exhibited distinct mechanical and energy absorption characteristics, enabling tailored compressive responses through custom spiral configurations. These findings lay the groundwork for designing advanced thin-walled tubes to meet diverse application demands, pushing the boundaries of bionic engineering.