Durian-Shell-Inspired Biostructures for Energy Absorption and Impact Protection

This study presents a novel bionic thin-walled tube with a complex cross-section (BS), inspired by the protective thorns of the durian fruit, to enhance crashworthiness and impact protection. The spiky durian shell dissipates impact energy and shields non-impact regions, motivating the biomimetic design. Quasi-static compression tests demonstrate that BS5 achieves a 9% higher Specific Energy Absorption (SEA) than Sinusoidal corrugated tubes (SIN) and 22% higher than Double Corrugated Tapered tubes (DT). The three BS configurations also exhibit 31–60% higher Crushing Force Efficiency (CFE) while reducing Undulation of Load-carrying Capacity (ULC) by 26–74%, resulting in smoother force–displacement responses. Bulkheads provide no advantage in axial energy absorption; in fact, BS5 without bulkhead achieves a 33% higher SEA. Structures with polygonal mid-sections show lower imperfection sensitivity than square ones, and when the side length-to-thickness ratio is preserved, larger-scale structures retain stable absorption efficiency, indicating potential for protective applications such as shelters. By integrating two antiprism units, BS5 delivers 45% higher SEA, 71% higher CFE, and 35% lower ULC than a single antiprism tube. A calibrated linear elastic constitutive model accurately predicts crushing behavior under quasi-static loading. Unlike SIN and DT double-layer structures that collapse in thick-walled modes, deformation analysis reveals that double-layer BSs possess an optimal interlayer spacing to avoid such degeneration, exhibit a more complex plastic hinge evolution mechanism and higher energy absorption efficiency. Low-velocity drop-weight tests confirm superior impact resistance of BSs compared with SIN and DT, while high-velocity simulations reveal only a 21% increase in Initial Peak Crushing Force (IPCF) from 5 to 50 m/s, demonstrating robust dynamic performance. Overall, the durian-inspired BS tubes exhibit excellent crashworthiness and strong potential for advanced defense and engineering impact protection applications.