Bio-Inspired Crash Box Design Based on Coconut Palm Trunk Structures for Improved Energy Absorption in Passenger Vehicles

Abstract This study investigates the crashworthiness performance of novel crash box geometries inspired by the structural configuration of coconut tree trunks. Six models were analyzed, comprising four bio-inspired designs with square and circular cross-sections in single- and double-shell forms, along with two conventional hollow configurations. Numerical impact simulations, validated against experimental data, were conducted to evaluate force–time, force– displacement, and energy absorption responses. Results indicate that the introduction of internal reinforcement significantly enhances energy absorption, while circular geometries provide lower peak forces and more stable deformation. The findings highlight the potential of bio-inspired crash boxes for improved passenger vehicle safety.