Effects of segmented circumferential reinforcements on the crashworthiness of bamboo bio-inspired composite columns: An experimental study

Lightweight energy-absorbing structures are crucial for enhancing crashworthiness in transportation vehicles, where managing impact loads and mitigating occupant injury risk are paramount. Inspired by the fibre-reinforced composite architecture and unique segmented nodes of natural bamboo, this study proposes a Bamboo Bio-inspired Composite Column (BBCC) fabricated from carbon fibre/epoxy composite via vacuum bag moulding. A comprehensive experimental and statistical investigation is conducted to evaluate the effects of key reinforcement parameters—internode length l, reinforcement axial length d, and ply number n—on crashworthiness performance of BBCC. Quasi-static compression tests reveal that these parameters critically control failure modes, ranging from stable progressive crushing, local buckling to interactive bilateral failure. Main-effect and ANOVA analyses quantify that n is the dominant factor for energy absorption capacity (specific energy absorption (SEA) and mean crushing force (MCF)) and crushing force efficiency (CFE), while d and its interaction with l govern the initial peak crushing force (IPCF). Entropy-based TOPSIS multi-objective optimisation resolves the inherent trade-off between maximising SEA and minimising IPCF, yielding the optimal design achieving an exceptional balance: a high SEA of 53.04 kJ/kg, a controlled IPCF of 28.84 kN, and an outstanding CFE of 84.4%. This study provides valuable reference for the design, analyse, and optimisation on lightweight, high-performance energy-absorbing components.