Quasi-Static Axial Crushing Behaviour of Rectangular Foam-Filled CFRP-Aluminium Hybrid Composite Tubes

This study investigates the quasi-static axial crushing behaviour of carbon fibre-reinforced polymer (CFRP) tubes with variations incorporating polyurethane foam (PU) and aluminium tubes. Six different composite configurations were fabricated, including a baseline hollow CFRP tube and hybrid structures with foam and aluminium reinforcements. The mechanical response was evaluated through load–displacement behaviour and energy absorption. Visual inspection of the failure modes revealed distinct fracture mechanisms influenced by the type of reinforcement. The results indicate that incorporating aluminium significantly enhances load-bearing capacity, energy absorption, and crushing efficiency, with the sample containing four aluminium secondary tubes exhibiting the highest specific energy absorption. Meanwhile, foam-filled samples improved load-bearing capacity while mitigating brittle failure. These findings suggest that CFRP hybrid structures with aluminium and foam reinforcements offer promising solutions for lightweight Crashworthiness applications in the automotive and aerospace industries.