Failure modes and energy absorption mechanism of CFRP thin-walled square tubes filled with gradient foam aluminum under axial compression

Abstract

Carbon Fiber Reinforced Plastic (CFRP) thin-walled square tube filled with gradient foam aluminum represents a novel component known for its exceptional energy absorption capabilities. This paper investigates the failure modes and energy absorption mechanisms of CFRP thin-walled square tubes filled with gradient foam aluminum using a combination of numerical simulations and quasi-static axial compression tests. The influences of some factors, including lay-up angles, lay-up sequences, and lay-up thicknesses have been analyzed. Additionally, the impact of the gradient foam aluminum filler on the crashworthiness characteristics has been scrutinized. The results reveal that the samples with lay-up angles below 45° showed a failure mode characterized by layer bundle buckling during axial compression. Conversely, the samples with lay-up angles exceeding 45° exhibited lateral shear failure during axial compression, with the latter demonstrating notably higher energy absorption efficiency. Increasing the proportion of circumferential angle and setting the circumferential angle on both the inner and outer sides of the axial lay-up, the energy-absorption capacity of the filled CFRP tubes under axial compression can be improved. This study demonstrates the potential of CFRP tubes filled with gradient foam aluminum to be used as energy absorbers.