Failure modes and energy absorption mechanism of CFRP Thin-walled square beams filled with aluminum honeycomb under dynamic impact

Abstract The CFRP thin-walled square beam filled with aluminum honeycomb is a new outstanding energy absorption component. In this paper, the failure modes and energy absorption mechanism of filled CFRP beams are studied by combining numerical simulation and dynamic impact test. Axial collapse process and lateral bending process of filled CFRP beams are analyzed by quasi-static test. Under the two different working conditions, the failure modes and corresponding energy absorption mechanism of specimens with different lay-up angles are analyzed. The results show that the failure modes under axial impact mainly include lateral fibre bending failure, lateral shear failure and local buckling failure. Among them, the large angle lay-up (e.g. [90°] 8) is prone to lateral shear failure and has a high material utilization rate. Under lateral impact, the failure modes are different from those under axial impact, which mainly include lateral shear failure and fibre bending failure. The energy absorbed under the two failure modes is less than that absorbed under axial impact, with obvious local failure and a low material utilization rate. Research also shows that the failure modes and energy absorption mechanism of filled CFRP beams are of great significance for the guidance of its structural design.