Low-velocity impact response and post-impact flexural behaviour of composite sandwich structures with corrugated cores

This paper aims to investigate the low-velocity impact response and post-impact flexural behaviour of hybrid sandwich structures consisting of carbon fibre-reinforced polymer (CFRP) face sheets and aluminium alloy corrugated cores. A combined experimental and numerical study is carried out over a range of impact energies and impact sites to evaluate the effects of the abovementioned factors on the impact damage and residual flexural strength. Low-velocity impact tests are performed to investigate the impact resistance of such structures with respect to impact load, absorbed energy and failure mode. Subsequently, three-point bending tests are conducted to determine and quantify the effects of impact damage on the residual properties of post-impact sandwich structures. Meanwhile, a procedure to numerically simulate the low-velocity impact tests and residual flexural strength tests of sandwich structures is developed by the VUMAT subroutine in ABAQUS/Explicit. Reasonably good agreement is achieved when comparing the impact response and flexural behaviour between experimental measurements and numerical predictions. These studies reveal that the damage depends on the impact energy and impact location. The residual flexural strength decreases significantly even though the impact energy is lower than 10 J, while there is a slight reduction with a further increase in the impact energy.