Delamination Formation in Curved Composite Laminates Subjected to Multiple Impacts

ABSTRACT Literatures show that vibrations induced by foreign object impacts on composite laminates influence delamination formation under multiple impacts. To further investigate this effect, composite laminates with different curvatures subjected to two identical ice sphere impacts at different locations were investigated. Based on a previously established and experimentally validated finite element model, the second impact was applied at equally spaced instants between the minimum and maximum vibration displacements at the impact location. The results show that the increased curvature reduces structural vibration, thereby decreasing the difference between the projected delamination areas caused by the first and second impacts. This could be due to the random ice sphere fragmentation induced by impact vibration. No delamination occurred in the case of ice sphere totally lost its structural integrity before delamination initiation, whereas ice sphere fragmentation during delamination formation leads to smaller (early‐stage fragmentation) or larger (late‐stage fragmentation) delamination areas. Besides, composite laminates have an optimal curvature that provides the greatest resistance to single‐impact‐induced delamination.