Effect of Anisotropy on Delamination Formation in Composite Laminates Under Multiple Impacts

This study investigates delamination formation mechanisms in composite laminates with different layup sequences subjected to two identical ice sphere impacts at different locations, using the finite element (FE) method. The two ice sphere impacts were applied at different locations on the laminate, with the second impact occurring at the moments corresponding to the minimum or maximum normal displacement peaks of the vibration at the impact location. The results show that the more quasi‐isotropic the laminate (i.e., the lower the degree of anisotropy), the smaller the difference between the delamination area induced by the second impact and that caused by the first one. Vibration causes additional delamination propagation in the laminate under multiple ice impacts and leads to random fragmentation of the ice sphere during the delamination formation process. When the fragmentation of the second ice sphere occurs during the additional delamination propagation stage, a larger projected delamination area than that from the single impact is formed. Otherwise, a smaller or identical projected delamination area can be observed.