Abstract:
Carbon fiber (CF) reinforced epoxy resin (EP) matrix composites were widely used in aircraft structural components due to their excellent impact resistance. Considering that some of the structures of aircraft were subjected to multiple impacts during flight, the CF/EP composite laminates were designed for multiple impacts and compression after impact tests. The mechanical response curves and internal damage diagrams of the multiple impacts were analyzed to obtain the effects of different impact loads on the mechanical properties of the composites during multiple impacts, as well as the main damage mechanisms and damage propagation modes during the multiple impacts. On this basis, the residual compression strength and failure morphology after impact were analyzed to obtain the damage tolerance and failure mode of CF/EP composite laminates after impact. The results show that an increase in the number of impacts will lead to a decrease in the energy absorption and impact resistance of the composites. During multiple impacts, the damage pattern of the composites is bottom-up. In addition, the main damage modes of the composites during compression after impact vary with the impact energy level.