Impact Damage and Residual Compression Strength of CNF/CFRP Hybrid Laminates

In the present study, the impact damage of CNF/CFRP hybrid laminates and influence of carbon nanofiber (CNF) interlayer on impact damages were investigated by the drop weight impact tests. Vapor grown carbon fiber (VGCF) has been employed for the toughener of the interlayer on the CFRP laminate. Drop weight impact tests were carried out using “Dynatup” impact test equipment. Damaged area occurring in the interlayer of the CFRP laminate was observed by ultrasonic flaw detection system. The damage properties of the CNF/CFRP hybrid laminates were considered from the viewpoint of the relation between damaged area and impact energy. Moreover, by compression after impact (CAI) tests, the relation between residual compression strength, impact energy and damaged area was investigated. It was confirmed that the damaged area could be reduced, and CAI strength became higher by inserting CNF interlayer. Moreover, the optimal additive amount of VGCF for the interlayer was about 20 g/m2.