Experimental Study on Delamination of Composite Laminates with 0°/45° Interface under Mode I, Mode II and Mixed-mode I/II Loading

High performance carbon-reinforced composite materials have become important aeronautical materials. During the service time, the delamination fracture of composite structures is a common failure mode. In this study, in order to investigate the delamination behaviours of T800/epoxy composite materials under different mixture ratios, DCB, ENF and MMB tests were conducted on composite laminates with pre-set 0°/45° interface respectively. From the test, the initial delamination fracture toughness and delamination growth behaviour were obtained. The test results show that the fracture toughness and delamination behaviour are significantly affected by the mixture ratio. With the increase of mixture ratio, the fracture toughness increases, and steady delamination growth behaviour is more difficult to maintain. Based on the data fitting method, a prediction function for fracture toughness of the 0°/45° interface at arbitrary mixture ratio is established, which has some engineering values