Experimental and numerical investigations of wrinkle effect on failure behavior of curved composite laminates

Compared with flat laminates, curved composite laminates are more susceptible to wrinkle defects which must be considered in the design and structural integrity assessment. Combined experimental testing and numerical simulations were carried out in this paper to investigate the influence of wrinkles on the failure behavior of L shaped laminates. Special lay-up and forming processes were used to generate the pre-defined wrinkle profiles, and mechanical test together with the DIC measurement were carried out to illustrate the impact of wrinkles. Numerical modelling with progressive failure analysis approach was developed to simulate the failure process and the influence of the wrinkles. It is revealed that wrinkles triggered premature delamination and alter the propagation process by inducing damages near wrinkle plies. A significant strength reduction of about 30–40% was observed for the specimen containing wrinkles by both the numerical simulation and experimental results. Failure mechanism analysis revealed that the influence of wrinkles on the failure behavior was attributed to local stress concentrations around the wrinkles. The geometrical features such as amplitude and locations of the wrinkles are important factors to be evaluated for engineering application of curved composite structures.