Damage and failure mechanisms of CFRP due to manufacturing induced wrinkling defects

Out-of-plane wrinkling is a typical defect in the manufacturing process of carbon fiber reinforced plastics (CFRP). The cross-ply composite laminates containing various wrinkles were designed and prepared based on a hybrid generation method of gaps and transverse strips. An analytical model based on the sine function was proposed to characterize the shape of wrinkles, and the severity of the defect was characterized by the wrinkle angle. With the aim to investigate the compression and out-of-plane shear failure performance of CFRP with wrinkles, experimental and numerical studies were conducted. Results show that the existence of wrinkled zone can significantly reduce the compressive strength of laminates and exacerbate delamination during compression failure, a maximum of 26.9% and 2.8% drop in the compressive and interlaminar shear strength was reported in the most severe experimental conditions. Meanwhile, it is indicated that wrinkles have little effect on interlaminar shear strength, but it can change the location and severity of the delamination failure. In addition, the failure mechanism of several models with different levels of wrinkling defects was studied through numerical analysis techniques. It is confirmed that the numerical model can effectively predict the failure intensity and failure modes. These findings are of great significance for the accurate evaluation of the mechanical properties of composites containing wrinkling defects.