Failure analysis of fiber‐reinforced composites under multiaxial cyclic stress

Abstract A preliminary study on the fatigue failure of continuous fiber reinforced composites under multiaxial stress has been presented. A model used to predict the direction of the critical plane of composite laminae under multiaxial cyclic stress is developed. First, two types of planes in the unidirectional lamina are defined in order to discriminate the different failure mechanisms, i.e. fibre failure and inter‐fibre failure. Based on planes of different types, the concept of effective stress is proposed to determine the direction of the critical plane. Second, fatigue experiments of filament wound composites under biaxial loading are carried out and the failure planes are described. Results show that the fracture planes in reality are close to the critical planes predicted by the model. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers