Simulation on size effect of notched quasi-isotropic composite laminates under tensile loading

Abstract

The formation of longitudinal splitting alleviates the extremely high stress concentration at notch tips of fiber-reinforced composites under remote tension. Theoretical foundation is provided to show that the true stress field along the potential splitting routes can be accurately modelled by inserting cohesive zones in finite element models, such that strength-based criteria can be used to predict damage initiation. Progressive failure analyses are performed to study the in-plane size effect of double-notched quasi-isotropic composite laminates. To capture the stress relief effect of longitudinal splitting during the loading process, surface-based cohesive contacts are introduced along the fiber directions to model the longitudinal splitting. To predict the possible delamination, interface cohesive contacts are also inserted between plies with different fiber orientations. The advantage of the surfaced-based cohesive contact method over the conventional cohesive element method is that it allows different mesh configurations for plies with different fiber orientations. Failure patterns and failure loads predicted by finite element analyses of three scaled composite laminates were compared with experimental results from open literature.