Buckling, post-buckling and failure of elliptical delaminations in laminates under compression

Abstract A nonlinear method to analyze composite panels with elliptical delaminations under compressive loads is presented. The method is based on solving the fully coupled partial differential equations for anisotropic elasticity using infinite series. The buckling loads predicted by the present method are compared to the predictions of other techniques available in the literature. A simple failure model to predict onset of delamination growth is presented. Tests conducted on selected laminates show good agreement with the theoretical predictions. The delamination threshold size below which the panel behavior is not affected by the presence of the delamination is defined. Knowledge of this delamination size is essential for the design of composite laminates and for establishing inspection standards in manufacturing of such panels.