Parametric study of delamination in composites with discontinuous plies using an analytical solution based on fracture mechanics

An analytical solution is derived for calculating the strain energy release rate concerning delamination along the interfaces of continuous and discontinuous (or 'dropped') plies in composite laminates under a combination of bending and axial loading. The solution allows for different axial Young's moduli in the continuous and discontinuous material. Hence the strain energy release rate, G, is determined for laminates with different lay-ups, and the effect of the ratio between bending and axial loading is assessed. The effect which the thickness and position of the discontinuous plies within the laminate has on the value of G is also studied. The observed trends lead to the proposal of a failure envelope for predicting delamination based on the axial strain in the discontinuous plies. (C) 1998 Elsevier Science Limited. All rights reserved.