Fracture Behaviour of FRP Composite Laminates with an Embedded Elliptical Delamination at the Interface

This study deals with the delamination initiation from an existing embed ded elliptical delamination at the interface of FRP composite laminates. A full 3D FE anal ysis has been performed to calculate the interlaminar stresses at the interface responsible for delamination. Concept of fracture mechanics has been used to calculate the components of strain energy release rates at the interface. An elliptical delamination has been simulated to be present at the interface of two sublaminates each consisting of several plies and the laminate has been subjected to a central concentrated transverse loading. Effects of impor tant factors like fiber orientation of the adjacent layers, laminate thickness and the aspect ratio of the elliptical delamination on strain energy release rate components have been stud ied. It has been observed that the strain energy release rates vary along the delamination front showing an anisotropic delamination. The magnitudes of strain energy release rate components depend upon the fiber orientation of the adjacent layers, laminate thickness and the aspect ratio of the delamination present at the interface.