Fracture Behaviour of FRP Composite Laminates with Two Interacting Embedded Delaminations at the Interface

Abstract

This study deals with the delamination growth behaviour of FRP composite laminates having two embedded delaminations at the interface under uniaxial and transverse loadings. A full 3D FE analysis has been performed to calculate the interlaminar stresses at the interface responsible for delamination. The concept of fracture mechanics has been used to calculate the strain energy release rate components at the interface. Elliptical delaminations have been simulated to be present at the interface of two sublaminates each consisting of several plies, and the effect of the neighbouring delaminations on the other delamination has been studied under concentrated transverse loading as well as uniaxial tensile loading. Effects of delamination size, shape and the center distance between the two delaminations on individual strain energy release rate components have been evaluated to assess the delamination behaviour. It has been observed that the shape, size and the relative spacing of the two delaminations have a strong effect on the overlapping stress field, and the two delaminations grow in size to form a single delamination depending upon these parameters.