A Numerical and Experimental Study of Delaminated Layered Composites

Abstract

This paper describes the development of a finite element-based computer model for the determination of stress fields and energy release rates around a delamination in a layered composite. The model is fully three-dimensional. Each layer of a composite material is modelled as homogeneous and orthotropic. The basic finite elements are isoparametric 20-noded bricks with collapsed, prismatic quarter-point elements around the delamination front. Contact theory is used to prevent interpenetration between the faces of a delamination. The modified crack closure method is used to calculate the energy release rates around a delamination. Preliminary experiments are performed to study the growth of a delamination between the layers of a two-layer laminate-one epoxy and the other graphite/epoxy. Initial results from the experiments and numerical simulations are shown to be consistent.