On modelling of laminates containing free-edge delaminations

Abstract

The stress field ahead of the delamination tip and the strain-energy release rate in symmetric composite laminates with mid-plane delamination subjected to mechanical and thermal strains have been studied with the aid of a modified form of the Whitney-Sun theory. The procedure considers the laminate cross-section in three zones based on the geometry. Governing equations have been derived from the principle of virtual displacements, and solutions have been obtained by enforcing the boundary and continuity conditions. Interlaminar normal stresses ahead of the delamination tip and the strain-energy release rates are presented for various sizes of the delamination and are compared with some of those available in the literature.