ON THE PREDICTION OF THE INITIATION OF DELAMINATION IN A [0/90]S LAMINATE WITH A CIRCULAR HOLE

Two approaches to predict the initiation of delamination at the edge of a hole in a graphite/epoxy laminate under in-plane compression loading are presented. The first approach, which is used to analyze interlaminar stresses without delamination, employs singular finite elements at the edge of the hole, the strength of the singularity being varied around the edge. The second analysis is a fracture mechanics analysis based on the strain energy release rate. Both analyses predict that the risk of delamination is highest about 60 degree away from the loading direction.