On the interaction of delamination buckling and damage growth in cross-ply laminates

The compressive behaviour of cross-ply laminates with delaminations and matrix cracked layers is investigated by means of an analytical modelling approach. Insight into the post-buckling and damage growth behaviour is obtained owing to comprehensive parametric studies varying delamination length and depth as well as matrix crack density for cross-ply laminates with different layups. The efficient modelling approach comprises the well-known total potential energy principle and the Equivalent Constrained Model for determining reduced stiffness properties depending on the matrix crack density. Thus, unlike previous studies on delamination buckling, the effect of matrix cracked layers is taken into consideration. The analysis of the energy release rates for delamination and matrix crack growth enables the identification of configurations (e.g. delamination depth and length, total thickness of the laminates) which are prone to delamination growth and matrix crack growth, respectively. Beyond that, relationships between post-buckling and damage growth behaviour are identified and discussed.