Delamination Buckling and Growth in Rings under Pressure

Abstract

A delaminated composite ring under external pressure is studied to understand the effect of curvature on delamination buckling and growth. Examples with differing crack lengths and delamination locations were considered. In all cases, the delamination surfaces come in contact rather early in the loading history, no matter what the initial imperfections are assumed to be. Furthermore, the delaminated part never becomes separated from the main ring. The modes of buckling given by standard linear stability analysis do not play any role in the behavior. Strain energy release rates were computed with the objective of predicting possible crack growth. Because of the contact, total energy release rate is dominated by the shear mode. Because the critical values of energy release rates are generally much higher in the shear mode than in the opening mode, one may conclude that shells tend to be more delamination tolerant than plates in which the opening modes tend to dominate.