The interlaminar stresses along the interface of the $90^\circ$ layer and the $0^\circ$ layer are calculated for[90n/0m]s laminate with transverse cracks. The interlaminar stresses far from the transverse crack tip show a little decrease as the crack spacing deceases. However the interlaminar stresses near crack tip have no significant change.
The strain energy release rate is calculated for various crack lengths. It is found that mode-I is dominant fracture mode for the delamination crack propagated from the transverse crack tip. The fracture criterion for strain energy release rate is used in order to predict the delamination onset strain. The predicted delamination onset strains are not influenced by initial crack lengths. The delamination onset strain reduces remarkably as the thickness of $90^\circ$ layer increase, but it is relatively insensitive to the thickness of $0^\circ$ layer.
