| In the case of large scale delamination,the cross section of laminate is divided into threeregions: inchding crack-tip,excluding delamination(interface crack)and delaminated re-gion. In each region,the eigen expansions of displacement and stress fields satisfying all ofgoverning equations, boundary conditions along delamination surfaces and conditions of con-tinuity along undelaminated portion of interface are derived.The other boundary conditionsand conditions of continuity between the two regions are satisfied by generalized variationalprinciple for multi-region,and then the generalized stress intensity factors can be deter-mined. |