Variational analysis of delamination growth for composite laminated cylindrical shells under circumferential concentrated load

The growth of delamination in cylindrical shells under external pressure may lead to structural failure. Based on the variational principle of moving boundary (Qian WC. Variational calculus and finite element. Beijing: Science Press; 1980 [in Chinese].) and considering the contact effect between delamination regions, in this paper, the nonlinear governing equations for the delaminated cylindrical shells are derived, and the corresponding boundary and matching conditions are given. Moreover, according to the Griffith criterion, the formulas of energy release rate along the delamination front are obtained. As the numerical example, the delamination growth of axisymmetrical laminated cylindrical shells is analyzed, and the effects of delamination sizes and depths, geometrical parameters, material properties and laminate stacking sequences on delamination growth are discussed.