New higher-order plate theory in modeling delamination buckling of composite laminates

A new higher-order plate theory for modeling delamination buckling and postbuckling of composite laminates is developed. Delaminations between layers of composite plates are modeled by jump discontinuity conditions, in both lower and higher order terms of displacements, at the delaminated interfaces. Some higher-order terms are identified at the beginning of the formulation by using the conditions that shear stresses vanish at all free surfaces including at the delaminated interfaces. Therefore, all boundary conditions for displacements and stresses are satisfied in the present theory. Geometric nonlinearity is included in computing layer buckling. The general governing equations, along with all boundary and continuity conditions of plates, are derived for predicting the delamination buckling and postbuckling behavior. The associated delamination growth problem is also examined using Griffith-type fracture criterion. A numerical example is presented to validate the theory. The results are also compared with experimentally obtained data.