Combined delamination and matrix cracking in adaptive composite laminates

An approach for modeling the response of laminated composite plates with piezoelectric patches, taking into account damage, is developed. An analytical model is presented that includes the effects of delamination and transverse matrix cracking. The equations of motion are formulated by using a coupled piezoelectric-mechanical theory that enables simultaneously solution for the mechanical strains and electric displacement. The finite element method is used with a refined, higher-order theory to model the composite plate response. Delamination is modeled by using a set of sublaminates, with continuity conditions that are enforced at the boundaries. Matrix cracking is incorporated as a reduction in ply stiffness that is a function of the crack density. Both matrix-crack closure and contact between the sublaminates are modeled, and a discrete time integration approach is used to compute the dynamic response. Results are shown for a simply-supported plate and illustrate the influence of composite damage on the electrical response of attached piezoelectric devices. The results demonstrate that this modeling technique approximates the influence of composite damage on the global response the damaged structure and predicts the transient electrical and mechanical response of piezoelectric smart composite structures.