Buckling, post-buckling and delamination propagation in debonded composite laminates: Part 1: Theoretical development

A new mechanical and computational model is presented in this part 1 of the paper for bucking, post-buckling and delamination propagation in debonded composite laminates. The layer-wise plate theory of Reddy [Reddy JN. A generalization of two-dimensional theories of laminated composite plates. Commun Appl Numer Methods 1987; 3: 173–80] is extended to account for delamination kinematics. The possible displacement jumps across delamination interfaces are incorporated in the assumed displacement field with step function supplements. The geometric non-linearity is included through the use of von Karman’s non-linear strain–displacement relationships. For computational efficiency and modelling effectiveness of delamination, both point and distributed interface spring models are developed. In order to predict the delamination propagation, the energy release rate at the delamination front is computed by means of the crack closure method. B-spline finite strip methods [Wang S, Dawe DJ. Spline FSM postbuckling analysis of shear-deformable rectangular laminates. Thin-Walled Struct 1999; 34: 163–78; Wang S, Zhang Y. Vibration analysis of composite laminated plates using layer-wise B-spline finite strip method. Comp Struct 2005; 68: 349–58, [30]] are extended to develop the computational model through the enrichment of displacement field by step functions.