On the numerical modelling of edge delamination in composites

A geometrically and physically nonlinear finite element approach is presented for the analysis of mode-I and mixed-mode free edge delamination in composite laminates, which properly accounts for the effects of initial thermal and hygroscopic stresses. A mode-I crack model and an orthotropic softening plasticity model are used to determine the initiation and propagation of mode-I and mixed mode delamination. Although both fracture criteria are based on stresses, it is proved, that, in combination with a softening type of post-failure response which is controlled by the fracture toughness of the fracturing interface, the proposed approach results in a unique and physically realistic solution upon mesh refinement. The results from the nonlinear finite element computations including predictive analyses - are compared with mode-I and mixed-mode free edge delamination experiments. This comparison shows that the numerical results are within 10% of the experimental data.