Analysis and testing of a thermoplastic composite stiffened panel under compression

This paper focuses on a novel numerical formulation based on cohesive elements and S-N diagram to simulate fatigue-driven delamination in composite laminates. The constitutive model adopts a two-parameters heuristic equation, which coefficients are evaluated using an idealization of the S-N diagram rather than the more commonly used Paris law. The approach is implemented in the finite element code ABAQUS and validated with analysis on Double Cantilever Beam specimen. The numerical outcomes are compared with experimental data taken from literature showing the capability of the model in predicting the crack growth rate. The model is then applied to evaluate the fatigue delamination growth in a specimen similar to the Double Cantilever Beam but with reinforcement plates which force the delamination front to change its shape during the propagation. The results compared with experimental data taken from literature show the effectiveness of the approach in predicting the load-displacement curve and the delamination front shape and position at different load cycles.