Predicting delamination and debonding in modern aerospace composite structures

This paper addresses the problem of modelling the onset of delamination/debonding in composite structures and then the consequent propagation. A new interface element is designed which embraces both the initiation (strength-based) and the propagation (fracture-based). The force/displacement law is monotonic to avoid the need for a very fine mesh, and an explicit solver is deployed to enable quick convergence if equilibrium is not satisfied exactly at each load increment. Several “benchmark” tests are illustrated to establish the credibility of the model and a final realistic test of stiffener debonding is displayed. The chosen validation examples have both theoretical and experimental values wherever possible.