Damage and plasticity at the interfaces in composite materials and structures

The structural behavior at the interface between two surfaces of ductile, brittle or quasi-brittle materials is studied by a new analytical elastoplastic damaging model. The model is developed in the framework of a thermodynamically consistent theory. The Helmholtz free energy is written to predict the materials’ hardening or softening. An isotropic damage is considered and the possible effects of dilatancy are taken into account including non-associative flow rules. The interface laws are presented both in a rate and a discrete incremental form. The analytical formulation is then implemented into a finite element code and two structural members are studied to validate the model. The numerical results are compared to experimental data available in literature. It is demonstrated that the new model is general and it includes the continuum damage mechanics and the elastoplasticity as limit cases.