Damage modelling of the elementary ply for laminated composites

In this paper, fibrous composite laminate damage is modelled at the elementary-ply scale. Damage mechanics is used to describe the matrix microcracking and fibre/matrix debonding. Damage variables are defined and associated with the material stiffness reduction. In order to take anelastic strains induced by damage into account, a plasticity model is built up. The behaviour differences between tension and compression in the fiber direction are treated. The model leads to a laminate failure criterion. The model-identification procedure is precisely detailed. It consists in performing three tension tests and one compression test on a laminate whose reinforcement directions are conveniently chosen. Some examples are developed in order to show the ability of such a model to describe ply behaviour effects on the mechanical and rupture behaviour of laminates.