Damage evolution in laminated advanced composites

This paper extends the theory for damage evolution in a single ply presented earlier by the authors. Simultaneous damage evolution in individual plies, at different rates, is accounted for; reduction of the rate of damage growth in a ply due to deformational restrictions imposed by adjacent plies is implicit in the formulation. The theory is valid for any sequence of external loading. However, unloading and cyclic loading cases are not considered in this paper. This is achieved by completely updating the material parameters in a ply that has reached a saturated damage state. This parameter updating is based on the identified damage mode (at failure) of the ply. Predicted results are compared with available experimental data for T300 Graphite-Epoxy. Further results that demonstrate the capabilities of the theory are also presented.