Direct method for life prediction of fibre reinforced polymer composites based on kinematic of damage potential

In this paper, a direct computational method of life prediction for fibre-reinforced polymers (FRP) is developed. This approach is based on a simplified direct method (SDM) which allows to predict the life from the stabilized damage state. The SDM is extended to the case of anisotropic continuous damage mechanics of FRP. It is shown that damage processes in composite material subjected to fatigue load can reach stabilized damage state. Damage state and thermodynamic forces associated with damage mechanisms at the stabilized state are related to life. Experimental validation was done on the standard glass-fibre/epoxy angle-ply and cross-ply laminate plates subjected to fatigue loading with different load ratios (R=0.1,0.5).