Structural Integrity and Durability of Advanced Composites

7.3. Modeling microdefect evolution in a lamina and stiffness degradation of unidirectional composites

In this section, we shall evaluate damage evolution in composite material at a lamina level. In describing damage behavior of fiber-reinforced composite structures, we are interested in defining this behavior based on some local measure of damage in real time as it accumulates. Moreover, it is desirable to include both the birth and the growth processes of microdefects simultaneously in order to accurately describe the damage-accumulation process in composite structures, which in turn influences the effective characteristics of the composite material. We propose that the microdamage-accumulation process is basically a consequence of actions governed ...