Statistical modelling of compression and fatigue damage of unidirectional fiber reinforced composites

A statistical computational model of strength and damage of unidirectional carbon fiber reinforced composites under compressive and cyclic compressive loading is presented in this paper. The model is developed on the basis of the Budiansky–Fleck fiber kinking condition, continuum damage mechanics concept and the Monte-Carlo method. The effects of fiber misalignment variability, fiber clustering, load sharing rules on the damage in composite are studied numerically. It is demonstrated that the clustering of fibers has a negative effect of the damage resistance of a composite. Further, the static compressive loading model is generalized for the case of cyclic compressive loading, with and without microdegradation of the matrix, and with and without random variations of loading. It was observed that the random variations of loading shorten the lifetime of the composite: the larger the variability of applied load, the shorter the lifetime.