Computational Mechanics of Fatigue and Life Predictions for Composite Materials and Structures

A multiscale fatigue analysis model is developed for brittle composite materials. The mathematical homogenization theory is generalized to account for multiscale damage effects in heterogeneous media and a closed form expression relating nonlocal microphase fields to the overall strains and damage is derived. The evolution of fatigue damage is approximated by the first order initial value problem with respect to the number of load cycles. An efficient integrator is developed for the numerical integration of the continuum damage based fatigue cumulative law. The accuracy and computational efficiency of the proposed model for both low-cycle and high-cycle fatigue are investigated by numerical experimentation.