Micromechanics Prediction of Fatigue Failure of Composite Materials

A micromechanics theory is proposed for the prediction of the fatigue failure of unidi-rectional composites and laminates under any loading system. The method is based on micro-failure criteria which are applied separately on the fiber and matrix regions. The resulting failure stresses of the composite depend explicitly on the elastic constants of the phases and the reinforcement volume ratio. Comparisons between the theoretical fatigue failure diagrams and experimental results are given for unidirectional composites and angle-ply laminates. 1