Open hole fatigue characteristic and probabilistic model for fatigue life prediction of CCF300/QY8911 and T300/QY8911 composite laminates

This study investigated open-hole tension fatigue characteristic of carbon fiber-reinforced composite laminates subjected to constant amplitude cyclic loading. Two kinds of composite laminates, the CCF300/QY8911 and T300/QY8911, were used for fatigue testing with maximum loading of 70% notched tensile strength. Ultrasonic C-scan method was employed for fatigue damage evolution in composite laminates investigation, and specimens showed that the cracks initiated at the edge of the hole and free edge before final fracture. For most of existing fatigue models for determining material degradation and life of composite laminates have tended to be limited in application to specific materials, laminate stacking sequence and loading conditions; this paper proposed a probabilistic model for fatigue life prediction. This model utilized the equality relationship of failure probability between fatigue life and residual strength for fatigue life connection establishing under different loading stresses, by which the fatigue life or reliability life could be evaluated by the static tensile testing data that was one of the critical ultimate stress point on the S-N curve. In this paper, the tension-dominated fatigue lives of notched CCF300/QY8911 and T300/QY8911 composite laminates were evaluated by this model. To compare with the experimental data, the predicted results showed a good agreement.