A Fatigue Crack Growth Model for Random Fiber Composites

Abstract

Fatigue crack growth behavior of a randomly oriented short carbon fiber rein-forced polyether ether ketone (PEEK) composite is studied at four different load ratios. Based on the experimental data, a new fatigue crack growth model is proposed which accounts for crack growth throughout the entire fatigue cycle and not just at the maximum load. The proposed model involves a weighted averaging procedure and is found to fit the fatigue crack growth rates at all load ratios in a single power law equation. Finally, it is observed that the fatigue threshold intensity of this material decreases with increasing load ratio.