Fatigue crack growth model and mechanism of a random fiber SMC composite

The primary purpose of this study is to investigate the fatigue crack growt h rate and mechanism in a random fiber sheet molding compound (SMC) composi te. The fatigue crack growth rate in this study was measured using a compli ance approach. The fatigue crack growth rate in the SMC studied here shows a good agreement with a new power law model proposed earlier. This new mode l takes into account not only the effect of the stress intensity factor ran ge, but also the effect of crack growth at various stages of loading using a weight average stress intensity factor. It was observed that this new mod el can represent the fatigue crack growth rate of the SMC at three differen t load ratios in a single unifying curve.