The effect of an irregular crack front on fatigue crack growth

Crack growth was initiated in 7075-T6 specimens from slits of different shapes in order to produce irregular and wavy crack fronts. Lower crack rates were found for more wavy crack fronts. Crack opening was also lower then, indicating that longer crack fronts produced lower $\text{K}$ values. Part of the environmental effect on crack growth is due to irregular crack fronts. The significance of fatigue fracture morphology for understanding certain influences and improving fatigue crack growth resistance is emphasized.