Application of the deformation criterion to the description of short fatigue crack growth

Expressions, cited in the literature, that describe the relation between deformation fatigue curve parameters and short surface crack growth parameters for limited lifetimes are examined. The relation between initial defect sizes and average grain sizes over the range of high-cycle fatigue lifetimes is introduced. Fatigue curves, plotted by the above relations, are in good agreement as to the criterion of origin of a 100-μm surface crack with experimental data for 45, 12KhN3A, and 40Kh steels. Such a result opens the way to calculation-experimental estimation of lifetime before the origin of a short crack without its direct measurement in the experiment.