Limitations of small-scale yielding for fatigue crack growth

The work described here has led to a simple criterion that defines the boundary of the small-scale yielding, SSY, regime to avoid invalid use of the LEFM parameter, ΔK , as the characterising parameter for fatigue crack growth rate. The approach proposed is based on the analysis of crack tip opening displacement, CTOD , and its separation into elastic and plastic components. SSY conditions are shown to dominate when the elastic component of CTOD...