'Towards a Proper Understanding of Fatigue Crack Growth and Crack Closure

Conventional theories to describe and predict FCG are based on a SIF parameter, ΔK. If ΔK is used as similitude parameter to predict FCG, an R-effect arises. This R-effect can be accounted for by means of plasticity induced crack closure: A plastic wake behind the crack tip causes the crack to close before a zero tensile load is applied. As such...