A statistical model for crack growth based on tension and compression Wöhler fields

First, the general form of a physically valid crack growth model is derived based on functional equations. It results that only a single argument function is required to define the model, and that models not satisfying this condition are incompatible. Second, a statistical crack growth model valid for any combination of σ_min, σ_max is presented. The model is based on an existing fatigue model based on physical, statistical and compatibility conditions, which predicts the Wöhler fields for any constant load test. It is shown how standard fatigue tests combined with one single crack growth test, can be used to derive a general formula for fatigue growth. This model is applied to some real data to illustrate its applicability to practical problems, and the results seem to be very promising.