Fatigue crack growth peculiarities and modifications of the Wheeler retardation model (Part 1)

What has been given consideration in the paper, are peculiarities of fatigue crack growth, ones referred to curves of a crack length vs. the number of cycles or the rate of propagation vs. the range of stress intensity factor, i.e. the curves typical of tests with overloads applied in cycles – for the PA7 aluminium alloy and 18G2A steel. Difficulties with the model-based description (based on the Wheeler retardation model) of fatigue crack growth have been shown as due to the peculiarities discussed.