A quantitative evaluation of ΔKeff estimation methods based on random loading crack growth data

Methods for estimation of the effective stress intensity factor range (ΔKeff) are evaluated for narrow and wide band random loading crack growth test data of 2024-T352 aluminum alloy. Three methods of estimating ΔKeff, conventional, 2/PI0 and 2/PI methods proposed by Donald and Paris, are compared in a quantitative manner by using the results of fatigue crack growth life prediction under random loading, for three methods of determining Kop, visual measurement, ASTM offset compliance method, and the neural network method proposed by Kang and Song. The 2/PI0 and 2/PI methods of estimating ΔKeff provide better results than the conventional method for narrow and wide band random loading data, for all Kop determination methods examined.