A comparative evaluation of K-op determination and Delta K-eff estimation methods

Abstract

Methods for determination of the crack opening stress intensity factor (K-op) and for estimation of the effective stress intensity factor range (DeltaK(eff)) are evaluated for crack growth test data of aluminum alloys. Three methods of determining K-op, visual measurement, ASTM offset compliance method, and the neural network method proposed by Kang and Song, and three methods of estimating DeltaK(eff), conventional, the 2/PI0 and 2/PI methods proposed by Donald and Paris, are compared in a quantitative manner by using evaluation criteria. For all K-op determination methods discussed, the 2/PI method of estimating DeltaK(eff) provides good results. The neural network method of determining K-op provides good correlation of crack growth data. It is recommended to use 2/PI estimation with the neural K-op determination method. The ASTM offset method used in conjunction with 2/PI estimation shows a possibility of successful application. It is desired to improve the ASTM method.