2001 Volume 44 Issue 1 Pages 117-122
This paper modifies the Wheeler retardation concept to improve the accuracy of crack growth predictions after a single overload. This modification is primarily based on the number of delay cycles, Nd, and on the overload affected crack length, ad. Nd is used to calibrate the Wheeler exponent, m, and ad is employed to assess the effective overload plastic zone size. In addition, the regression equations for m and ad are established in terms of the overload ratio OLR. The modified Wheeler model together with these equations performed well in reproduction of the actual crack growth behavior in 5083-O aluminum alloy. All predictions of the number of delay cycles were within a factor of 1.1 of the experimental observations.