Abstract
The distribution of fatigue crack propagation life with retardation was investigated by the use of a Markov approximation method. By supposing the situation where some overloads are superimposed on cyclic loading process, the probability distribution of total delay time was first derived according to the Arone's phenomenological method. Next, it was applied to revise the residual life distribution function in order to take into account the effect of overloads, under the condition that both stress amplitude and crack propagating resistance were random. Finally, with the aid of numerical calculations, it was clarified that the effect of retardation due to overloads was insignificant in the range of high reliability.
