A Randomized Endurance Limit in Fatigue Damage Accumulation Models

The use of random parameters for describing S‐N curves requires special caution. A Peculiar Fatigue Curves (PFC) method based on a linear damage accumulation rule is proposed for modelling the fatigue damage accumulation process. The fatigue properties of a component are presented in the PFC form by randomizing its endurance limit which facilitates a simple technique to predict fatigue life and residual life distributions. Possible usages of the models and their restrictions are illustrated for some common load histories of a component. Particular attention is paid to the stochastic relations between random variables having in some cases improper distributions. The problem of experimental testing of the models is also discussed.