On the applicability of mean stress correction models in the very high cycle fatigue regime (VHCF)

The objective of this research was to evaluate the applicability of mean stress correction models (Goodman, Gerber, Soderberg, and ASME) beyond their conventional validation boundaries (failures between 1E4–1E7 cycles) for predicting fatigue life in the very high cycle fatigue (VHCF) regime (failures after 1E7 cycles). Cyclic tests were performed on a high-strength structural steel under fully reversed and partially reversed loading conditions to compare experimental results with fatigue life predictions from these models. The material was tested under both fully reversed and mean stress loading conditions to determine fatigue life. Each model was employed to calculate the equivalent stress amplitude for fitting Basquin curves. Statistical tools were subsequently used to compare the Basquin curve derived from each model with the experimental curve obtained under fully reversed loading. The linear models (Goodman and Soderberg) demonstrated better agreement with experimental VHCF data, whereas the quadratic models exhibited greater inconsistency in the VHCF regime.