Influence of the irregularity coefficient of loading on calculated fatigue life

The paper presents comparison of two methods for determination of the fatigue damage degree in a material subjected to random loadings with participation of the mean loading and including the irregularity coefficient of the loading. The authors estimated effectiveness of the method where the stress history was transformed considering the global mean value of the load history and the method for which the stress mean value of the distinguished loading cycles was taken into account. When the irregularity coefficient of loading increases, we can observe significant divergences of the calculated fatigue life of the material related to the model of amplitude transformation because of the loading mean value.