Steel fatigue under non-stationary cyclic loading with low cycle overloads

Abstract

The regularities and mechanisms of the elastoplastic strain of structural steels of two different types under two-stage cyclic loading regime conditions combining multicycle fatigue loading and hard elastoplastic strain under repeated overloading are considered. Based on experimental results and metallographic studies, repeated elastoplastic overloads on changes in the structural state of the material, mechanisms of fatigue damage accumulation, and lifetime indicators compared to the stationary process of cyclic loading are evaluated. It is shown that the combination of multicycle loading modes and low-cycle overloading leads to a change in fatigue resistance mechanisms of steels and changes in fatigue life depending on the loading history. Predict the effect of pre-elastoplastic loading of different types of metals, a change ratio in lifetime depending on the parameters of the two-step cyclic loading regime is proposed.