A microelement plastic strain accumulation model for fatigue life prediction

In this article, we present a novel approach to fatigue life prediction based on a Jenkin-Masing model. The Jenkin-Masing model describes the mechanical response of a material through a large number of parallel microelements, which are taken to be elastic-perfectly plastic with different yield strengths. Even below the macroscopic yield of the material, plastic strain is accumulated in the weaker microelements during cyclic loading. These microelements are taken to fail when a critical level of plastic strain is accumulated in them. We study the monotonic response, cyclic behavior and fatigue life of this model. In particular, the model shows how different realizations of distributions of microelement strengths may show similar monotonic behavior but very different fatigue behavior. This model provides insight into the origin of the large scatter in fatigue life widely observed in experimental results.