Numerical modeling of the low cycle fatigue: effect of manufacturing imperfections caused by machining process

¹ Department of Physics, Faculty of Sciences, Abdelmalek Essaadi University, 93002 Tetouan, Morocco
² Department of Industrial and Civil Sciences and Technologies, National School of Applied Sciences, Abdelmalek Essaadi University, 93030 Tetouan, Morocco
³ Division of Civil and Building Services Engineering, School of the Built Environment and Architecture, London South Bank University, SE1 0AA London, United Kingdom

^* Corresponding author: aberkan.ikraam@gmail.com

Abstract

The majority of mechanical components in nuclear power plants must be designed to withstand extreme cyclic loading conditions. In fact, when these components are subjected to low cycle fatigue, machining imperfections are considered one of the most significant factors limiting their service life. In the present work, using finite element analysis, a methodology has been suggested to predict the fatigue life of cylindrical parts made of 316 SS, at ambient temperature, under nominal strain amplitude ranging from ± 0.5 to ±1.2% with various surface roughness conditions. Two different multiaxial strain-life criteria have been considered to estimate the fatigue life, namely Brown-Miller and maximum shear strain. The comparison between the predicted and the experimental fatigue lifetimes has revealed that the adopted multiaxial strain life criteria can successfully estimate the fatigue life of 316 SS grade under uniaxial loading conditions. Furthermore, it has been found that the fatigue life decreases as the surface roughness average value increases, which indicates that surface regularities have a significant impact on low cycle fatigue life. Therefore, the proposed methodology is found to be capable of assessing the impact of surface roughness on the fatigue life of this specific steel in the low cycle fatigue regime.