Ratcheting strain and simulation of 16MnR steel under uniaxial cyclic loading

摘要

16MnR steel is widely used in pressure vessel in China and its ratcheting and fatigue behavior have attracted numerous interest during the past years. In this study, a series of experiments were performed on the uniaxial ratcheting deformation of 16MnR steel. The effects of stress amplitude and mean stress on the ratcheting strain were discussed under uniaxial asymmetrical stress cycling. It shows that ratcheting strain and ratcheting strain rate increase with mean stress and stress amplitude increased under the same stress amplitude and mean stress. At the same time, the increasing ratcheting strain causes fatigue damage, which reduces fatigue life of the material. With the mean stress increased, the fatigue life decreases correspondingly. The fatigue lives obtained from the fully reversed uniaxial loading are also compared with the ratcheting-fatigue experiment results. Finally, the modified model based on Ohno-Wang model by Chen and Jiao is used to predict ratcheting strain. The modified model predicts the uniaxial ratcheting strain of 16MnR steel till 400 cycles very well.