Notch stress-strain estimation method based on pseudo stress correction under multiaxial thermo-mechanical cyclic loading

Abstract

In this paper, a notch stress correction method based on the structural yield surface is proposed, in which the actual stress increment at the notch root can be obtained by multiplying two quantities, that is, the pseudo stress increment and the ratio of the slopes of the material and structural stress-strain curves. In the proposed method, the influence of temperature on the notch stress correction can be taken into account, and no iteration is required during the calculation process. Moreover, based on the proposed notch correction method and a unified viscoplastic constitutive model at high temperature condition, a notch stress-strain estimation method is developed under multiaxial thermo-mechanical cyclic loading. In order to assess the prediction accuracy of the proposed method, the calculated results are correlated to those from thermal-structural non-linear finite element analysis under various proportional and non-proportional mechanical loadings at non-isothermal high temperature condition. The comparison between the calculated and analyzed results shows that the proposed method can precisely estimate the notch stress and strain under multiaxial thermo-mechanical cyclic loading.