Effect of Temperature Rate Term while Predicting Thermal Ratcheting of a Thin Cylinder due to Cyclic Temperature Variation

摘要

The occurrence of progressive plastic deformation due to ratcheting under thermal cycling governs the integrity and life of industrial components such as the main vessel of sodium cooled fast reactors (SFR). Present work firstly discussed a constitutive model with temperature rate terms (TRT) to highlight the effect of thermal load rate (TLR) during the ratcheting behavior of the two-bar mechanical system (SS 316 LN). The influence of TLR is studied for various stress controlled cyclic thermo-mechanical loadings considering temperature dependent material parameters. Secondly, the approach is used to reveal the effect of TRT while predicting thermal ratcheting of a thin cylinder caused by change in peak temperature during temperature front movement. Such loading situations are more relevant to the SFR when the pool temperature varies with free-level variations. Visco-plastic formulation with and without TRT is used for analysis, which is validated by comparing the published experimental and numerical results.