Thermal Stress Calculation Based on Enhanced 3-Dimensional Green’s Function Approach Considering Temperature-Dependent Effect

In this paper, an enhanced 3-dimensional (3D) Green’s function approach (GFA), which can be utilized more practically in fatigue monitoring systems, is proposed. The proposed approach can not only calculate the accurate thermal stress history since it considers the temperature-dependent effect, but it also enables a robust calculation of the thermal stress since the steady state term is separated. To verify the proposed approach, thermal stresses of the System integrated Modular Advanced ReacTor (SMART) shutdown cooling system (SCS) nozzle subjected heat-up transient are calculated based on the proposed 3D GFA, and are compared with results computed by a detailed finite element (FE) analysis considering the temperature-dependent material properties. Since the comparison results are in good agreement with each other, it is concluded that the proposed approach enables an accurate thermal stress evaluation in fatigue monitoring.