Damage simulation and experimental verification of thermomechanical fatigue in nickel-based single crystal turbine blades considering the influence of transverse crystal orientation

Abstract

Due to the complexity of loads and structures, as well as the uncertainty of transverse crystal orientation, accurately predicting thermomechanical fatigue (TMF) damage in nickel-based single crystal turbine blades remains a challenge. In this paper, a slip-based damage model reflecting the coupling of creep damage and low-cycle fatigue damage was employed to describe the in-phase thermomechanical fatigue (IP TMF) damage behavior of nickel-based single crystal turbine blades. The lifetime prediction results of creep, low-cycle fatigue, and IP TMF based on this model were essentially within a 2x scatter band. Then, the damage model was integrated into the slip-based Walker constitutive model, and the finite element implementation of the improved damage-coupled crystallographic constitutive model was performed using the secondary development tool (User Programmable Features, UPFs) provided by ANSYS. Furthermore, considering the influence of the randomness of transverse crystal orientation, the IP TMF damage of nickel-based single crystal turbine blade was simulated, and the predicted dangerous zone was consistent with the crack initiation zone observed in previous IP TMF experiments.