Aircraft engine turbine blade lifespan prediction based on a novel creep-fatigue interaction damage model

To address the challenges associated with predicting the creep-fatigue interaction (CFI) lifespan of turbine blades in aircraft engines, a novel creep-fatigue interaction damage (CFID) model is proposed. The model simultaneously incorporates different damage action coefficients and interaction indices, establishing a quantitative relationship for the varying weights of creep damage (CD), fatigue damage (FD), and CFID. A systematic methodology is then developed for constructing a CFI lifespan prediction model by incorporating the stress adjustment coefficient ζ, which accounts for material-to-structural behavior. Then, numerical simulations of the stress–strain-temperature fields were conducted to explore an equivalent approach for characterizing the CFI load spectra. Subsequently, CFI experiments were carried out on smooth DZ125 specimens as well as actual blade body features. The experimental results demonstrate that the proposed CFI lifespan prediction model achieves a high level of accuracy, with an error margin of only 3.21%. This study presents a robust modeling strategy for accurately evaluating the lifespan of materials and structural components under high-temperature conditions, offering significant practical value for engineering applications and a theoretical foundation for damage-resistant design of critical high-temperature components in aircraft engines.