Anti-Fretting Fatigue Reliability Optimization Design of Turbine Blade Tenon Based on Crystal Orientation Regulation

Nickel-based single-crystal turbine blade tenons in aero engines are prone to fretting fatigue failure during service. Crystal orientation directly affects the mechanical properties of NBSC superalloys, thereby influencing their fretting fatigue damage. In this work, the effects of crystal orientation on the stress distribution and fretting fatigue life of an NBSC blade tenon are evaluated based on the crystal plasticity finite element method. The results showed that the deviations of maximum resolved shear stress can reach 182.10 MPa, respectively, and the life deviation can be as high as 30,629 cycles. The RBF-kriging surrogate model was established to calculate the fretting fatigue life of the NBSC blade tenon, and the reliability optimization of crystal orientation, considering its dispersion, was performed to improve its fretting fatigue life. The results showed that the fretting fatigue life increased by more than 30% with reliability exceeding 99%. This work provides a technique for the anti-fretting fatigue design of NBSC turbine blades in aero engines, introducing a consideration not accounted for in existing design methodologies.