A Macro‐Mesoscopic Life Prediction Method of the Fatigue Short Crack in Turbine Disks Based on CP‐XFEM

Aircraft engine turbine disks experience high‐temperature cyclic loading, making precise low‐cycle fatigue (LCF) life prediction critical for ensuring reliability. This study proposes a macro‐mesoscopic life prediction framework by coupling crystal plasticity theory with the extended finite element method (CP‐XFEM). The framework employs submodeling techniques, localized mesh refinement, and macro‐mesoscopic constitutive modeling to address the scale mismatch between real engineering structures and microlevel models. Life predictions are conducted for turbine disks under ideal surface conditions, surfaces with tool marks, and surfaces containing inclusions, considering varying grain orientations. Results show that, for turbine disks without inclusions, fatigue life has a substantial safety margin, with an average life reaching 502,757 cycles even in the presence of tool marks. In contrast, the presence of inclusions significantly reduces fatigue life, with the minimum life in the throat region dropping to 5523 cycles. Moreover, under the most adverse inclusion conditions, the calculated safe life is 3894 cycles, highlighting the need for stringent inclusion standards in turbine disk design to optimize fatigue life. The proposed macro‐mesoscopic method provides a basis for structural optimization of turbine disks with respect to short crack fatigue life in engineering contexts.