To ensure the structural integrity of life-limiting component of aeroengines, Probabilistic Damage Tolerance (PDT) assessment is applied to evaluate the failure risk as required by airworthiness regulations and military standards. The PDT method holds the view that there exist defects such as machining scratches and service cracks in the tenon-groove structures of aeroengine disks. However, it is challenging to conduct PDT assessment due to the scarcity of effective Probability of Detection (POD) model and anomaly distribution model. Through a series of Nondestructive Testing (NDT) experiments, the POD model of real cracks in tenon-groove structures is constructed for the first time by employing the Transfer Function Method (TFM). A novel anomaly distribution model is derived through the utilization of the POD model, instead of using the infeasible field data accumulation method. Subsequently, a framework for calculating the Probability of Failure (POF) of the tenon-groove structures is established, and the aforementioned two models exert a significant influence on the results of POF.

The paper designs a novel material-level specimen and its dedicated fixture suitable for applying Combined high- and low- Cycle Fatigue (CCF) loads. Unlike full-scale or simulation specimens, the CCF specimen eliminates geometrically induced stress gradients in the test region. Experimental data on CCF life and strain responses of ZSGH4169 alloy are acquired under different CCF loads. The Maximum Strain within Each (MSE) CCF cycle is demonstrated to be independent of the Low-Cycle Fatigue (LCF) loads and High-Cycle Fatigue (HCF) stress amplitudes, but exhibits a correlation with the Cycle Ratio of HCF/LCF (R_f). The growth law of MSE changes from linear to logarithmic as R_f decreases. Strain amplitudes in the dwell stage, observed unaffected by R_f, are quantified as a function of LCF nominal stresses and HCF stress amplitudes. However, under a defined CCF load, strain amplitudes in the dwell stage remain constant. Strain peaks in the dwell stage in a single CCF cycle decrease in a power function with increasing HCF cycles.