Design of Stress Gradient Simulated Specimen of Aeroengine Disc Groove and Test Verification

The high temperature fatigue test of mockup featuring structural characteristicses is an important reference for the strength design of aeroengine disc. To investigate the low-cycle fatigue performance and failure mechanism of a turbine disc groove, based on the principle of the same geometric characteristics and the same stress gradient, a stress gradient mockup for turbine disc groove of an aeroengine was designed. The strain distribution characteristics of the mockup were obtained using the digital image correlation method, and the stress gradient of the mockup was consistent with the design target. Under high temperature fatigue loads, the fracture failure of the stress gradient simulated specimen all occurred at the expected test positions. The high temperature fatigue test revealed that class cleavage initiation cracks appeared in the FGH96 stress gradient simulated specimen under the fatigue load at 550 ℃, and the fracture showed obvious fatigue band characteristics. In the later stage of fatigue life, obvious cleavage surface and dimple characteristics were observed at the fracture site.