轮 盘 低 周 疲 劳 模 拟 件 设 计 及 试 验

The discs in aero-engines are continuously subjected to large cyclic loading，of which the bores，bolt holes，curvic couplings and other feature areas are susceptible to Low Cycle Fatigue（LCF）failure. To accurately predict the fatigue life of the discs，it is necessary to design simulating specimens to reflect the stress gradient and perform fatigue experiments，which will provide an important basis for the design of the aero-engine structure. The existing simulating specimen design methods usually require that the stress and strain distribution within a certain range of the hotspot of simulating specimen should be consistent with those of the disc. However，the definition of "certain range" in these methods lacks theoretical basis and no uniform understanding has been reached. This study proposes a simulating specimen design method considering the consistency of SWT parameter distribution at the hotspots of simulating specimens and discs. The simulating specimens for the bores，bolt holes，curvic couplings of the disc are designed. A series of LCF experiments on simulating specimens are conducted. The average fatigue life of the curvic coupling simulating specimens corresponding to 100% rotational speed is compared with the results of the turbine disc rotational fatigue experiment，and the relative error is 7%，with both cracks initiating from the weak crystallographic facets on the surface. Finally，the robustness of the simulating specimen design method is discussed.