基于临界面-损伤参量法的高压涡轮盘多轴疲劳寿命预测

基于临界面法对某高压涡轮（HPT）盘及GH4169合金试样进行多轴疲劳寿命预测，得出SWT（Smith-Watson-Topper）模型对单轴疲劳具有较好的预测效果而对多轴疲劳的预测效果较差，Fatemi-Socie （FS）模型也能较好地预测单轴加载下的疲劳寿命，但FS模型仅考虑最大剪应变幅平面上的正应力对疲劳损伤的影响，导致其多轴疲劳寿命预测偏保守。基于此，本文以最大剪应变幅为主要损伤控制参数，同时以最大剪应变幅平面上的正应力和正应变组成的修正参数作为多轴疲劳损伤的第二控制参数，提出了一个新的多轴疲劳临界面-损伤参量模型。结合GH4169合金及某高压涡轮盘试验验证。结果表明，对比SWT、FS和Wang-Brown （WB）模型，新模型的多轴疲劳寿命预测精度更高。

Multiaxial fatigue life prediction of an HPT disc based on critical plane-damage parameter

Multiaxial fatigue life prediction for a High Pressure Turbine (HPT) disc and a GH4169 alloy sample was performed using critical plane methods. Results show that the SWT (Smith-Watson-Topper) model can accurately predict uniaxial fatigue life, but demonstrates poor accuracy for multiaxial fatigue life prediction. The Fatemi-Socie (FS) model shows a good ability for uniaxial fatigue life prediction, but gives conservative multiaxial fatigue life predictions as it takes into account only the effect of the normal stress of the maximum shear strain amplitude plane on fatigue damage. In this paper, a new multiaxial fatigue critical plane-damage parameter model is proposed by considering the maximum shear strain amplitude as the main damage control parameter, and the correction parameter formed by normal stress/strain on the maximum shear strain amplitude plane as the second control parameter for fatigue damage prediction. Experimental data of a GH4169 alloy sample and an HPT disc show that the proposed damage parameter model can provide better predictions than the SWT, FS and Wang-Brown (WB) models.