FGH96高温变幅疲劳载荷试验及损伤累积模型研究

High temperature variable amplitude fatigue loading test and damage accumulation modeling of FGH96

针对涡轮盘用镍基高温合金FGH96,开展两级疲劳载荷试验以及谱载荷试验。试验载荷设计参考了涡轮盘关键点载荷及实测飞行任务谱特征。采用常见损伤累积模型对试验结果进行分析。结果显示,FGH96在低-高载荷次序下循环分数和大于1,在高-低载荷次序下循环分数和小于1,符合常见非线性疲劳损伤累积模型的预期;对于谱载荷的疲劳寿命,由Chaboche非线性疲劳损伤模型与时间分数模型组成的损伤累积模型的预测则偏保守,且具有较高的预测精度,预测结果均在2倍偏差带内。

The investigated material is nickel-based alloy FGH96 used for turbine discs.Firstly,two-level fatigue loading test and spectrum loading tests were conducted.The test loads refer to the turbine disc critical point loads and the measured flight mission spectrum characteristics.Then the test results were analyzed using common damage accumulation models.The results show that FGH96 has a cyclic fraction sum greater than 1 in the low-high loading sequence and less than 1 in the high-low loading sequence,which is in accordance with the expectation of common nonlinear fatigue damage accumulation models.For the fatigue life of the spectrum load⁃ing,the prediction of the damage accumulation model consisting of the Chaboche nonlinear fatigue damage model and the time fraction model is conservative and has a high prediction accuracy,with all the predictions within the 2-fold deviation band.