轮盘低周疲劳寿命预测的一种新方法

A NEW METHOD FOR DISK LOW CYCLE FATIGUE LIFE PREDICTION

低循环疲劳失效是轮盘失效的主要形式。为了找到更加精确可靠地预测轮盘低周疲劳寿命的方法,基于三参数幂函数公式,提出了描述Walker等效应变参量与疲劳寿命关系的修正寿命预测模型。应用修正寿命预测模型对1Cr11Ni2W2Mo V、GH4133、TC4及TC11合金材料不同条件下的低周疲劳试验数据进行模拟,发现拟合曲线能够很好地描述Walker等效应变与寿命之间的关系,寿命预测点全部位于2倍分散带内。采用不同方法对高压压气机I级盘60℃下的寿命进行预测,并将预测结果与轮盘试验值进行比较。结果表明:修正模型的预测寿命值为1 048,与试验值1 340相近,相对误差仅为-21.8%,预测精度明显高于另外三种模型,并且修正模型能够考虑平均应力的变化对疲劳寿命所产生的影响,可为发动机轮盘的低周疲劳寿命预测提供参考方法。

Low cycle fatigue failure is the main failure form of disks. In order to find a more accurate and reliable method to predict disks＇ low cycle fatigue life, a correction life prediction model that describes the relation between Walker equivalent strain parameter and fatigue life was proposed based on the formula of three-parameter power function. The low cycle fatigue experimental data of 1Crl 1Ni2W2MoV, GH4133, TC4 and TC11 materials at different conditions was simulated by the correction life prediction model and found the fitting curves can well describe the relation between Walker equivalent strain and fatigue life, and the life forecasting points are all in the 2 scatter band. In addition, using different methods to predict its life of high pressure compressor disk I at 60℃ and compared them with the experimental result. The results show that the correction model has a higher prediction accuracy than the other three models, its prediction value is 1048 that is close to the experimental value 1340 and the relative error is only -21.8% , moreover, this correction model can consider the influence on fatigue life that brought by the mean stress＇ s change and provide a reference method for aircraft engine disks＇ low cycle fatigue life prediction.