基于SWT模型的概率寿命分析体方法

为了研究大应力体积对航空发动机轮盘低周循环疲劳破坏的影响,提高轮盘概率寿命预估精度,针对应变体方法对中、长寿命轮盘预测精度不准的缺陷,提出基于SWT模型的概率寿命分析体方法。该方法以最大主应变平面为临界面的SWT模型为基础,结合考虑尺寸效应的体方法,且不需要进行平均应力修正。通过对某风扇盘进行概率寿命分析,得到的轮盘中值寿命与试验结果吻合良好,预测精度高于应变点方法、应力修正系数法得到的结果。表明基于SWT模型的概率寿命分析体方法可以用来预估航空发动机轮盘概率寿命。

Volume method based on the SWT model for the analysis of the probability life

To study the high stress volume effect on the low cycle fatigue damage of disk, and improve the fore- casting precision in the life of disk, considering the deficiency of precision in forecasting the medium and long life of disks by the volume method based on the strain life, a volume method based on the SWT model for analysis of the probability life of disk is proposed. The method is based on the SWT model which regards the maximum principal strain plane as critical plane, combining with the volume method in which the size effect are consid- ered, and it is unnecessary to consider the correction of mean stress, Then the fatigue probability life of a fan disk is analyzed using the given method. The results of computational median life agree well with the experi- mental one, and forecasting precision is higher than the result by the point method based on the strain life and the method of stress correction coefficient. It is shown that volume method based on the SWT model can be used to estimate the medium and long probability life of aero-engine fan disks.