用局部应力应变法进行高周疲劳寿命预测的研究

概述局部应力应变法的基本原理和目前的使用方法,指出在计算中现行方法对低周疲劳有较好的寿命预测精度,但对高周疲劳寿命预测精度不高.这主要是因为没有考虑应力集中、表面加工状况、尺寸和环境介质的影响.在充分考虑四者之后,对应变寿命曲线的弹性分量进行修正,并推导出高周疲劳下的局部应力应变法修正公式.本方法计算简单、精度高.通过实例对传统局部应力应变法和文中提出的方法进行比较,得出本方法不仅适用于低周疲劳寿命分析,也可用于高周疲劳寿命计算.在工程中有良好的应用前景.

HIGH CYCLE FATIGUE LIFE PREDICTION BY LOCAL STRESS-STRAIN METHOD

The principle of local stress-strain method and the current theory were introduced and reviewed. It pointed out that the local stress-strain method is accurate to estimate the medium and low cycle fatigue life prediction, but hard to get an accuracy result in high cycle fatigue life prediction. This is mostly because the effect of stress gradient, surface working and dimension are not taken into consideration in current method. Taking the three factors into account, a modified strain-stress equation is expounded. This method has an advantage of requiring simple calculation and is more accurate to estimate high cycle fatigue life than others. A case is used to demonstrate that the approach is suitable not only for predicting medium and low-cycle fatigue life, but also for high-cycle fatigue life prediction. It has a good application on engineering design and provides a practical reference in fatigue design.