基于考虑应力梯度的寿命预测模型,深入研究了不同应力比对应力梯度影响指数的影响。通过引入新的参数,对模型进行修正,并以典型合金的试验数据为基础,进行寿命预测并考核计算精度。结果表明:修正后的模型能够更合理地考虑局部应力比对应力梯度影响指数的影响,寿命预测结果相比于修正前更接近试验值,对TC4(200 ℃)、GH4169(500、650 ℃)缺口试件的疲劳寿命预测结果多在2.0倍分散带以内,部分数据的预测结果可在1.5倍分散带以内。
A new equation for fatigue life prediction considering the stress ratio was established. The expression introduced a new parameter which reflected the effect of stress ratio on the stress gradient exponent based on the previous fatigue life model with stress gradient. Life prediction and precise checking were carried out using exiting test data of typical alloy. The results showed that the local stress ratio had a considerable influence on the stress gradient exponent. The calculation results of the modified model were more close to the experiment results than the previous model. Predictions of notched specimens for TC4(200 ℃) and GH4169(500, 650 ℃) showed a scatter band within 2.0. Even better, some of the results showed a scatter band within 1.5.