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.
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魏大盛,马梦弟,王延荣.考虑应力比修正的应力梯度影响指数计算方法[J].航空动力学报,2019,34(9):1888~1894. Method to determine modified influence exponent of stress gradient considering stress ratio[J]. Journal Of Aerospace Power,2019,34(9):1888-1894.