基于背应力功的疲劳能量模型及其在轮槽构件寿命预测中的应用

Back Stress Work-based Fatigue Energy Model and Its Application in Life Prediction of Turbine Rotor Grooves

基于局部应力-应变法与疲劳损伤能耗结构,以疲劳过程中背应力塑性功累积为基础,建立了一种新的缺口构件疲劳寿命预测能量模型,并将其应用于某型汽轮机轮槽结构件的疲劳寿命预测。通过与试验结果相比较,初步验证了模型的预测精度(预测寿命与试验寿命误差小于20%)。此外,还进一步将上述能量模型与传统疲劳寿命预测能量方法进行了比较。结果表明,基于背应力塑性功累积的疲劳损伤描述可进一步提高疲劳寿命预测精度,值得工程疲劳设计者重视。

Based on the local stress-strain method and the dissipation structure of fatigue damage,a new model for predicting the fatigue life of notched components was proposed on the basis of accumulation of the back stress plastic work during fatigue process.This model was applied in the fatigue life prediction of groove components of a turbine rotor.By comparing with the testing results,the prediction accuracy of the model is preliminarily verified(The relative error of the predicted life and the measured life is less than 20%).In addition,the proposed model was also compared with the traditional fatigue life prediction energy method.It is shown that the fatigue damage description based on the back stress plastic work accumulation can further improve the fatigue life prediction accuracy,and it is therefore worthy of emphasis in engineering fatigue designs.