考虑耦合损伤的燃气轮机叶片材料高低周复合疲劳寿命研究

Combined High and Low Cycle Fatigue Life of Gas Turbine Blade Materials Considering Coupling Damage

关键词:  燃气轮机  叶片  高低周复合载荷  耦合损伤  低载强化  疲劳寿命

Key words:  Gas turbine  Blade  Combined high and low cycle load  Coupling damage  Strengthening under low amplitude load  Fatigue life

摘要:

燃气轮机叶片在实际工作过程中，受到高低周载荷共同作用而易发生疲劳失效。针对高低周复合疲劳损伤演化和寿命预测比较复杂这一问题，考虑高低周载荷叠加形成的耦合损伤，建立了一种新的高低周复合疲劳寿命预测模型，在此基础之上，引入弱化函数描述某些低幅高周载荷对复合损伤的弱化作用，建立了具有低载强化寿命效应的高低周复合疲劳寿命预测模型。通过试验数据的验证分析并和Miner模型、Zhu模型的预测结果进行对比，建立的高低周复合疲劳寿命预测新模型的适用性和准确性较高，为叶片完整性设计、损伤分析和寿命预测奠定基础。

Abstract:

In practical work， gas turbine blades are prone to fatigue failure due to the combined high and low cycle loads. In view of the complexity in the fatigue damage evolution and life prediction under combined high and low cycle loads， a new combined fatigue life prediction model was established considering the coupling damage formed by superposition of high and low cycle loads. On this basis， the weakening function to describe the weakening effect of certain low-amplitude and high-cycle loads on coupling damage was introduced， and a combined high and low cycle fatigue life prediction model with strengthening effect under low amplitude loads was established. Through the verification and analysis of test data and the comparison with the prediction results of the Miner model and the Zhu model， the new combined fatigue life prediction model has high applicability and accuracy， which lays the foundation for blade integrity design， damage analysis and life prediction.