This paper develops a dual-threshold modelling approach to characterize fatigue performance and predict the fatigue life of turbine blades and their alloys under combined high and low cycle fatigue (CCF). This approach investigates the influence of high cycle fatigue (HCF) superimposed to low cycle fatigue (LCF) on fatigue life through the HCF and LCF stress amplitude ratio threshold. Also, the damage threshold reveals the accelerated failure due to load interactions. Several available test data are applied to validate the presented approach. Results indicate that the approach can obtain higher prediction accuracy than others. This approach has the potential to be generalized to other mechanical structures.

本文开发了一种双阈值建模方法来表征疲劳性能并预测涡轮叶片及其合金在高低周联合疲劳 (CCF) 下的疲劳寿命。该方法通过 HCF 和 LCF 应力幅值比阈值研究叠加到低周疲劳 (LCF) 上的高周疲劳 (HCF) 对疲劳寿命的影响。此外，损坏阈值揭示了由于负载相互作用而导致的加速失效。应用了几个可用的测试数据来验证所提出的方法。结果表明，该方法可以获得比其他方法更高的预测精度。这种方法有可能推广到其他机械结构。