The fatigue life prediction of FV520B-I blade with fatigue crack is a critical study in the fatigue analysis of shrouded impeller. However, the relationship between fatigue crack and fatigue life of FV520B-I blade has not been well studied. In this paper, finite element analysis (FEA) for FV520B-I blade with fatigue crack is conducted; both centrifugal load and aerodynamic load involved, and the stress distribution and the fatigue failure at decisive positions are analyzed. The new correlation between mean stress and fatigue crack is found based on the results of FEA, which is helpful to the development of fatigue life model of FV520B-I blade. Then fatigue test for blade material FV520B-I is performed to determine the fatigue limit. A fatigue life evaluation model for FV520B-I blade is then achieved, by taking fatigue crack as main variable, combining with the comprehensive application of FEA, fatigue test, actual operating parameters and existing fatigue modeling theory. The model is proved to be reliable by comparing the theoretical predicted life with simulated one. Study on fatigue life evaluation method of FV520B-I blade with fatigue crack is novel and essential to improve precision of fatigue life prediction of shrouded impeller in engineering practice.

带有疲劳裂纹的FV520B-I叶片的疲劳寿命预测是带罩叶轮疲劳分析的关键研究。但是，FV520B-I叶片的疲劳裂纹与疲劳寿命之间的关系尚未得到很好的研究。本文对具有疲劳裂纹的FV520B-I叶片进行了有限元分析（FEA）。分析了离心载荷和气动载荷，并分析了决定性位置的应力分布和疲劳破坏。基于有限元分析的结果，发现了平均应力与疲劳裂纹之间的新关系，这有助于FV520B-I叶片疲劳寿命模型的建立。然后对叶片材料FV520B-I进行疲劳测试，以确定疲劳极限。然后，以疲劳裂纹为主要变量，得出FV520B-I叶片的疲劳寿命评估模型，结合有限元分析，疲劳测试，实际运行参数和现有疲劳建模理论的综合应用。通过将理论预测寿命与模拟寿命进行比较，证明该模型是可靠的。研究具有疲劳裂纹的FV520B-I叶片的疲劳寿命评估方法是新颖的，对于提高实际应用中带罩叶轮疲劳寿命的预测精度至关重要。