In this study, a failure analysis and design optimization of a shrouded blade in a transonic fan were performed. A visible crack was observed on the pressure side of the shroud, and its origin was located using scanning electron microscopy. The results indicate that the initial crack originated from the pressure-side contact surface edge, and several small cracks were observed in the source region. To determine the reasons for the failure, a shroud-cutting model with a three-dimensional displacement harmony boundary was established. The crack propagation process was simulated, and the stress intensity factor values along the crack front were calculated. Subsequently, a nonlinear static strength analysis was performed, which indicated that stress concentration at the crack origin led to crack initiation. Design optimization considering the pre-deformation angle, friction factor, and initial tightness was performed to determine the figure of merit of the design. The wear pattern of the refined shrouded fan blade demonstrated that the optimized design was effective, with a satisfactory contact state after the engine test. The proposed optimization method is cost-effective and can be used in practical engineering applications.

在这项研究中，对跨音速风扇中的带罩叶片进行了故障分析和设计优化。在护罩的压力侧观察到可见的裂纹，并使用扫描电子显微镜确定其起源。结果表明，初始裂纹起源于压力侧接触面边缘，在源区中观察到一些小裂纹。为了确定失败的原因，建立了具有三维位移和谐边界的覆盖物切割模型。模拟了裂纹的扩展过程，并计算了沿裂纹前沿的应力强度因子值。随后，进行了非线性静强度分析，这表明裂纹起点处的应力集中导致裂纹萌生。进行了考虑预变形角，摩擦系数和初始密封性的设计优化，以确定设计的优劣。精致的带罩风扇叶片的磨损模式表明，优化的设计是有效的，在发动机测试后具有令人满意的接触状态。所提出的优化方法具有成本效益，可用于实际工程应用中。