286 / 2025-06-16 11:09:24

Fault diagnosis method for blade fracture of aero-engines based on casing vibration

aero-engine,blade fracture,fault diagnosis,blade passing frequency,ordered cluster analysis,fault localization

Special Sessions > SSL 05 Condition monitoring, fault diagnosis and intelligent maintenance of mechanical equipment

Blade fracture is one of the most difficult faults to diagnose in rotating machinery. Most aero-engines can only measure casing vibration rather than directly measuring blade vibration with other sensors, making monitoring and diagnosing such faults more challenging. Research on vibration characteristics and fault diagnosis methods of blade fracture is critical to ensure the safe and reliable operation of aero-engines. The current paper presents a new method to monitor the blade fracture faults from the vibration signal of the casing. Firstly, based on the function mechanism of blade wake excitation forces, the transfer path of the vibration response of aero-engine blades and the variation rule of the wake excitation force have been investigated. Then, based on the casing vibration response model, we analyzed the dynamic evolution of vibration response in the pre- and post-fracture stages of rotor blade failure. The results indicate that the response characteristics of velocity RMS, blade passing frequency (BPF), and fundamental frequency can effectively characterize blade fracture faults. Secondly, based on the vibration-sensitive characteristics of blade fracture faults, we propose an Improved Ordered Cluster Analysis (IOCA) identification method. Considering that the blade fracture can decrease the BPF amplitude and lead to the appearance of side-frequency bands. We propose a Fault Localization Estimation (FLE) method, which constructs a fracture localization factor called ΔU_BF, and the highest ΔU_BF value corresponds to the stage where the blade fracture has appeared. Finally, A fault diagnosis scheme for aero-engine blade fracture based on casing vibration is proposed. An engineering case of a aero-engine blade fracture fault is analyzed. The results show that the proposed method can timely and effectively diagnose the aero-engine blade fracture fault from the vibration signal of the casing. They can further localize the blade fracture fault at the 8th and 9th stages of the rotor blades. Therefore, the proposed method offers a practical engineering approach for timely warning and analysis of blade fracture faults.