Research on modal measurement method of turbine engine blade

During the operation process of turbine blades in aero-engine, the exhaust gas flow generates complex interaction with the blade surfaces. When the excitation frequency induced by the airflow approaches the inherent natural frequency of the blade structure, resonance phenomenon occurs. This resonance not only leads to performance degradation of the engine but may also result in structural damage or even fracture of the blades, posing serious threats to the safety and reliability of the engine. Therefore, precise measurement and analysis of blade modal parameters hold significant importance. This study establishes a methodology for measuring blade modal parameters. The proposed approach employs the Single Input Single Output (SISO) technique, applying sinusoidal sweep-frequency excitation to measure blade responses, and ultimately calculates the Frequency Response Function (FRF). Additionally, the Matrix Pencil Method (MPM) is utilized to perform matrix decomposition on the FRF, thereby extracting modal characteristic parameters within the sweep frequency range of the blades. Experimental results demonstrate that the measurement method adopted in this study can accurately obtain blade modal parameters, providing valuable reference for optimizing the dynamic design of turbine blades.