The Method for Identifying Rotating Blade Asynchronous Vibration and Experimental Verification

Based on the principle of blade tip timing (BTT) and the vibration principle of one degree of freedom, the parameter identification algorithm of rotating blade asynchronous vibration is established by using all phase FFT(apFFT) and least square method. The algorithm is verified by numerical simulation. The tests of asynchronous vibration parameter identification were launched on a fan rotor, while high pressure nitrogen was used to shock the blades to produce single frequency absolute occupancy vibration. Results show that the method for asynchronous vibration identification could accurately identify blade vibration parameters, and the vibration frequencies of all blades obtained are exactly the same. Frequency identification accuracy is high with the maximum relative error of 1.12% using strain analysis frequency as a baseline. Results verify that the method of asynchronous vibration parameter identification is correct.