Aero-engine Supporting Transmission System Fault Diagnosis Based On Vibration Analysis

Aero-engine supporting transmission system is the virtual part of the aero-engine and the supporting transmission core component is rolling bearing.The main shaft bearings usually are roller and ball bearing.This paper combined main shaft bearings fault characteristic theory with aero-engine underground test,and carried out aero-engine supporting transmission system fault diagnosis.The main contents of this paper include:1.A fault diagnosis model was developed based on roller bearings,and propose the appropriate methods namely wavelet-envelope and blind source separation-envelope to analysis the fault of the main shaft bearing under no-dismantled the aero-engine.2.The experiment of rolling bearings at different speed were carried out based on test condition,and the aeroengine main shaft bearings were studied at the same time.Extracting the roller bearings feature fault signals and carrying out fault diagnosis at the same time and as a reference on the diagnosis of the main shaft bearing.3.Use wavelet de-noise to analysis the aero-engine vibration signals.After that apply wavelet transform to extract the main shaft bearing feature signals.Then Hilbert envelope and spectral analysis are carried out to obtain the characteristic peak frequencies.This method can detect the high pressure turbine rear bearing outer fault.4.Using the wavelet de-noise to eliminate the noise of the engine system,the BSS is carried out in order to obtain independent source signals.The envelope and spectral analysis are carried out to processing the source signals.The obtained independent components spectral waves extract successfully the high pressure turbine rear bearing outer and roller fault information.5.Turning the speed signal to angle-time signal when integrate the speed in time when the engine runs down.Then the equal angle distributed data obtains which interpolate the data.Therefore the synchronous transient vibration signals of aero-engine case during run-down condition are resample use this time series and finally the order spectrum was got via envelope and Fourier transform.The results show this method can extraction the high pressure turbine rear bearing outer and roller feature signals.The fault diagnosis of the main shaft bearing was via the aero-engine case vibration and acoustic emission signal based on the main shaft bearings vibration fault theory and characteristics frequency,and combined with rolling bearing and aero-engine main shaft bearing experiment This methods can diagnosis the faults of the main shaft bearing under no-dismantled the aero-engine,and has important engineering practical significance...