Research On Inflight Engine Vibration Monitoring

With the development of the aero-engine On-Condition Maintenance, technology of engine condition mortoring and fault diagnosis has been broadly used in developed contry. Vibration analysis is an effective method to diagnose the engine fault related to structure and intension, so engine vibration mortoring is regard as an important content of engine condition mortoring and fault diagnosis. This Thesis targets to research the technique of engine vibration mortroing when performing flight test and lays the foundation for the engine condition mortroing and fault diagnosis in the future.The principle and character of engine vibration is investigated and general engine faults are summarized. The configuration and functions of a engine vibration motoring system have been determined in the second chapter. Aimming at the practical problems occurred when processing the signal sampled in engine flight test, the relevant techniques on vibration data processing have been analysed. Based on the different work states of engine, the engine vibration signal collected in it's steady work conditions is analysed by the technique of confrequency spectrum; the signal related to the fast run-up state is processed by STFT and wavelet analysis. The collected historical engine vibraiton data are used to trend analysing and vibration mortoring.On the basis of above research, the application software of aero-engine vibration mortoring system which is adapted to engine flight test are programmed applying technique of Virtural Instrument and modularization design. The effective method of signal processing has been integrated in this software.The importantance of database in the aero-engine vibration mortoring system is analysed in chapt 5. According to the requirement of vibration mortoring in flight test, a database has been designed with Mircrosoft Access2000. The test data show that the database presents expected function and works well with software of aero-engine vibration mortoring system.