Vibration Fault Diagnosis For Whole-Body Aero-Engine

Aero-engine is a mechanism with high rotation speed and complex structure. Because the aero-engine usually works in bad conditions such as high temperature, high pressure, high stress and alternating load, its failure rate in the whole body vibration is high. The whole-body vibration of an aero-engine restricts the improvement of the whole quality. The maintenance and manufacture cost of the aero-engine is increased. Therefore, taking effective control measures to reduce engine vibration failure and developing reasonable measures to effectively eliminate vibration failure has become one of the focuses of current research on engine.Frequency analysis is one of the widely useful methods in the aero-engine fault diagnosis. The simple FFT can be directly used to analyze the frequency for the vibrational signal, but the defect of the simple FFT is lower resolution. The wavelet package and harmonic wavelet have higher resolution and can be divided at any time and any frequency. The wavelet pakage and harmonic wavelet are applied into analysis the frenquency and the time frequency of the practicality vibrational signal. According to the characteristics of frequency, six faults are diagnosed in this paper. By the contrast with wavelet package, the result has indicated the harmonic wavelet is higher resolution and better frequnency division than wavelet package, but the wavelet package is faster than harmonic wavelet.The system of the whole-body vibration fault diagnosis is designed based on Microsoft Visual Basic6.0, Oracle10g database and Matlab7.0 in this paper. Three different modules are included in this system, including user management module, data management module and fault diagnosis module. The Matlab is utilized to design the diagnosis algorithm. The vibration engine information and corresponding data are saved in the Oracle database. The interface of the whole system is designed by Visual Basic.