To solve the difficulty that the observed signals on aircraft engine case are generally a mixture of multiple vibration sources
a blind source separation algorithm is proposed based on the characteristics of aircraft engine vibration sources
where the spectral characteristics of the rotating shaft vibration signal of aircraft engine are aimed at. The vibration spectrum of shaft fault signals of rotating machinery usually includes fundamental frequency
harmonic components and sub-harmonic components
corresponding to such as misalignment
rubbing and crack. The observed signals from different channels are decomposed by continuous wavelet transform
the main vibration sources and the corresponding fundamental frequencies are determined according to the spectral peak analysis
and the harmonics and subharmonic components of each vibration source are extracted from each observed signal with time synchronous averaging method
thus an image of each source can be extracted from each observation channel
and several image signals are obtained for the same source. The optimal estimation is determined by comparing the 2-norm of image signals of each source. The proposed algorithm is validated by numerical simulation signal and measured aerodynamic acceleration signal from aircraft engine case. The results show that the algorithm can estimate the number of main vibration sources inside the engine and extract the main components of each source signal in the case of a certain priori knowledge of the engine speed.
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references
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