A method and system for detecting cyclic shock vibration based on harmonic signal decomposition

Abstract

The invention provides a cyclic shock vibration detection method and system based on harmonic signal decomposition and can be applied to fault diagnosis of rotating machinery. The method is characterized in that a frequency band determination step, a frequency band in which a periodic shock signal is located is determined according to a spectral kurtosis map; a harmonic signal decomposition step,a signal decomposition method is utilized to decompose a harmonic signal in the frequency band in which the periodic shock signal is located, and the decomposed harmonic signals are superimposed to obtain a reconstructed periodic shock signal; and an envelope analysis step, envelope analysis of the reconstructed periodic shock signal is performed, according to a peak-to-peak value of the envelopeand the envelope spectrum, a rubbing fault of the rotating machinery is diagnosed. The method is advantaged in that the relationship between the periodic impact signal and a frequency domain equally-spaced harmonic signal cluster is revealed, good noise resistance is realized, and obtaining the reliable rubbing fault diagnosis result can be facilitated through the extracted high signal-to-noise ratio shock signal.

Description

technical field [0001] The invention relates to the field of vibration signal processing and fault diagnosis of rotating machinery, in particular to a method and system for detecting cyclic shock vibration based on harmonic signal decomposition. Background technique [0002] Large rotating machinery, such as generator sets, aero engines, and sea and land fans, play a very important role in current industrial production and applications. Their operational failure may lead to serious industrial accidents and significant economic losses. Therefore, it is very necessary to deeply study the operation failure mechanism and diagnosis method of rotating machinery. The rubbing phenomenon is a frequent fault that widely exists in various rotating machinery. It is caused by the periodic impact of the rotor on the stator in the rotor system of the rotating machine. With the current increase in the operating speed of rotating machinery and the continuous improvement of the assembly ac...

AI Technical Summary

Problems solved by technology

However, the signal reconstruction method based on band-pass filtering has two inherent disadvantages: 1) the band-pass filter has boundary effects; 2) the noise contained in the selected frequency band will be mixed into the reconstructed signal

These two shortcomings will lead to waveform distortion of the reconstructed impact signal and a low reconstructed signal-to-noise ratio, which will affect the diagnostic results of rubbing faults.

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