The Research Of Quantitative Diagnosis Technology On Rolling Contact Fatigue Of Bearing Based On Acoustic Emission

In conventional operation condition, the rolling contact fatigue failure of bearings is one of the most common bearing failures. It is a dynamic development process for bearings from normal state to contact fatigue failure, therefore, considered from two aspects of safety and economy, monitoring of bearing rolling contact fatigue for real-time and timely diagnosis is of great significance. Base on the acoustic emission technology at home and abroad of the bearing rolling contact fatigue diagnosis research in present situation, this paper put forward a system scheme used in quantitative diagnosis of bearing rolling contact fatigue state monitoring and a related experimental research was carried out.This article carry out the research works mainly from the following several aspects:(1) The correlation processing methods of acoustic emission signal of the bearing rolling contact fatigue is studied. Mainly includes: the pretreatment methods of acoustic emission signal, apply the wavelet packet decomposition and the empirical mode decomposition methods to the filtration and denoise of the acoustic emission signal; the feature extraction methods of acoustic emission signal, apply the wavelet packet analysis method to extract acoustic emission signal energy features and information entropy features respectively; the feature selection method of acoustic emission signal, apply principal component analysis to compress and reduct dimensions of the extracted characteristics of acoustic emission signal; the pattern recognition methods of the characteristics of acoustic emission signal, mainly apply support vector machine and BP neural network for pattern recognition to the selected characteristics, then judge the bearing rolling contact fatigue states.(2) The quantitative diagnosis scheme of bearing rolling contact fatigue based on information fusion technology is designed. Apply the “characteristics of serial” method which belongs to the middle level of the information fusion method, then combine acoustic emission signal acquired by the two channel acoustic emission sensors with each other and in the end come to the bearing rolling contact fatigue criterion.(3) The bearing rolling contact fatigue quantitative diagnosis system based on theacoustic emission technology is designed and established. Then the hardware part and the function, structure, and the necessary algorithm of the software part of the quantitative diagnosis system is designed and built combined with the existing equipments and technical conditions of the laboratory.(4) Do tests to verify the veracity and reliability of the quantitative diagnosis system.The diagnostic results are obtained through the analysis and processing to the acoustic emission signal data acquired in the testing process, then the diagnostic results were compared with the bearing specimen samples to verify the accuracy of the quantitative diagnosis system.