Feature Extraction Of Axial Acoustic Emission Signal Based On Lifting Wavelet Entropy

With the continuous advancement of urbanization in China,the urban population continues to increase,the railway vehicle has become one of the more and more important choices of people travel,occupy an irreplaceable position.In the rail vehicle system,the axle in the running section is undoubtedly one of the important components,which is a key component of the dynamic load of the locomotive vehicle.With large areas of the vehicle speed,axle and passenger transport,cargo security relations are getting closer.As the axle of their own factors or the environment is relatively poor,often accompanied by friction,corrosion,cyclic stress,etc.,These complex factors will lead to axle cracks,surface damage,serious even broken,if not able to timely detect these conditions,it may lead to serious accidents,resulting in loss of life and property.Therefore,in order to ensure the safe and reliable operation of the vehicle,it is of great significance to effectively extract the axle fault.This paper first introduces the basic knowledge and related theories of fault diagnosis,acoustic emission detection technology,lifting wavelet and axle fault mechanism and detection.On the basis of this,the first part of this paper is based on the wavelet entropy theory,and defines the concept of lifting wavelet entropy and LMD energy entropy respectively,and verifies the feasibility of the actual signal.Finally,the comparison of the two methods of processing and analysis of the results,illustrates its advantages and disadvantages.On the basis of the theory of acoustic emission detection,the second part of the paper introduces the principle process of the acoustic emission test and the material equipment used in the axle,and collects the acoustic emission signal of the axle in the test.Then,based on the lifting wavelet entropy analysis method proposed in the first part,analyzed and described entropy values of acoustic emission signals characteristic of the axle of the resulting.The entropy values of the acoustic emission signals of the axle fatigue crack are discussed from the overall entropy of the signal and the detail entropy of the signal,to achieve the characteristics of the axial AE signal extraction,which provides a new idea for the feature extraction of axle fault signal.