Research On Application Of Acoustic Emission Technique For The Detection Of Defects In Rolling Element Bearings

As an important non-destructive testing technology, Acoustic Emission(AE) technique is widely used in machinery, construction, mining and marine and other fields. Bearing is one of the important parts of rotating machinery, which fault detection is widespread concern. The detection of defects in rolling element bearing base on AE technique is a hot in current non-destructive testing field. At present, there have many limitations in the bearing fault detection, such as signal extraction, feature recognition, etc.An AE detection system is constructed in this paper, based on the computer, PCI-2 AE data acquisition card of PAC company and the LabVIEW virtual instrument software of NI company, the system can automatic acquisition, storage, display and analysis. The rolling bearing fault test experiment platform is developed, sample with artificial defects(inner ring and outer ring) was made. The denoising method of bearing defects were studied, based on the db10 wavelet and heursure threshold for signal processing, using Hilbert marginal spectrum analysis method on the basis of the EMD recognize the frequency characteristics of the signals.The experiment results show that,the AE detection system of the rolling bearing is stable performance and easy operation, using wavelet transform method can remove the noise of AE signals effectively, AE signals characteristic parameters, such as ring count, energy count and the maximum amplitude can distinguish the fault signal, the Hilbert marginal spectrum method based on EMD can recognize the fault type.