Observations and Location of Acoustic Emissions for a Naturally Degrading Rolling Element Thrust Bearing

Acoustic Emission (AE) technology applied to condition monitoring is gaining acceptance as a useful complimentary tool. This article demonstrates the use of traditional AE parameters, the Enegry Index and Kolmogorov-Smirnov test (KS-test) to detect, locate, and monitor natural defect initiation and propagation in a conventional rolling element thrust bearing. To undertake this task a special purpose test-rig was built to allow for accelerated natural degradation of a bearing race. It is concluded that sub-surface initiation and subsequent crack propagation can be detected using a range of data analysis techniques on AE's generated from natural degrading bearings. The article also investigates the source characterization on AE signals associated with such a bearing while in operation.