Elforjani, MohamedMba, David2012-01-262012-01-262009-01-31M. Elforjani, D. Mba, Natural mechanical degradation measurements in slow speed bearings, Engineering Failure Analysis, Volume 16, Issue 1, January 2009, Pages 521–532.1350-6307http://dx.doi.org/10.1016/j.engfailanal.2008.06.005http://dspace.lib.cranfield.ac.uk/handle/1826/6894Acoustic emission (AE) technology applied to condition monitoring is gaining acceptance as a useful complimentary tool. This paper demonstrates the use of AE measurements to detect, monitor the growth and locate natural defect initiation and propagation in a conventional rolling element 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 crack initiation and its subsequent propagation is detectable with AE technology. The paper also investigates the source characterisation of E signals associated with a defective bearing whilst in operation.en-UKNOTICE: this is the author’s version of a work that was accepted for publication in Engineering Failure AnalysisChanges resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Engineering Failure Analysis, VOL 16, ISSUE 1, (2009) DOI:10.1016/j.engfailanal.2008.06.005Acoustic emission Condition monitoring Natural degradation Thrust bearings rolling element bearings acoustic-emissionArticle