Detection and location of defects in rolling element bearing using acoustic emission

Abstract

Rolling element bearings become worn and eventually fail by developing surface defects, such as spalls, dents and pits. Researchers have developed many methods to detect and estimate the size of defects in rolling element bearings. However, these methods do have limitations, such as when a defect with a circumferential length that is larger than the separation angle of the rolling elements cannot be distinguished from a smaller defect, and they cannot be located on the contact surfaces. This work presents a method to detect and locate defects in an operational bearing as it degrades over time, using the time delay between signals from several acoustic emission sensors. Experiments involved putting abrasive garnet into the bearing grease to accelerate the failure of the bearing, which could occur in practice from a defective seal.