Defect Diagnosis of Low-Speed Heavy-Duty Bearings Using Acoustic Emission

A sudden failure of a heavy-duty rolling bearing normally causes high economic loss and has potentially disastrous consequences for the machine operators present. The most established technique for monitoring the integrity of rolling-element bearings is vibration analysis. However, at very slow rotational speeds (less than 3 rpm), monitoring the health of rolling-element bearings is fraught with difficulty. The usefulness of acoustic emission (AE) measurements for the detection of defects in roller bearings has been investigated in this study. Defects were simulated in the roller, inner raceway, and outer raceway of the bearings by the spark erosion method. The AE signals detected on the slewing bearing with no defects (ND), roller element defects (RD), inner raceway defects (IRD), and outer raceway defects (ORD) are done, respectively. Energy-duration correlation of AE signals has been found to be a very good parameter for the detection of bearing with or without defects. Through wavelet analysis of AE signals, the location of defects (RD, IRD, or ORD) can be distinguished.