A comparison of acoustic emission and vibration on bearing fault detection

Rolling element bearings are among the most common components in industrial rotating machinery. Condition monitoring technologies for bearing fault detection and diagnosis are critical to avoid machines from productivity reduction and emergency breakdown. Acoustic emission (AE) technology which detects the expanding of cracks in the fatigued material is able to monitor bearings before visual defects formed in contacting surfaces. This advantage may help the AE method identify the fault before the commonly used vibration method does. In this paper, the effectiveness of AE method on bearing diagnosis is compared with vibration method. The two methods were tested on the same bearing fault under three rotary speeds, and two kinds of signals were both processed by envelope analysis method. The results show that the quality of acoustic emission signal decreases more significantly than vibration signal when rotary speed slows down, and the attenuation of high frequency component of AE signal should be specially addressed before applying to industrial equipment.