웨이블릿 변환이 접목된 포락처리를 이용한 구름요소베어링 결함 진단 = Rolling element bearing fault detection using AE signal analyzed by envelop analysis added DWT

다국어 초록 (Multilingual Abstract)

Acoustic Emission (AE) technique is a non-destructive testing method and is widely used for the early detection of faults in rotating machines in these days, because the sensitivity of AE transducers is higher than normal accelerometers. So it can detect low energy vibration signals. The faults in the rotating machines are generally occurred at bearings and/or gearboxes which are the principal parts of the machines. To detect the bearing faults, envelope analysis was studied and presented for several decade years. And the researches showed that AE had a possibility of the application in condition monitoring system(CMS) using the envelope analysis for the rolling element bearing. And peak ratio (PR) was developed for expression of the bearing condition in condition monitoring system using AE. Noise level is needed to reduce to take exact PR value because the PR is calculated from total root mean square (RMS) and the harmonics peak levels of the defect frequencies of the bearing. Therefore, in this paper, the discrete wavelet transform (DWT) was added in the envelope analysis to reduce the noise level in the AE signals. And then, the PR was calculated and compared with general envelope analysis result and the result of envelope analysis added the DWT.