title: Bi-spectrum based-EMD applied to the non-stationary vibration signals for bearing faults diagnosis.
abstract: Empirical mode decomposition (EMD) has been widely applied to analyze vibration signals behavior for bearing failures detection. Vibration signals are almost always non-stationary since bearings are inherently dynamic (e.g., speed and load condition change over time). By using EMD, the complicated non-stationary vibration signal is decomposed into a number of stationary intrinsic mode functions (IMFs) based on the local characteristic time scale of the signal. Bi-spectrum, a third-order statistic, helps to identify phase coupling effects, the bi-spectrum is theoretically zero for Gaussian noise and it is flat for non-Gaussian white noise, consequently the bi-spectrum analysis is insensitive to random noise, which are useful for detecting faults in induction machines. Utilizing the advantages of EMD and bi-spectrum, this article proposes a joint method for detecting such faults, called bi-spectrum based EMD (BSEMD). First, original vibration signals collected from accelerometers are decomposed by EMD and a set of IMFs is produced. Then, the IMF signals are analyzed via bi-spectrum to detect outer race bearing defects. The procedure is illustrated with the experimental bearing vibration data. The experimental results show that BSEMD techniques can effectively diagnosis bearing failures.
authors: University of Tunis, Tunis National Higher School of Engineering (ENSIT), Laboratory of Signal Image and Energy Mastery (SIME), 5 avenue Taha Hussein, PO Box 56, 1008 Tunis, Tunisia. Electronic address: lotfi.saidi@esstt.rnu.tn.
authors: Lotfi
authors: L
authors: Saidi
authors: University of Tunis, Tunis National Higher School of Engineering (ENSIT), Laboratory of Signal Image and Energy Mastery (SIME), 5 avenue Taha Hussein, PO Box 56, 1008 Tunis, Tunisia.
authors: Jaouher Ben
authors: JB
authors: Ali
authors: University of Tunis, Tunis National Higher School of Engineering (ENSIT), Laboratory of Signal Image and Energy Mastery (SIME), 5 avenue Taha Hussein, PO Box 56, 1008 Tunis, Tunisia.
authors: Farhat
authors: F
authors: Fnaiech
keywords: Bi-spectrum; Empirical mode decomposition; Fault diagnosis; Induction motor; Intrinsic mode function; Rolling element bearing