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Shock and Vibration
Volume 19, Issue 6, Pages 1373-1383

Bearing Fault Detection Using Multi-Scale Fractal Dimensions Based on Morphological Covers

Pei-Lin Zhang,1 Bing Li,1,2 Shuang-Shan Mi,2 Ying-Tang Zhang,1 and Dong-Sheng Liu2

1First Department, Mechanical Engineering College, Shijiazhuang, Hebei, China
2Forth Department, Mechanical Engineering College, Shijiazhuang, Hebei, China

Received 4 November 2010; Revised 29 October 2011

Copyright © 2012 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Vibration signals acquired from bearing have been found to demonstrate complicated nonlinear characteristics in literature. Fractal geometry theory has provided effective tools such as fractal dimension for characterizing the vibration signals in bearing faults detection. However, most of the natural signals are not critical self-similar fractals; the assumption of a constant fractal dimension at all scales may not be true. Motivated by this fact, this work explores the application of the multi-scale fractal dimensions (MFDs) based on morphological cover (MC) technique for bearing fault diagnosis. Vibration signals from bearing with seven different states under four operations conditions are collected to validate the presented MFDs based on MC technique. Experimental results reveal that the vibration signals acquired from bearing are not critical self-similar fractals. The MFDs can provide more discriminative information about the signals than the single global fractal dimension. Furthermore, three classifiers are employed to evaluate and compare the classification performance of the MFDs with other feature extraction methods. Experimental results demonstrate the MFDs to be a desirable approach to improve the performance of bearing fault diagnosis.