0
Research Papers

Modal Analysis of Rubbing Acoustic Emission for Rotor-Bearing System Based on Reassigned Wavelet Scalogram

[+] Author and Article Information
Yongyong He

The State Key Laboratory of Tribology, Department of Precision Instruments, Tsinghua University, Beijing 100084, P.R. Chinaheyy@mail.tsinghua.edu.cn

Xinyun Yin, Fulei Chu

The State Key Laboratory of Tribology, Department of Precision Instruments, Tsinghua University, Beijing 100084, P.R. China

J. Vib. Acoust 130(6), 061009 (Oct 22, 2008) (8 pages) doi:10.1115/1.2981091 History: Received October 07, 2007; Revised May 19, 2008; Published October 22, 2008

Rubbing between the rotor and the stator is the frequent and harmful malfunction in the rotating machinery, which will cause a very serious accident, even catastrophe, to the machine. Thus, such fault needs timely detection to avoid severe consequences. Vibration based methods are the traditional ones for the detection and diagnosis of the rubbing fault, which are effective when the rubbing has been severe, but always do not work in early detection of such fault. Rubbing between the rotor and the stator will cause elastic strain in the rubbing location and thus can produce acoustic emission (AE). Apparently, such AE contains direct and abundant information about the rubbing and thus can be used to detect and diagnose such fault effectively. In this paper, the AE based method is proposed for detecting and identifying the rubbing of the rotor-bearing system. Using the modal acoustic emission (MAE) theory and reassigned wavelet scalogram, the present study emphasizes on modal analysis and time-frequency characteristics analysis for further understanding the characteristics, phenomenon, and features of the rubbing AE. The results show that the rubbing AE is the elastic wave with multiple modals, which has an impact characteristic and mainly consists of the flexural wave and extensional wave. The transmission of the rubbing AE has some directivity. Moreover, different modals have different transmission characteristics: The flexural wave has lower frequency and its attenuation is influenced mainly by the sectional area of the transmission passage. The extensional wave has higher frequency and its attenuation is mainly sensitive to the interface transmission between the two surfaces. The results also reveal that the reassigned wavelet scalogram is more effective than its original scalogram for the characteristic analysis of the rubbing AE.

FIGURES IN THIS ARTICLE
<>
Copyright © 2008 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

A comparison of wavelet scalogram and its reassigned scalogram

Grahic Jump Location
Figure 2

Experimental setup

Grahic Jump Location
Figure 3

Rubbing device: (a) vibration signal and its spectrum without rubbing and (b) vibration signal and its spectrum with weak rubbing

Grahic Jump Location
Figure 4

An example of denoising by wavelet-based method: (a) acoustic emission and its spectrum without rubbing and (b) acoustic emission and its spectrum with weak rubbing

Grahic Jump Location
Figure 5

Vibration signal of rotor-bearing system: (a) original rubbing AE signal and (b) denoised rubbing AE signal

Grahic Jump Location
Figure 6

Acoustic emission of rotor-bearing system: (a) analysis results of rubbing AE from position 1, (b) analysis results of rubbing AE from position 2, (c) analysis results of rubbing AE from position 3, and (d) analysis results of rubbing AE from position 4

Grahic Jump Location
Figure 7

Analysis of rubbing AE for experimental scheme 1: (a) analysis results of rubbing AE from position 1, (b) analysis results of rubbing AE from position 2, (c) analysis results of rubbing AE from position 3, and (d) analysis results of rubbing AE from position 4

Grahic Jump Location
Figure 8

Analysis of rubbing AE for experimental scheme 2: (a) analysis results of rubbing AE from position 1, (b) analysis results of rubbing AE from position 2, (c) analysis results of rubbing AE from position 3, and (d) analysis results of rubbing AE from position 4

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In