Vibration analysis is a powerful diagnostic tool for rotating machinery problems. Traditional approaches to vibration signature analysis have focused on the Fourier transform, which tends to average out transient effects. Recent work in the area of wavelets has allowed for the characterization of signals in frequency and in time, which, if properly interpreted, can provide substantial insight, particularly with regard to transient behaviors. There are many different types of wavelets, but the harmonic wavelet was developed specifically for vibration analysis. It uses an algorithm based upon the fast Fourier transform (FFT), which makes it particularly attractive to many in the vibration analysis community. This paper considers the harmonic wavelet as a tool for extracting transient patterns from measured vibration data. A method for characterizing transient behaviors using the harmonic wavelet is described and illustrated with simulation and experimental results.

Issue Section:
Gas Turbines: Structures and Dynamics
Keywords:
data analysis, wavelet transforms, transient analysis, feature extraction, vibrations, signal processing, fast Fourier transforms
Topics:
Signals, Transients (Dynamics), Vibration, Wavelets, Simulation, Algorithms, Fast Fourier transforms, Rotor vibration, Vibration analysis, Whirls
1.
Wowk, V., 1991, Machinery Vibration: Measurement and Analysis, McGraw-Hill, New York.
2.
Vance, J. M., 1988, Rotordynamics of Turbomachinery, John Wiley and Sons, New York.
3.
Hubbard, B. B., 1996, The World According to Wavelets: The Story of a Mathematical Technique in the Making, A. K. Peters, Wellesley, MA.
4.
Newland
,
D. E.
,
1993
, “
Harmonic Wavelet Analysis
,”
Proc. R. Soc. London, Ser. A
,
443
, pp.
203
–
225
.
5.
Newland, D. E., 1993, An Introduction to Random Vibrations, Spectral & Wavelet Analysis, Longman, Singapore.
6.
Chancey
,
V. C.
,
Flowers
,
G. T.
, and
Howard
,
C. L.
,
2000
, “
Characterization of Transient Behaviors in Rotordynamic Vibrations From Experimental Data Using Harmonic Wavelets
,”
Int. J. Vib. Acoust.
,
6
(
1
), pp.
15
–
22
.
7.
Newland
,
D. E.
,
1994
, “
Harmonic and Musical Wavelets
,”
Proc. R. Soc. London, Ser. A
,
444
, pp.
605
–
620
.
8.
Newland, D. E., 1997, “Practical Signal Analysis: Do Wavelets Make Any Difference,?” 1997 ASME Design Engineering Technical Conferences, Sacramento, CA, 12 pp.
9.
Newland, D. E., 1997, “Application of Harmonic Wavelets to Time-Frequency Mapping,” Fifth International Congress on Sound and Vibration, University of Adelaide, South Australia, pp. 2043–2053.
10.
Morrison, N., 1994, Introduction to Fourier Analysis, John Wiley and Sons, New York, pp. 238–256.
Copyright © 2003
 by ASME
You do not currently have access to this content.