Acoustical emission source location in thin rods through wavelet detail crosscorrelation
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Authors
Jerauld, Joseph G.
Subjects
Advisors
Wu, Edward M.
Date of Issue
1998-03-01
Date
March 1998
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
Flaws in structural elements release strain energy in the form of stress waves that can be detected through acoustical emission techniques. The transient nature of a stress wave is analytically inconsistent to Fourier Transforms, and the wave characteristics under the effects of dispersion and attenuation deviate from the formal basis of the Windowed Fourier Transform. The transient solid body elastic waves contain multiple wave types and frequency components which lend themselves to the time and frequency characteristics of Wavelet Analysis. Software implementation now enables the exploration of the Wavelet Transform to identify the time of arrival of stress wave signals for source location in homogeneous and composite materials. This investigation quantifies the accuracy and resolution of two existing source location methods and develops a third technique using the Discrete Wavelet Transform on a windowed portion of the stress wave signal. A refined method for the spatial location of material damage induced stress waves can be used to directly monitor the safe life of structures and provide a quantitative measure for the risk assessment of critical and aging structures.
Type
Thesis
Description
Series/Report No
Department
Department of Aeronautics and Astronautics
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Engineering and Environmental Science Division, Army Research Office Grant No. 32384---EG
Funder
Format
xi, 138 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.