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Title: Cumulative Second Harmonic Generation in Lamb Waves for the Detection of Material Nonlinearities

Abstract

An understanding of the generation of higher harmonics in Lamb waves is of critical importance for applications such as remaining life prediction of plate-like structural components. The objective of this work is to use nonlinear Lamb waves to experimentally investigate inherent material nonlinearities in aluminum plates. These nonlinearities, e.g. lattice anharmonicities, precipitates or vacancies, cause higher harmonics to form in propagating Lamb waves. The amplitudes of the higher harmonics increase with increasing propagation distance due to the accumulation of nonlinearity while the Lamb wave travels along its path. Special focus is laid on the second harmonic, and a relative nonlinearity parameter is defined as a function of the fundamental and second harmonic amplitude. The experimental setup uses an ultrasonic transducer and a wedge for the Lamb wave generation, and laser interferometry for detection. The experimentally measured Lamb wave signals are processed with a short-time Fourier transformation (STFT), which yields the amplitudes at different frequencies as functions of time, allowing the observation of the nonlinear behavior of the material. The increase of the relative nonlinearity parameter with propagation distance as an indicator of cumulative second harmonic generation is shown in the results for the alloy aluminum 1100-H14.

Authors:
 [1];  [1];  [2]; ;  [3]
  1. School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0355 (United States)
  2. (United States)
  3. G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405 (United States)
Publication Date:
OSTI Identifier:
21054955
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 894; Journal Issue: 1; Conference: Conference on review of progress in quantitative nondestructive evaluation, Portland, OR (United States), 30 Jul - 4 Aug 2006; Other Information: DOI: 10.1063/1.2717971; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACOUSTICS; ALUMINIUM; ALUMINIUM ALLOYS; AMPLITUDES; DETECTION; DISTANCE; FOURIER TRANSFORMATION; HARMONIC GENERATION; HARMONICS; INTERFEROMETRY; LASER RADIATION; NONLINEAR PROBLEMS; PLATES; PRECIPITATION; SOUND WAVES; SURFACES; TIME DEPENDENCE; TRANSDUCERS; ULTRASONIC TESTING; VACANCIES

Citation Formats

Bermes, Christian, Jacobs, Laurence J., G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405, Kim, Jin-Yeon, and Qu, Jianmin. Cumulative Second Harmonic Generation in Lamb Waves for the Detection of Material Nonlinearities. United States: N. p., 2007. Web. doi:10.1063/1.2717971.
Bermes, Christian, Jacobs, Laurence J., G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405, Kim, Jin-Yeon, & Qu, Jianmin. Cumulative Second Harmonic Generation in Lamb Waves for the Detection of Material Nonlinearities. United States. doi:10.1063/1.2717971.
Bermes, Christian, Jacobs, Laurence J., G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405, Kim, Jin-Yeon, and Qu, Jianmin. Wed . "Cumulative Second Harmonic Generation in Lamb Waves for the Detection of Material Nonlinearities". United States. doi:10.1063/1.2717971.
@article{osti_21054955,
title = {Cumulative Second Harmonic Generation in Lamb Waves for the Detection of Material Nonlinearities},
author = {Bermes, Christian and Jacobs, Laurence J. and G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405 and Kim, Jin-Yeon and Qu, Jianmin},
abstractNote = {An understanding of the generation of higher harmonics in Lamb waves is of critical importance for applications such as remaining life prediction of plate-like structural components. The objective of this work is to use nonlinear Lamb waves to experimentally investigate inherent material nonlinearities in aluminum plates. These nonlinearities, e.g. lattice anharmonicities, precipitates or vacancies, cause higher harmonics to form in propagating Lamb waves. The amplitudes of the higher harmonics increase with increasing propagation distance due to the accumulation of nonlinearity while the Lamb wave travels along its path. Special focus is laid on the second harmonic, and a relative nonlinearity parameter is defined as a function of the fundamental and second harmonic amplitude. The experimental setup uses an ultrasonic transducer and a wedge for the Lamb wave generation, and laser interferometry for detection. The experimentally measured Lamb wave signals are processed with a short-time Fourier transformation (STFT), which yields the amplitudes at different frequencies as functions of time, allowing the observation of the nonlinear behavior of the material. The increase of the relative nonlinearity parameter with propagation distance as an indicator of cumulative second harmonic generation is shown in the results for the alloy aluminum 1100-H14.},
doi = {10.1063/1.2717971},
journal = {AIP Conference Proceedings},
number = 1,
volume = 894,
place = {United States},
year = {Wed Mar 21 00:00:00 EDT 2007},
month = {Wed Mar 21 00:00:00 EDT 2007}
}