Cumulative second harmonic generation in lamb waves for the detection of material nonlinearities

Christian Bermes, Laurence J. Jacobs, Jin Yeon Kim, Jianmin Qu

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations

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.

Original languageEnglish
Title of host publicationReview of Progress in Quantitative Nondestructive Evaluation
Subtitle of host publicationVolume 26
Pages177-184
Number of pages8
DOIs
StatePublished - 2007
EventREVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION - Portland, OR, United States
Duration: 30 Jul 20064 Aug 2006

Publication series

NameAIP Conference Proceedings
Volume894
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

ConferenceREVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION
Country/TerritoryUnited States
CityPortland, OR
Period30/07/064/08/06

Keywords

  • Lamb waves
  • Nonlinear ultrasound
  • Short-time fourier transformation

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