A micromechanics model for the acoustic nonlinearity parameter in solids with distributed microcracks

Youxuan Zhao, Yanjun Qiu, Laurence J. Jacobs, Jianmin Qu

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

21 Scopus citations

Abstract

As a longitudinal wave propagates through a linearly elastic solid with distributed cracks, the solid is subjected to cyclic tension and compression. During the tensile cycles, a crack might be open and its faces are traction-free. During the compressive cycles, a crack might be closed and its faces are in contact. Such contact may also be frictional because of crack face roughness. Such tension and compression asymmetry causes acoustic nonlinearity. This paper develops a micromechanics model that relates the crack density to the acoustic nonlinearity parameter. The model is based on a micromechanics homogenization of the cracked solid under dynamic loading. It is shown that the acoustic nonlinearity parameter is proportional to the crack density. Furthermore, the acoustic nonlinearity parameter also depends on the frequency of the wave motion, and the coefficient of friction of the crack faces. Unlike the second harmonic generated by dislocations, the amplitude of the second harmonic due to crack face contact is proportional to the amplitude of the fundamental frequency. To validate the micromechanics model, the finite element method is used to simulate wave propagation in solid with randomly distributed microcracks. The micromechanics model predictions agree well with the finite element simulation results.

Original languageEnglish
Title of host publication42nd Annual Review of Progress in Quantitative Nondestructive Evaluation
Subtitle of host publicationIncorporating the 6th European-American Workshop on Reliability of NDE
EditorsLeonard J. Bond, Dale E. Chimenti
ISBN (Electronic)9780735413535
DOIs
StatePublished - 10 Feb 2016
Event42nd Annual Review of Progress in Quantitative Nondestructive Evaluation, QNDE 2015, Incorporating the 6th European-American Workshop on Reliability of NDE - Minneapolis, United States
Duration: 26 Jul 201531 Jul 2015

Publication series

NameAIP Conference Proceedings
Volume1706
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference42nd Annual Review of Progress in Quantitative Nondestructive Evaluation, QNDE 2015, Incorporating the 6th European-American Workshop on Reliability of NDE
Country/TerritoryUnited States
CityMinneapolis
Period26/07/1531/07/15

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