TY - GEN
T1 - A micromechanics model for the acoustic nonlinearity parameter in solids with distributed microcracks
AU - Zhao, Youxuan
AU - Qiu, Yanjun
AU - Jacobs, Laurence J.
AU - Qu, Jianmin
N1 - Publisher Copyright:
© 2016 AIP Publishing LLC.
PY - 2016/2/10
Y1 - 2016/2/10
N2 - 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.
AB - 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.
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U2 - 10.1063/1.4940507
DO - 10.1063/1.4940507
M3 - Conference contribution
AN - SCOPUS:84976362777
T3 - AIP Conference Proceedings
BT - 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation
A2 - Bond, Leonard J.
A2 - Chimenti, Dale E.
T2 - 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation, QNDE 2015, Incorporating the 6th European-American Workshop on Reliability of NDE
Y2 - 26 July 2015 through 31 July 2015
ER -