Location

La Jolla, CA

Start Date

1-1-1991 12:00 AM

Description

Last summer I showed that for the pure mode directions the nonlinear terms in the equation describing propagation of ultrasound in a crystalline lattice take the same general form as those describing propagation in a fluid.1 This makes possible the definition of a nonlinearity parameter for solids in analogy with the nonlinearity parameter for liquids and gases. The magnitudes of such nonlinearity parameters were shown to be associated with physical properties of the sample under study. Since one can define nonlinearity parameters in terms of linear combinations of second order elastic (SOE) and third order elastic (TOE) constants, it now is possible to go into much more detail. Recent measurements of the TOE constants in diamond lattice solids (cubic symmetry) have been interpreted in terms of the interatomic potential function2 through the use of the Keating model.3Additional measurements have been made in copper single crystals,4 as well as perovskites5 and NaCl which exhibits a very large nonlinearity parameter.6 The research has been expanded to include theoretical work7 and experimental measurements8 for crystals of symmetry other than cubic. Recently the research is devoted to an understanding of the effect of piezoelectricity on nonlinearity measurements.9

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

10B

Chapter

Chapter 7: Characterization of Materials

Section

Non-Linear Acoustic Properties

Pages

1797-1803

DOI

10.1007/978-1-4615-3742-7_86

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Anharmonicity, Piezoelectricity, and Solid State Nonlinearity

La Jolla, CA

Last summer I showed that for the pure mode directions the nonlinear terms in the equation describing propagation of ultrasound in a crystalline lattice take the same general form as those describing propagation in a fluid.1 This makes possible the definition of a nonlinearity parameter for solids in analogy with the nonlinearity parameter for liquids and gases. The magnitudes of such nonlinearity parameters were shown to be associated with physical properties of the sample under study. Since one can define nonlinearity parameters in terms of linear combinations of second order elastic (SOE) and third order elastic (TOE) constants, it now is possible to go into much more detail. Recent measurements of the TOE constants in diamond lattice solids (cubic symmetry) have been interpreted in terms of the interatomic potential function2 through the use of the Keating model.3Additional measurements have been made in copper single crystals,4 as well as perovskites5 and NaCl which exhibits a very large nonlinearity parameter.6 The research has been expanded to include theoretical work7 and experimental measurements8 for crystals of symmetry other than cubic. Recently the research is devoted to an understanding of the effect of piezoelectricity on nonlinearity measurements.9