Accession Number : ADA181649

Title :   Nonlinear and Random Phenomena in Electromagnetic and Acoustic Wave Propagation.

Descriptive Note : Final rept. 15 Jan 85-14 Jan 87,

Corporate Author : STANFORD UNIV CA

Personal Author(s) : Keller,Joseph B

PDF Url : ADA181649

Report Date : Mar 1987

Pagination or Media Count : 5

Abstract : The acoustoelastic effect is the dependence of sound speed upon stress in an elastic solid due to nonlinearity. This effect can be used for nondestructive testing of structural components of aircraft, vehicles, etc. A theory of the effect was developed which involved analyzing acoustic wave propagation in random anisotropic solids. A related theory of the effective elastic constants of solids composed of aggregates of polycrystals was also developed. For anisotropic composite materials reciprocal relations satisfied by their effective thermal or electrical conductivity tensors were discovered. In the case of scalar materials such relations have been very useful, so the new ones may be useful too. It has also been shown how the elastic properties of the ground could be determined from seismic scattering data. This method used the Born approximation, and led to results involving Fourier transforms. Keywords: Electromagnetic wave propagation; Acoustic wave propagation; Acoustoelastic effect; Random media; Nonlinearity.

Descriptors :   *ACOUSTIC WAVES, *NONLINEAR PROPAGATION ANALYSIS, *ELASTIC WAVES, WAVE PROPAGATION, AIRCRAFT, ELASTIC PROPERTIES, SOLIDS, NONDESTRUCTIVE TESTING, ELECTROMAGNETIC WAVE PROPAGATION, POLYCRYSTALLINE, MATERIALS, SCALAR FUNCTIONS, ELECTRICAL CONDUCTIVITY, TENSORS, FOURIER TRANSFORMATION, NONLINEAR SYSTEMS, SCATTERING, SEISMIC DATA, ANISOTROPY, INVERSE SCATTERING, STRUCTURAL MEMBERS, ACOUSTIC VELOCITY, THERMAL CONDUCTIVITY

Subject Categories : Mechanics
      Electricity and Magnetism
      Acoustics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE