Effective Dynamic Material Parameters and Localized Scattering

Abstract

A modification of the classical effective wave vector in randomly inhomogeneous media ksubp * = ksubp + 2pinfsubp(1,0)/ksubp is discussed, which replaces the single particle far field forward scattering amplitude, fsubp(1,0), by an average pair scattering amplitude, fsubp(2,0). The Perkus-Yevick radial distribution function is used to find the average of fsubp(2,0) over radial separations extending to the first nearest neighbor maximum. The results is applied to random distributions of mass loaded polyurethane spheres in syntactic foam and to lead spheres in an epoxy resin matrix and compared with calculations based on the single particle amplitude. In the case of high concentrations of lead inclusions in epoxy, the mode conversion cross section as well as the real and imaginary parts of the effective wave vector are significantly, altered by pair scattering. In the case of mass loaded polyurethane in syntactic foam, on the other hand, the effects are negligible.

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Document Details

Document Type
Technical Report
Publication Date
Mar 20, 1991
Accession Number
ADA241957

Entities

People

  • Kurt P. Scharnhorst

Organizations

  • Naval Surface Warfare Center

Tags

Communities of Interest

  • Biomedical
  • Energy and Power Technologies
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Absorption Coefficients
  • Absorption Cross Sections
  • Availability
  • Composite Materials
  • Distribution Functions
  • Elastic Waves
  • Epoxy Resins
  • Far Field
  • Forward Scattering
  • Materials
  • Polyurethanes
  • Resins
  • Scattering Cross Sections
  • Secondary Waves
  • Security
  • Syntactic Foams
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Approximation Theory.
  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Reinforced Composite Materials