Influence of Shear Modulus on the Behavior of Acoustically Transparent Materials.

Abstract

Materials are under construction that match the density, rho and dilatational sound speed, c as closely as possible to the values of seawater, while maintaining sufficient rigidity to serve for structural purposes. The demand for rigidity implies a larger shear modulus than is typical for the usual rho-c elastomers. Matching of density and sound speed results in transparency for fluids only; the finite shear modulus in a solid admits the presence of a shear wave, which causes deviation from ideal rho-c behavior. In this report the effect is analyzed of a finite shear modulus on the reflection of plane waves by an infinite plate of the rho-c material. Examples are given of the reflection coefficient as a function of incidence angle for various combinations of density and sound speed close to ideal, and various ratios of plate thickness to dilatational wavelength. The effect of a finite loss factor in the shear modulus is known. Keywords: Reflection of acoustic waves.

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Document Details

Document Type
Technical Report
Publication Date
Apr 30, 1986
Accession Number
ADA169289

Entities

People

  • Pieter S. Dubbelday

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Acoustic Propagation
  • Acoustic Waves
  • Acoustics
  • Bulk Modulus
  • Classification
  • Coefficients
  • Computer Programs
  • Frequency
  • Materials
  • Military Research
  • Reflection
  • Secondary Waves
  • Security
  • Shear Modulus
  • Sound Waves
  • Structural Response
  • Waves

Fields of Study

  • Engineering

Readers

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  • Structural Dynamics.