Theoretical Investigation of the Half Wavelength Theory,

Abstract

The research reported herein was initiated to derive a method for predicting the thicknesses of layers in a layered medium by use of induced forced-wave motion at the surface of the medium. Each layer of the medium was assumed to be homogeneous, isotropic, elastic, and in welded contact with both the layer above and beneath it. The general differential equations of motion were employed separately in each layer of the medium. The mathematical difficulties of solving n-layer system were overcome by using the condition at the interface of two adjacent layers. The solution presented herein was found to give satisfactory results and to be more accurate than the half wavelength criterion which simply states that the calculated modulus applies to the material at a depth equal to one-half the surface wavelength. It is recommended that an extensive field test on controlled layered systems be conducted and complete descriptions of the dispersion curves for a multilayer system be obtained in order to verify the solution.

Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1970
Accession Number
ADA033144

Entities

People

  • G. Y. Baladi

Tags

DTIC Thesaurus Topics

  • Differential Equations
  • Dispersions
  • Equations
  • Equations Of Motion
  • Field Tests
  • Materials
  • Mathematics
  • Thickness

Readers

  • Calculus or Mathematical Analysis
  • Electromagnetic Wave Scattering and Antenna Radiation Engineering
  • Structural Dynamics.