A Study of the Nearfield of an Excited Spherical Shell.

Abstract

In this study, the acoustic near field of excited spherical shells is investigated. The interaction of the acoustic medium with the vibration response of an elastic spherical shell due to an excitation by a point force or an acoustic point source is investigated analytically and experimentally. Thus, only axisymmetric, nontorsional motion of the spherical shell is considered, with a thin shell theory that includes extensional and bending deformation. The elastic spherical shell resonances were computed when in vacuo and when submerged in light (air and heavy (water) acoustic medium. These were verified experimentally by testing two duralumin shells, a = 8 inches in radius and wall thicknesses h = 0.0514 and 0.1069 inch. The measured resonance frequencies were within 5% of those predicted in air and in water for identified mode numbers up to 34. The measured mean-line driving point admittance also agreed well with the predicted ones to within 3 dB.

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Document Details

Document Type
Technical Report
Publication Date
Mar 17, 1980
Accession Number
ADA086008

Entities

People

  • Edmond Wong

Organizations

  • Pennsylvania State University

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Acoustic Absorption
  • Acoustic Impedance
  • Acoustic Propagation
  • Acoustic Resistance
  • Acoustic Waves
  • Acoustics
  • Anechoic Chambers
  • Diffraction
  • Geometric Forms
  • Measurement
  • Modulus Of Elasticity
  • Numerical Analysis
  • Physical Properties
  • Resonant Frequency
  • Scattering
  • Three Dimensional
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Electromagnetic Wave Scattering and Antenna Radiation Engineering
  • Metallurgy