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Research in Nondestructive Evaluation

, Volume 9, Issue 1, pp 25–39 | Cite as

Ultrasonic Determination of Stiffness Properties of an Orthotropic Viscoelastic Material

  • K. J. Newell
  • A. N. Sinclair
  • Y. Fan
  • C. Georgescu
Article
  • 18 Downloads

Abstract.

Ultrasonic velocity measurements were used to populate the real portion of the stiffness matrix of an orthotropic viscoelastic material, as a function of frequency. The orthotropy originated from short cellulose reinforcing fibers cast into the polypropylene matrix. The results were consistent with a Zener relaxation model for the material, with a time constant of the order of a few microseconds. It was found that the shape of the dispersion curve varied markedly with orientation: The frequency dependence of the phase velocity was at a minimum along the primary axis of the reinforcing fibers; the fibers were shown to inhibit viscoelastic behavior in this direction. The attenuation coefficient was measured along one primary axis of the material, and found to be consistent with the dispersion curves and localized form of the Kramers-Kronig relationships linking the real and imaginary components of the stiffness matrix.

Keywords

Phase Velocity Stiffness Matrix Ultrasonic Velocity Imaginary Component Test Plane 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag New York Inc. 1997

Authors and Affiliations

  • K. J. Newell
    • 1
  • A. N. Sinclair
    • 1
  • Y. Fan
    • 1
  • C. Georgescu
    • 1
  1. 1.Department of Mechanical and Industrial EngineeringUniversity of TorontoTorontoCanada

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