Comparison of different methods to measure structural damping

Authors

  • Jan-Gerrit Richter National Research Council Canada, 1200 Montreal Road, Ottawa, ON KlA 0R6, Canada
  • Berndt Zeitler National Research Council Canada, 1200 Montreal Road, Ottawa, ON KlA 0R6, Canada
  • Ivan Sabourin National Research Council Canada, 1200 Montreal Road, Ottawa, ON KlA 0R6, Canada
  • Stefan Schoenwald National Research Council Canada, 1200 Montreal Road, Ottawa, ON KlA 0R6, Canada

Keywords:

Architectural acoustics, Energy dissipation, Frequency bands, Reverberation, Bending wave, Coupling loss, Excitation points, Far field, Infinite plate, Internal loss, Loss mechanisms, Low frequency, Material damping, Near fields, Point sources, Reverberation time, Structural damping, Vibration pattern

Abstract

Structural damping indicates the energy loss in materials and systems respectively. Hereby, different loss mechanisms must be distinguished: namely internal losses or material damping due to conversion of kinetic energy into heat and coupling losses due to transmission of energy to adjoining systems. The reverberation time was obtained by exciting the specimen with a small force hammer at three positions using three repeats and measuring the acceleration at eight points distributed over the specimen. Schroeder Plots. A very simplistic approach is used assuming a circular bending wave front around a point source on an isotrupic infinite plate in the far field. The low agreement of the drawaway method is explained by the multiple simplifications made by the model. Even in the midrange frequency bands, reflections make detecting a clear decay impossible. At low frequencies the near field additionally distort the vibration pattern especially closer to the excitation point.

Published

2011-09-01

How to Cite

1.
Richter J-G, Zeitler B, Sabourin I, Schoenwald S. Comparison of different methods to measure structural damping. Canadian Acoustics [Internet]. 2011Sep.1 [cited 2021Apr.19];39(3):54-5. Available from: https://jcaa.caa-aca.ca/index.php/jcaa/article/view/2407

Issue

Section

Proceedings of the Acoustics Week in Canada

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