COMPUTATIONAL EVALUATION OF DECOUPLING AND DAMPING MATERIALS

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Authors
  1. Foin, O.
  2. Berry, A.
  3. Nicholas, J.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);Sherbrooke Univ, Sherbrooke QUE (CAN) Dept of Mechanical Engineering
Abstract
The report summarizes the development of theoretical tools to evaluate the effect of damping and decoupling materials on the sound radiation from finite size plates. The simply supported baffled plates were semi-submerged, i.e. fluid loaded on one side and air backed on the other, and excited with either a point force or a plane wave. The fluid loading due to the water is taken into account using an original method for the calculation of the radiation impendances. This method allows for high frequency results with short computational times and without convergence problems. For decoupling materials, the decoupling layer was modeled by evenly distributed, locally reacting springs on the plate. This model avoids the complexity of using a three-dimensional theory of elasticity for the decoupling layer. For viscoelastic damping, theoretical models for two- and three-layered plates were proposed (i.e. free-layer damping and constrained-layer damping) that used the variational approach and are solved by the Rayleigh-Ritz method. Experimental verification of the models for viscoelastic damping was carried out for several cases by measurement of the mean square velocity over the plate using laser Doppler velocimetry. These tests showed very good agreement between measurement and theory. All theoretical models presented in this report were integrated into a computer program called VIBRO, described in Report DREA/CR/96/428.
Keywords
Decoupling;Vibro-acoustics
Report Number
DREA-CR-96-427 — Contractor Report
Date of publication
01 Jul 1996
Number of Pages
160
DSTKIM No
96-03533
CANDIS No
500051
Format(s):
Hardcopy;Document Image stored on Optical Disk

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