An axisymmetric free vibration of circular plates with partial coverage of constrained viscoelastic layers is analyzed by employing transfer matrix method. Loss factors of partially covered circular plates are determined by evaluating strain energies of each layer from the calculated modes of vibration, and damping properties of plates are discussed. Detailed considerations are aimed at the influence of area and location of the laminated portion, thickness of each layer, and edge conditions on the loos factors of plates. An eminent result on this analysis is that, if the suitable portion of a plate is covered with constrained viscoelastic layers, the partial coverage of comparatively small area ratio can be expected to give higher damping effect that the uniform coverage. It is also pointed out that, when the area ratio of the laminated portion isn't very small, the loss factor of the plate with central coverage dominates that of plates with other coverage of the same area ratio without regard to the edge conditions. The experimental data is also presented, and close agreement with the theoretical predictions is found.
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