A Study on Optimum Design of a Two-Layer Plate by Changing Position of Viscoelastic Damping Layer Elements

Abstract

In the present study, optimum distributions of unconstrained viscoelastic damping layer elements for plates are discussed from the viewpoint of the modal loss factor. The modal loss factor is expressed in terms of both the mechanical properties of the plate and damping layer and their thickness ratio. Optimum distributions of the thickness ratios of elements are obtained by sequentially changing the position of a piece of layer to another position which contributes to maximizing the modal loss factors. Results are presented for (1, 1) and (1, 3) modes of edge-fixed plates. These results indicate that the modal loss factor can be increased by as much as 200%, or more, by optimizing the thickness distribution of the damping treatment. The optimum configurations of the (1, 1) and (1, 3) mode of plates are revealed by positions where added damping treatments become most effective. The results are validated by both suitable experimental results and the calculated results obtained by the Ross-Kerwin-Ungar's model in the case of a uniformly treated viscoelastic damping layer over the entire area of the plate.