초록
Optimum design of a viscoelastic damping layer which is unconstrainedly cohered on a steel plate is discussed from the viewpoint of the modal loss factor. Themodal loss factor is analyzed by using the energy method to the base steel plate and cohered damping layer. Optimum distributions of the viscoelastic damping layer for modes are obtained by sequentially changing the position of a piece of damping layer to another position which contributes to maximizing the modal loss factors. Analytical procedure performed by using this method simulated for 3 fundamental modes of an edge-fixed plate. Simulated results indicate that the modal loss factor ratios can be increase by as much as 210%, or more, by optimizing the thickness distribution of the damping layer to two times of the initial condition which is entirely covered. Optimum configurations for the modes are revealed by positions where added damping treatments become most effective. The calculated results by this method are validated by comparison with the experimental results and the calculated results obtained by the Ross-Ungar-Kerwin's model in the case of the layer is uniformly treated over the steel plate.