Optimum Design of an Unconstrained Viscoelastic Damping Layer under Consideration of Some Modes.

Abstract

The optimum configuration of the composite plate covered with an unconstrained viscoelastic damping layer is discussed from the viewpoint of the modal loss factor. When the configuration of a damping layer is optimized to an arbitrary mode, it's modal loss factor becomes maximum. In general, however, loss factors of the other modes are much lower than those obtained by optimization to each mode. Therefore, in this study, the optimum configuration of a damping layer is investigated under consideration of modal loss factor to some modes. The optimum distribution of the damping layer is obtained by sequentially changing the position of a section of the layer to another position to optimize the composite modal loss factor. Results are compared with the modal loss factors of (1, 1), (1, 2) and (1, 3) modes, which are optimized to their individual modes. These results indicate that although the maximum loss factor is decreased by 2∼8% compared to those optimized only to each mode, those of the other modes could be increased by 5∼23%. The results are validated by suitable experimental results.