Nam D., Kim K.

To make the modal loss factor of sandwich plate maximum, thickness of the damping layer could be optimized by the conventional RKU equation. Since, however, the equation is derived based on simply supported boundaries, it is applicable to high frequency range for other boundary conditions. In this presentation, a modification the RKU procedure to low frequency vibrations of sandwich plates will be proposed and actually used to modal loss factor optimization. How to deal with damping layer, which is not self adhesive and hence two more adhesive tape layers between metal layers, is also presented for modal property estimation. In order to reflect frequency-dependent characteristics of elastic modulus of the damping layer, an iteration method is proposed in determining the modal properties. Test results on sandwich plates for optimum damping layer thickness are finally compared with predictions by the proposed method.