ASA 125th Meeting Ottawa 1993 May

3aSA5. Dispersive waves in fluid-loaded, multilayer, composite plates with lossy material.

M. Kim

Y. F. Hwang

David Taylor Model Basin, Carderock Div., Naval Surface Warfare Ctr., Bethesda, MD 20084-5000

One of the outstanding features of the multilayer composite plate is that it can be tailored for a specific structural-acoustic application by intelligently arranging the various layers of elastic and viscoelastic materials. In this study, the multilayer composite plate under consideration possesses a layer of viscoelastic material with high material loss factor for attenuating the propagating waves. For a fluid-loaded case, certain propagating modes dissipate their energy through radiation into surrounding fluid medium, and decreases in amplitude in the direction of propagation even if no material loss factor is assumed. Study of the wave dispersion of this composite plate indicates that the dispersion characteristics and the mode shape of the propagating wave are affected by the amount of damping in the viscoelastic material. The reasons for the aforementioned effect are discussed. Numerical examples are presented for various plate configurations with the viscoelastic layer given a range of material loss factor. [Work supported by ONR.]