CONSTRAINED-LAYER DAMPING ANALYSIS FOR EXTENSIONAL WAVES IN INFINITE, FLUID-LOADED PLATES

This study concerns the mathematical analysis of constrained-layer damping of extensional waves in plates of infinite extent, with and without fluid loading. Previous work was mostly limited to flexural waves. Some aspects of fluid loading for flexural waves may be understood by means of thin-plate theory. Therefore, a similar theory was developed for extensional waves. The description and examples presented here are based on three models: The first is an extension of Kerwin's 1959 model [E. M. Kerwin, J. Acoust. Soc. Am. 31, 952-962 (1959)], the second is a hybrid model in which the base plate is described by exact elasticity theory and the other two layers by Kerwin's concepts, and the third uses exact elasticity theory for all three layers. It is shown that the extended Kerwin model is useful in the design of constrained-layer damping for extensional waves as well as for flexural waves.