Dynamic Interactions Between The Bending Vibrations Of A Plate And A Fluid Layer Attenuator

Abstract A recently developed formalism is applied to the analysis of wave blocking phenomena observed in plate-fluid layer systems. In addition to the well-known dissipative dynamic behavior, this study calls attention to the locally reacting and stiffness-dominated characteristics of viscous compressible fluid layers. It is shown that, at small layer thicknesses, the increased flow resistance leads to shorter wavelengths and inefficient pumping of the fluid, and causes the locally reacting dynamic behavior of a fluid layer. The spatial variation of the reactive and resistive dynamic properties of a rectangular fluid layer are studied by using a surface impedance. In the applications, linear dynamic interactions between the flexural waves of a plate and a small air layer attenuator are investigated by considering a physical structure. Following the dissipative-to-stiffness transition, the increased local stiffness at relatively small layer thicknesses is observed to block the propagation of the bending waves. The influence of the frequency and the layer thickness on the wave-blocking characteristics of the air layer are discussed based on mobility, power flow and velocity distributions in the system. The predicted frequency response characteristics are confirmed by comparing the results with detailed experimental measurements.