Effects of Layer Thickness on the Vibration Response of a Plate-Fluid Layer System

Abstract Dynamic interaction between the bending vibrations of a plate and a fluid layer is investigated by using analytical and experimental methods. The frequency response behavior of the coupled plate-fluid layer system is studied, with emphasis on the influence of the layer thickness. The effects of compressibility, viscosity and inertia of the fluid are included in the analytical model. A critical layer thickness is introduced and utilized in the illustration of linear dynamic regimes of a fluid layer. A detailed analysis is carried out for the wave modes of the system, the free wave number of the fluid layer and for the mode shapes of the plate. The use of a powerful transfer matrix method is demonstrated in the formulation of the coupled plate-fluid layer system response. The drive-point mobility, the power flow and the resonance behavior of a physical system are analyzed at different layer thicknesses. Detailed experiments are conducted to confirm the predicted frequency response behavior of a particular plate-air layer system. The attenuation and frequency shift of the plate's resonances are demonstrated with experimental results. Air layer attenuation is found to be very effective in damping the low frequency flexural vibrations of the plate.