ANOMALOUS ABSORPTION OF SHEAR PLATE MODES BY A THIN-LAYER OF VISCOUS-FLUID

The anomalous absorption of shear plate modes by a thin fluid layer enclosed between & plate butt-end and an elastic halfspace, or between butt-ends of two different plates, is analyzed in the frictional contact approximation. General equations describing the anomalous absorption are derived for arbitrarily thick plates. Specific cases of thin plates, as compared to the wavelengths, are given particular attention. Typical fluid layer thicknesses corresponding to the absorptivity maximum which may be as good as unity, are obtained. The case when fluid does not fill the entire space between the butt-ends of plates, or between the plate butt-end and the halfspace, is also considered.