Rendell R. Torres
Victor W. Sparrow
Alan D. Stuart
Grad. Prog. in Acoust., Penn State Univ., P.O. Box 30, State College, PA 16804
The geometric-mean drive-point admittance of a complex structure can be found by examining the admittance of the corresponding infinite structure (i.e., ``characteristic admittance,'' Y[inf c]) [Skudrzyk, J. Acoust. Soc. Am. 67, 1105--1135 (1980)]. The frequency response of an infinite plate, for example, coincides with the geometric-mean response of a finite plate, i.e., the response equidistant from the resonance maxima and antiresonance minima, plotted on a logarithmic scale. Skudrzyk's ``mean-value theorem'' was derived (and experimentally verified) without consideration of fluid coupling, which introduces a reactive effect that physically resembles a mass loading. The purpose of this research is to find whether the response of the fluid-loaded infinite plate still corresponds to the geometric-mean response of the fluid-loaded finite plate. Numerical results indicate that, in the presence of fluid loading and at low frequencies (below critical), the mean-line drive-point admittance of the finite plate still corresponds to the infinite-plate drive-point admittance that has been derived analytically [Crighton, J. Sound Vib. 54, 389--391 (1977)]. [Work supported by the Applied Research Laboratory.]