3aSAb5. Fractal sound radiation by layered elastic structures.

Session: Wednesday Morning, May 15

Time: 11:45

Author: Leonid M. Lyamshev
Location: N. N. Andreev Acoust. Inst., Shvernik Ste. 4, 117036 Moscow, Russia


A general method of calculation of sound radiation by layered elastic structures is developed. The reciprocity theorem formulated by the author in 1958 is used. It is shown that plane structure sound radiations are determined by external acting forces and the structure transmission coefficient. The method is very convenient for the analysis and calculation since the external force characteristics are given and the transmission coefficient is a known function of impedances of layers. Several particular problems are considered. Sound radiation by a thin plate or a thick three-layered structure are considered when concentrated or fractal distributed statistical external forces act. The method for moving media in layers is generalized. Sound radiation by curved inhomogeneous layered structures is discussed. The plane structure formula, Green's theorem, and the Kirchhoff approximation are used in last cases. Sound radiation fractal characteristics are discussed.

from ASA 131st Meeting, Indianapolis, May 1996