## 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**

**Abstract:**

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