ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

5aSA7. A numerical experiment on the coupling of structural-borne sound into an aircraft interior.

Brian H. Houston

Martin H. Marcus

Earl G. Williams

Douglas M. Photiadis

J. A. Bucaro

Naval Res. Lab., Washington, DC 20375-5350

Numerical experiments have been carried out to study the broadband structural acoustics of an aircraftlike shell under point excitation. The dominant mechanisms that lead to the enhancement of interior acoustic modes of this finite shell are examined. To this end, the shell response is studied for both the fluid-loaded and in vacuo cases. A rigid shell calculation was also performed to determine the importance of the wall compliance on the interior acoustics. It was found that the low-frequency shell response is not dependent on the free-wave dispersions, and is driven by the interior volume acoustic modes. At higher frequencies, the shell and fluid are coupled at shell wave numbers determined by the free-wave dispersions. In general, the shell and fluid couple at primarily one circumferential mode.