ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

3pSA1. On the use of acoustical holography for the determination of intensity in structures.

Anthony J. Romano

Earl G. Williams

Charles G. DelVecchio

Naval Res. Lab., Code 7132, Washington, DC 20375-5000

An overview of the methods for determining structural intensity from information obtained using near-field acoustical holography (NAH) is presented. Toward these ends, a presentation of the theoretical basis and practical methodologies involved in NAH is given, as well as a brief restatement of the structural intensity formulation appropriate for thin shells and plates. A method for obtaining the unknown displacement and stress components from a knowledge of surface pressure and normal velocity is discussed, and these methods are applied to experimental data obtained for the particular cases of a point-driven, fluid-loaded rectangular plate and cylindrical shell. A movie will be presented which displays the instantaneous structural intensity corresponding to the situations previously outlined. [sup a)]Also at Sachs/Freeman Associates, Inc., 1401 McCormick Dr., Landover, MD 20785.