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

3aSA8. Structural intensity of acoustically excited waves in a fluid-loaded elastic plate.

Steven L. Means

Ralph R. Goodman

Appl. Res. Lab., P.O. Box 30, Penn State Univ., State College, PA 16804

When an acoustic plane wave is incident on a elastic plate, various wave types are excited in the plate for different angles of incidence. The present study determines the structural intensity as a function of incident angle at different depths along the cross section. It is found that for near normal incidence the direction of the intensity parallel to the plane of the plate is opposite the intensity in the fluid and for other angles of incidence. Previously, a similar analysis for a semi-infinite medium by Bunney and Goodman [ 1658--1662 (1973)] did not yield such a result. To gain physical insight into this phenomenon, a study was performed to determine which wave modes are excited at these angles of incidence and to calculate their group velocities.