### ASA 127th Meeting M.I.T. 1994 June 6-10

## 2aPA13. The dynamic response of a window embedded in a 3-D structure to
sonic boom overpressures.

**Kyle Martini
**

**
Joel Garrelick
**

**
**
*Cambridge Acoust. Assoc., Inc., 200 Boston Ave., Ste. 2500, Medford, MA
02155-4243
*

*
*
Ground level sonic boom overpressures are often in the linear acoustic
regime, allowing structural damage assessments to be performed using structural
acoustic techniques. In this talk the boom-induced dynamic response and stress
of a glass window is computed. The window, modeled as an elastic thin plate, is
embedded in an enclosure that may also be elastic. Solutions are obtained
numerically using nashua, a general purpose finite element/boundary element
computer code. Peak response/stress is calculated as a function of the relative
orientation of the incident wave in azimuth and elevation, the former
determined by the flight path and the latter by the Mach number. For a given
boom spectrum level, the peak response probability density function (PDF) is
calculated assuming a uniform probability of flight direction. By invoking
structural acoustic reciprocity, this is related to the directivity of the
pressure radiated by a force applied to the window at the peak response
location. Finally, the effects of enclosure baffling on the surface pressure
itself is presented and compared with free field and infinite baffle
approximations. [Work sponsored by Armstrong Laboratory, WPAFB, U.S. Air
Force.]