An Evaluation of Structural Damage (Window Breakage) Potential in Callente, NV Under Current Supersonic Flight Restrictions at Nellis AFB.
Interim rept. Oct 96-Jan 97,
CAMBRIDGE ACOUSTICAL ASSOCIATES INC MA
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During November 1996 a series of tests was performed in and around Caliente, NV. These tests, performed by the firms of Cambridge Acoustical Associates, Inc., and Wyle Laboratories, Inc., are part of a Small Business Innovative Research SBIR project, being sponsored by the Armstrong Laboratory of the United States Air Force. The project objective is to perfect measurement techniques that simulate structural response to sonic booms, and in turn allow one to assess potential damage, especially to unconventional structures. The goals of the Caliente tests were twofold. The first was to provide additional data for the validation of the techniques. The second was to demonstrate the process by which such measurements may be used to perform an environmental structural damage assessment. This report focuses on the latter. To limit the overall environmental impact on Caliente, supersonic operations from Nellis AFB have recently been prohibited within five miles of the town. To evaluate the adequacy of this restriction with respect to avoiding structural damage, window damage to be exact, a part of our test plan was devoted to a measurement survey of various windows throughout the town. From these data we have simulated their peak response stress to the sonic boom environment evaluated under the above mentioned flight restriction. Twenty windows were tested, including those of a number of commercial buildings, the library, train station, and one of the auxiliary hospital buildings. Window installations with a noticeable rattle are not readily simulated and were excluded from the ensemble. Based on our simulations Table 3, the least susceptible to damage is a window of the Bureau of Land Management BLM Building and a train station window is the most vulnerable. For all windows, no additional breakage is anticipated under current flight restrictions.