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Proceedings Paper

Mode shape analysis using a commercially available "peak-store" video frame buffer
Author(s): Walter L. Snow; Brooks A. Childers
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Paper Abstract

Time exposure photography, sometimes coupled with strobe illumination, is an accepted method for motion analysis that bypasses frame by frame analysis and re synthesis of data. Garden variety video cameras can now exploit this technique using a unique frame buffer that is a non integrating memory that compares incoming data with that already stored. The device continuously outputs an analog video signal of the stored contents which can then be redigitized and analyzed using conventional equipment. Historically, photographic time exposures have been used to record the displacement envelope of harmonically oscillating structures to show mode shape. Mode shape analysis is crucial, for example, in aeroelastic testing of wind tunnel models. Aerodynamic, inertial, and elastic forces can couple together leading to catastrophic failure of a poorly designed aircraft. This paper will explore the usefulness of the peak store device as a videometric tool and in particular discuss methods for analyzing a targeted vibrating plate using the `peak store' in conjunction with calibration methods familiar to the close-range videometry community. Results for the first three normal modes will be presented.

Paper Details

Date Published: 6 October 1994
PDF: 8 pages
Proc. SPIE 2350, Videometrics III, (6 October 1994); doi: 10.1117/12.189126
Show Author Affiliations
Walter L. Snow, NASA Langley Research Ctr. (United States)
Brooks A. Childers, NASA Langley Research Ctr. (United States)


Published in SPIE Proceedings Vol. 2350:
Videometrics III
Sabry F. El-Hakim, Editor(s)

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