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Proceedings Paper

Material damping experiments at cryogenic temperatures
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Paper Abstract

A unique experimental facility has been designed to measure damping of materials at cryogenic temperatures. The test facility pays special attention to removing other sources of damping in the measurement by avoiding frictional interfaces, decoupling the test specimen from the support system, and by using a non-contacting measurement device. Damping data is obtained for materials (Al, GrEp, Be, Fused Quartz), strain amplitudes (<10-6 ppm), frequencies (20 Hz-330Hz) and temperatures (20K - 293K) relevant to future precision optical space missions. The test data shows a significant decrease in viscous damping at cryogenic temperatures and can be as low as 10-4%, but the amount of the damping decrease is a function of frequency and material. Contrary to the other materials whose damping monotonically decreased with temperature, damping of Fused Quartz increased substantially at cryo, after reaching a minimum at around 150°K. The damping is also shown to be insensitive to strain for low strain levels. At room temperatures, the test data correlates well to the analytical predictions of the Zener damping model. Discrepancies at cryogenic temperatures between the model predictions and the test data are observed.

Paper Details

Date Published: 12 December 2003
PDF: 12 pages
Proc. SPIE 5179, Optical Materials and Structures Technologies, (12 December 2003); doi: 10.1117/12.506838
Show Author Affiliations
Marie B. Levine, Jet Propulsion Lab. (United States)
Christopher White, Jet Propulsion Lab. (United States)


Published in SPIE Proceedings Vol. 5179:
Optical Materials and Structures Technologies
William A. Goodman, Editor(s)

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