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Proceedings Paper

Real-time two-color laser speckle-shift strain measurement system
Author(s): Meg L. Tuma; Lawrence C. Greer; Michael J. Krasowski; Lawrence G. Oberle; Kristie A. Elam; Daniel C. Spina
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Paper Abstract

A real-time two-color laser speckle-shift strain measurement system based on Yamaguchi's technique was designed, built, and tested at room temperature. This non-contact 1D system detects surface strain in a structural fiber as it is pulled in a tensile test machine. Interference or speckle patterns from the laser illuminated fiber test specimen are recorded. As the fiber is pulled, its speckle patterns shift in proportion to the strain, translation, and rotation components of the sample deformation. Shifting speckle patterns are detected at real-time rates using 2 linear CCD arrays with image processing performed by a hardware correlator. Surface strain detected in fibers with diameters on the order of 100 micrometers can be resolved to 19 microstrain. This system was designed to be compact and robust and generally does not require surface preparation of the structural fibers.

Paper Details

Date Published: 30 June 1998
PDF: 8 pages
Proc. SPIE 3478, Laser Interferometry IX: Techniques and Analysis, (30 June 1998); doi: 10.1117/12.312951
Show Author Affiliations
Meg L. Tuma, NASA Lewis Research Ctr. (United States)
Lawrence C. Greer, NASA Lewis Research Ctr. (United States)
Michael J. Krasowski, NASA Lewis Research Ctr. (United States)
Lawrence G. Oberle, NASA Lewis Research Ctr. (United States)
Kristie A. Elam, Gilcrest Electric (United States)
Daniel C. Spina, Cortez III Service Corp. (United States)


Published in SPIE Proceedings Vol. 3478:
Laser Interferometry IX: Techniques and Analysis
Malgorzata Kujawinska; Gordon M. Brown; Mitsuo Takeda, Editor(s)

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