Optical strain measurement system development. Final report

Conference · Wed Jul 01 04:00:00 EDT 1987

OSTI ID:5910382

Lant, C T; Qaqish, W

A laser speckle, differential strain measurement system has been built and tested for future applications in hostile environments. One-dimensional electronic correlation of speckle pattern movement allows a quasi-real time measure of strain. The system has been used successfully to measure uniaxial strain reaching into plastic deformation of a test specimen, at temperatures ranging to 450 C. A resolution of 16 microstrain is given by the photodiode array sensor pitch and the specimen to sensor separation. The strain measurement error is estimated to be +/-18 microstrain +/-3 percent of the strain reading. The upper temperature limit of the gauge is determined by air density perturbations causing decorrelation of the reference and shifted speckle patterns, and may be improved by limiting convective flow in the immediate vicinity of the test specimen.

• Research Organization: Sverdrup Technology, Inc., Arnold Air Force Station, TN (USA)
• OSTI ID: 5910382
• Report Number(s): N-87-26326; NASA-CR-179646; E-3678; NAS-1.26:179646; CONF-8708110-22
• Country of Publication: United States
• Language: English

Related Subjects

440300* -- Miscellaneous Instruments-- (-1989)
47 OTHER INSTRUMENTATION
COHERENT SCATTERING
DESIGN
DIFFRACTION
HIGH TEMPERATURE
MEASURING INSTRUMENTS
OPTICAL SYSTEMS
REFRACTION
SCATTERING
STRAIN GAGES