31 July 1989 A Stabilized Laser Speckle Strain Gauge
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Proceedings Volume 1084, Stress and Vibration: Recent Developments in Industrial Measurement and Analysis; (1989) https://doi.org/10.1117/12.952904
Event: Sira/Stress and Vibration: Recent Developments in Measurement and Analysis, 1989, London, United Kingdom
The strain gauge using a speckle correlation method is described. A diffuse object is illuminated with a narrow laser beam and the speckle displacement caused by surface deformation is optoelectronically detected at two symmetrical scattering angles. For this purpose, the hardware correlators, which detects the cross-correlation peak between successive frames of a linear image sensor, have been newly developed. High stability in the measurement has been realized, which could not be attained by using the spatial filtering detectors used earlier. We applied the gauge to extension of a metal plate comparing with a resistance strain gauge and also to extension of polymer films comaring with a displacement transducer. The results are in good agreement at loading velocity between a few millistrain/s and a few tens of millistrain/s. The minimum sensitivity is equal to a few tens of microstrains using linear photodiode arrays of pitch 15 μm. There is no upper limit on the strain to be measured because an incremental strain is integrated. The gauge length, which is given by a beam diameter, is an order of one millimeter.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ichirou Yamaguchi, Ichirou Yamaguchi, Koichi Kobayashi, Koichi Kobayashi, Shigesumi Kuwashima, Shigesumi Kuwashima, "A Stabilized Laser Speckle Strain Gauge", Proc. SPIE 1084, Stress and Vibration: Recent Developments in Industrial Measurement and Analysis, (31 July 1989); doi: 10.1117/12.952904; https://doi.org/10.1117/12.952904


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