Fei-peng ZHU, Yan GONG, Peng-xiang BAI, et al. Study on strain measurement accuracy of optical extensometers based on digital image correlation[J]. Optics and precision engineering, 2018, 26(5): 1061-1069.
DOI:
Fei-peng ZHU, Yan GONG, Peng-xiang BAI, et al. Study on strain measurement accuracy of optical extensometers based on digital image correlation[J]. Optics and precision engineering, 2018, 26(5): 1061-1069. DOI: 10.3788/OPE.20182605.1061.
Study on strain measurement accuracy of optical extensometers based on digital image correlation
Although optical extensometers based on Digital Image Correlation (DIC) method have widespread applications in strain measurement
there is a lack of systematic research on the strain measurement accuracy. For the uniaxial tensile test
testing equipment including the traditional 2D-DIC optical extensometer
three-dimensional digital image correlation (3D-DIC) optical extensometer
2D-DIC optical extensometer equipped with dual-reflector imaging capability
and strain gauge were employed to measure the strain of stainless steel simultaneously. The results of axial and transverse strain measurement using different optical extensometers were compared
and the corresponding sources of measurement error were analyzed. The experimental results revealed that the traditional 2D-DIC optical extensometer yields low measurement accuracy because of the presence of out-of-plane motion. The 2D-DIC optical extensometer equipped with dual-reflector imaging capability can eliminate the effect of out-of-plane rigid body displacement and thus
ensure higher measurement accuracy
especially for transverse strain measurement
compared to other optical extensometers. Notably
the strain measurement results obtained using the 2D-DIC optical extensometer equipped with dual-reflector imaging capability were in good agreement with those obtained using a strain gauge. The measurement accuracy of transverse strain using 3D-DIC optical extensometer is apparently lower than that of axial strain.
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