• Title/Summary/Keyword: Grating Shearography

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Visualization of Surface Deformation on an Open-Hole Specimen Based on Grating Shearography

  • Lee, Jung-Ryul;Lee, Seung-Seok;Chung, Won-Seok
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.6
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    • pp.563-575
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    • 2007
  • This contribution contained the classical work of an open-hole tensile plate to demonstrate the performance of grating shearography and to compare with the results obtained by other full-field measurement techniques, The isotropic plate with an open-hole has often appeared in the previous contributions introducing novel full-field method and system. Grating shearography directly provided six quantitative measurands about the specimen's surface kinematics by using a single measurement set: three in-plane strains, in plane rotation, and two out-of-plane slopes. The quasi-plane wavefront of grating metrology led to high signal-to-noise ratio (SNR) and thus neither fitting nor filtering was applied, and the small shearing distance of $101{\mu}m$ could be used. The small shearing distance provided the outstanding spatial resolution of $80{\mu}m$ and sensitivity appropriate for experimental mechanics. Finally, the grating shearography enabled the visualization of the complex surface deformation around the hole and also detected parasitic flexions of the specimen in the micrometer regime during the tensile test.