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Three-dimensional Displacement and Shape Measurement with a Diffraction-assisted Grid Method

Notbohm, J. and Rosakis, A. and Kumagai, S. and Xia, S. and Ravichandran, G. (2013) Three-dimensional Displacement and Shape Measurement with a Diffraction-assisted Grid Method. Strain: An International Journal for Experimental Mechanics, 49 (5). pp. 399-408. ISSN 0039-2103.

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The grid method is a full-field optical technique for computing surface displacements and strains of a material by analyzing the phase of grid lines patterned on the specimen. To date, most experiments using the grid method have measured only two-dimensional in-plane deformations. Here, the grid method is extended to three dimensions by using a crossed grid pattern and a diffraction grating which enables acquiring images from multiple viewing angles on a single camera. In-plane displacements and strains are computed using the conventional grid method, and the corresponding three-dimensional (3D) displacements—including out-of-plane displacements or shapes—are computed by analyzing the images collected at different viewing angles. The technique is demonstrated by measuring 3D rigid body motion, the 3D displacements of a membrane in a pressure-bulge experiment, and the out-of-plane curvature of a cylindrical specimen.

Item Type:Article
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URLURL TypeDescription
Rosakis, A.0000-0003-0559-0794
Ravichandran, G.0000-0002-2912-0001
Additional Information:© Wiley Publishing Ltd. Issue published online: 17 September 2013; Article first published online: 16 August 2013; Manuscript Accepted: 30 June 2013; Manuscript Revised: 27 June 2013; Manuscript Received: 5 May 2013. We thank Professors F. Pierron and M. Grédiac for providing a short course on the grid method at Caltech and an example Matlab code for obtaining 2D displacements from the grid method. J.N. was supported by a National Science Foundation Graduate Research Fellowship under grant # DGE-1144469. S. K. was supported by the Tokyo Institute of Technology through the TiROP program while he was a visiting student researcher at Caltech. S.X. gratefully acknowledges the support of the Haythornthwaite Foundation.
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE-1144469
Tokyo Institute of TechnologyUNSPECIFIED
Haythornthwaite FoundationUNSPECIFIED
Subject Keywords:3D displacement; diffraction; grid method; phase; strain
Issue or Number:5
Record Number:CaltechAUTHORS:20131115-115806236
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Official Citation:Notbohm, J., Rosakis, A., Kumagai, S., Xia, S. and Ravichandran, G. (2013), Three-dimensional Displacement and Shape Measurement with a Diffraction-assisted Grid Method. Strain, 49: 399–408. doi: 10.1111/str.12046
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42499
Deposited By: Jason Perez
Deposited On:20 Nov 2013 20:14
Last Modified:09 Mar 2020 13:19

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