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Published October 2013 | metadata_only
Journal Article

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


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.

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.

Additional details

August 22, 2023
August 22, 2023