Assessment of Measuring Errors in Strain Fields Obtained via DIC on Planar Sheet Metal Specimens with a Non-Perpendicular Camera Alignment

Abstract:

The determination of strain fields based on displacement components obtained via 2D-DIC is subject to several errors that originate from various sources. In this contribution, we study the impact of a non-perpendicular camera alignment to a planar sheet metal specimen’s surface subject to biaxial loading conditions. The errors are estimated in a numerical experiment. To this purpose, deformed images - that were obtained by imposing finite element (FE) displacement fields on an undeformed image - are numerically rotated for various Euler angles. It is shown that a 3D-DIC stereo configuration induces a substantial compensation for the introduced image-plane displacement gradients. However, higher strain accuracy and precision are obtained - up to the level of a perfect perpendicular alignment - in a proposed ”rectified” 2D-DIC setup. This compensating technique gains benefit from both 2D-DIC (single camera view, basic amount of correlation runs, no cross-camera matching nor triangulation) and 3D-DIC (oblique angle compensation).

• Periodical: Applied Mechanics and Materials (Volume 70)
• Pages: 165-170
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.70.165
• Online since: August 2011
• Authors: Pascal Lava, Sam Coppieters, Yue Qi Wang, Paul van Houtte, Dimitri Debruyne
• Keywords: Digital Image Correlation (DIC), Finite Element (FE) Simulation, Stereo Vision, Strain Calculations, Systematic Errors

References

[1] S. Cooreman, D. Lecompte , H. Sol, J. Vantomme , D. Debruyne : Exp Mech Vol. 48 (2008), p.421.

DOI: 10.1007/s11340-007-9094-0

[2] W. Van Paepegem, A.A. Shulev, I.R. Roussev, S. De Pauw, J. Degrieck, V.C. Sainov: Opt Lasers Eng Vol. 47 (2009), p.390.

DOI: 10.1016/j.optlaseng.2008.03.005

[3] P. Lava, S. Cooreman, S. Coppieters, M. De Strycker, D. Debruyne: Opt Lasers Eng Vol. 47 (2009), p.747.

DOI: 10.1016/j.optlaseng.2009.03.007

[4] P. Lava, S. Cooreman, D. Debruyne: Opt Lasers Eng Vol. 48 (2010), p.457.

[5] M.A. Sutton, J.H. Yan, V. Tiwari, H.W. Schreier, J.J. Orteu: Opt Lasers Eng Vol. 46 (2008), p.746.

[6] P. Lava, S. Coppieters, Y. Wang, P. Van Houtte, D. Debruyne: Opt Lasers Eng Vol. 49 (2011), p.57.

[7] Information on http: /www. matchid. org.