Abstract
It is well known that the derivative-based classical approach to strain is problematic when the displacement field is irregular, noisy, or discontinuous. Difficulties arise wherever the displacements are not differentiable. We present an alternative, nonlocal approach to calculating strain from digital image correlation (DIC) data that is well-defined and robust, even for the pathological cases that undermine the classical strain measure. This integral formulation for strain has no spatial derivatives and when the displacement field is smooth, the nonlocal strain and the classical strain are identical. We submit that this approach to computing strains from displacements will greatly improve the fidelity and efficacy of DIC for new application spaces previously untenable in the classical framework.
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Acknowledgements
This work was supported in part by Sandia National Laboratories. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under Contract DE-AC04-94AL85000.
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© 2016 The Society for Experimental Mechanics, Inc.
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Turner, D.Z., Lehoucq, R.B., Reu, P.L. (2016). A Nonlocal Strain Measure for DIC. In: Jin, H., Yoshida, S., Lamberti, L., Lin, MT. (eds) Advancement of Optical Methods in Experimental Mechanics, Volume 3. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, Cham. https://doi.org/10.1007/978-3-319-22446-6_10
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DOI: https://doi.org/10.1007/978-3-319-22446-6_10
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-22445-9
Online ISBN: 978-3-319-22446-6
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