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Digital image correlation

About: Digital image correlation is a research topic. Over the lifetime, 7842 publications have been published within this topic receiving 132166 citations.


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TL;DR: It is shown that time varying drift distortion is a larger problem at high magnification while spatial distortion is more problematic at low magnification and the new use of sample-independent calibration and a method to eliminate the detrimental effects of stress relaxation in the displacement fields prior to distortion correction are introduced.
Abstract: The recent combination of scanning electron microscopy and digital image correlation (SEM-DIC) enables the experimental investigation of full-field deformations at much smaller length scales than is possible using optical digital image correlation methods. However, the high spatial resolution of SEM-DIC comes at the cost of complex image distortions, long image scan times that can capture gradients from stress relaxation, and a high noise sensitivity to SEM parameters. In this paper, it is shown that these sources of error can significantly impact the quality of the results and must be accounted for in order to perform accurate SEM-DIC experiments. An existing framework for distortion corrections is adapted to improve accuracy and the procedures are described in detail. As the results demonstrate, time varying drift distortion is a larger problem at high magnification while spatial distortion is more problematic at low magnification. Additionally, the new use of sample-independent calibration and a method to eliminate the detrimental effects of stress relaxation in the displacement fields prior to distortion correction are introduced. The impact of SEM settings on image noise is quantified and noise minimization schemes are examined. Finally, a uniaxial tension test on coarse-grained 1100-O aluminum is used to demonstrate these techniques, where active slip planes are identified and strain localization is examined in relation to the underlying microstructure.

234 citations

Journal ArticleDOI
TL;DR: In this paper, a simple, easy-to-implement yet effective high-temperature digital image correlation (DIC) method is established for non-contact full-field deformation measurement at elevated temperatures.
Abstract: A simple, easy-to-implement yet effective high-temperature digital image correlation (DIC) method is established for non-contact full-field deformation measurement at elevated temperatures. The technique employs a bandpass optical filter to eliminate the influence of black-body radiation of high-temperature objects on the intensity of captured images. With the bandpass filter, high-quality digital images of an object at high temperatures up to 1200 °C can be easily acquired and directly compared with the reference image recorded at room temperature using the DIC technique to extract full-field deformation information with high fidelity. To verify the performance of the proposed technique, a chromium-nickel austenite stainless steel sample was heated from room temperature to 1200 °C using an infrared heating device, and the surface images at various temperatures were captured using the bandpass filter imaging system. Afterwards, full-field thermal deformation and coefficient of thermal expansion of the sample were determined using the DIC technique. Experimental results indicate that the proposed high-temperature DIC method is easy to implement and can be applied to practical full-field high-temperature deformation measurement with high accuracy.

232 citations

Journal ArticleDOI
TL;DR: An algorithm based on a two-dimensional discrete cross correlation between subimages from different images is presented, and the reliability and accuracy is analyzed by using computer-generated speckle patterns.
Abstract: Replacing photographic recording by electronic processing has some obvious advantages. An algorithm used for electronic speckle pattern photography is presented, and the reliability and accuracy is analyzed by using computer-generated speckle patterns. The algorithm is based on a two-dimensional discrete cross correlation between subimages from different images. Subpixel accuracy is obtained by a Fourier series expansion of the discrete correlation surface. The accuracy of the algorithm was found to vary in proportion to sigma/n(1 - delta)(2), where sigma is the speckle size, n is the subimage size, and delta is the amount of decorrelation, with negligible systematic errors. For typical values the uncertainty in the displacement is approximately 0.05 pixels. The uncertainty is found to increase with increased displacement gradients.

227 citations

Journal ArticleDOI
TL;DR: In this paper, the eXtended finite element method is applied to the measurement of displacements through digital image correlation, and an algorithm, initially based on a finite element decomposition of displacement fields, is extended to benefit from discontinuity and singular enrichments over a suited subset of elements.
Abstract: The methodology of eXtended finite element method is applied to the measurement of displacements through digital image correlation. An algorithm, initially based on a finite element decomposition of displacement fields, is extended to benefit from discontinuity and singular enrichments over a suited subset of elements. This allows one to measure irregular displacements encountered, say, in cracked solids, as demonstrated both in artificial examples and experimental case studies. Moreover, an optimization strategy for the support of the discontinuity enables one to adjust the crack path configuration to reduce the residual mismatch, and hence to be tailored automatically to a wavy or irregular crack path. Copyright © 2007 John Wiley & Sons, Ltd.

227 citations

Journal ArticleDOI
Satoru Yoneyama1, A. Kitagawa1, S. Iwata1, K. Tani1, Hisao Kikuta1 
TL;DR: It is found that the deflections can be measured even if the artificial random pattern is not applied to the surface of the bridge girder, and noncontact displacement measurement is possible by simple and easy procedure with digital image correlation for the structural evaluation of infrastructures.
Abstract: Digital image correlation technique is used for measuring vertical deflections of bridge girders during a bridge load testing. A bridge is loaded by a heavy cargo truck on the bridge road. Then, the deflection distribution is measured by digital image correlation. The applicability of digital image correlation to bridge deflection measurement is investigated by comparing the results obtained by digital image correlation with those obtained by displacement transducers. The effect of random pattern on an object surface is also investigated by measuring with and without random pattern. The results show that the deflection distributions of the bridge obtained by digital image correlation agree well with those obtained by the displacement transducers when the random pattern is attached on the bridge surface. In addition, it is found that the deflections can be measured even if the artificial random pattern is not applied to the surface of the bridge girder. It is emphasized that noncontact displacement measurement is possible by simple and easy procedure with digital image correlation for the structural evaluation of infrastructures.

227 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023582
20221,120
2021667
2020646
2019636
2018567