Topic
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: In this article, the authors used microlithography, digital image correlation and tensile test in order to investigate the reasons behind the heterogeneous strain distribution at the grain scale, which was carried out on single phase ferritic steel and two dual phase steels with ferrite and different hard particle martensite contents.
Abstract: This work uses microlithography, digital image correlation and tensile test in order to investigate the reasons behind the heterogeneous strain distribution at the grain scale. Scanning Electron Microscope images are taken to examine the relationship between microstructure features and strain heterogeneity. The study is carried out on single phase ferritic steel and two dual phase steels with ferrite and different hard particle martensite contents. Useful image correlation is obtained in grains with diameters of 2–3 μm for the martensite and ranging from 10 to 20 μm for the ferrite. To prevent a decrease of image correlation success, some technical aspects as the microgrid step and bar width are extensively tackled with for intermediate deformations (>10 %). The different levels of longitudinal intragranular strains observed inside the ferrite grains are not correlated with their orientation, shape, size or the presence (and content) of hard phase in the material.
45 citations
TL;DR: In this article, three digital cameras placed on radii at intervals of 120° viewed on plan outside a transparent triaxial cell were used to capture images of a deforming cylindrical soil specimen at various instants.
Abstract: This paper describes the development of a new digital image-based deformation measurement system for triaxial tests on soils. Three digital cameras placed on radii at intervals of 120° viewed on plan outside a transparent triaxial cell were used to capture images of a deforming cylindrical soil specimen at various instants. A digital image correlation program was written to analyze the captured images, using ray tracing to take account of image distortion due to refraction at the interfaces between the cell fluid, the cell wall, and the atmosphere. The technique is validated with reference to a sand specimen tested in drained triaxial compression. Typical implementations of the system to study surface deformation characteristics (e.g., barreling, onset of localization, and shear band evolution) of deforming soil specimens are illustrated.
45 citations
Journal Article•
TL;DR: In this article, the authors present results of experimental investigations of strain localization in concrete using a non-destructive method called Digital Image Correlation (DIC) technique, which measures surface displacements from digital images.
Abstract: The paper presents results of experimental investigations of strain localization in concrete using a non-destructive method called Digital Image Correlation (DIC) technique. This technique measures surface displacements from digital images. The model tests were carried out with notched concrete specimens under three-point bending. Three dierent beam sizes and two dierent concrete mixes were used. During experiments, load‐deflection curves and evolution of fracture process zone were determined. The measured size eect in strength was compared with the deterministic size eect law by Bazant (1984) and experimental results by Le Bell´ ego et al (2003).
44 citations
TL;DR: Digital volume correlation (DVC) provided the internal strain distribution both in the elastic regime and up to failure inside the vertebral body, including analysis of strain in all directions.
Abstract: The strain distribution in vertebral body has been measured in vitro in the elastic regime but only on the bone surface by means of strain gauges and digital image correlation. Digital volume correlation (DVC) based on micro-computed tomography (micro-CT) images allowed measurements of the internal strain distribution in bone at both tissue (trabecular and cortical bone) and organ (vertebra) levels. However, DVC has been mainly used to investigate failure of the vertebral body but has not yet been deployed to investigate the internal strain distribution in the elastic regime. The aim of this study was to investigate strain in the elastic regime and up to failure inside the vertebral body, including analysis of strain in all directions. Three porcine thoracic vertebrae were loaded in a step-wise fashion at increasing steps of compression (5, 10 and 15%). Micro-CT images were acquired at each step of compression. DVC successfully provided the internal strain distribution both in the elastic regime and up to failure. Micro-CT images successfully identified regions of failure initiation and progression, which were well quantified by DVC-computed strains. Interestingly, the same regions where failure eventually occurred experienced the largest strain magnitude also for the lowest degrees of compression (yet in the elastic regime).
44 citations
TL;DR: In this article, a closed-form solution for the work-conjugate equivalent strain for an arbitrary yield function was derived for simple shear loading that is readily amenable to experimental characterization and is entirely consistent with the logarithmic strain measure.
44 citations