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.

Multiscale experimental investigation of crystal plasticity and grain boundary sliding in synthetic halite using digital image correlation

Abstract: [1] There is a renewed interest in the study of the rheology of halite since salt cavities are considered for waste repositories or energy storage. This research benefits from the development of observation techniques at the microscale, which allow precise characterizations of microstructures, deformation mechanisms, and strain fields. These techniques are applied to uniaxial compression tests on synthetic halite done with a classical press and with a specific rig implemented in a scanning electron microscope. Digital images of the surface of the sample have been recorded at several loading stages. Surface markers allow the measurement of displacements by means of digital image correlation techniques. Global and local strain fields may then be computed using ad hoc data processing. Analysis of these results provides a measure of strain heterogeneity at various scales, an estimate of the size of the representative volume element, and most importantly an identification of the deformation mechanisms, namely crystal slip plasticity and grain boundary sliding, which are shown to be in a complex local interaction. Indeed, the applied macroscopic loading gives rise locally to complex stress states owing to relative crystallographic orientations, density and orientation of interfaces, and local deformation history. We have quantitatively estimated the relative importance of crystal slip plasticity and grain boundary sliding for different microstructures and evidenced their dependence on grain size. The two mechanisms of deformation and their link to the microstructure should thus be considered when modeling polycrystalline viscoplasticity.

Curvature Monitoring of Beams Using Digital Image Correlation

Abstract: A method for measuring longitudinal strains with the height at a section, and thus the curvature, using a technique based on digital image correlation (DIC), is presented. The background to this technique is introduced as well as previous work in this area. The accuracy of DIC under ideal conditions is established using artificially generated images that represent beams with various curvatures. The practical accuracy of DIC is established by comparing the strains measured using DIC to those predicted by elastic theory and measured using strain gauges for a steel beam. The correlation between these results is found to be excellent. DIC is then used to measure curvatures in RC beams and these results are compared with analytically predicted results with good agreement. The choice of an appropriate gauge length for RC is discussed and is shown to be one of the significant advantages of using DIC as opposed to strain gauges in both laboratory testing and field monitoring of bridge structures.