3D Strain Mapping of Opaque Materials Using an Improved Digital Volumetric Speckle Photography Technique with X-Ray Microtomography

Abstract

Digital volumetric speckle photography (DVSP) method has been used to strain investigation in opaque materials. In this paper, an improved DVSP algorithm is introduced, in which a multi-scale coarse–fine subset calculation process and a subvoxel shifting technique are applied to increase accuracy. We refer to the new algorithm as Multi-scale and Subvoxel shifting Digital Volumetric Speckle Photography (MS-DVSP). The displacement and strain fields of a red sandstone cylinder exposed to uniaxial compression and a woven composite beam under three-point bending are mapped in detail. The characteristics of the interior deformation of the specimens are clearly depicted, thus elucidating the failure mechanism of the materials.

Ultrasonic Imaging of the Onset and Growth of Fractures Within Partially Saturated Whitby Mudstone Using Coda Wave Decorrelation Inversion

“…Time‐lapse synchrotron microtomography undoubtedly provides the highest spatial resolution, as it is able to resolve the detailed structure of macroscopic fractures (Kandula et al., 2018; Renard et al., 2017, 2018), and microscopic strain localization through digital volume correlations (Mao & Chiang, 2016; Mao et al., 2019; McBeck et al., 2018). The main limitation of this method is that it requires access to an X‐ray beam in a synchrotron of sufficient energy to image a sample housed within a bespoke pressure vessel.…”

Special Issue on Advances in Digital Image Correlation (DIC)

“…Increasingly, the measurement of 3D fields in material bulk (DVC) is leading mechanical engineers to rethink the way they conduct tests, developing, in addition to new image correlation algorithms, special machines that allow in-situ testing. This trend is illustrated in article [13]. Volume measurement with X-ray tomography is not the only volume imaging method of interest in mechanics.…”

Ultrasonic Imaging of the Onset and Growth of Fractures within Partially Saturated Whitby Mudstone using Coda-Wave Decorrelation Inversion

“…While there are several other techniques which provide spatiotemporal information on inelastic strain at in situ conditions, they often require substantial investment in equipment and postprocessing, or are inherently less sensitive to subtle localized microscopic changes. Time-lapse synchrotron microtomography undoubtedly provides the highest spatial resolution, as it is able to resolve the detailed structure of macroscopic fractures (Kandula et al, 2018;Renard et al, 2017Renard et al, , 2018, and microscopic strain localization through digital volume correlations (Mao & Chiang, 2016;Mao et al, 2019;McBeck et al, 2018). The main limitation of this method is that it requires access to an X-ray beam in a synchrotron of sufficient energy to image a sample housed within a bespoke pressure vessel.…”