@article{PowierzaGollwitzerWolgastetal.2019,
  author    = {Powierza, Bartosz and Gollwitzer, Christian and Wolgast, Dagmar and Staude, Andreas and Bruno, Giovanni},
  title     = {Fully experiment-based evaluation of few digital volume correlation techniques},
  series = {Review of scientific instruments : a monthly journal devoted to scientific instruments, apparatus, and techniques},
  volume    = {90},
  journal   = {Review of scientific instruments : a monthly journal devoted to scientific instruments, apparatus, and techniques},
  number    = {11},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0034-6748},
  doi       = {10.1063/1.5099572},
  pages     = {10},
  year      = {2019},
  abstract  = {Digital Volume Correlation (DVC) is a powerful set of techniques used to compute the local shifts of 3D images obtained, for instance, in tomographic experiments. It is utilized to analyze the geometric changes of the investigated object as well as to correct the corresponding image misalignments for further analysis. It can therefore be used to evaluate the local density changes of the same regions of the inspected specimens, which might be shifted between measurements. In recent years, various approaches and corresponding pieces of software were introduced. Accuracies for the computed shift vectors of up to about 1 parts per thousand of a single voxel size have been reported. These results, however, were based either on synthetic datasets or on an unrealistic setup. In this work, we propose two simple methods to evaluate the accuracy of DVC-techniques using more realistic input data and apply them to several DVC programs. We test these methods on three materials (tuff, sandstone, and concrete) that show different contrast and structural features. Published under license by AIP Publishing.},
  language  = {en}
}
@article{MuellerCooperLangeetal.2017,
  author    = {M{\"u}ller, B. R. and Cooper, R. C. and Lange, A. and Kupsch, Andreas and Wheeler, M. and Hentschel, M. P. and Staude, A. and Pandey, A. and Shyam, A. and Bruno, Giovanni},
  title     = {Stress-induced microcrack density evolution in beta-eucryptite ceramics},
  series = {Acta materialia},
  volume    = {144},
  journal   = {Acta materialia},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {1359-6454},
  doi       = {10.1016/j.actamat.2017.10.030},
  pages     = {627 -- 641},
  year      = {2017},
  abstract  = {In order to investigate their microcracking behaviour, the microstructures of several beta-eucryptite ceramics, obtained from glass precursor and cerammed to yield different grain sizes and microcrack densities, were characterized by laboratory and synchrotron x-ray refraction and tomography. Results were compared with those obtained from scanning electron microscopy (SEM). In SEM images, the characterized materials appeared fully dense but computed tomography showed the presence of pore clusters. Uniaxial tensile testing was performed on specimens while strain maps were recorded and analyzed by Digital Image Correlation (DIC). X-ray refraction techniques were applied on specimens before and after tensile testing to measure the amount of the internal specific surface (i.e., area per unit volume). X-ray refraction revealed that (a) the small grain size (SGS) material contained a large specific surface, originating from the grain boundaries and the interfaces of TiO2 precipitates; (b) the medium (MGS) and large grain size (LGS) materials possessed higher amounts of specific surface compared to SGS material due to microcracks, which decreased after tensile loading; (c) the precursor glass had negligible internal surface. The unexpected decrease in the internal surface of MGS and LGS after tensile testing is explained by the presence of compressive regions in the DIC strain maps and further by theoretical arguments. It is suggested that while some microcracks merge via propagation, more close mechanically, thereby explaining the observed X-ray refraction results. The mechanisms proposed would allow the development of a strain hardening route in ceramics.},
  language  = {en}
}