Browsing by Author "Blecha, Christian"

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    Visual Analysis of a Full-Scale-Emplacement Experiment in the Underground Rock Laboratory Mont Terri using Fiber Surfaces
    (The Eurographics Association, 2020) Raith, Felix; Blecha, Christian; Rink, Karsten; Wang, Wenqing; Kolditz, Olaf; Shao, Hua; Scheuermann, Gerik; Dutta, Soumya and Feige, Kathrin and Rink, Karsten and Zeckzer, Dirk
    In the Underground Rock Laboratory Mont Terri, research has been conducted for over 20 years into the storage of radioactive waste in Opalinus Clay. The fitness for such storage depends on the prevailing geological material. Experiments and multiphysics simulations investigate the long-term changes in the Opalinus Clay. The resulting data are highly multivariate, and environmental scientists visually analyze the data using predefined color lookup tables. The fiber surfaces of Raith et al. offer the researchers a new approach for visual analysis. However, the existing algorithm for the calculation is subject to certain limitations due to special cases that lead to no or incomplete fiber surfaces. In this paper, we improve the fiber surface algorithm of Raith et al., which reduces numerical errors and accelerates the existing algorithm. This improvement also makes it possible that the interactor no longer needs to be closed and convex. We then use the Full-Scale Emplacement Experiment to show how the improved algorithm can help in the visual analysis of multivariate data.
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    Visual Analysis of the Relation Between Stiffness Tensor and the Cauchy-Green Tensor
    (The Eurographics Association, 2021) Blecha, Christian; Hergl, Chiara; Nagel, Thomas; Scheuermann, Gerik; Agus, Marco and Garth, Christoph and Kerren, Andreas
    Stress and strain tensors, two well-known quantities in mechanical engineering, are linked through a fourth-order stiffness tensor, which is not considered by many visualizations due to its complexity. Considering an orthotropic material, the tensor naturally decomposes into nine known material properties.We used fiber surfaces to analyze a data set representing a biological tissue. A sphere is pushed into the material to confirm the mathematical link as well as the possibility to extract highly deformed regions even if only the stiffness tensor is available.
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    Visualization of Tensor Fields in Mechanics
    (© 2021 Eurographics ‐ The European Association for Computer Graphics and John Wiley & Sons Ltd, 2021) Hergl, Chiara; Blecha, Christian; Kretzschmar, Vanessa; Raith, Felix; Günther, Fabian; Stommel, Markus; Jankowai, Jochen; Hotz, Ingrid; Nagel, Thomas; Scheuermann, Gerik; Benes, Bedrich and Hauser, Helwig
    Tensors are used to describe complex physical processes in many applications. Examples include the distribution of stresses in technical materials, acting forces during seismic events, or remodeling of biological tissues. While tensors encode such complex information mathematically precisely, the semantic interpretation of a tensor is challenging. Visualization can be beneficial here and is frequently used by domain experts. Typical strategies include the use of glyphs, color plots, lines, and isosurfaces. However, data complexity is nowadays accompanied by the sheer amount of data produced by large‐scale simulations and adds another level of obstruction between user and data. Given the limitations of traditional methods, and the extra cognitive effort of simple methods, more advanced tensor field visualization approaches have been the focus of this work. This survey aims to provide an overview of recent research results with a strong application‐oriented focus, targeting applications based on continuum mechanics, namely the fields of structural, bio‐, and geomechanics. As such, the survey is complementing and extending previously published surveys. Its utility is twofold: (i) It serves as basis for the visualization community to get an overview of recent visualization techniques. (ii) It emphasizes and explains the necessity for further research for visualizations in this context.