Integrated high-resolution experimental in-situ X-ray Computed Tomography system

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A large number of physical phenomena can only by analyzed and understood, if small-scale processes on the length scale of the material inherent microstructure is included in the formulation of physical models. Especially for coupled multi-phase processes in porous media, investigated in the CRC 1313 and the cluster of excellence EXC 2075 at University of Stuttgart, the combination of experimental characterization of materials on the pore scale and multi-scale-based modelling approaches are still a challenge. The Development of novel innovative high-resolution characterization methods plays a key role in the advancement of modern modelling approaches. Data obtained from X-ray Computed Tomography could be either used as source for direct numerical simulations or integrated on the constitutive level in continuum-based models. For a large variety of porous materials which play a substantial role in environmental sciences and geosciences like sedimentary and crystalline rocks, granular matter, and soils etc., the pore space of the materials could be characterized with high-resolution X-ray Computed Tomography. Static and quasi-static situations could be visualized and analyzed with high spatial resolution in three dimensions. But often the pore space morphology as well as the (evolved or damaged) microstructure depends on the applied stress state and/or further physical conditions like temperature, humidity or partial fluid pressures in multiphase-saturated porous media. With commercially available X-ray Computed Tomography devices or even X-ray Microscopes, the combination of image-based characterization and physical, i.e. hydro-thermo-chemo-mechanically-coupled experiments is still very demanding in our days. Limitations are e.g. due to space limitations of fully covered X-ray devices which do not allow any setup of complex experiment within the X-ray device. Thus mechanical uni- or multi-axial testing devices cannot be applied. This is exactly the point where this proposal is aiming at! The applied X-ray Computed Tomography device of this proposal intrinsically combines X-ray Computed tomography with a modern state-of- the-art multi-axial testing device. As a result, the high precision testing device allows a combined experimental and image-based characterization of the micro-structured material for complex stress and deformation states. Therefore, the high-resolution X-ray Computed Tomography system includes complex in-situ experiments as basis for the subsequent development of multi-scale modelling approaches of complex materials. Besides nano- and micro-focused X-ray sources and detectors, it consists of a high precision testing device with two rotational stages and two axial movable traverses driven by linear motors. The X-ray sources as well as the detectors do not move during the X-ray scan. This guarantees a high-quality adjustment and calibration.