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

大量的物理现象只有在将材料固有微观结构的长度尺度上的小尺度过程纳入到物理模型的制定中，才能被分析和理解。特别是对于多孔介质中的耦合多相过程，在CRC 1313和斯图加特大学的卓越集群EXC 2075中进行了研究，将孔隙尺度上的材料实验表征和基于多尺度的建模方法相结合仍然是一个挑战。新型创新的高分辨率表征方法的发展对现代建模方法的进步起着关键作用。从x射线计算机断层扫描获得的数据既可以用作直接数值模拟的来源，也可以在基于连续体的模型中集成本构水平。对于在环境科学和地球科学中发挥重要作用的各种多孔材料，如沉积岩和结晶岩，颗粒物质和土壤等，材料的孔隙空间可以用高分辨率x射线计算机断层扫描来表征。静态和准静态情况能够以高空间分辨率进行三维可视化和分析。但通常孔隙空间形态以及（演化或破坏）微观结构取决于施加的应力状态和/或进一步的物理条件，如多相饱和多孔介质中的温度、湿度或分流体压力。利用市售的x射线计算机断层扫描设备甚至x射线显微镜，基于图像的表征和物理（即水-热-化学-机械耦合实验）的结合在我们的时代仍然非常苛刻。例如，由于全覆盖x射线设备的空间限制，不允许在x射线设备内设置任何复杂的实验。因此机械单轴或多轴试验装置不能应用。这正是这个提议的目的所在！本建议的应用x射线计算机断层扫描设备本质上结合了x射线计算机断层扫描与现代最先进的多轴检测设备。因此，高精度测试装置允许对复杂应力和变形状态的微结构材料进行结合实验和基于图像的表征。因此，高分辨率x射线计算机断层扫描系统包括复杂的原位实验，为后续开发复杂材料的多尺度建模方法奠定基础。除了纳米和微聚焦x射线源和探测器外，它还包括一个具有两个旋转级和两个轴向可移动导线的高精度测试装置，该装置由直线电机驱动。x射线源和探测器在x射线扫描期间不移动。这保证了高质量的调整和校准。

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.