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

大量的物理现象只有将材料内在微观结构的长度尺度上的小尺度过程纳入物理模型的制定中，才能被分析和理解。特别是对于在斯图加特大学的CRC 1313和EXC 2075卓越集群中研究的多孔介质中的耦合多相过程，在孔隙尺度上材料的实验表征和基于多尺度的建模方法的组合仍然是一个挑战。新型创新高分辨率表征方法的开发在现代建模方法的进步中发挥着关键作用。从X射线计算机断层扫描获得的数据可以用作直接数值模拟的源，也可以在基于连续介质的模型中的本构水平上进行集成。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。静态和准静态的情况可以可视化，并以三维的高空间分辨率进行分析。但通常孔隙空间形态以及（演化或受损）微观结构取决于所施加的应力状态和/或进一步的物理条件，如多相饱和多孔介质中的温度、湿度或流体分压。对于商业上可用的X射线计算机断层扫描设备或甚至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）的组合在当今仍然是非常苛刻的。限制例如是由于完全覆盖的X射线设备的空间限制，其不允许在X射线设备内进行任何复杂实验的设置。因此，不能应用机械单轴或多轴测试装置。这正是这个建议的目的所在！本提案所应用的X射线计算机断层扫描设备本质上将X射线计算机断层扫描与现代最先进的多轴测试设备相结合。因此，高精度测试装置允许针对复杂应力和变形状态对微结构材料进行组合的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，作为复杂材料的多尺度建模方法的后续开发的基础。除了纳米和微米聚焦X射线源和探测器外，它还包括一个高精度的测试设备，该设备具有两个旋转平台和两个由直线电机驱动的轴向可移动横梁。X射线源以及探测器在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.