A multifunctional mechanical testing stage for micro x-ray computed tomography

An existing open and modular designed micro X-Ray Computed Tomography (μXRCT) system is extended by a test rig in order to combine mechanical and hydro-mechanical experiments with μXRCT characterization. The aim of the system is to cover the complete resolution range of the underlying μXRCT system in combination with a broad load capacity range. A characteristic feature of the developed setup is that it consists mainly of standard components. This makes the shown test rig potentially interesting for other researchers considering extending an existing μXRCT system with an apparatus for mechanical and hydro-mechanical in situ testing. For the load frame, an uniaxial 10 kN universal testing machine with a digital control system was employed, which was extended by two aligned rotational stages. The uniaxial load capacity is ±3.1 kN and can be combined with torque moments of up to ±15 N m both limited by the used rotational stages. The setup is designed in such a way that different x-ray transparent cells (flow cells, oedometer cells, triaxial cells, etc.) can be integrated to generate three-dimensional stress/strain states as required for porous media research. Three applications demonstrate the possible versatile use of the system. As part of these examples, we show how corresponding x-ray transparent cells are designed and implemented. Finally, we discuss the presented approach's technical advantages and disadvantages and suggest improvements.