DFG large-scale equipment computer tomography
Contact: Phlipp Grohn
The German Research Foundation (DFG) and the state of Rhineland-Palatinate have funded a new computed tomography laboratory with the TomoScope L computer tomography from Werth Messtechnik GmbH at the department of Mechanical Process Engineering.
The computer tomography is equipped with a dual X-ray tube system consisting of two transmission tubes (160 kV and 240 kV), each with a small focal spot (minimum focal spot diameter: 500 nm and 1.5 µm), and a high-resolution, large-area detector (approx. 400 mm x 400 mm with 4000 x 4000 pixels) (Figure 1). This configuration provides high, proven detail detectability of structures ≥ 1.1 µm and great flexibility to measure materials of different densities and sample thicknesses (e.g., aluminum, steel, titanium, ceramics, elastomers, hybrid plastics, fiberglass-reinforced plastics, etc.).
Micro-CT analyses are used for the following investigations:
- Mechanisms of structure formation of agglomerates
Relationships between the parameters of agglomeration processes and the microstructure and mechanical properties of agglomerates are investigated.
Micro-CT analyses can be used to obtain the microstructure data (primary particle packing, porosity, binder distribution, size and shape of solid bridges, coating layer thickness) that significantly influence agglomerate deformation and fracture. From this, conclusions can be drawn about the mechanisms of agglomerate formation in different processes. Figure 2 shows the micro-CT image of an agglomerate.
These µCT data are important for generating the microstructure in the simulation. For the simulation, the discrete element method (Figure 3) coupled with computational fluid dynamics (DEM-CFD) are used.
- Deformation and fracture behavior of particles and agglomerates
For modeling the deformation and fracture processes of particles and agglomerates, knowledge of the deformation (shape change) and fracture behavior (crack initiation locations, crack progression, size of fracture pieces) is necessary. These important data also serve to validate the DEM fracture models and can become with in-situ compression and tensile experiments of particles and agglomerates in the computer tomography.