Mechanical interactions of micrometer-sized particles based on calibrated contact models

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Research and modelling of the contact behaviour between individual particles was the main objective in the first two working periods. In the final period of PiKo, the focus will be on the comparison between bulk experiments and experimentally calibrated DEM simulations using single particle interaction models. A cooperation between the research groups Dr. Zetzener (iPAT, Braunschweig) and Dr. Auernhammer (MPI for Polymer Research, Mainz) will be installed. Also a scientific exchange with Prof. Guido Grundmeier, Prof. Hans-Joachim Schmid (University of Paderborn) and Prof. Volker Schmidt (University of Ulm) is intended. Data gathered using available measurement equipment (X Ray micro-tomography, Braunschweig; confocal laser scanning microscope, Mainz) and new measuring tools (mixer model, Birkenfeld) will be shared between all groups. These experiments will be run using TiO2 agglomerates (Source: PiKo service project and Paderborn) and Maltodextrin. Based on common analysing tools from Mainz, Birkenfeld, Braunschweig and Ulm, the experimental data will be compared with DEM-simulations developed by TUHH. Due to this network of working groups, a more profound scientific understanding of interparticulate contacts in bulk materials will be achieved. Objective of this research is to use experimentally determined particle trajectories of irregularly shaped particles within bulk solids to validate simulations with highest accuracy. The interaction of particles under small normal forces will be measured and described based on the knowledge of the first periods. These interactions will be examined in a new experimental set-up, which will be realised in Birkenfeld in order to allow 3D measurement of mixing processes using X-Ray micro-tomography. As well as for DEM simulations these data will be used for validation purposes. Experiments related to the bulk behaviour with different modes of loading will also be carried out by Dr. Zetzener, iPAT and Dr.S. Aman, OVGU, resulting in experimentally determined material properties. DEM simulations based on these material properties will generate speed, force and contact distributions in combination with particle trajectories of individual particles. Additionally the stress on equipment walls and tools resulting from the bulk contact will be considered. Supporting DEM/FEM-simulations of collisions involving irregularly shaped particles will be carried out. The shape of these particles will be gathered by X-Ray micro-tomography (IMiP, iPAT). The collisions themselves will be analysed by high-speed cameras (TUHH). As a result the effect of particle morphology on contact properties can be studied. Also the DEM-software MUSEN will be further developed and enhanced by installing new software modules (indentation test, compression test, angle of repose), the implementation of multi-sphere-methods and the modelling of interparticulate binding forces in agglomerates.