Mechanical Interactions of Solid Particles Based on Experimentally Calibrated Contact Models

Dr.-Ing. Sergii Kozhar

Motivation

During the various manufacturing processes and transportation steps, the behaviour of industrial granular materials is strongly affected by time-dependent particle-particle, particle-apparatus and particle-gas/liquid interactions. To numerically simulate these interactions in particle collectives, the discrete element method (DEM) is widely used. The selection of inappropriate contact models of particle-particle/particle-wall interactions or wrong material parameters in DEM can lead to erroneous results. Therefore, to estimate material parameters the experimental investigations must be performed.

Aims of the projects

The goal of this research is to investigate experimentally the mechanical properties of fine particles with diameter of 20…100 µm at contact interactions and to describe particles behavior with different contact models which must be implemented into DEM-code. To this end, the contact model parameters are validated by real experiments including compression, torsional and shear loading of single granules (Figure), performed at the Institute for Micro-Process-Engineering and Particle Technology, Environmental Campus Birkenfeld (Prof. Dr.-Ing. U. Bröckel).

Methods

Often it is assumed that particles have spherical shape in DEM simulations of granular materials. Such assumption can lead to wrong numerical results, since a spherical particle behaves different than a particle with a complex shape. To overcome this deviation, the multi-sphere approach (MSA) and bonded-particle model (BPM) combined with X-ray computer tomography can be employed. The former mimics the shape of an irregular particle with a set of overlapped non-interacting spheres (Figure a). According to the shape representation in the bonded-particle model, the granule with complex shape is composed of an assembly of primary particles, which are connected with the solid bond material (Figure b). In order to mimic the influence of the particle shape on force-displacement curve, additional finite element simulations can be carried out (Figure c).

Selected publications

Gilson L., Kozhar S., Antonyuk S., Bröckel U., Heinrich S. (2013). Contact models based on experimental characterization of irregular shaped, micrometer-sized particles. Granular Matter 16, 313-326.
Kozhar S., Antonyuk S., Heinrich S., Gilson L., Bröckel U.. (2014). Numerical and Experimental Study of Micrometer-sized Titanium Dioxide Agglomerates, Presentation at WCPT7, China.
Funding: German Research Foundation (DFG), SPP 1486 “PiKo (Particles in contacts)”  
Cooperation partners
Institute for Micro-Process-Engineering and Particle Technology, Environmental Campus Birkenfeld, Birkenfeld, Germany (Prof. Dr.-Ing. U. Bröckel)

Project funding

German Research Foundation (DFG), SPP 1486 “PiKo (Particles in contacts)”

Cooperation partners

Institute for Micro-Process-Engineering and Particle Technology, Environmental Campus Birkenfeld, Birkenfeld, Germany (Prof. Dr.-Ing. U. Bröckel)

Contact Details

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