Comparison of different capillary bridge models for application in the discrete element method

Weakly wetted granular material is the subject of many studies. Several formulations were proposed to calculate the capillary forces between wet particles. In this paper some of such models have been implemented in a DEM-framework, and simulation results were compared to experimental measurements. Also, the influence of capillary model type on macro parameters like local shear viscosity and cohesive parameters of sheared material have been investigated through the simulation of spherical beads using a DEM-model of a split-bottom shear-cell. It was concluded that the water content, simulated with the help of capillary bridge models, changes the macro-properties of the simulated granular material. Different capillary bridge models do not influence the macroscopic results visibly

Discrete element modeling of deformable particles in YADE

In this paper we describe the open-source discrete element framework YADE and the implementation of a new deformation engine. YADE is a highly expandable software package that allows the simulation of current industrial problems in the field of granular materials using particle-based numerical methods. The description of the compaction of powders and granular material like metal pellets is now possible with a pure and simple discrete element approach in a modern DEM-framework. The deformation is realized by expanding the radius of the spherical particles, depending on their overlap, so that the volume of the material is kept constant. Keywords: YADE, Discrete element method, Granular materials, Deformatio

Discrete element modeling of deformable particles in YADE

In this paper we describe the open-source discrete element framework YADE and the implementation of a new deformation engine. YADE is a highly expandable software package that allows the simulation of current industrial problems in the field of granular materials using particle-based numerical methods. The description of the compaction of powders and granular material like metal pellets is now possible with a pure and simple discrete element approach in a modern DEM-framework. The deformation is realized by expanding the radius of the spherical particles, depending on their overlap, so that the volume of the material is kept constant. Keywords: YADE, Discrete element method, Granular materials, Deformatio

Rheology of weakly wetted granular materials - a comparison of experimental and numerical data

Shear cell simulations and experiments of weakly wetted particles (a few volume percent liquid binders) are compared, with the goal to understand their flow rheology. Application examples are cores for metal casting by core shooting made of sand and liquid binding materials. The experiments are carried out with a Couette-like rotating viscometer. The weakly wetted granular materials are made of quartz sand and small amounts of Newtonian liquids. For comparison, experiments on dry sand are also performed with a modified configuration of the viscometer. The numerical model involves spherical, monodisperse particles with contact forces and a simple liquid bridge model for individual capillary bridges between two particles. Different liquid content and properties lead to different flow rheology when measuring the shear stress-strain relations. In the experiments of the weakly wetted granular material, the apparent shear viscosity TeX scales inversely proportional to the inertial number TeX, for all shear rates. On the contrary, in the dry case, an intermediate scaling regime inversely quadratic in TeX is observed for moderate shear rates. In the simulations, both scaling regimes are found for dry and wet granular material as well