Discrete Element Method

• Periodic boundary conditions are an important tool for the simulation of space with unlimited extend that is continuously filled with matter of a specific type. The example shows a simple simulation with 3D periodic boundary conditions and Pasimodo's contact model for non-convex polyhedral geometries. For a better perception of the periodicity of the simulation domain, it can be useful to concentrate on the red torus while viewing the video in a loop.

  Implementation and model creation: Florian Fleißner



• Bonding of particles with beam-elements. The deformation is computed from the relative positions and orientations of the connected particles. Model development and implementation: Martin Obermayr (Fraunhofer ITWM)


• The contact point between ellipsoids is computed by an optimization procedure. The frames indicate the current closest points on both particles. The optimization loop is interupted in case of no contact. Model development and implementation: Martin Obermayr (Fraunhofer ITWM)


• 1152 hard cubes are falling on a rigid support. Simulation including sticking and slipping friciton. Model creation: Frank Nägele (student research project), Florian Fleißner


• Particles can be arbitrarily assembled to compounds. Model creation: Florian Fleißner


• Granular flow through a hopper with different particle coloring. Model creation: Florian Fleißner


• Particle flow with rigid obstacles represented by 3D-surface meshes. Note the very different behavior of the medium with (left) and without (right) the consideration of sticking, slipping and drilling friction and the rolling resistance. Model creation: Florian Fleißner


• Arbitrary non-convex CAD-geometries as e.g. the shop cart geometry below, can be imported e.g. as STL-files. Model creation: Florian Fleißner


• Identification of the piling angle of glass beads. To allow for a better perception of the rotation, the beads are colored with a checkered color pattern. The simulations consider sticking friction, slipping friction and drilling friction and, moreover, the rolling resistance of the glass beads. Model creation: Florian Fleißner


• Simulation of a laboratory test to determine the performance of a flow obstacle. The performance is defined as the obstacle's capability to reduce the flow momentum. Model creation: Florian Fleißner


• Interactions between rigid macro-bodies and particles. To obtain a steady flow, particles are created and removed via particle sources and sinks during the simulation. Model creation: Florian Fleißner


• Particle sources can move freely. Model creation: Florian Fleißner


• Examples for different ways of flow visualization for particle systems. Bounding boxes with velocity glyphs, streamlines, surface reconstruction and transparent surface with particles. Model creation: Florian Fleißner


• Particle driven water wheel. Model creation: Florian Fleißner


• Simulation of a tumble sieving machine. Model creation: Christian Ergenzinger (diploma thesis), Florian Fleißner


• Simulations of a double lane change maneuver of a single-compartment tank truck carrying a granular cargo. The simulations were performed as co-simulations between Pasimodo (granulate) and Simpack (multibody system of the truck) with a data exchange via Matlab/Simulink and TCP/IP connections. The maneuver is depicted with a track velocity of v=17.5 m/s on the left and a track velocity of v=20 m/s on the right. Model creation: Vincenzo D'Alessandro (master thesis), Florian Fleißner

Hybrid Discrete Element Method

• Simulation of an orthogonal cutting process. Model creation: Timo Gaugele, in the framework of the DFG Priority Program SPP 1180


• Simulation of a tensile test with a highly elastic polysiloxane specimen. Model creation: Christian Ergenzinger


• Ballast made from bonded particles is subjected to different loadings:
  1. Cyclic compression.
  2. Oedometric compression. (Firstly, all particles are shown in the movie. Subsequently, only those particles are displayed, which are involved in fracture processes.)
  3. A sleeper is pressed into a ballast bed.

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  2.

  3.

  Model creation: Christian Ergenzinger in the framework of the DFG SFB 716


• Simulation of a multiaxial copression test with a rock specimem (breakage color coded). Model creation: Celine Geiger (student research project), Christian Ergenzinger


• Oblique rebound of an elastic sphere from a rigid plane. Model creation: Florian Fleißner


• Simulation of a nearly limp membrane falling on an obstacle. Model creation: Florian Fleißner


• Torus falling on a membrane. The membrane consists of bonded spherical particles. Only the bonds are displayed and color coded with respect to the tensile force in the bonds. Model creation: Florian Fleißner


• Simulation of a plastic string dangling under gravity. Model creation: Timo Gaugele


• Simulation of wattling with five threads, modelled as beaded spherical particles. The spheres are bonded by linear-elastic force elements. Model creation: Florian Fleißner

Smoothed Particle Hydrodynamics

• Simulation of a rigid sphere falling in a liquid tank.
  Model creation and simulation: David Vetsch (Laboratory of Hydraulics Hydrology and Glaciology of Swiss Federal Insitute of Technology Zurich)


• Simulation of a filling process.
  The video shows the outpouring of water from a nozzle into a stand-up pouch.
  
  Model creation: Alexandra Müller


• Simulation of a freezing process.
  The temperature of the particles on the upper border as well as those in the center is fixed over time.
  Frozen particles are shown larger than liquid ones.
  
  Model creation: Alexandra Müller


• Simulation of a laser welding process of aluminum.
  The workpiece is located on an inclined plane and the initial temperature is 20 °C.
  During the simulation, a weld pool is formed and the molten material flows downward.
  
  Model creation: Haoyue Hu


• Simulation of a phase transition during laser welding of aluminum.
  The blue solid particles behave thermoelastically, whereas the red fluid particles follow the Navier-Stokes equations and form the weld pool.
  
  Model creation: Haoyue Hu


• Simulation of deep penetration laser welding of aluminum.
  The grey particles form the solid material, the blue particles form the liquid weld pool, and the light grey particles show the resolidified material.
  Evaporation is considered through recoil pressure on the liquid melt, the gas phase is currently not modeled.
  
  Model creation: Haoyue Hu


• Simulation of deep penetration laser welding of ice.
  On the left, the light grey particles form the solid ice block and the blue particles form the liquid weld pool (water).
  Evaporation is considered through recoil pressure on the liquid melt, the gas phase is currently not modeled.
  On the right, the absorbed intensities (max: red, min: blue) from the laser beam at the capillary front are visualized using a ray-tracing scheme developed at the IFSW.
  Model creation: Haoyue Hu


• Simulation of two immiscible fluids with different densities in a breaking dam scenario.
  
  Model creation: Weiran Lin (student research project), Haoyue Hu


• A Rayleigh-Taylor instability occurs at the interface between two fluids of different densities when the fluids are accelerated against each other.
  
  Model creation: Weiran Lin (student research project), Haoyue Hu


• Simulations involving elastic materials including tensile failure.
  The particles are coloured according to either damage from 0 (undamaged) to 1 (completely damaged) or von Mises tension.
  

  Shear test of basalt. The material on the upper border is pushed to the right.		Tensile test of basalt. The last columns of particles on the right are pulled towards outwards.		Tensile test of basalt with notches.

  Compact tension test (CT test, DIN EN ISO 12737) aluminium. A notched sample is pulled asunder above and below the notch.

  Model creation: Thomas Erk (student research project), Alexandra Müller
  
  
  Charpy impact test (DIN 10045) used to characterize the behavior of material AlMg3 under impact loading.
  The rigid body model of the hammer deforms the notched specimen and is slowed down.
  
  Model creation: Fabian Spreng


SPH simulation of an orthogonal cutting process for the heat-treated steel C45E with a cutting speed of 1.6 m/s (blue = low von Mises equivalent stress; red = high von Mises equivalent stress).

Model creation: Fabian Spreng


Adaptive SPH simulation of an orthogonal cutting process for the aluminium alloy AlMg3 with a cutting speed of 1.6 m/s (blue = original particles; red = refined particles).

Model creation: Fabian Spreng


Three-dimensional SPH simulation of a cutting process for the heat-treated steel C45E with a cutting speed of 1.6 m/s (blue = low von Mises equivalent stress; red = high von Mises equivalent stress).

Model creation: Fabian Spreng


• Simulations involving elastic materials.
  The particles are coloured according to von Mises tension.

  Collision of elastic rings.		Oscillating plate. The plate is fixed on the left end and is deflected on the right side by an imposed velocity.

  Model creation: Alexandra Müller


• Simulation of sloshing liquids dependent on the viscosity.

  0.001Pas		1Pas		100Pas

  Model creation: Alexandra Müller


• Adaptive SPH simulation of a breaking dam with two obstacles (blue = original particles; red = refined particles).
  
  
  
  Implementation SPH-plugin and plugin for adaptive refinement/coarsening: Alexandra Müller
  
  Model creation and simulation: Dirk Schnabel, Fabian Spreng


• Simulation of sloshing liquids in tank trucks. Model creation: Alexandra Müller, Florian Fleißner


• Smoothed Particle Hydrodynamics simulations, some of them coupled with Discrete Element simulations. Model creation: Alexandra Müller (diploma thesis), Florian Fleißner

Links

Contact

• Dr.-Ing. Florian Fleißner