MV-7021: MotionSolve/EDEM Co-Simulation

In this tutorial, you will learn about the set-up and co-simulation of MotionSolve and EDEM through MotionView.

MotionSolve has the ability to interface with Altair EDEM, a state-of-the-art bulk material simulation tool. EDEM is based on the Discrete Element Method (DEM) that simulates and analyzes the behavior of bulk materials such as sand, granules, capsules, grass, rock masses etc. For more information about this method refer to www.edemsimulation.com and the Discrete Element Simulation in MotionSolve topic in the MotionSolve User Guide.

This tutorial assumes minimum knowledge in both Altair’s MotionSolve/MotionView and EDEM.

Requirements
The following pre-requisites are necessary for a successful interaction between MotionSolve and EDEM:
Software Version
HyperWorks 2019.1 or later for rigid body coupling

2021 or later for flexible body coupling
EDEM 2019.1 or later for rigid body coupling

2020.3.1 or later for flexible body coupling
Problem Definition
The problem consists of a wheel, that can only rotate around its center. A number of particles is impinged on the wheel blades, causing it to rotate. The wheel is modeled in MotionSolve, while the particles and its interaction with the wheel is modeled in EDEM. A rigid Wheel to particle interaction is set up first. The wheel is later replaced with a flexible body to show flexible body to particle interaction.
Both the wheel and the particle data are given in the table below:
Property Units Values
Particles (Bulk material)
Radius [m] 0.10
Poisson's ratio [-] 0.25
Density [kg/m3] 2500
Shear Modulus [Pa] 108
Wheel (Equipment material)
Poisson's ratio [-] 0.30
Density [kg/m3] 7860
Shear Modulus [Pa] 80.77.109

Set Up the Motion Model

  1. Copy the wheel.step file located in the mv_hv_hg\mbd_modeling\motionsolve\cosimulation\edem folder into your working directory.
  2. Open a new session of MotionView.
  3. Click on Import Geometry, , from the Standard toolbar.
    The Import Geometry dialog is displayed.
  4. Click the File browser , locate and select the wheel.step file from your <working directory>.
  5. Click OK.


    Figure 1. Model in MotionView after wheel geometry import
  6. Right-click on the Joint icon from the Constraint toolbar.
    The Add Joint or JointPair dialog is displayed.
  7. Select Revolute Joint from the drop-down list.
  8. Click OK.
  9. In the Joint panel that appears, select the wheel and Ground Body as Body 1 and Body 2 collectors respectively.
  10. Double click on the Point collector of Origin, navigate to the Bodies > Wheel > Inertia Props and select cg.


    Figure 2. Select a Point dialog to select the CG of the wheel body
  11. Click OK.
  12. Change the Alignment Axis type to Vector and select Global Z.
  13. From the Project Browser, select Solver Gravity dataset and set Gravity in the Y direction to -9810.


    Figure 3. Dataset - Solver Gravity
  14. Save the model as wheel.mdl.

Set Up the EDEM Model

Next, we will set up the EDEM model. EDEM modeling for this example broadly assumes the following steps that are detailed out further below:
  • Define a bulk material
  • Define a particle shape
  • Define an equipment material
  • Define the equipment geometry
  • Define a virtual geometry/particle factory
  • Define environment parameters
  • Define the simulation options
  1. Open EDEM 2019.1 or later.
  2. In the Creator Tree, right click on Bulk Material and select Add Bulk Material.
    A new material named 'BulkMaterial 1' is created. Leave the material properties unchanged.
  3. Click on + under Interaction.
  4. Select BulkMaterial1 in the pop-up window.
  5. In the Creator Tree, right-click on BulkMaterial1 (which was just added) and select Add Particle.
  6. Select Single Sphere from the Shape Library, shown in the section below the Creator tree, and set the Physical Radius (m) to 0.1.


    Figure 4. Particle Shape Library
    1. Optional: Due to the change in particle size, you can reset the view of the particle by selecting on the View panel.
  7. Go to Properties under the New Particle 1 in the Creator Tree and select Auto Calculation.
    The particle geometry is defined now. Next, we will define the equipment material which represents the material properties for the wheel in EDEM.
  8. In the Creator Tree, right-click on Equipment Material and select Add Equipment Material.
    A new material named 'EquipmentMaterial 1' is created.
  9. Change the Solids density() to 7860 and Shear Modulus(G) to 80.77e9.
  10. Click on + under Interaction.
  11. In the pop-up window, click OK for BulkMaterial1.
  12. From the toolbar on the top, click on the Start Coupling Server icon to turn on the coupling server.


    Figure 5. Turning on the coupling server
    This setting allows coupling with MotionView and MotionSolve.
  13. Return to MotionView and click on the EDEM Subsystem icon from the Bulk Material Interface toolbar.


    Figure 6. EDEM Subsystem Toolbar
  14. In the panel that appears, define the EDEM server on the right side of the panel.
    1. For EDEM server, choose between Local or Remote. Select Local if EDEM and MotionView/MotionSolve are on the same machine. Select Remote if EDEM resides on a different machine.
    2. If Remote has been selected, you will have to define the settings for the remote co-simulation, which are defined in the Bulk Material Interaction topic.
    3. Click on the Graphics collector and select the wheel graphics.
  15. Click on Transfer to EDEM.
  16. Switch to the EDEM graphical user interface and observe the process of geometry being imported.
  17. Once the import process is complete, click on the drop-down menu within the View section on the toolbar and select the -Z view and zoom in.


    Figure 7. View Section
    The graphic screen should appear as shown below:


    Figure 8. Wheel geometry in EDEM
    Observe the component under Geometries in the Creator tree. The wheel has the name 'component_0000'.
    Note: For components that interface with MotionSolve, the name should follow the convention 'component_0000, component_0001' and so on.
    Next, we will set up the geometry for the particle factory.
  18. In the Creator Tree, right-click on Geometries and select Add Geometry and then Polygon.
    A geometry with the name 'New Section 1' is added.
  19. Change the Type from Physical to Virtual.


    Figure 9. Polygon geometry for the particle factory
  20. Select Transform under 'New Section 1' and set the following properties:
      Position Rotation
    X 1.6 1.5708
    Y 1.7 0
    Z 0 0


    Figure 10. Transform section of the Polygon
  21. Select Polygon under 'New Section 1' and set the following properties.
      Length
    Edge A 0.2
    Edge B 0.2


    Figure 11. Polygon properties
  22. Right-click on New Section 1 and select Add Factory.
  23. Set the Target number (per second) equal to 5.
  24. Set bcc in Position.


    Figure 12. Adding Factory
  25. Click on the gear icon to display the Position - Lattice Parameters dialog.
    1. Under Start Point, set X and Y to 1.6 and 1.7 respectively.
    2. Leave the remaining fields set to the default values.


    Figure 13. Position - Lattice Parameters
  26. In the Creator Tree, select Environment and set the Gravity – Y to -9.81.


    Figure 14. Setting gravity
  27. Save the model as model.dem using the File menu or Save icon on the top toolbar.

Simulation Set Up in EDEM

  1. Switch to the Simulator.


    Figure 15. Simulator icon on the toolbar
  2. Deselect the Auto Time Step check box and set the Time Step equal to 1e-5.


    Figure 16. Simulator settings
  3. Click on Estimate Cell Size and accept the derived cell size.


    Figure 17. Estimating cell size
  4. Confirm that the Coupling Server is on.
    Tip: Hovering over the icon should show a tool tip text similar to “Listening on port 32969”.
The EDEM model is now ready to simulate with MotionSolve.

Create an EDEM System

  1. Return to MotionView. Dismiss the Message Log if it is displayed.
  2. In the Discrete Element Method panel, with the wheel graphics being selected, click on Create EDEM System.
    A system called 'DEM 0' is added to the MotionView model. This system contains all of the necessary entities for MotionSolve to simulate with EDEM.
  3. Save the model.

Run the Simulation

  1. Go to the Run panel .
  2. Click on Simulation Settings and go to the Transient tab.
    1. Set Maximum step size to 0.001.
    2. Close the dialog.
  3. Change the End time to 10.
  4. Click on the Run button to start the simulation.
    MotionSolve is invoked and the simulation should also begin on EDEM side. The simulation process should also be visible in EDEM.


    Figure 18. EDEM graphic screen during simulation
  5. In EDEM, Click on Auto update on the top toolbar to update the graphic visualization as simulation progresses.


    Figure 19. Auto update
  6. Once the simulation is complete, close the MotionSolve solver window.

Post-processing

For components that are interacting in EDEM, the animation can be visualized in EDEM through the Analyst page.

  1. Click on the Analyst icon in the toolbar.


    Figure 20. Analyst icon on the toolbar
  2. Reset the animation with the toolbar at the bottom.


    Figure 21. Animation bar in EDEM
  3. Click the Animate Forwards icon .
  4. Translate EDEM particle results to HyperView H3D.
    1. In MotionView, from the EDEM menu, select Generate H3D from EDEM results.
    2. Provide the DEM file as input.
    3. Click OK.
      The file model_edem.h3d is generated.
  5. Visualize the animation in HyperView.
    1. From the MotionView Run panel, click Animate to load the MotionSolve H3D result in a HyperView window.
    2. In HyperView, activate the Overlay check box in the Load Model panel.
    3. Use the Open Model file browser to locate and select the model_edem.h3d file from the working directory.
    4. Click Apply (answer Yes to the pop-up warning message).
    5. Animate using the Start/Pause Animation button .

Flexible Body Coupling

Setting up and running a co-simulation with a flexible body follows the same steps as those performed with a rigid body in the previous step.
Note: A flexible body interaction can be set up directly. It's not necessary to perform its rigid body interaction first.

An equivalent flexible body H3D file of the wheel is available.

  1. Copy the file flex_wheel_flex_blades.h3d, located in the mv_hv_hg\mbd_modeling\motionsolve\cosimulation\edem folder to your working directory
  2. The flexible body is created with the following features:
    • The rotor elements are assigned the material property steel.
    • The blade element material has a material with 10% of Modulus of elasticity and density as steel.
    • The center node is connected to the nodes on the inner surface of the rotor using rigid (RBE2 elements).
    • The center node and a node on each blade (arbitrary) has been selected as interface nodes for an adequate modal representation.


    Figure 22.
  3. Return to the MotionView window.
  4. Select the DEM system (DEM_0), deactivate it through the right-click context menu Deactivate > Selected only.
  5. Select the body (wheel_90000) from the Model browser or through the graphics area.
  6. From the Body panel, active Flex Body (CMS).
  7. Select the flexible body H3D file flex_wheel_flex_blades.h3d as the Graphical source.
  8. If a confirmation dialog prompts you to confirm the use of the same file as the Functional source, click Yes.
  9. Click Nodes….
  10. Find a node in the flexible body corresponding to the center joint location by clicking either Find All or Find on the row entry for the Joint Marker.
  11. Close the dialog.
  12. In the EDEM GUI, click Creator to return to the creator context.
  13. Reset the time to 0 s.
  14. Select the wheel component (component_0000) and delete it.
  15. Save the EDEM file as model_flex.dem.
  16. Click Simulator, . Change the Total time under Simulation Time to 5s (to match with the End time in MotionView Run panel)
  17. In MotionView, load the EDEM System panel.
  18. Change the collector to the Body collector. Pick the wheel (flex) body.
  19. Click Transfer to EDEM.
    The flex body should be transferred to EDEM and displayed as flex_component_0000.
  20. Click Create EDEM system.
    A new DEM system is created.
  21. Go to the Run panel. Change the XML filename to wheel_flex.xml.
  22. Click Run.
  23. Once the run is complete, follow the procedures mentioned in Post-processing, steps 4 and 5, to visualize the results