Define the Bulk Material

The first step in setting up the model is to add a bulk material, particle shapes, and their associated interaction properties.

To define the bulk material:
  1. Add the bulk material.
    1. Right-click Bulk Material in the Creator Tree, select Add Bulk Material , and enter the name 'rock' in the Material highlighted field. Alternatively, you can also use the icons in the Toolbar.
  2. Define the bulk material properties.
    1. Select rock in the Bulk Material section.


    2. In the rock Properties dialog box, specify the Poisson's Ratio, Solids Density, and Shear Modulus.
  3. Define the bulk material interactions.
    1. In the Interactions section, click the icon.
    2. In the Select Material dialog box, select rock from the dropdown list to define the interaction between all elements made of the material 'rock'.
    3. Specify the coefficients as follows:


  4. Create a new particle shape after defining the bulk material and interaction properties.
    1. Right-click rock in the Bulk Material section and then select Add Particle > Add Multi-Sphere.
    2. Enter the name 'rock Particle' in the Particle highlighted field.

      Optionally, you can rename the particle by right-clicking the particle and selecting Rename Particle.

  5. Define the spheres and properties.
    Note: Multi-Sphere particles are made up of one or more spheres. In this tutorial, we are going to import a CAD template of a rock and fit four spheres to the template shape.
    1. In the right-hand corner, in the Templates section, click Edit....
    2. In the Import dialog box, click Import... and navigate to the folder that contains the mesh file that will be used as the template.
    3. In the Import Options dialog box, specify the units of measurement to Millimeters (mm).
    4. In the Mesh Control type ensure that all the settings have the default values and then click OK.
      Note: In this lesson, we are importing the particle template rock_particle.stl. The STL file format is already meshed, and changing the meshing options does not impact the mesh of the imported template. For other file formats such as STEP or IGES, you can modify the Geometry/template mesh by changing the element size options in the Import dialog box.
    5. Click the icon.
    6. Rename the template to Rock Template, and then click OK.
    7. On the right-hand corner, in the Templates section, select Rock Template from the Display Templates dropdown list.


    8. In the Creator Tree, select the rock particle and then select Modify Shape in the Detailed View section.
    9. Select Single Sphere from the Shape Library as follows:


    10. In the rock particle Spheres section, under the Viewer, change the Physical Radius of the sphere from 0 to 18 mm and the Position X, Y, Z to (0, -3, 0) mm.
    11. Add another sphere to the particle shape by right-clicking the rock particle Spheres table and then selecting Add Sphere.

    12. Set the radius of this new sphere (sphere 1) to 18 mm and the Position X, Y, Z to (-13, 0, 0) mm.
    13. With one of the spheres selected from the table in the Rock Particles Spheres section, click the Highlight Sphere icon in the View menu to distinguish the spheres.


    14. Add two more spheres and set their positions and radii as follows:




    15. In the rock particle Properties section, select Imported Template and then click Calculate Properties.
      Note:
      • When using the Imported Template option, the mass, volume, and moments of inertia are calculated from the CAD template.
      • Alternatively, you can use the Spheres option to calculate these properties from a collective assembly of spheres.
      • An automated way to generate spheres to fill a template is outlined in the following section. It is recommended in this tutorial to use the manually created four-sphere particle.
  6. Specify the size distribution of the bulk material.
    1. Expand the rock particle section in the Creator Tree and then select Size Distribution.
    2. In the Size Distribution section, select user-defined from the dropdown list.
    3. In the Scale By section, select Radius.
    4. Right-click the User Defined Size Distribution Parameters table and select Add three times.
    5. Specify the distribution parameters as follows:


Generate Particles from a Template

When defining the Bulk Material, you specify the positions of the particles in the template. You can use the alternative option of generating particles from a template.

To generate particles from a template:
  1. Select Bulk Material and then select Add Bulk Material in the Creator.
  2. Select the new Bulk Material and then right-click Add Shape from Library > Single Sphere.
  3. Click Edit... next to the Select Template dropdown list and import the CAD template (if not already imported).
  4. Use the following settings for the grid cells and sphere radius:


    EDEM then automatically generates the particle shape. These settings create approximately ten spheres that fill the template with the higher fidelity model shown on the left and the manually created four-sphere template on the right.