Rigid Link Condition

Rigid Link is a factory setup parameter that allows you to link particles with a single specified Geometry, whether physical or virtual. Once linked, the particles will follow its motion.

To use the Rigid Link condition:
  1. In the Creator Tree, select Geometries and then select Factories.


  2. In the Parameters dialog box, select an option for Rigid Link from the Option dropdown list.
    Note:
    • Rigid Links can be formed between particles and Geometries that are not in contact as well. Upon link formation, the particles will have the same velocities as the Geometry they are linked to, regardless of their previous motion. This link overrides the rigidly linked particles' updated position from the contact model.
      Figure 1. Falling particle is linked to the moving Geometry
    • Each Factory can only have one Rigid Link with one Geometry.
    • Meta-Particles will behave differently compared to standalone particles.
  3. Click the icon to configure the Rigid Link settings and specify the following:
    Option Description Settings
    On Contact Select to link the particles to the specified physical Geometry upon contact. This may occur anytime throughout the simulation. Click the arrow to select an appropriate physical Geometry from the dropdown list.
    On Creation Select to link the particles to the specified Geometry, only upon particle creation. The particles are linked once they are created and will follow the linked Geometry. It is not necessary that they are in contact with the Geometry. Click the arrow to select an appropriate Geometry to link to from the dropdown list. The Geometry can be physical or virtual.
    On Time This option is a variation of the previous two methods but will allow you to specify the link formation time.

    Rigid Links will not form before or after this time has passed, for contact-based links.

    Rigid Links can be formed at the specified time with or without contact between the Geometry and particles. This is similar to how particles are linked by selecting On Creation, but will allow you to specify the time.

    		 Click the arrow to select an appropriate physical Geometry to link to from the dropdown list. Specify the appropriate contact time in the Time field.
    Clear the Link in particles in contact only checkbox to link particles and Geometry at the specified time, without them being in contact. This will show virtual Geometries in the Geometry dropdown list.
    Note: Particle contact radius is applied for the Rigid Link contacts as well.
    Figure 2. Rigid Link between box and particles with 0.0015m contact radius.
    Meta-Particles will behave differently if they are linked or not linked with a contact. For example, linking a Meta Particle with a Geometry that it is in contact with will cause only the particle that is in contact with the specified Geometry to be linked. The rest of the particles in the chain will be free to move. If the Meta-Particle is linked to a Geometry that it is not in contact with, all particles in the particles in the chain will be linked. This can only occur when you select On Creation and On Time (link particles in contact is not selected) settings.
    Figure 3. Meta-Particle chain is completely linked to the box when the link is applied without contact.
    Figure 4. Only particles that are in contact with the box are linked and the rest are free to move independently.
  4. Click Color Rigid Link Particles on the right side of the Toolbar in both the Creator and Simulator tabs to view the linked particles.
  5. In the Analyst tab, select Rigid Link from the Color By dropdown list as an additional coloring option for the particles that are in a Rigid Link bond with a Geometry.

    Similar to selecting BondStatus in Contacts, Rigid Link has '1' and '0' as the maximum and minimum values, respectively, for the particles that are in contact and not in contact.

    The following images explain the function of the On time setting of Rigid Link:
    Figure 5. Rigid Link with "On Time" setting of 0.05s

    Here, the is activated after 0.05 s on particles that are in contact with the Geometry. Other particles can move freely.

    Figure 6. Rigid Link with On Time setting and Link only particles in contact only disabled

    Here, the Rigid Link is activated after 0.02 s, linking the particles with the Geometry. The Rigid Link has been set up to require no contacts to link the particles and Geometry, so that all particles in the contact chain are linked to the moving Geometry.