Rigids

Rigid elements are created in a space between two nodes of a model where a rigid connection is desired.

An option to calculate independent node is available.

Rigid elements are element config 5 and are displayed as a line between two nodes with the letter R written at the centroid of the element.

Figure 1. Single Node Rigidlink
Figure 2. Multiple Nodes Rigidlink

Rigid link elements are element config 55 and are displayed as lines between the independent node and the dependent node(s) with RL displayed at the independent node of the element.

Rigid link elements can be created with dependent nodes attached to an element as a SET, if allowed by the solver. If a rigid link with an automatically generated dependent node set is deleted, the associated node set is also deleted. If the automatically generated dependent node set is deleted, for example from browser or idle, the connected rigid link element is also deleted. Dependent node sets are automatically created when rigid link elements are created for solvers that require a set even though node selection was input by the user. A node set created independently can be selected as the dependent nodes and referenced by the rigid link element.
Note: Two-node rigids with a dependent node set attached are always created as rigid link elements (config 55), not as rigid elements (config 5).

Create Rigid Elements

Use the Rigids tool to create rigid or rigid link elements.

  1. From the Model ribbon, select the Rigids too.
    Figure 3.


  2. Define the element.
    OptionAction
    Type Select a rigid element type.
    Linear 1D Create one-dimensional elements based on a projection of Elems A to Elems B.
    Elems A Select the elements where you want the elements to begin.
    Restriction: Only available when the Linear 1D check box is selected.
    Elems B Select the elements where you want the elements to end.
    Restriction: Only available when the Linear 1D check box is selected.
    Density A-B Specify the number of plot elements you want created between each of the selected elements.
    Restriction: Only available when the Linear 1D check box is selected.
    Calculate independent node The independent node is calculated to be at the centroid of previously selected dependent nodes. So independent node selection is made unavailable.
    Independent node Select the independent node of the rigid element.
    Dependent node(s) Select one or more dependent nodes.
    Dependent DOF Select degrees of freedom at dependent nodes.
  3. Click Create.

Update Rigid Elements

Use the Entity Editor to update rigid elements.

This includes: modifying the independent and dependent node(s) selection, modifying the DOF, where applicable for the solver, and recalculating the independent node location.
Note: To change the element type, see Change Element Type.

Combine Rigid Elements

  1. From the Model ribbon, click the arrow next to the Interactions tool group and select Combine Rigids.
  2. Define parameters.
    Option Action
    Elements Select the rigid elements that you wish to combine. The rigids and rigidlinks must have the same independent node and DOFs.

    If any combined rigid link elements have dependent nodes attached as a set, the resulting rigid link will also have dependent nodes attached as a set. This set is created for a result element. The nodes sets attached to combined elements are deleted after combining.
    Combine Rigid With: Choose between common independent node and any common node.
  3. Click Combine.