Using Constraints

Constraints couple the motion of a set of nodes to the motion of a reference node. Rigid bodies and kinematic constraints do exactly this for blocks and sidesets, respectively. A distributing constraint allows users to average the constrained motion of a sideset by using weight factors to control force transmission (to be specified outside of CUBIT). A tie constraint can be used to tie the elements of one sideset to the elements of another. Currently, only the Abaqus Exporter supports this type of constraint.

Note that as of CUBIT 13.0, constraints are supported by the Abaqus Importer/Exporter only. Contact the CUBIT support team if support in additional file formats is needed.

To create a constraint, use one of the following commands:

Create Constraint {Kinematic|Distributing} [name '<name>'] [vertex|node] <id> sideset <id>

Create Constraint Rigidbody [name '<name>'] [vertex|node] <id> block <id>

Create Constraint Tie [name '<name>'] primary sideset <id> secondary sideset <id>

A constraint’s name, dependent object, and independent object can be changed using the following commands:

Modify Constraint <id|name> [name '<name>'] [vertex|node] <id> sideset <id>

Modify Constraint <id|name> [name '<name>'] [vertex|node] <id> block <id>

Modify Constraint <id|name> [primary sideset <id>] [secondary sideset <id>]

Constraints can be listed or deleted using the following commands:

List Constraint <id_range>

Delete Constraint <id_range>