17.6.4.1. Coupling

While setting up a model for analysis, you can establish relationships among the different degrees of freedom of the model by physically modeling the part or a contact condition. However, sometimes there is a need to be able to model distinctive features of a geometry (for example, models that have equipotential surfaces) which cannot be adequately described with the physical part or contact. In this instance, you can create a set of surfaces/edges/vertices which have a coupled degree of freedom by using the Coupling boundary condition.

Coupling the degrees of freedom of a set of geometric entity constrains the results calculated for one member of the set to be the same for all members of the set.

This page includes the following sections:

Analysis Types

Coupling is available for the following analysis types:

Dimensional Types

The supported dimensional types for the Coupling boundary condition include:

  • 3D Simulation. Apply to one or more faces or edges or at least two vertices.

  • 2D Simulation. Apply to one or more edges or at least two vertices.

Geometry Types

The supported geometry types for the Coupling boundary condition include:

  • Solid

  • Surface/Shell

  • Wire Body/Line Body/Beam

Topology Selection Options

The supported topology selection options for Coupling include:

  • Face: Supported for 3D only.

  • Edge

  • Vertex

Applying a Coupling Boundary Condition

To apply a Coupling boundary condition:

  1. On the Environment Context tab: click Conditions>Coupling. Alternatively, right-click the Environment tree object or in the Geometry window and select Insert>Coupling.

  2. Define the Scoping Method.

Restrictions

Make sure that you meet the following restrictions when scoping Coupling;

  • You cannot specify more than one Coupling (the same DOF) on the same geometric entity, such as two edges sharing a common vertex or two faces sharing a common edge.

  • Coupling should not be applied to a geometric entity that also has a constraint applied to it.

Details Pane Properties

The selections available in the Details pane are described below.

CategoryProperty/Options/Description
Scope

Scoping Method: Options include:

  • Geometry Selection - Default setting, indicating that the boundary condition is applied to a geometry or geometries, which are chosen using a graphical selection tool.

    • Geometry - Visible when the Scoping Method is set to Geometry Selection. Displays the type of geometry (Body, Face, etc.) and the number of geometric entities (for example: 1 Body, 2 Edges) to which the boundary has been applied using the selection tools.

  • Named Selection - Indicates that the geometry selection is defined by a Named Selection.

    • Named Selection - Visible when the Scoping Method is set to Named Selection. This field provides a drop-down list of available user–defined Named Selections.

Definition

DOF Selection - For a Thermal-Electric analysis, select either Temperature or Voltage, otherwise this is a read-only field displaying the DOF selection type.

Suppressed - Include (No - default) or exclude (Yes) the boundary condition.

Mechanical APDL References and Notes

Coupling is achieved through the use of the CP command.

API Reference

For specific scripting information, see the Coupling section of the ACT API Reference Guide.