17.6.3.5. Frictionless Support

You use this boundary condition to prevent one or more flat or curved faces from moving or deforming in the normal direction. The normal direction is relative to the selected geometry face. No portion of the surface body can move, rotate, or deform normal to the face.

For tangential directions, the surface body is free to move, rotate, and deform tangential to the face.

For a flat surface body, the frictionless support is equivalent to a symmetry condition.

Important:  Due to an internal processing requirement, if you specify a user-defined (local) Coordinate System when defining this boundary condition, the nodal coordinate system axes may differ from the local Coordinate System axes. As needed, you can verify the actual nodal orientation in the Mechanical APDL application.

Also, for more information about how the application manages nodal DOF constraints, see the Converting Boundary Conditions to Nodal DOF Constraints (Mechanical APDL Solver) section.

This page includes the following sections:

Analysis Types

Frictionless Support is available for the following analysis types:
Dimensional Types

The supported dimensional types for the Frictionless Support boundary condition include:

  • 3D Simulation

  • 2D Simulation

Geometry Types

The supported geometry types for the Frictionless Support boundary condition include:

  • Solid

  • Surface/Shell

  • Wire Body/Line Body/Beam

Topology Selection Options

The supported topology selection options for Frictionless Support include:

  • Face: Supported for 3D only.

  • Edge: Supported for 2D only.

Applying a Frictionless Support Boundary Condition

To apply a Frictionless Support:

  1. Select the Frictionless option from the Structural group on the Environment Context tab. Alternatively, right-click the Environment tree object or in the Geometry window and select Insert>Frictionless Support.

  2. Specify Scoping Method and Geometry or Named Selection.

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

Type: Read-only field that describes the object - Frictionless Support.

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

API Reference

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