Defining Frozen Areas

Define a Frozen Area in Tosca ANSA® environment

Context:

Frozen areas are used to exclude the so-called frozen elements from being modified during the optimization, even though these elements are included in the design space. This is the case, e.g., when the elements are used in order to fix the component and therefore should be preserved independently of their internal loads. The inclusion into the design space may be necessary, e.g., to control the target volume (see constraints "absolute volume" or "relative volume", Bd.1, Chapter 5.5.1).

To define a frozen area, choose DV_CONSTRAINTS item and select New > FROZEN_AREA.
Each of these restrictions relates to an element group that is either the design area or a subset of it. For the definition of the frozen area, only an element group is necessary. No further properties have to be set.

The following figure shows frozen areas due to functional requirements.

Define a Frozen Area in Tosca Structure.gui

To define a frozen area, choose Command > DVCON_TOPO in Tosca Structure.pre screen.
Name the element group that is to be frozen in the ID_NAME field. If the element group is not already defined, it is necessary to define it in advance using GROUP_DEF command.
As Type select Frozen.

The resulting command looks like:
```
DVCON_TOPO
 ID_NAME = frozen_area

 EL_GROUP = frozen_grp

 CHECK_TYPE = FROZEN
END_
```
This constraint for the design variables is activated when it is referenced in the OPTIMIZE command.

Define a Frozen Area in Tosca Extension for ANSYS® Workbench

To add a Frozen Area to the project, select Topology > Frozen Area.
Select and assign a geometry or surface as shown in the following figure.
Predefined Named Selection are possible, too. Edges, vertices or nodes are not available to choose.