Transition Zone

Use the transition zone manufacturing constraint to gain a smoother transition from design area to nondesign area.

See Also
About Mesh Smoothing (MESH_SMOOTH)
In Other Guides
DVCON_SHAPE

Applicable for Controller (SHAPE_CONTROLLER) Sensitivity (SHAPE_SENSITIVITY)
TRANSITION OK OK

A transition area shall create a smooth transition from design nodes to nondesign nodes. Tosca supports defining a transition area by using mesh smooth options. But these transition areas are located outside of the design area. This manufacturing constraint is used to create the transition area as part of the design area.

The command is explained with the following example code block. 

DVCON_SHAPE
  ID_NAME         = MY_TRANSITION_AREA
  ND_GROUP        = <node_group_name>
  REFERENCE_NDGR  = <node_group_fixed_edge>
  CHECK_TYPE      = TRANSITION
  [CHECK_NDGR     = <design area nodes without <node_group_name> >]
  FUNCTION        = SMOOTH | LINEAR
END_
  • ND_GROUP: Nodes that form the transition area.
  • REFERENCE_NDGR: The nodes on the fixed edge.
  • CHECK_NDGR: The distance of ND_GROUP to the design area must be determined. But in some cases the model might be in such a way, that the distance of some nodes to the design area is not as desired: In the figure below, most of the transition nodes will get the distance to the lower part of the design area. In such cases, only the upper part of the design area can be specified with CHECK_NDGR.
  • FUNCTION: Control the form of the transition area.


The functionality is similar to the MESH_SMOOTH -> FREE_SF command. Both aim for building transitions between design- and nondesign area.

A transition zone was traditionally defined outside the design area and implicitly with the number of element layers in MESH_SMOOTH.

With the definition of the transition zone as DVCON command, an explicit definition inside the design area is possible. This gives more flexibility and control.

Tip: The group used in the REFERENCE_NDGR item is thought to lie outside the design area and be already fixed. However, this is not mandatory and Tosca does not take any automatic action to fix this group. To be on the safe side, it is good practice to fix the node group using a CHECK_DOF = CS_0, FIX, FIX, FIX in a DVCON_SHAPE command.