Assigning Link/Coupling Conditions (CHECK_LINK)

A parameter-free optimization is performed for shape optimization in SIMULIA Tosca Structure, that is, each of the design nodes can be moved independent of the other design nodes. However, in some cases certain restrictions are specified that make it required to link or couple design nodes. The design nodes are then no longer allowed to move freely; there is an interdependent relationship between the individual design nodes. This relationship is defined by a link condition.

See Also
Link and Coupling Conditions (LINK_SHAPE)
In Other Guides
LINK_SHAPE

Applicable for Controller (SHAPE_CONTROLLER) Sensitivity (SHAPE_SENSITIVITY)
CHECK_LINK OK (OK) - Not all link conditions are available.

The following are examples of the type of restrictions that might necessitate the activation of link conditions: All design nodes in the start model are located on a cylinder and should also be located on a cylinder (with an altered radius) in the optimized model. Another example: Because of a specified punch direction, the design nodes must lie along the punch direction. Yet another example: an originally symmetrical component should still be symmetrical following the optimization despite asymmetric stress. The parameter

CHECK_LINK = link_shape_name

activates a link condition for the nodes of the node group (ND_GROUP parameter). This link condition must be defined with the LINK_SHAPE parameter and referenced with its unique name (link_shape_name). The possibilities for defining link conditions are numerous and varied. Since it is not required to know the link conditions for the basic definition of a shape optimization job, inexperienced readers should skip this chapter at this time. This section can be read when the need arises.

Note:

  • An individual link condition can be assigned several times, that is, an individual link condition can be activated in several DVCON_SHAPE entries for several node groups.
  • Some manufacturing restrictions require the definition of numerous node groups and restrictions. To make this easier, you can automatically generate node groups using the GROUP_AUTO_DEF command and automatically assign link conditions as restrictions using the DVCON_AUTO_SHAPE command.
  • Coupling conditions can be defined using the modules LINK_SHAPE and DVCON_SHAPE.