Defining Cluster Groups

Shell thicknesses can be clustered to have equal values in certain areas (in each element group) during the optimization (CHECK_TYPE = CLUSTER_GROUPS). Clustering reduces the number of design variables (without influence on calculation time).

This task shows you how to:

See Also
In Other Guides
DVCON_SIZING

Define Cluster Groups in Tosca Structure.gui

  1. Choose Command | DVCON_SIZING in Tosca Structure.prescreen.
  2. Apply an ID_NAME and select your cluster groups. If the element group is not already defined, it is necessary to define it in advance using the GROUP_DEF command.
  3. If the element group is not already defined, it is necessary to define it in advance using the GROUP_DEF command.
  4. Choose Type = Cluster Groups:

Parameter File

The resulting command looks like: 

DVCON_SIZING
 ID_NAME    = cluster_area
 EL_GROUP   = cluster_grp_1
 EL_GROUP   = cluster_grp_2
 EL_GROUP   = cluster_grp_3
 ...
 CHECK_TYPE = CLUSTER_GROUPS
END_

Within each element group, the elemental thicknesses will be equal but between the groups the thicknesses will be different. This constraint for the design variables is activated when it is referenced in the OPTIMIZE command.

In general, clustering areas correspond to areas made from one sheet metal. Nevertheless, performing the optimization without clustering might give you ideas where to construct borders between (that is, where to combine or cut) your single sheets.

The following figures demonstrate an example with free sizing optimization and clustering for certain (approx. 200) areas: