Plane Symmetry (PLANE_SYM)

Couple design nodes that are symmetric to a plane - for symmetric meshes.

See Also
In Other Guides
LINK_SHAPE

CLIENT / Applicable for SHAPE_CONTROLLER SHAPE_SENSITIVITY
PLANE_SYM OK -

To be able to couple displacements symmetric to a plane, the position and the orientation of the plane must be exactly specified. It is also necessary to specify tolerances to identify symmetric nodes. The following four parameters are necessary for the definition of the link condition:


CLIENT     = PLANE_SYM
CLIENT_DIR = <X_1>, <X_2>, <X_3>
CS         = name_of_coord_system
TOL        = <tol_1>, <tol_2>, <tol_3>

The origin of the coordinate system referenced by CS defines a point on the plane. The direction specified by the CLIENT_DIR parameter defines the normal of the plane. The symmetry of the nodes (assigned by ND_GROUP in the DVCON_SHAPE command) is checked against the symmetry plane. Symmetric nodes are assembled into a symmetry group (normally two symmetric nodes per symmetry group). Then the main node of the symmetry group is determined and the displacements of the client nodes are calculated in such a way that they move symmetrically to the plane of the main node (see the following figure).

The tolerances are required to identify symmetric nodes. Symmetric nodes share equal coordinates in the plane and inversely equal coordinates normal to the plane (and added tolerances). The three tolerance values tol_* are assigned to the three coordinate directions of the coordinate system referenced by CS.

Important:

  • The coordinate system referenced by CS must be a Cartesian coordinate system.
  • Only the MAIN=MAX or MAIN=MIN criteria are allowed for determination of the main node.