Rotational symmetry (ROTATION_SYM)

To couple displacements rotational symmetric about an axis, the position and the orientation of the axis must be exactly specified. It is also necessary to specify tolerances in order to identify nodes lying rotational symmetric relative to the axis. The mesh of the coupled node group should be rotational symmetric. These parameters are specified as follows:

      
        CLIENT = ROTATION_SYM
        CLIENT_DIR = <x_1>,<x_2>,<x_3>
        CS = name_of_coord_system
        OL = <tol_1>, <tol_2>, <tol_3>
      
    

The origin of the coordinate system referenced by CS defines a point on the axis. The direction specified by the CLIENT_DIR parameter defines the axis direction. The symmetry of the nodes assigned by ND_GROUP in the DVCON_SHAPE command is checked against the symmetry axis. Symmetric nodes are assembled into a symmetry group (a simplification of the GROUP_AUTO_DEF command, where these symmetry groups can be build according to cylindrical coordinate systems, in combination with LINK_SHAPE, CLIENT=VECTOR and DVCON_AUTO_SHAPE). Then the master node of the symmetry group is determined and the displacements of the client nodes are calculated in such a way that they move rotational symmetric to the axis (see the following figure).

Additionally an angle can be defined to divide the search area into discrete sections:

      ANGLE =  <real>