Cyclic Symmetry for Nonsymmetric Meshes (SURF_CYCLIC_SYM)

Couples nodes in a not necessarily symmetric mesh that reoccur in a cyclic manner around a rotational axis.

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LINK_SHAPE

CLIENT / Applicable for SHAPE_CONTROLLER SHAPE_SENSITIVITY
SURF_CYCLIC_SYM OK OK

  • This link condition couples nodes that reoccur in a cyclic manner around a rotational axis. This is supported for both symmetric and unsymmetric meshes.
  • To be able to build up the coupling, a symmetry axis and an angle must be specified. The following six parameters are necessary for the definition of the link condition: 
    
CLIENT           = SURF_CYCLIC_SYM
CLIENT_DIR       = <X_1>, <X_2>, <X_3>
CS               = name_of_coord_system
TOL              = tolerance_value
ANGLE            = angle_in_degree
CYCLIC_SYM_START = <X_1>, <X_2>, <X_3>
  • The CLIENT_DIR parameter defines the rotational axis and is specified in coordinates of the coordinate system CS. Like for the SURF_PLANE_SYM link condition the TOL parameter is used in intersection tests as absolute tolerance. The ANGLE divides the area around the axis (CLIENT_DIR) in pieces of equal size that will be made symmetric. Thus, the angle must be a divisor of 360°. The CYCLIC_SYM_START point defines the starting point for the partitioning (see the following figure). Its coordinates are given with reference to the global cartesian coordinate system. It must not lie on the rotational axis.

Like for the SURF_PLANE_SYM link condition a main strategy might be selected: MAIN = MAX | MIN

The strategy determines if the maximum or the minimum displacement of the linked nodes should be used to return a symmetric result. The link is determined in a similar way as for plane symmetry: for each node, reference points on the surface with respect to the rotational cyclic symmetry and their interpolated displacements are calculated. The main criterion then influences which optimization displacement will be applied.



Important:

  • The coordinate system referenced by CS must be a Cartesian coordinate system.
  • Only the MAIN=MAX or MAIN=MIN criteria are allowed to determine the main node.
  • The coordinates of the parameter CYCLIC_SYM_START are given with respect to the global Cartesian coordinate system.