DSYM
DSYM, Lab, Normal, KCN
Specifies symmetry or antisymmetry degree-of-freedom constraints on nodes.
MP ME ST PR PRN <> <> <> EM EH DY PP <> EME MFS
Lab

Symmetry label:

SYMM — 

Generate symmetry constraints as described below (default).

ASYM — 

Generate antisymmetry constraints as described below.

Normal

Surface orientation label to determine the constraint set (surface is assumed to be perpendicular to this coordinate direction in coordinate system KCN):

X — 

Surface is normal to coordinate X direction (default). Interpreted as R direction for non-Cartesian coordinate systems.

Y — 

Surface is normal to coordinate Y direction.  θ direction for non-Cartesian coordinate systems.

Z — 

Surface is normal to coordinate Z direction.  Φ direction for spherical or toroidal coordinate systems.

KCN

Reference number of global or local coordinate system used to define surface orientation.

Notes

Specifies symmetry or antisymmetry degree-of-freedom constraints on the selected nodes. The nodes are first automatically rotated (any previously defined rotations on these nodes are redefined) into coordinate system KCN, then zero-valued constraints are generated, as described below, on the selected degree-of-freedom set (limited to displacement, velocity, and magnetic degrees of freedom) [DOFSEL]. Constraints are defined in the (rotated) nodal coordinate system, as usual. See the D and NROTAT commands for additional details about constraints and nodal rotations.

This command is also valid in PREP7.

Symmetry and Antisymmetry Constraints:

Symmetry or antisymmetry constraint generations are based upon the valid degrees of freedom in the model, i.e., the degrees of freedom associated with the elements attached to the nodes. The labels for degrees of freedom used in the generation depend on the Normal label.

For displacement degrees of freedom, the constraints generated are:

 SYMMASYM
Normal2-D3-D2-D3-D
XUX, ROTZUX, ROTZ, ROTYUYUY, UZ, ROTX
YUY, ROTZUY, ROTZ, ROTXUXUX, UZ, ROTY
Z--UZ, ROTX, ROTY--UX, UY, ROTZ

For velocity degrees of freedom, the constraints generated are:

 SYMMASYM
Normal2-D3-D2-D3-D
XVXVXVYVY, VZ
YVYVYVXVX, VZ
Z--VZ--VX, VY

For magnetic degrees of freedom, the SYMM label generates flux normal conditions (flux flows normal to the surface). Where no constraints are generated, the flux normal condition is "naturally" satisfied. The ASYM label generates flux parallel conditions (flux flows parallel to the surface).

 SYMMASYM
Normal2-D3-D2-D3-D
X--AXAZAY, AZ
Y--AYAZAX, AZ
Z--AZ--AX, AY

Menu Paths

Main Menu>Preprocessor>Loads>Define Loads>Apply>Magnetic>Boundary>VectorPot>Flux Normal>On Nodes
Main Menu>Preprocessor>Loads>Define Loads>Apply>Magnetic>Boundary>VectorPot>Flux Par'l>On Nodes
Main Menu>Preprocessor>Loads>Define Loads>Apply>Structural>Displacement>Antisymm B.C.>On Nodes
Main Menu>Preprocessor>Loads>Define Loads>Apply>Structural>Displacement>Symmetry B.C.>On Nodes
Main Menu>Solution>Define Loads>Apply>Magnetic>Boundary>VectorPot>Flux Normal>On Nodes
Main Menu>Solution>Define Loads>Apply>Magnetic>Boundary>VectorPot>Flux Par'l>On Nodes
Main Menu>Solution>Define Loads>Apply>Structural>Displacement>Antisymm B.C.>On Nodes
Main Menu>Solution>Define Loads>Apply>Structural>Displacement>Symmetry B.C.>On Nodes

Release 14.0 - © 2011 SAS IP, Inc. All rights reserved.