Cyclic Symmetry dialog box (Multiphysics/Simcenter Nastran)

Type
Type	Specifies the face pair creation method.Automatic Cyclic Symmetry PairingSelect to use automatic cyclic symmetry pairing, where you select the faces on the source region and the software automatically finds the matching target faces. For more information, see Automatic face pairing and Create Automatic Face Pairs dialog box (Cyclic Symmetry boundary coupling).Manual Cyclic SymmetrySelect to use manual cyclic symmetry pairing, where you manually create and pair the source and target regions. Automatic Cyclic Symmetry from ElementsAppears for SOLs 401, 402, and 414.Select to let the solver find the source and target faces based on the 3D cyclic symmetry elements that you select.
Destination Folder
Simulation Object Container	Specifies the folder in the Simulation Navigator in which to store the simulation object. The list includes the root container and existing folders that you created using the New Folder command. Examples of a root container include Load Container, Constraint Container, and Simulation Object Container.
Folder Manager	Displays a hierarchical list of existing folders. To create a new folder, right-click any level of the hierarchy and choose New Folder.
Automatic Face Pair Creation
Face Pairs	Appears when type is set to Automatic Cyclic Symmetry Pairing.Opens the Create Automatic Face Pairs dialog box, which enables you to specify face pair generation properties, preview face pairs, and generate face pairs automatically.
Source Region
Source Region	Appears when type is set to Manual Cyclic Symmetry.Lets you select the Region that defines the surface in the pair. The source is the independent DOF.Select an existing region or click New Region to create a new region. See Working with reusable regions.Note: For manual cyclic symmetry, source and target regions can contain different elements. For example, one region can contain element faces and the other region can contain polygon faces.
Target Region
Target Region	Appears when type is set to Manual Cyclic Symmetry.Lets you select the Region that defines the surface in the pair. The target is the dependent DOF. Select an existing region or click New Region to create a new region. See Working with reusable regions.
Swap Regions
	Reverses the source and target regions.
Model Objects
Appears when Type is set to Automatic Cyclic Symmetry from Elements.Lets you select the 3D cyclic symmetry objects for:Creating the cyclic symmetry condition. The software uses the solid elements to automatically create the source and target coupling.Defining the elements to include in the stage that you designate in the Stage Number box.You can select from the geometry, selection recipes, or mesh (solid elements, spring elements, and so on). Every element (3D, 2D, spring, and so on) that contributes to stiffness and that is connected to the sector needs to be included.
Group Reference	Lets you use groups to select the 3D elements on your cyclic symmetry model.For more information, see Group Reference options.
Select Object	Lets you select the 3D cyclic symmetry objects from the graphics window or Simulation Navigator.
Stacked Smart Selector Methods	Opens the Smart Selector Methods dialog box where you can specify a progression of smart selection filters.For more information, see Smart Selector Methods dialog box.
Excluded	Lets you remove individual entities from within the selected object.
Direction
Appears when Type is set to Manual Cyclic Symmetry or Automatic Cyclic Symmetry from Elements.
CSYS	Lets you select an existing cylindrical system or create a new one. The default is the global cyclic analysis coordinate system. The coordinate system you select must be cylindrical and its Z-axis must be collinear with the global cyclic analysis coordinate system.
Local	Appears when CSYS is set to User-Defined Cylindrical. Lets you create or select a local coordinate system.Click CSYS Dialog to open the CSYS dialog box where you can create a new one, or select one from the list.
Set Displacement CSYS	Instructs the software to assign the designated reference coordinate system to the source and target as the nodal displacement coordinate system.
Segments
Appears when Type is set to Manual Cyclic Symmetry or Automatic Cyclic Symmetry from Elements.
The following options appear when Type is set to Manual Cyclic Symmetry.
Distance Tolerance	Appears when type is set to Manual Cyclic Symmetry.Specifies the maximum search distance when determining face pairs.Using sample points, the software computes bounding boxes in the source and target regions. The bounding boxes must be the same within the distance tolerance you specify. In addition, the software rotates the source into the target region. It uses the distance tolerance to compare that the source and target have matching topology. Caution: Modeling non-cyclic symmetric features is not an ideal modeling scenario.Features, such as holes or slots, that are present in one region but not in the other can cause the regions to fail the compatibility check. When this occurs, the software cannot compute the number of segments (NSEG). For manual cyclic symmetry, you can override the software's inability to find the NSEG by entering a value for it in the Number of Segments box.
Angle Tolerance	Appears when type is set to Manual Cyclic Symmetry.Specifies the tolerance allowed between the actual segment angle of the geometry as it is modeled and the segment angle computed using the integer in Number of Segments (NSEG) box.The software computes the difference between the actual segment angle as it is modeled, and the segment angle computed using the closest integer number of segments (Number of Segments (NSEG)) in a full circumference. The angles should match within the angle tolerance. For example, if you model the geometry as a 20.5° segment, the closest integer number of segments in a full circumference is 18, which corresponds to a 20° segment. The Angle Tolerance value, in this case, must be larger than (20.5 – 20) = .5°.
Calculated Segment Angle	Appears when type is set to Manual Cyclic Symmetry.Displays the angle the software computed. For example, if your model is a 20.5° segment, the software displays 20.5.
Calculated Number of Segments	Appears when Type is set to Manual Cyclic Symmetry.Displays the calculated number of segments (360° divided by the angle between the regions). For example, if the value in the Calculated Segment Angle box is 20.5, the value in the Calculated Number of Segments box is 17.56 (360/20.5 = 17.56).
Override Calculated Number of Segments (NSEG)	Appears when type is set to Manual Cyclic Symmetry.Overrides the values the software calculated for the number of segments (NSEG) and lets you enter your own value in the Number of Segments (NSEG) box.
Number of Segments (NSEG)	Available when the Override Calculated Number of Segments (NSEG) check box is selected.Lets you specify the number of segments:When the Override Calculated Number of Segments (NSEG) check box is selected, enter the number of segments (NSEG) value.The software writes the value to the Nastran input file in the NSEG field on the CYCSET bulk entry. It also uses the NSEG value when sweeping the source nodes into the target regions during the automatic coupling process. When the Override Calculated Number of Segments (NSEG) check box is cleared, the Number of Segments (NSEG) box displays the value computed in the Calculated Number of Segments box rounded to the closest integer.Using the 20.5° segment example, the software displays 18 (360/20.5 = 17.56, then rounded to 18).
Calculate Segment	Appears when type is set to Manual Cyclic Symmetry.Instructs the software to compute the segment properties.
The following options appear when Type is set to Automatic Cyclic Symmetry from Elements.
Segment number method	Specifies how you want the number of segments to be determined.ExplicitLets you set the number of segments.Computed from AngleLets the software compute the number of segments based on the angle you enter.
Number of Segments (NSEG)	Appears when the segment number method is set to Explicit.Sets the number of segments. The software uses this value when sweeping the source nodes into the target regions during the automatic coupling process. The software writes the value to the Nastran input file in the NSEG field on the CYCSET bulk entry.
Angle	Appears when the segment number method is set to Computed from Angle.Sets the angle you want the software to use to calculate the number of segments. For example, if you enter 20, the number of segments is 18 (360/20 = 18).
Additional Thermal Properties
Appears for Thermal and Coupled solutions and when type is set to Manual Cyclic Symmetry.
Enable Radiative Thermal Rotational Periodicity	Computes the radiation exchange taking into account the complete rotated model.
Coupling Resolution	Specifies the accuracy of the coupling. The software subdivides primary elements according to the Coupling Resolution value before it determines conductances.With the One-to-One resolution, the solver calculates a single conductance from each primary element to the nearest secondary element. With the Coarse through Finest resolutions, the software subdivides each primary element into a progressively larger number of sub-elements. Although it may seem that the finer subdivision level would produce more accurate results, this is not always the case.
Only Connect Overlapping Elements	Controls how the software establishes the conductances between the selected elements.
Overlap Projection Direction	Appears when the Only Connect Overlapping Elements check box is selected.Specifies the normal to use to check for overlapping elements in thermal couplings: Primary Element Normals or Secondary Element Normals.For more information, see Using the Overlap Projection Direction option.
Stages
Group Reference	Appears when Type is set to Manual Cyclic Symmetry.Lets you use groups to select the 3D elements that you want to include in this stage.For more information, see Group Reference options.
Select Elements	Appears when Type is set to Manual Cyclic Symmetry.Lets you use the graphics window to select the elements on the 3D cyclic symmetry mesh that you want to include in this stage.If the model contains a user-defined coating on the solid, you must select the coating elements to correctly compute thermal properties.
Stacked Smart Selector Methods	Appears when Type is set to Manual Cyclic Symmetry.Opens the Smart Selector Methods dialog box where you can specify a progression of smart selection filters.For more information, see Smart Selector Methods dialog box.
Excluded	Appears when Type is set to Manual Cyclic Symmetry.Lets you remove individual entities from within the selected object.
Stage Number (STAGE)	Appears when Type is set to Manual Cyclic Symmetry or Automatic Cyclic Symmetry From Elements.Sets the stage number for the selected 3D cyclic symmetry elements. The stage number is useful for grouping the 3D elements that belong to the same sector for post-processing.
Optional Parameter
Search Distance for Pair of Regions (SDIST)	Specifies the value the solvers use to pair source and target nodes. The default is blank (no value).For more information, see Cyclic Symmetric in the Quick Reference Guide.
Boundary Condition Generation
Associate to Automatic Pair Recipe	Appears when Type is set to Automatic Cyclic Symmetry Pairing.(Optional) Specifies whether to associate the automatically generated face pairs with the automatic pair recipe. Note: The automatic pair recipe is the set of parameters on the Create Automatic Face Pairs dialog box that determines how to compute and group face pairs. When the Associate to Automatic Pair Recipe check box is selected, the generated contact pairs appear in the Simulation Navigator with the prefix Auto. If the master part is updated, the software recalculates the face pairs and updates the boundary condition. When the Associate to Automatic Pair Recipe check box is cleared, the generated contact pairs are not associated with the face pair recipe. If the master model changes, the software does not update the contact pairs. These contact pairs behave the same as manually created contact pairs.

These options are available when you click More Options .
Find	Lets you search for an object by typing the full name of the object. For example, to find a group named ABC_group, you must type ABC_group into the search box.After typing the name, press Enter or click Find . If the object is found, it is selected automatically.
Filter by Name	Lets you filter the list by the names of the objects. This filter supports wildcards. The default wildcard of * displays all entries in the list. For example, to filter the list to display every object with a name starting with the letter "a," enter a* as the filter string.
Filter by Label	Lets you filter the list by the names or labels of the objects. This filter supports wildcards. The default wildcard of * displays all entries in the list. For example, to filter the list to display every object with a name starting with the letter "a," enter a* as the filter string.

How do I

Define boundary coupling using the Automatic method

Define boundary coupling using the Manual method

Learn more

Cyclic symmetric boundary coupling

Automatic face pairing

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Cyclic Symmetry dialog box (Multiphysics/Simcenter Nastran), Simcenter 3D 2021.1 Series

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