Scalable Interfaces for Geometry and Mesh based Applications

AssyGen Input File Keyword Definitions

Posted by on Jun 24, 2014 in RGG

NOTE: common.inp is a reserved file name for RGG process, when present AssyGen loads it for all assemblies that form the core. This avoids repetition of keywords across all assemblies forming the core model.

1. Geometry: Assembly geometry can be output as a collection of 2D surfaces, or as a collection of volumes swept out by those surfaces. If this keyword is not used, AssyGen produces a volumetric model by default.


2. GeometryType: This keyword defines the geometry type and can take values ‘Hexagonal’ or ‘Rectangular’. GeomType keyword sets the arrangement of cells specified in the ‘Assembly’ keyword.


3. GeomEngine: This keyword can take values ‘ACIS’ and ‘OCC’. Note, specified engine type matches with geometric engine used for building ‘iGeom’. The o/p geometry file has extension ‘.stp’ with ‘OCC’ and ‘.sat. with ‘ACIS’.


4. MeshType: AssyGen can create Cubit journal files for ‘hex’ and ‘tet’ meshing of volumes. MeshType keyword can have values: ‘hex’ or ‘tet’, the default is ‘hex’.


5. Materials: Materials keyword is used to define all the material names, names are followed by their aliases. First input to this keyword is the number of materials. Material aliases defined here are used in subsequent keywords to assign materials.


6. Duct: The layers of duct wall material are described using this keyword, with the first layer of duct corresponding to the background material in the unit cells of the assembly. The first field specifies the number of layers in the duct wall, followed by the X, Y location of center of the duct wall layers, and the starting and ending Z coordinates for all duct wall material. The width of the layers in X and Y (rectangular) or the flat-to-flat distance (hexagonal)appears next. Next, the material aliases for each layer of background material are specified.


7. Pincells: A pincell corresponds to a unit cell type as described in Section 3. This keyword’s first input field is the number of pincells. The next keyword is the pitch (hexagonal) or X and Y pitch (rectangular). Alternatively; all pincells can define their pitch using ‘Pitch’ Keyword.


8. ‘Pincell Alias’: This is not a keyword, it begins with pincell name defined by the user,followed by the pincell alias and finally the number of subsequent lines this pincell will use to define its properties.


9. Pitch: For ‘Hexagonal’ Geometry this keyword has only one field, the pitch of the hexagonal unit cell. For ‘Rectangular’ geometry this keyword takes 3 inputs – the X and Y pitch of the unit cell, and the length, width and height of the pincell.


10. Cylinder: First input to this command is the number of concentric cylinders in the pincell. Next X, Y of the center and the Z start and Z end of the cylinders is specified. Finally the radii and material alias for the cylinders are specified.


11. CellMaterial: This creates a background material for the unit cell, and results in unit cell boundaries appearing explicitly in the assembly. The starting and ending axial position is specified, along with the material alias for the background material.


12. Assembly: The lattice arrangement is specified using this keyword. For rectangular lattices,the first two fields indicate the number of unit cells in the X and Y directions; for hexagonal lattices, the first field indicates the number of rings in the lattice.


13. <cell_alias>: Unit cell aliases are given, one line of aliases per row in the assembly starting from top left proceeding to bottom right.


14. Rotate: Rotates the entire assembly model by the specified angle (in degrees) around the specified axis. The second keyword is axis and the third is angle is degree.


15. Center: If no axis is specified, it centers the assembly about X and Y axis. ‘X’ or ‘Y’ or ‘Z’ can be specified as the second keyword for centering the assembly about a specific axis.


16. Section: Subtracts everything on the negative side of the specified. if Reverse is given, the positive side of that axis. If offset is given, model is sectioned at that coordinate on the specified axis, instead of at the zero value.


17. Move: This keyword is followed by three double precision numbers indicating the distance(in X, Y and Z direction) by which the entire model is moved.


18. AxialMeshSize: Mesh size in the axial direction; for assemblies where the “Geoemtry Surface” keyword is not specified, this size is specified in the meshing script. When varying axial volumes are created an axial mesh size must be specified for axial regions.


19. RadialMeshSize: Mesh size in the radial direction; this size is written to the journal file for meshing the assembly model.


20. TetMeshSize: This keyword is used to specify a double precision number specifying the ‘tetmesh’ size for the entire model.


21. NeumannSet_StartId: When creating core mesh, individual assembly meshes mush have different Neumann set Id’s. This keyword allows the specification of an integer that marks the startid of Neumann sets in the assembly mesh.


22. MaterialSet_StartId: Similar to Neumann sets, Material sets, must also have different Id’s. This keyword allows the specification of an integer that marks the startid of material sets in the assembly mesh.


23. End: This command marks the end of AssyGen input file.


24. EdgeInterval: Specify the interval on outer edges of the assembly, often needed to constraint meshing on the skin of the model


25. MergeTolerance: Tolerance of merging geometric entities in the model.


26. CreateSideSet: Option to disable sideset creation for CUBIT journal file. Takes values ‘yes’ or ‘no’.


27. CreateFiles: This creates assygen input files with block numbers shifted. It is useful, when multiple assemblies with same configuration and different materials is desired.


28. MeshScheme: For concentric cylinder or outermost ducts scheme (CUBIT) “hole” is often desired. This keyword when specified sets all such concentric surfaces to scheme hole. Default scheme is pave.


29. StartPinId: When using info keyword (on), this keyword can be used to define the start pin id’s for a particular assembly.


30. HBlock: When material blocks are created by using hex elements varying in Z direction HBlock is used. This keyword takes 3 arguments – number of blocks long Z, start Z height and end Z height.


32. SaveExodus: Flag to indicate that final assembly must be saved as a .exo file. Default is .h5m.


33. MeshScheme: Takes a string: “Hole” or “Pave”. Default is Pave. Some assemblies with too many concentric cylinders that are closely spaced are hard to mesh using ‘pave’ scheme, so scheme ‘hole’ must be used.


34. NumSuperBlocks:  Superblocks is specified when some of the material blocks must be combined to form a super block. This keywords takes in the total number of such block required by the assembly model.


35. Superblocks: This keyword takes several 3 arguments: Id, alias and contents of the superblock.


36. List_MaterialSet_StartId: Only used when using superblocks and createfiles option together, this keyword takes in an integer specifying the startid of material set in a particular AssyGen file.


37. List_NeumannSet_StartId:  Only used when using superblocks and createfiles option together, this keyword takes in an integer specifying the startid of Neumann set in a particular AssyGen file.


Note: ‘&’ sign can be used for continuing the line input on the next line.

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