|
»Click here to display Table of Contents«
|
SURF |
|
|
|
|
|
SURF |
|
|
|
|
|
»Click here to display Table of Contents«
|
SURF |
|
|
|
|
|
SURF |
|
|
|
|
Bulk Data Entry
SURF – Surface Definition
Defines a face of a 2D or 3D element as part of a surface.
Format
(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
SURF |
SRFID |
ELFACE |
|
|
|
|
|
|
|
|
EID1 |
GA1 |
GB1 |
NORMAL1 |
|
|
|
|
|
|
EID2 |
GA2 |
GB2 |
NORMAL2 |
|
|
|
|
|
|
EID3 |
... |
... |
... |
|
|
|
|
|
|
... |
... |
|
|
|
|
|
|
|
In this format, surface is represented as collection of 3- or 4-noded polygons (facets). Each facet is defined by 3 or 4 GRID IDs.
(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
SURF |
SRFID |
FACE |
|
|
|
|
|
|
|
|
GA1 |
GB1 |
GC1 |
GD1 |
|
|
|
|
|
|
GA2 |
GB2 |
GC2 |
GD2 |
|
|
|
|
|
|
GA3 |
... |
... |
... |
|
|
|
|
|
|
... |
... |
|
|
|
|
|
|
|
A surface may also be defined using a form of the SET bulk data entry. With this approach, the surface is composed of all selected 2D elements and the external faces of all selected 3D elements; that is, those faces that are not connected to any other 3D elements faces in the model.
To use this format, the SURF keyword is used in place of the SET keyword and the TYPE must be ELEM. All methods for defining a set of type ELEM are valid for this form of surface definition. Refer to the SET bulk data entry.
Field |
Contents |
SRFID |
Surface identification number. No default (Integer > 0) |
ELFACE |
Flag indicating that the surface is composed of an element face. |
EID# |
2D or 3D element identification number. No default (Integer > 0) |
GA# |
Grid point identification number at the corner of the desired face of a 3D element. This field must be blank for 2D elements. Default = blank (Integer > 0, blank) |
GB# |
Optional grid point identification number. Used to identify face of 3D elements. See comment 1. Default = blank (Integer > 0, blank) |
NORMAL |
Identifies the normal direction for a face of the surface. The normal of a face of a surface may be different from the normal of the underlying elements. 0: normal matches the normal of the underlying element. For 3D elements, this is pointing into the element. 1: normal direction is opposite of the underlying element. For 3D elements, this is pointing out of the element. Default = 0 (0 or 1) |
FACE |
Flag indicating that the surface is composed of 3-noded or 4-noded polygons (facets). |
GA#, GB#, GC#, GD# |
Grid point identification numbers at the corners of the facet of a 3-noded or 4-noded element. If only GA#, GB#, GC# are specified, it references the facet of a 3-noded element. If GA#, GB#, GC#, and GD# are specified, it references the facet of a 4-noded element. No default (Integer > 0) |
Comments
| 1. | GB is used to identify faces of solid elements based on the following table: |
For HEXA elements: |
Grid point identification number at a corner of the desired face that is diagonally opposite GA. |
|
|---|---|---|
For PENTA elements: |
Quad faces: |
Grid point identification number at a corner of the desired face that is diagonally opposite GA. |
Tria faces: |
Leave blank. |
|
For TETRA elements: |
Grid point identification number at the corner opposite the desired face. |
|
For PYRA elements: |
Quad faces: |
Leave blank |
Tria faces: |
GA and GB must specify the grids on the edge of the face that borders the quadrilateral face, and the grids must be ordered so that they define an inward normal using the right hand rule. |
|
| 2. | ELIST is an alternative to SET and SURF, but ELIST is intended only to provide compatibility with Nastran decks. It is recommended to use SURF/SET instead of ELIST. Additionally, |
| • | The SURF and SET entries may not be combined with ELIST entries to define damp elements. |
| • | ELIST entries are internally converted to SET entries. If ELIST is referenced on a minimum of one MFLUID entry, then all MFLUID entries in a model must reference ELIST entries. In such cases, if an MFLUID entry references a particular Set Identification Number (<SID>) to define WSURF1/WSURF2 fields without a corresponding ELIST,<SID> in the model, then OptiStruct will not search for a SET/SURF,<SID>. |
| 3. | This card is represented as a contactsurface in HyperMesh. |
See Also: