RBE2GS

Bulk Data Entry Defines a rigid element connecting two grid points which are closest to the grid point referenced by the field GS.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
RBE2GS EID GS TYPE     R CM ALPHA  
  XS YS ZS GNi GMi        

Alternate Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
RBE2GS EID GS TYPE     R CM ALPHA  
  XS YS ZS GNi GMi        
  GMk THRU GMl            

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
RBE2GS 19 8       2.1   1.2E-6  
        endl 33 92      

Alternate Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
RBE2GS 19 8       2.1   1.2E-6  
        33 THRU 92 endl 23  
  34 THRU 41            

Definitions

Field Contents SI Unit Example
EID Unique element identification number.

No default (Integer > 0)

  
GS The grid point which is to be used to search for two nearby grids to create RBE2GS element.

Default = blank (Integer > 0)

  
TYPE Type of search conducted for connecting grids. 5
Blank (Default)
The complete model is searched for connecting grids.
NMFLIP
Independent and dependent degrees of freedom are switched.
IIRBE2
Selected grid points will be the independent GN’s of closest existing RBE2 elements.
NMIIRBE2
Behavior is similar to IIRBE2 option, and the independent and dependent grids are switched.
  
R
Real > 0.0
Search Radius to identify connection grids. 5
Real < 0.0
Connection grids, GN, GM are made coincident to GS (or location identified via XS, YS, ZS).
  
CM Components of dependent dof for grid GM.

Default = Blank (Integers 1 through 6 with no embedded blanks: Default blank is 123456)

  
ALPHA Thermal expansion coefficient.

(Real or blank)

  
XS, YS, ZS Identifies the location of the search point if the GS field is blank.

Default = blank (Real)

  
GNi Grid points which are excluded from candidate grids for GN. GNi list, if provided, should end with endl.

Default = blank (Integer > 0, THRU, or blank)

  
GMi Grid points which are excluded from candidate grids for GM. If GNi list is not provided, and GMj list is present, then GNi should have an endl entry.

Default = blank (Integer > 0, THRU, or blank)

  

Comments

  1. EID field values for RBE2GS are unique with respect to all other element IDs.
  2. Either one of GS or XS, YS, ZS fields should be specified, otherwise, the run will print an error.
  3. GNi and GMj lists should end with endl in the field following the last entry in the list. All grid points are not required to exist in the range, if THRU option is used.
  4. Blanks are allowed for GNi and GMj lists. Also, THRU should not be the first populated entry of a continuation line.
  5. If GS is a structural grid attached to part of the physical structure:

    RBE2GS internally generates an RBE2 element with the same ID as the RBE2GS entry. By default, GS is chosen as GN, which is the independent grid and the closest grid within the search radius R, is chosen as GM, the dependent grid (TYPE=blank). After grids in GNi, GMj lists are excluded from the search, the grid GS is chosen as GN and GM is the closest grid within radius R from GS, in this order. If TYPE=NMFLIP, then GN, GM grids are reversed.

    If GS is not a structural grid or if XS, YS, ZS is specified:

    RBE2GS internally generates an RBE2 element with the same ID as the RBE2GS entry. By default, GN is the independent grid and GM is the dependent grid (TYPE=blank). After grids in GNi, GMj lists are excluded from the search, the first two grids within the radius R from GS (or XS, YS, ZS) are identified as GN and GM, in this order. If TYPE=NMFLIP, then GN, GM grids are reversed.

    If TYPE=IIRBE2 or NMIIRB2:

    The rules for identifying the grid points remains the same, as mentioned above, based on GS. After grid identification, the two grids chosen will be the independent GN’s of existing RBE2 elements whose independent grids lie within the search radius R. If TYPE=NMIIRB2, then GN and GM will be reversed. OptiStruct will error out, if there is just one or no RBE2 elements with independent grids in the search radius.