DMIGMOD

Bulk Data Entry Defines changes in the contents of a super element from H3DDMIG input.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
DMIGMOD MTXNAME SHFGID SHFSPID SHFSPID_F SHFCID SHFEID SHFRID    
  HYBDAMP METHOD SDAMP KDAMP METHOD_F SDAMP_F KDAMP_F    
  ORIGIN A1 A2 A3          
  GIDMAP GID1 GID1A GID2 GID2A GID3 GID3A    
  CIDMAP CID1 CID1A CID2 CID2A CID3 CID3A    
  RELOC PA1 PA2 PA3 PB1 PB2 PB3 MIRROR  
  GRDTOL ERREXT TOLEXT ERRINT TOLINT        

Definitions

Field Contents SI Unit Example
MTXNAME Matrix name defined on ASSIGN,H3DDMIG.

No default (1 to 6 characters)

  
SHFGID All Grid identification numbers in the superelement are shifted by the specified value. If this field is left blank, then a shift does not occur. 2

Default = blank (Integer or blank)

  
SHFSPID All SPOINT identification numbers in the superelement are shifted by the specified value. If this field is left blank, then a shift does not occur. 2

Default = blank (Integer or blank)

  
SHFSPID_F All Fluid SPOINT identification numbers in the superelement are shifted by the specified value. If this field is left blank, then a shift does not occur. 2

Default = blank (Integer or blank)

  
SHFCID All Coordinate System identification numbers in the superelement are shifted by the specified value. If this field is left blank, then a shift does not occur. 2

Default = blank (Integer or blank)

  
SHFEID All Element identification numbers in the superelement are shifted by the specified value. If this field is left blank, then a shift does not occur. 2

Default = blank (Integer or blank)

  
SHFRID All Rigid Element identification numbers in the superelement are shifted by the specified value. If this field is left blank, then a shift does not occur. 2

Default = blank (Integer or blank)

  
HYBDAMP Keyword for the remaining data for superelement damping.  
METHOD EIGRL card identification number. Hybrid damping would be applied on the superelements for the modes referred by EIGRL card. If blank, then applied damping on all the modes.

Default = blank (Integer > 0, or blank)

  
SDAMP Identification number of TABDMP1 entry for modal damping.

No default (Integer > 0)

  
KDAMP
-1
Viscous modal damping is entered into the complex stiffness matrix as structural damping instead of viscous damping.

Default = 1 (Integer)

  
METHOD_F EIGRL card identification number. Hybrid damping would be applied on the fluid part of superelement for the modes referred by the EIGRL card. If blank, then modal damping is applied damping to all the fluid modes.  
SDAMP_F Identification number of TABDMP1 entry for fluid modal damping of the superelement.

No default (Integer > 0)

  
KDAMP_F
-1
Viscous modal damping is entered into the complex stiffness matrix as structural damping instead of viscous damping.

Default = 1 (Integer)

  
ORIGIN Keyword for defining the new ORIGIN for DMIG.  
A1, A2, A3 Defines the new location of the origin of the DMIG.

Default = 0.0 (Real)

  
GIDMAP Keyword for defining mapped grid ID pairs.  
GIDn, GIDnA Mapped grid ID pairs.  
CIDMAP Keyword for defining mapped coordinate system ID pairs.  
CIDn, CIDnA Mapped coordinate system ID pairs.  
RELOC Keyword indicating that matching grid point ID pairs in the residual structure and superelement are to follow. 1  
PA1, PA2, PA3 ID's of three non-collinear grid points in the residual structure.  
PB1, PB2, PB3 ID's of three non-collinear grid points in the superelement that will be matched to corresponding grid points in the residual structure (defined by PA1, PA2 and PA3).  
MIRROR Flag to indicate that a relocation operation is mirroring/reflecting. 4  
GRDTOL Indicates that the grid point tolerance settings between matching residual and superelement grids are to follow.  
ERREXT Specifies whether OptiStruct will:
ERROR (Default)
Errors out.
WARN
Outputs a warning for inconsistent exterior grid locations based on a defined tolerance value (TOLEXT).
  
TOLEXT Tolerance value to compare exterior grid locations.

Default = 1.0e-15

  
ERRINT Specifies whether OptiStruct will:
ERROR (Default)
Errors out.
WARN
Outputs a warning for inconsistent interior grid locations based on a defined tolerance value (TOLINT).
  
TOLINT Tolerance value to compare interior grid locations.

Default = 1.0e-5

  

Comments

  1. The RELOC entry and its related fields define three matching grid point pairs on the residual structure and the superelement. The superelement defined using ASSIGN, H3DDMIG is relocated (translated and rotated, as required) such that the three non-collinear grids PB1, PB2, and PB3 coincide with PA1, PA2, and PA3, respectively on the residual structure.


    Figure 1.
  2. Identification numbers of certain entities in a superelement can be modified during H3DDMIG input. Negative integers can be input in the shift fields on this entry (see fields beginning with 'SHF' above), however, care should be taken to ensure that the identification numbers are not shifted to negative values. The values of identification numbers after shifting should always be greater than zero, otherwise, the run will error out.
  3. The use-case of GIDMAP is to renumber the interface grids IDs such that they match with the IDs used in the residual structure. Also, renumbering interior grids IDs such that they do not conflict with exterior grids or with interior grids in another superelement. For the latter use-case, SHFGID will also be used to avoid the conflict. If both GIDMAP and SHFGID are used together for the same superelement, the renumbered grids with GIDMAP will not be renumbered again by SHFGID.
  4. When RELOC and MIRROR are used, there are two ways of defining the reflection.
    • Define PA1, PA2, and PA3 which identify the plane of reflection about which the entire superelement will be mirrored/reflected.
    • Define PA1, PA2, and PA3 in the residual structure and PB1, PB2, and PB3 in the super element. In that case, the super element is mirrored/reflected after being relocated.
    Note: Any rotation, translation or mirroring required to complete the mirroring process is accomplished internally by OptiStruct. These three grid points cannot be collinear.