Bulk Data Entry Specifies grids that determine the Rotor Line
model.
Format
| (1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
| ROTORG |
ROTORID |
GRID1 |
GRID2 |
etc. |
GRIDn |
|
|
|
|
Alternate Format
| (1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
| ROTORG |
ROTORID |
GRID1 |
THRU |
GRID2 |
|
|
|
|
|
Example
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(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
| ROTORG |
25 |
2345 |
2356 |
2400 |
2450 |
|
|
|
|
Example (Alternate Format)
| (1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
| ROTORG |
30 |
2300 |
THRU |
2400 |
|
|
|
|
|
Definitions
| Field |
Contents |
SI Unit Example |
| ROTORID |
- setid
- The identification number of a rotor.
<INTEGER > 0>
|
|
| GRIDi |
List of grids that define
the rotor line model. No default <INTEGER > 0>
|
|
| THRU
(optional) |
Flag indicating that a
range of grid identification numbers is defined. The initial and
final grids are specified on the fields either side of the field
containing the THRU flag. |
|
Comments
- All grid point entries specified on the
ROTORG entry must be unique. The program will run into an
error, if duplicate grid entries are specified.
- Multiple ROTORG entries
can be defined with the same ROTORID.
- This ROTORG entry is
used to define a Rotor Line model; therefore, for a specific
ROTORID, all grids specified on the ROTORG
entry must be collinear. OptiStruct automatically checks
if the grids are collinear during a run.
- Rotors in frequency response and complex
eigenvalue solutions can be replaced using superelements. Superelements can be
attached to the grids that define the rotor in the ROTORG Bulk
Data Entry. Craig-Bampton Nodal Formulation (CBN) or Guyan Reduction (GUYAN) can be
specified on the METHOD field in the CMSMETH Bulk Data Entry to generate the
superelements. The superelement replaces the beam elements used to model the rotor.
The ASET grid points should correspond to the
GRIDi points specified on the ROTORG Bulk
Data Entry. The interface grid points of the superelement used to model the rotor
should be exactly the same grid points defined on the ROTORG
entry. The General Modal Formulation (GM method) cannot be used to generate
superelements for Rotor dynamics.
- If superelements are not used, connections
between grids in the Rotor Line model and those not listed on the
ROTORG entry must be defined using MPC's
or rigid elements.
- If superelements are used, connections
between grids in the Rotor Line model and those in the residual structure must be
defined using MPC's or rigid elements.
- The mass of the Rotor Line model should be
defined on the grids defined on the grids specified by the ROTORG
Bulk Data Entry.