RSPINR
Bulk Data Entry Defines the relative spin rates between rotors and rotor damping parameters during a rotor dynamic analysis in Static, Modal Complex Eigenvalue or Frequency Response solution sequences.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
RSPINR | ROTORID | GRIDA | GRIDB | SPDUNIT | SPTID | ||||
GR | ALPHAR1 | ALPHAR2 | WR3R | WR4R | WRHR | HYBRID |
Example
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
RSPINR | 130 | 2400 | 2401 | FREQ | 200 | ||||
0.03 | 1000 | 1500 | 1200 | 3 |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
ROTORID |
No default <Integer > 0> |
|
GRIDA | Identifies a grid on the
Rotor Line Model (ROTORG) or 3D rotor axis
(ROTOR). GRIDA and GRIDB define the positive rotor spin direction. The vector connecting GRIDA and GRIDB is the positive direction vector. For 1D rotors, the rotor axis is defined using the ROTORG Bulk Data Entry and the two grids (GRIDA, GRIDB) are also specified on the ROTORG Bulk Data Entry. For 3D rotors, the rotor axis is defined using the ROTOR Bulk Data Entry. No default <Integer > 0> |
|
GRIDB | Identifies a grid on the
Rotor Line Model (ROTORG) or 3D rotor axis
(ROTOR). GRIDA and GRIDB define the positive rotor spin direction. The vector connecting GRIDA and GRIDB is the positive direction vector. For 1D rotors, the rotor axis is defined using the ROTORG Bulk Data Entry and the two grids (GRIDA, GRIDB) are also specified on the ROTORG Bulk Data Entry. For 3D rotors, the rotor axis is defined using the ROTOR Bulk Data Entry. No default <Integer > 0> |
|
SPDUNIT |
No default |
|
SPTID |
No default <Integer > 0/Real> |
|
GR | Rotor structural damping factor. 4
6 Default = 0.0 <Real> |
|
ALPHAR1 | Scale factor applied to the rotor mass matrix for Rayleigh
damping. 5
6 Default = 0.0 <Real> |
|
ALPHAR2 | Scale factor applied to the rotor stiffness matrix for Rayleigh
damping. 5
6 Default = 0.0 <Real> |
|
WR3R | Average excitation frequency for calculation of rotor damping and
circulation terms for rotor structural damping specified through
GR field. Default = 0.0 <Real> |
|
WR4R | Average excitation frequency for calculation of rotor damping and
circulation terms for rotor structural damping specified through
GE (material, bushing etc.)
entries. Default = 0.0 <Real> |
|
WRHR | Average excitation frequency for calculation of rotor damping and
circulation terms for rotor structural hybrid damping specified
through HYBRID entry. Default = 0.0 <Real> |
|
HYBRID | Hybrid damping. References the identification number of a
HYBDAMP entry for hybrid damping
specification. Can be used to specify frequency-dependent hybrid
damping value for each rotor (ROTORID). 6 Default = 0 <Integer ≥ 0> |
Comments
- A RSPINR or RSPINT Bulk Data Entries must exist for each rotor, whether the rotor is defined as a 1D rotor (ROTORG) or 3D rotor (ROTOR).
- GRIDA and GRIDB define the positive rotor spin direction. The vector connecting GRIDA and GRIDB is the positive direction vector. For 1D rotors, the rotor axis is defined using the ROTORG Bulk Data Entry and the two grids (GRIDA, GRIDB) are also specified on the ROTORG Bulk Data Entry. For 3D rotors, the rotor axis is defined using the ROTOR Bulk Data Entry.
- An integer or a real number can be input in the SPTID field. If SPTID is an integer, it references a DDVAL Bulk Data Entry that specifies the relative rotor spin rates. Each rotor must be assigned the same number of spin rates. To determine relative spin rates, the table entries which contain the sequence of spin rates are correlated. The i'th entry for each rotor corresponds to the relative spin rates between rotors at RPMi/FREQi. The spin rates for the reference rotor must be specified in ascending or descending order.
- Rotor structural damping factor
(
) can be incorporated as either
equivalent viscous damping or structural damping depending on the solution sequence.
Or,
Where, WR3 is a parameter defined as a field on RSPINR entry, or by PARAM, WR3. In case both are defined, then WR3 on RSPINR takes precedence. GR is defined as a field on the RSPINR Bulk Data Entry.
The selection depends on the following factors:- Modal frequency response or Complex eigenvalue analysis
- Synchronous or Asynchronous solutions
- Value of PARAM, GYROAVG
- The Rayleigh damping
value for the rotor is calculated from ALPHA1 and
ALPHA2.
and
are used to define the Rayleigh viscous damping
as:
and
- For detailed information on how each type of rotor damping enters into the system equations through their corresponding damping and circulation terms. Refer to Rotor Dynamics in the User Guide.
- Rotor damping is cumulative and caution should be exercised when multiple damping effects are assigned.