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
setid
Rotor identification number.

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
RPM
Specifies that the relative spin rates are input in Revolutions Per Minute.
FREQ
Specifies that the relative spin rates are input in revolutions (cycles) per unit time.

No default

SPTID
<Integer > 0>
If an integer value (must be greater than 0) is input, it references a DDVAL Bulk Data Entry that specifies the relative rotor spin rates. 3
<Real>
If a real number is input, the value is considered constant.

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

  1. 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).
  2. 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.
  3. 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.
  4. Rotor structural damping factor ( GR MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaebbnrfifHhDYfgasaacH8srps0l bbf9q8WrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbba9q8WqFfea0=yr0R Yxir=Jbba9q8aq0=yq=He9q8qqQ8frFve9Fve9Ff0dmeaabaqaciGa caGaaeqabaqaaeaadaaakeaacaWGhbGaamOuaaaa@335D@ ) can be incorporated as either equivalent viscous damping or structural damping depending on the solution sequence.

    ( C R ) Structural =( GR WR3 ) K R MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaebbnrfifHhDYfgasaacH8srps0l bbf9q8WrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbba9q8WqFfea0=yr0R Yxir=Jbba9q8aq0=yq=He9q8qqQ8frFve9Fve9Ff0dmeaabaqaciGa caGaaeqabaqaaeaadaaakeaadaqadaqaaiaahoeadaWgaaWcbaGaam OuaaqabaaakiaawIcacaGLPaaadaWgaaWcbaGaam4uaiaadshacaWG YbGaamyDaiaadogacaWG0bGaamyDaiaadkhacaWGHbGaamiBaaqaba GccqGH9aqpdaqadaqaamaalaaabaGaam4raiaadkfaaeaacaWGxbGa amOuaiaaiodaaaaacaGLOaGaayzkaaGaaC4samaaBaaaleaacaWGsb aabeaaaaa@4746@

    Or,

    ( C R ) Viscous =( 1+iGR ) K R MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaebbnrfifHhDYfgasaacH8srps0l bbf9q8WrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbba9q8WqFfea0=yr0R Yxir=Jbba9q8aq0=yq=He9q8qqQ8frFve9Fve9Ff0dmeaabaqaciGa caGaaeqabaqaaeaadaaakeaadaqadaqaaiaahoeadaWgaaWcbaGaam OuaaqabaaakiaawIcacaGLPaaadaWgaaWcbaGaamOvaiaadMgacaWG ZbGaam4yaiaad+gacaWG1bGaam4CaaqabaGccqGH9aqpdaqadaqaai aaigdacqGHRaWkcaWGPbGaam4raiaadkfaaiaawIcacaGLPaaacaWH lbWaaSbaaSqaaiaadkfaaeqaaaaa@4475@

    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
  5. The Rayleigh damping value for the rotor is calculated from ALPHA1 and ALPHA2. α R 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaiabeg7aHnaaBa aaleaacaWGsbGaaGymaaqabaaaaa@3949@ and α R 2 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaiabeg7aHnaaBa aaleaacaWGsbGaaGymaaqabaaaaa@3949@ are used to define the Rayleigh viscous damping as:
    ( C R ) R a y l e i g h = α R 1 M R + α R 2 K R MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaebbnrfifHhDYfgasaacH8srps0l bbf9q8WrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbba9q8WqFfea0=yr0R Yxir=Jbba9q8aq0=yq=He9q8qqQ8frFve9Fve9Ff0dmeaabaqaciGa caGaaeqabaqaaeaadaaakeaadaqadaqaaiaahoeadaWgaaWcbaGaam OuaaqabaaakiaawIcacaGLPaaadaWgaaWcbaGaamOuaiaadggacaWG 5bGaamiBaiaadwgacaWGPbGaam4zaiaadIgaaeqaaOGaeyypa0Jaeq ySde2aaSbaaSqaaiaadkfacaaIXaaabeaakiaah2eadaWgaaWcbaGa amOuaaqabaGccqGHRaWkcqaHXoqydaWgaaWcbaGaamOuaiaaikdaae qaaOGaaC4samaaBaaaleaacaWGsbaabeaaaaa@4920@

    and

    ( C R C ) R a y l e i g h = α R 1 M R C + α R 2 K R C MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaebbnrfifHhDYfgasaacH8srps0l bbf9q8WrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbba9q8WqFfea0=yr0R Yxir=Jbba9q8aq0=yq=He9q8qqQ8frFve9Fve9Ff0dmeaabaqaciGa caGaaeqabaqaaeaadaaakeaadaqadaqaaiaahoeadaqhaaWcbaGaam OuaaqaaiaadoeaaaaakiaawIcacaGLPaaadaWgaaWcbaGaamOuaiaa dggacaWG5bGaamiBaiaadwgacaWGPbGaam4zaiaadIgaaeqaaOGaey ypa0JaeqySde2aaSbaaSqaaiaadkfacaaIXaaabeaakiaah2eadaqh aaWcbaGaamOuaaqaaiaadoeaaaGccqGHRaWkcqaHXoqydaWgaaWcba GaamOuaiaaikdaaeqaaOGaaC4samaaDaaaleaacaWGsbaabaGaam4q aaaaaaa@4B7B@

  6. 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.
  7. Rotor damping is cumulative and caution should be exercised when multiple damping effects are assigned.