Abstract

The effect of bearing length to diameter (L/D) ratio and large disk position on nonlinear vibration of a flexible rotor-bearing system was investigated. The rotor consisted of a shaft modeled by one-dimensional finite elements (FEs) and disks. It was supported by a self-aligning ball bearing (BB) and an axial-groove journal bearing (JB). Two JB's L/D ratios of 0.4 and 0.6, two large disk positions of 340 and 575 mm measured from the BB, and two bearing models that consider both journal's lateral and angular motion (model A) and consider only journal's lateral motion (model B) were investigated. The degrees-of-freedom (DOF) of the equation of motion (EOM) were reduced to those of the boundary DOF by real mode component mode synthesis (CMS) that retains only the first forward and backward modes of the internal DOF. Shooting method and Floquet multiplier analysis were applied to the reduced EOM to obtain limit cycles and their stability, which indicates Hopf bifurcation type. Numerical results indicated that supercritical bifurcation only occurred in the case of L/D = 0.4 and large disk position 575 mm for both bearing models. Otherwise, the subcritical bifurcation occurred except the case of L/D = 0.6 with the large disk position 575 mm that supercritical bifurcation occurred if model B was used. The experiment with the same parameters used in the calculation was conducted as verification. The experimental results showed the same bifurcation type as calculated by using model A.

References

1.
Muszynska
,
A.
,
1988
, “
Stability of Whirl and Whip in Rotor/Bearing Systems
,”
J. Sound Vib.
,
127
(
1
), pp.
49
64
.10.1016/0022-460X(88)90349-5
2.
Childs
,
D.
,
1993
, “
Turbomachinery Rotordynamics: Phenomena
,”
Modeling, & Analysis
,
Wiley
,
New York
.
3.
Noah
,
S. T.
, and
Sundararajan
,
P.
,
1995
, “
Significance of Considering Nonlinear Effects in Predicting the Dynamic Behavior of Rotating Machinery
,”
J. Vib. Control
,
1
(
4
), pp.
431
458
.10.1177/107754639500100403
4.
Castro
,
H. F.
,
Cavalca
,
K. L.
, and
Nordman
,
R.
,
2006
, “
Rotor-Bearing Systems Instabilities Considering a Non-Linear Hydrodynamic Model
,” Ph.d. thesis,
Seventh IFToMM-Conference on Rotor Dynamics
, Vienna, Austria, Sept. 25–28, pp.
1
10
.
5.
Ma
,
H.
,
Li
,
H.
,
Zhao
,
X.
,
Niu
,
H.
, and
Wen
,
B.
,
2013
, “
Effects of Eccentric Phase Difference Between Two Discs on Oil-Film Instability in a Rotor–Bearing System
,”
J. Mech. Syst. Signal Process
,
41
(
1–2
), pp.
526
545
.10.1016/j.ymssp.2013.05.006
6.
Castro
,
H. F.
,
Cavalca
,
K. L.
, and
Nordman
,
R.
,
2008
, “
Rotor-Bearing Systems Instabilities Considering a Non-Linear Hydrodynamic Model
,”
J. Sound. Vib.
,
317
(
1–2
), pp.
273
293
.10.1016/j.jsv.2008.02.047
7.
Cao
,
J. F.
,
2012
, “
Transient Analysis of Flexible Rotors With Nonlinear Bearings, Dampers and External Forces
,”
Ph.D. thesis
,
University of Virginia
, Charlottesville, VA.https://libraetd.lib.virginia.edu/public_view/fx719m78b
8.
Zheng
,
T.
, and
Hasebe
,
N.
,
2000
, “
Nonlinear Dynamic Behaviors of a Complex Rotor-Bearing System
,”
ASME J. Appl. Mech.
,
67
(
3
), pp.
485
495
.10.1115/1.1286208
9.
Arumugam
,
P.
,
Swarnamani
,
S.
, and
Prabhu
,
B. S.
,
1997
, “
Effects of Journal Misalignment on the Performance Characteristics of Three-Lobe Bearings
,”
Wear
,
206
(
1–2
), pp.
122
129
.10.1016/S0043-1648(96)07337-1
10.
Nikolakopoulos
,
P. G.
, and
Papadopoulos
,
C. A.
,
1994
, “
Non-Linearities in Misaligned Journal Bearings
,”
Tribol. Int.
,
27
(
4
), pp.
243
257
.10.1016/0301-679X(94)90004-3
11.
Nikolakopoulos
,
P. G.
, and
Papadopoulos
,
C. A.
,
1995
, “
Lyapunov's Stability of Nonlinear Misaligned Journal Bearings
,”
ASME J. Eng. Gas Turbines Power
,
117
(
3
), pp.
576
581
.10.1115/1.2814134
12.
Koondilogpiboon
,
N.
, and
Inoue
,
T.
,
2019
, “
Nonlinear Vibration Prediction of a Highly Flexible Rotor Supported by an Axial Groove Journal Bearing Considering Journal Angular Whirling Motion
,”
ASME J. Eng. Gas Turbines Power
, 142(4), p. 041025.10.1115/1.4044761
13.
Guyan
,
R. J.
,
1965
, “
Reduction of Stiffness and Mass Matrices
,”
AIAA J.
,
3
(
2
), pp.
380
380
.10.2514/3.2874
14.
Qu
,
Z.
,
2004
,
Model Order Reduction Techniques
,
Springer-Verlag
,
New York
.
15.
Van der Valk
,
P.
,
2010
, “
Model Reduction & Interface Modeling in Dynamic Substructuring: Application to a Multi-Megawatt Wind Turbine
,” M.Sc. thesis, TU Delft, Delft, The Netherlands.
16.
Kano
,
H.
,
Ito
,
M.
, and
Inoue
,
T.
,
2019
, “
Order Reduction and Bifurcation Analysis of a Flexible Rotor System Supported by a Full Circular Journal Bearing
,”
Nonlinear Dyn.
,
95
(
4
), pp.
3275
3294
.10.1007/s11071-018-04755-z
17.
Craig
,
R.
, and
Bampton
,
M.
,
1968
, “
Coupling of Substructures for Dynamic Analyses
,”
AIAA J.
,
6
(
7
), pp.
1313
1319
.10.2514/3.4741
18.
Kobayashi
,
M.
, and
Aoyama
,
S.
,
2011
, “
Transient Response Analysis of a High-Speed Rotor Using Constraint Real Mode Synthesis
,”
JSME J. Environ. Eng.
,
6
(
3
), pp.
527
541
.10.1299/jee.6.527
19.
Craig
,
R. R.
, and
Chang
,
C. J.
,
1976
, “
A Review of Substructure Coupling Methods for Dynamic Analysis
,”
Adv. Eng. Sci.
,
2
, pp.
393
408
.https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770003325.pdf
20.
Genta
,
G.
,
2005
,
Dynamics of Rotating Systems
,
Springer-Verlag
,
New York
.
21.
Matsushita
,
O.
,
Tanaka
,
M.
,
Kanki
,
H.
,
Kobayashi
,
M.
, and
Keogh
,
P.
,
2017
,
Vibrations of Rotating Machinery
,
Springer-Verlag
,
Japan, Tokyo
.
22.
Glasgow
,
D. A.
, and
Nelson
,
H. D.
,
1980
, “
Stability Analysis of Rotor-Bearing Systems Using Component Mode Synthesis
,”
ASME J. Mech. Des.
,
102
(
2
), pp.
352
359
.10.1115/1.3254751
23.
Nelson
,
H. D.
,
Meacham
,
W. L.
,
Fleming
,
D. P.
, and
Kascak
,
A. F.
,
1983
, “
Nonlinear Analysis of Rotor-Bearing Systems Using Component Mode Synthesis
,”
ASME J. Eng. Power
,
105
(
3
), pp.
606
614
.10.1115/1.3227460
24.
Sundararajan
,
P.
, and
Noah
,
S. T.
,
1998
, “
An Algorithm for Response and Stability of Large Order Non-Linear Systems—Application to Rotor Systems
,”
J. Sound Vib.
,
214
(
4
), pp.
695
723
.10.1006/jsvi.1998.1614
25.
Kim
,
S.
, and
Palazzolo
,
A.
,
2018
, “
Shooting/Continuation Based Bifurcation Analysis of Large Order Nonlinear Rotordynamic System
,”
14th International Conference on Vibration Engineering and Technology of Machinery (VETOMAC XIV)
,
Lisbon, Portugal
, Sept. 10–13.10.1051/matecconf/201821118003
26.
Harris T
,
A.
,
1991
,
Rolling Bearing Analysis
,
Wiley
,
New York
.
27.
Khonsari
,
M. M.
, and
Booser
,
E. R.
,
2001
,
Applied Tribology
,
Wiley
,
New York
.
28.
Szeri
,
A. Z.
,
2010
,
Fluid Film Lubrication
, 2nd ed.,
Cambridge University Press
,
Cambridge, UK
.
29.
Lund
,
J. V. V.
, and
Thomsen
,
K. K.
,
1978
, “
A Calculation Method and Data for the Dynamic Coefficients of Oil-Lubricated Journal Bearings
,”
Topics in Fluid Film Bearings and Rotor Bearing System Design and Optimization
, American Society of Mechanical Engineer,
New York
, pp.
1
28
.
30.
Kim
,
S.
, and
Palazzolo
,
A. B.
,
2017
, “
Bifurcation Analysis of a Rotor Supported by Five-Pad Tilting Pad Journal Bearings Using Numerical Continuation
,”
ASME J. Tribol.
,
140
(
2
), p. 021701.10.1115/1.4037699
31.
Nayfeh
,
A. H.
, and
Balachandran
,
B.
,
1995
,
Applied Nonlinear Dynamics
,
Wiley
,
New York
.
32.
Seydel
,
R.
,
1994
,
From Equilibrium to Chaos: Practical Bifurcation and Stability Analysis
,
Springer-Verlag
,
New York
.
You do not currently have access to this content.