Rod-fastened rotors are composed of some disks clamped together by a central tie rod or several tie rods distributed along the circumference. Due to the nonlinear flexural stiffness of the contact interfaces in disks, especially when the contact surfaces are partially separated, the dynamics of the rod-fastened rotors are potentially different from that of the solid rotors. In this paper, the nonlinear flexural stiffness of a rod-fastened Jeffcott rotor is calculated by the finite element method (FEM). Then the harmonic balance method is adopted to analyze the dynamics of the rotor. The flexural stiffness of a rod-fastened Jeffcott rotor dramatically decreased with the increase of the dimensionless load γ1 from 1 to 2.5. Thus, the dynamics of the rotor were nonlinear when it was subjected to a large unbalance force. The response of the rotating rotor contains a predominantly forward 1X component or both forward 1X component and backward 1X components. However, the rotor may settle in a state depending upon both the operating parameters and its history.

Issue Section:
Research Papers
Keywords:
rod-fastened Jeffcott rotor, nonlinear flexural stiffness, nonlinear rotor dynamics
Topics:
Rotors, Stiffness

References

1.
Zhang
,
Y. C.
,
Du
,
Z. G.
,
Shi
,
L. M.
, and Liu, S. Q.,
2010
, “
Determination of Contact Stiffness of Rod-Fastened Rotors Based on Modal Test and Finite Element Analysis
,”
ASME J. Eng. Gas Turbines Power
,
132
(
9
), p.
094501
.10.1115/1.4000591
Google Scholar
Crossref
Search ADS
 
2.
Kim
,
Y. C.
 and
Kim
,
K. W.
,
2006
, “
Influence of Lamination Pressure Upon the Stiffness of Laminated Rotor
,”
KSME Int. J
,
49
(
2
), pp.
426
–
431
.10.1299/jsmec.49.426
3.
Isa
,
A. A. M.
,
Penny
,
J. E. T.
, and
Garvey
,
S. D.
,
2000
, “
The Dynamics of Bolted and Laminated Rotors
,”
Proc. SPIE
,
4062
, pp.
867
–
872
.
4.
Klompas
,
N.
,
1983
, “
Effects of Anomalous Rotor Joints on Turbomachine Dynamics
,”
ASME J. Eng. Power
,
105
(
4
), pp.
927
–
934
.10.1115/1.3227502
Google Scholar
Crossref
Search ADS
 
5.
Liu
,
H.
,
Li
,
C.
,
Wang
,
W. M.
,
Qi,
,
X. B.,
 and
Jing,
,
M. Q.,
2010
, “
Nonlinear Dynamic Analysis of a Flexible Rod Fastening Rotor Bearing System
,”
ASME
Paper No. GT2010-23368.10.1115/GT2010-23368
6.
Lee
,
A. S.
 and
Lee
,
Y. S.
,
2001
, “
Rotordynamic Characteristics of an APU Gas Turbine Rotor-Bearing System Having a Tie Shaft
,”
KSME Int. J.
,
15
(
2
), pp.
152
–
159
.
7.
Lu
,
M. J.
,
Geng
,
H. P.
,
Yang
,
B. S.
, and Yu, L.,
2010
, “
Finite Element Method for Disc-Rotor Dynamic Characteristics Analysis of Gas Turbine Rotor Considering Contact Effects and Rod Preload
,”
2010 IEEE International Conference on Mechatronics and Automation
(ICMA)
, Xi'an, China, August 4–7, pp.
1179
–
1183
.10.1109/ICMA.2010.5587948
8.
Darlow
,
M. S.
,
Murphy
,
B. T.
,
Elder
,
J. A.
, and
Sandor
,
G. N.
,
1980
, “
Extension of the Transfer-Matrix Method for Rotordynamic Analysis to Include a Direct-Representation of Conical Sections and Trunnions
,”
ASME J. Mech. Des.
,
102
(
1
), pp.
122
–
129
.10.1115/1.3254702
9.
Rao
,
Z. S.
,
Xia
,
S. B.
, and
Wang
G. M.
,
1994
, “
A Study of Contact Stiffness of Flat Rough Surfaces
,”
J. Mech. Strength
,
16
(
3
), pp.
72
–
75
(in Chinese).
10.
Powell
,
M. J. D.
,
1978
, “
A Fast Algorithm for Nonlinearly Constrained Optimization Calculations Numerical Analysis
,”
Numerical Analysis, Biennial Conference, Dundee, Scotland, June 28–July 1
, Springer, Berlin, pp.
144
–
157
.
11.
Kim
,
Y. B.
, and
Noah
S. T.
,
1990
, “
Bifurcation Analysis for a Modified Jeffcott Rotor With Bearing Clearances
,”
Nonlinear Dyn.
,
1
(
3
), pp.
221
–
241
.10.1007/BF01858295
Google Scholar
Crossref
Search ADS
 
12.
Meng
,
G.
, and
Gasch
R.
,
2000
, “
Stability and Stability Degree of a Cracked Flexible Rotor Supported on Journal Bearings
,”
ASME J. Vibr. Acoust.
,
122
(
2
), pp.
116
–
125
.10.1115/1.568448
Google Scholar
Crossref
Search ADS
 
13.
Kang
,
Y.
,
Shih
,
Y.-P.
, and
Lee
,
A.-C.
,
1992
, “
Investigation on the Steady-State Responses of Asymmetric Rotors
,”
ASME J. Vibr. Acoust.
,
114
(
2
), pp.
194
–
208
.10.1115/1.2930249
Google Scholar
Crossref
Search ADS
 
14.
Genta
G.
,
2005
,
Dynamics of Rotating Systems
,
Springer
,
Torino, Italy
, pp.
347
–
358
.
Copyright © 2014 by ASME
You do not currently have access to this content.