Many practical rotor dynamic systems contain shaft/rotor elements that are highly susceptible to transverse cross-sectional cracks due to fatigue. The early detection of mechanical malfunction that can be provided by an effective vibration monitoring system is essential. Two theoretical analyses, global and local asymmetry crack models, are utilized to identify characteristics of the system response that may be directly attributed to the presence of a transverse crack in a rotating shaft. A model consisting of an overhung whirling rotor is utilized to match an experimental test rig. A 2X harmonic component of the system response is shown to be the primary response characteristic resulting from the introduction of a crack. Once the unique characteristics of the system response are identified, they serve then as target observations for the monitoring system.

Issue Section:
Gas Turbines: Structures and Dynamics
Keywords:
rotors, condition monitoring, fatigue cracks, vibration measurement, crack detection
Topics:
Fracture (Materials), Rotors, Stiffness
1.
Zou
,
M.
,
Dayan
,
J.
, and
Green
,
I.
,
2000
, “
Dynamic Simulation and Monitoring of a Non-Contacting Flexibly Mounted Rotor Mechanical Face Seal,” IMechE
,
Proc. Inst. Mech. Eng.
214
(C9), Part C, pp.
1195
–
1206
.
2.
Lee
,
A. S.
, and
Green
,
I.
,
1994
, “
Rotordynamics of a Mechanical Face Seal Riding on a Flexible Shaft
,”
ASME J. Tribol.
,
116
(
2
), pp.
345
–
351
.
3.
Lee
,
A. S.
, and
Green
,
I.
,
1994
, “
Higher Harmonic Oscillations in a Noncontacting FMR Mechanical Face Seal Test Rig
,”
ASME J. Vibr. Acoust.
,
116
(
2
), pp.
161
–
167
.
4.
Lee
,
A. S.
, and
Green
,
I.
,
1995
, “
An Experimental Investigation of the Steady-State Response of a Noncontacting Flexibly Mounted Rotor Mechanical Face Seal
,”
ASME J. Tribol.
,
117
(
1
), pp.
153
–
159
.
5.
Lee
,
A. S.
, and
Green
,
I.
,
1995
, “
Physical Modeling and Data Analysis of the Dynamic Response of a Flexibly Mounted Rotor Mechanical Seal
,”
ASME J. Tribol.
,
117
, pp.
130
–
135
.
6.
Zou
,
M.
, and
Green
,
I.
,
1999
, “
Clearance Control of a Mechanical Face Seal
,”
STLE Tribol. Trans.
,
42
, pp.
535
–
540
.
7.
Zou, M., Dayan, J., and Green, I., 1999, “Parametric Analysis of Contact Control of a Noncontacting Mechanical Face Seal,” in Proceedings of Vibration, Noise and Structural Dynamics, pp. 493–499, April.
8.
Dayan
,
J.
,
Zou
,
M.
, and
Green
,
I.
,
2000
, “
Sensitivity Analysis for the Design and Operation of a Noncontacting Mechanical Face Seal,” IMechE
,
Proc. Inst. Mech. Eng.
214
(C9), Part C, pp.
1207
–
1218
.
9.
Zou
,
M.
,
Dayan
,
J.
, and
Green
,
I.
,
2000
, “
Feasibility of Contact Elimination of a Mechanical Face Seal Through Clearance Adjustment
,”
ASME J. Eng. Gas Turbines Power
,
122
, pp.
478
–
484
.
10.
Dayan, J., Zou, M., and Green, I., 1999, “Contact Elimination in Mechanical Face Seals Using Active Control,” in Proceedings of the IEEE 7th Mediterranean Conference on Control and Automation (MED99), pp. 618–619, June.
11.
Tondl, A., 1965, Some Problems in Rotor Dynamics, Czechoslovakian Academy of Sciences, Chapman & Hall, London.
12.
Henry, T. A., and Okah-Avae, B. E., 1976, “Vibrations in Cracked Shafts,” in Conference on Vibrations in Rotating Machinery, pp. 15–19.
13.
Murray, D. B., and McCraith, J. R., 1984, “Vibrational Method for the Detection of Cracks in Rotating Shafts,” in First Parsons International Turbine Conference, pp. 229–236.
14.
Rao, J. S., 1991, Rotor Dynamics, 2nd edition, Wiley, New York.
15.
Gasch, R., 1976, “Dynamic Behavior of Simple Rotor With a Cross-Sectional Crack,” in Conference on Vibrations in Rotating Machinery, p. 123.
16.
Mayes, I. W., and Davies, W. G. R., 1976, “The Vibrational Behavior of a Rotating Shaft System Containing a Transverse Crack,” in Conference on Vibrations in Rotating Machinery, pp. 53–64.
17.
Imam
,
I.
, and
Azzaro
,
S. H.
,
1989
, “
Development of an On-Line Rotor Crack Detection and Monitoring System
,”
ASME J. Vib., Acoust., Stress, Reliab. Des.
,
111
(
3
), pp.
241
–
250
.
18.
Huang
,
S. C.
,
Huang
,
Y. M.
, and
Shieh
,
S. M.
,
1993
, “
Vibration and Stability of a Rotating Shaft Containing a Transverse Crack
,”
J. Sound Vib.
,
162
, pp.
387
–
401
.
19.
Tsai
,
T.
, and
Wang
,
W.
,
1998
, “
Vibration of a Rotor With a Transverse Open Crack
,”
Proc. Natl. Sci. Counc., Repub. China, Part A: Phys. Sci. Eng.
,
22
, pp.
372
–
384
.
20.
Grabowski
,
B.
,
1980
, “
The Vibrational Behavior of a Turbine Rotor Containing a Transverse Crack
,”
ASME J. Mech. Des.
,
121
, pp.
140
–
146
.
21.
Dimarogonas, A. D., and Paipetis, S. A., 1983, Analytical Methods in Rotor Dynamics, Applied Science.
22.
Herbert, R. G., 1987, “Turbine-Alternator Run-Down Vibration Analysis: Automated Crack Detection,” in 11th Biennial Conference on Mechanical Vibration and Noise, Vol. 2, pp. 631–636.
23.
Inagaki
,
T.
,
Kanki
,
H.
, and
Shiraki
,
K.
,
1982
, “
Transverse Vibrations of a General Cracked-Rotor Bearing System
,”
ASME J. Mech. Des.
,
104
(
2
), pp.
345
–
355
.
24.
Schmied, J., and Kraemer, E., 1984, “Vibrational Behavior of a Rotor With a Cross-Sectional Crack,” in Conference on Vibrations in Rotating Machinery, pp. 183–192.
25.
Nelson
,
H. D.
, and
Nataraj
,
C.
,
1986
, “
The Dynamics of a Rotor System With a Cracked Shaft
,”
ASME J. Vib., Acoust., Stress, Reliab. Des.
,
108
, pp.
189
–
196
.
26.
Sofker, D., Bajkowski, J., and Muller, P. C., 1993, “Crack Detection in Turbo Rotors, Vibrational Analysis and Fault Detection,” in Conference on Mechanical Vibration and Noise, Vol. 60, pp. 277–287.
27.
Meng, G., and Hahn, E. J., 1994, “Dynamic Response of a Cracked Rotor With Some Comments on Crack Detection,” in Proceedings of the International Gas Turbine and Aeroengine Congress and Exposition, June.
28.
Dirr
,
B. O.
, and
Rothkegel
,
W.
,
1994
, “
Detection and Simulation of Small Transverse Cracks in Rotating Shafts
,”
Arch. Appl. Mech.
,
64
(
3
), pp.
206
–
222
.
29.
Inagaki
,
T.
,
Kanki
,
H.
, and
Shiraki
,
K.
,
1980
, “
Response Analysis of a General Asymmetric Rotor-Bearing
,”
ASME J. Mech. Des.
,
102
(
1
), pp.
147
–
157
.
30.
Dimarogonas
,
A. D.
, and
Papadopoulos
,
C. A.
,
1983
, “
Vibration of Cracked Shafts in Bending
,”
J. Sound Vib.
,
91
, pp.
583
–
593
.
31.
Davies
,
W. G. R.
, and
Mayes
,
I. W.
,
1984
, “
The Vibrational Behavior of a Multi-Shaft, Multi-Bearing System in the Presence of a Propogating Transverse Crack
,”
ASME J. Vib., Acoust., Stress, Reliab. Des.
,
106
(
1
), pp.
146
–
153
.
32.
Gasch
,
R.
,
1993
, “
A Survey of the Dynamic Behavior of a Simple Rotating Shaft With a Transverse Crack
,”
J. Sound Vib.
,
160
, pp.
313
–
332
.
33.
Papadopoulos, C. A., and Dimarogonas, A. D., 1987, “Stability of Cracked Rotors in the Coupled Vibration Mode,” in 11th Biennial Conference on Mechanical Vibration and Noise, Vol. 1, pp. 25–34.
34.
Papadopoulos
,
C. A.
, and
Dimarogonas
,
A. D.
,
1987
, “
Coupled Longitudinal and Bending Vibrations of a Rotating Shaft With an Open Crack
,”
J. Sound Vib.
,
117
, pp.
81
–
93
.
35.
Casey, C., 2000, “Crack Detection in Rotor Dynamic System by Vibration Monitoring,” M.S. thesis, Georgia Institute of Technology.
36.
Green
,
I.
, and
Etsion
,
I.
,
1986
, “
A Kinematic Model for Mechanical Seals With Antirotation Locks or Positive Drive Devices
,”
ASME J. Tribol.
,
108
(
1
), pp.
42
–
45
.
37.
Tada, H., Paris, P. C., and Irwin, G. R., 1985, The Stress Analysis of Cracks Handbook, 2nd Ed., Paris Productions, St. Lous, MO.
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