This paper addresses self-diagnostic properties of active magnetic bearing (AMB) supported rotors for online detection of the transverse crack on a rotating shaft. In addition to pure levitation, the rotor supporting bearing also serves as an actuator that transforms current signals additionally injected into the control loop into the superimposed specially selected excitation forces into the suspended rotor. These additional excitations induce combination frequencies in the rotor response, providing unique signatures for the presence of crack. The background of theoretical modeling, experimental, and computer simulation results for the AMB supported cracked rotor with self-diagnostic excitation forces are presented and discussed.

Issue Section:
Gas Turbines: Structures and Dynamics
Keywords:
crack detection, magnetic bearings, rotors, structural engineering
Topics:
Excitation, Rotors, Magnetic bearings, Bearings
1.
Maslen
,
E. H.
, 2008, “
Smart Machine Advances in Rotating Machinery
,”
9th International Conference on Vibrations in Rotating Machinery
,
IMechE
,
Exeter, UK
, Sept. 8–10.
2.
Larsonneur
,
R.
, and
Richard
,
P.
, 2008, “
Smart Turbomachines Using Active Magnetic Bearings
,” ASME Paper No. GT2008-51299.
3.
Penny
,
J. E. T.
,
Friswell
,
M. I.
, and
Zhou
,
C.
, 2006, “
Condition Monitoring of Rotating Machinery Using Active Magnetic Bearings
,”
ISMA 2006
, Leuven, Belgium, pp.
3497
–
3506
.
4.
Penny
,
J. E. T.
, and
Friswell
,
M. I.
, 2007, “
The Dynamics of Cracked Rotors
,”
IMAC XXV
, Orlando, FL, Paper No. 198, 2007.
5.
Mayes
,
I. W.
, and
Davies
,
W. G. R.
, 1984, “
Analysis of the Response of a Multi-Rotor-Bearing System Containing a Transverse Crack in a Rotor
,”
ASME J. Vib., Acoust., Stress, Reliab. Des.
0739-3717,
106
, pp.
139
–
145
.
Crossref
Search ADS
 
6.
Sawicki
,
J. T.
,
Friswell
,
M. I.
,
Pesch
,
A. H.
, and
Wroblewski
,
A.
, 2008, “
Condition Monitoring of Rotor Using Active Magnetic Actuator
,” ASME Paper No. GT2008-51169.
7.
Mani
,
G.
,
Quinn
,
D. D.
, and
Kasarda
,
M.
, 2006, “
Active Health Monitoring in a Rotating Cracked Shaft Using Active Magnetic Bearings as Force Actuators
,”
J. Sound Vib.
0022-460X,
294
, pp.
454
–
465
.
Crossref
Search ADS
 
8.
Ishida
,
Y.
, and
Inoue
,
T.
, 2006, “
Detection of a Rotor Crack Using a Harmonic Excitation and Nonlinear Vibration Analysis
,”
ASME J. Vibr. Acoust.
0739-3717,
128
, pp.
741
–
749
.
Crossref
Search ADS
 
9.
Sawicki
,
J. T.
, and
Lekki
,
J. D.
, 2008, “
Smart Structural Health Monitoring of Rotating Components Using Active Magnetic Force Actuators
,”
NASA Aviation Safety Technical Conference
, Denver, CO, Oct. 21–23.
10.
Sawicki
,
J. T.
, 2009, “
Rotor Crack Detection Using Active Magnetic Bearings
,”
Solid State Phenom.
1012-0394,
144
, pp.
9
–
15
.
Crossref
Search ADS
 
11.
Sawicki
,
J. T.
,
Sen
,
A. K.
, and
Litak
,
G.
, 2009, “
Multiresolution Wavelet Analysis of the Dynamics of a Cracked Rotor
,”
Int. J. Rotating Mach.
1023-621X,
2009
, p.
265198
.
12.
Storozhev
,
D. L.
, 2009, “
Smart Rotating Machines for Structural Health Monitoring
,” MS thesis, Cleveland State University, Cleveland, OH.
13.
Litak
,
G.
, and
Sawicki
,
J. T.
, 2009, “
Intermittent Behaviour of a Cracked Rotor in the Resonance Region
,”
Chaos, Solitons Fractals
0960-0779,
42
, pp.
1495
–
1501
.
Crossref
Search ADS
 
14.
Litak
,
G.
,
Sawicki
,
J. T.
, and
Kasperek
,
R.
, 2009, “
Cracked Rotor Detection by Recurrence Plots
,”
Nondestr. Test. Eval.
1058-9759,
24
(
4
), pp.
347
–
351
.
Crossref
Search ADS
 
16.
Wu
,
X.
,
Sawicki
,
J. T.
,
Friswell
,
M. I.
, and
Baaklini
,
G.
, 2005, “
Finite Element Analysis of Coupled Lateral and Torsional Vibration of a Rotor With Multiple Cracks
,” ASME Paper No. GT2005-68839.
Copyright © 2011
 by American Society of Mechanical Engineers
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