A laboratory rotor, representing a scaled-down model of a three-stage compressor supported by fluid film bearings on anisotropic flexible supports was analyzed. The support characteristics were measured at the bearing locations by exciting the bearing housings with electromechanical shakers and measuring the acceleration. Direct, cross-coupled, and cross-talk accelerance between supports were measured. Unbalance response and stability analyses of the rotor were performed using polynomial transfer functions extracted from the measured accelarance data. The predicted critical speeds and instability threshold agree with measured data. Predictions using other support models are included to show the effectiveness of this method.

1.
American Petroleum Institute, 1995, “Centrifugal Compressors for Petroleum, Chemical and Gas Service Industries,” API Standard 617, Sixth Ed.
2.
Barrett, L. E., Nicholas, J. C., and Dhar, D., 1986, “The Dynamic Analysis of Rotor-Bearing Systems Using Experimental Bearing Support Compliance Data,” Proceedings of the Fourth International Modal Analysis Conference, Union College, Schenectady, NY, Society for Experimental Mechanics, Bethel, CT, pp. 1531–1535.
3.
Nicholas
,
J. C.
, and
Barrett
,
L. E.
,
1986
, “
The Effect of Bearing Support Flexibility on Critical Speed Prediction
,”
ASLE Trans.
,
29
, No.
3
, pp.
329
338
.
4.
Nicholas, J. C., Whalen, J. K., and Franklin, S. D., 1986, “Improving Critical Speed Calculations Using Flexible Bearing Support FRF Compliance Data,” Proceedings of the 15th Turbomachinery Symposium, Texas A&M University, College Station, TX.
5.
Redmond, I., 1995, “Practical Rotordynamics Modeling Using Combined Measured and Theoretical Data,” Proceedings of the 13th International Modal Analysis Conference, Nashville, TN, Society for Experimental Mechanics, Bethel, CT.
6.
Redmond, I., 1996, “Rotordynamic Modelling Utilizing Dynamic Support Data Obtained From Field Impact Tests,” Proceedings of Sixth International Conference on Vibrations in Rotating Machinery, Oxford, Sept., Paper C500/055/96.
7.
Rouch, K. E., McMains, T. H., and Stephenson, R. W., 1989, “Modeling of Rotor-Foundation Systems Using Frequency-Response Functions in a Finite Element Approach,” 1989 ASME Design Technical Conference 12th Biennial Conference on Mechanical Vibration and Noise, Montreal, Canada ASME, New York, pp. 157–166.
8.
Stephenson
,
R. W.
, and
Rouch
,
K. E.
,
1992
, “
Generating Matrices of the Foundation Structure of a Rotor System From Test Data
,”
J. Sound Vib.
,
154
, No.
3
, pp.
467
484
.
9.
Feng, M. S., and Hahn, E. J., 1998, “On the Identification of a Flexibly Supported Rigid Foundation With Unknown Location of the Principal Axes of Inertia,” Proceedings of ISROMAC-7, the 7th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, Honolulu, HI, Feb., Pacific Center of Thermal Fluid Engineering, Bird Rock Publishing, pp. 705–714.
10.
Lees
,
A. W.
, and
Friswell
,
M. I.
,
1997
, “
The Evaluation of Rotor Imbalance in Flexibly Mounted Machines
,”
J. Sound Vib.
,
208
, No.
5
, pp.
671
683
.
11.
Lees, A. W., Friswell, M. I., Smart, M. G., and Prells, U., 1998, “The Identification of Foundation Vibration Parameters From Running Machine Data,” Proceedings of ISROMAC-7, the 7th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, Honolulu, HI, Feb., Society for Experimental Mechanics, Bethel, CT, pp. 715–724.
12.
Edwards, S., Lees, A. W., and Friswell, M. I., 1999, “The Identification of Rotor Unbalance From Measured Foundation Response Data,” Proceedings of the 17th International Modal Analysis Conference, Feb. 8–11, Kissimmee, FL, Pacific Center of Thermal Fluid Engineering, Bird Rock Publishing, pp. 1610–1615.
13.
Va´zquez, J. A., and Barrett, L. E., 1998, “Representing Flexible Supports by Polynomial Transfer Functions,” ASME Paper 98-GT-27.
14.
Va´zquez, J. A., and Barrett, L. E., 1999, “Transfer Function Representation of Flexible Supports and Casings of Rotating Machinery,” Proceedings of the 17th International Modal Analysis Conference, Feb., 8–11, Kissimmee, FL, Society of Experimental Mechanics, Bethel, CT.
15.
Va´zquez, J. A., 1999, “Using Transfer Functions to Model Flexible Supports and Casings of Rotating Machinery,” Ph.D. dissertation, University of Virginia, Charlottesville, VA, Jan.
16.
Va´zquez, J. A., Barrett, L. E., and Flack, R. D., 1999, “A Flexible Rotor on Flexible Bearing Supports. Part I: Stability,” Proceedings of the 1999 Vibration Conference, Sept. 12–16, Las Vegas, NV, Paper DETC99/VIB-8285.
17.
Va´zquez, J. A., Barrett, L. E., and Flack, R. D., 1999, “A Flexible Rotor on Flexible Bearing Supports. Part II: Unbalance Response,” Proceedings of the 1999 Vibration Conference, Sep. 12–16, Las Vegas, NV, Paper DETC99/VIB-8286.
18.
Branagan, L. A., 1988, “Thermal Analysis of Fixed and Tilting Pad Journal Bearings Including Cross-Film Viscosity Variations and Deformations,” Ph.D. dissertation, University of Virginia, Charlottesville, VA.
19.
Sanathanan
,
C. K.
, and
Koerner
,
J.
,
1963
, “
Transfer Function Synthesis as a Ratio of Two Complex Polynomials
,”
IEEE Trans. Autom. Control
, Jan., Society for Experimental Mechanics, Bethel, Ct, pp.
56
58
.
20.
Richardson, M. H., and Formenti, D. L., 1982, “Parameter Estimation From Frequency Response Measurements Using Fraction Polynomials,” Proceedings of the 1st International Modal Analysis Conference, Orlando, FL, Society for Experimental Mechanics, Bethel, CT, pp. 167–181.
21.
Richardson, M. H., and Formenti, D. L., 1985, “Global Curve Fitting of Frequency Response Measurement using Rational Fraction Polynomial Method,” Proceedings of the 3rd International Modal Analysis Conference, Orlando, FL, Nov., Society for Experimental Mechanics, Bethel, CT, pp. 390–397.
22.
Friswell
,
M. I.
, and
Penny
,
J. E. T.
,
1993
, “
The Choice of Orthogonal Polynomials in the Rational Fraction Polynomial Method
,”
Int. J. Anal. Exp. Modal Anal.
,
8
, No.
3
, pp.
257
262
.
23.
Maia N. M. M., and Silva, J. M. M., 1997, Theoretical and Experimental Modal Analysis, Research Studies Press LTD.
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