Cracked Continuous Rotors Vibrating on Nonlinear Bearings

  • C. A. PapadopoulosEmail author
  • A. C. Chasalevris
  • P. G. Nikolakopoulos
Conference paper
Part of the IUTAM Bookseries book series (IUTAMBOOK, volume 1011)


The dynamic behavior of cracked rotors continues to attract the interest of both designers and maintenance engineers. In this work, a continuum mechanics approach is used to simulate rotor vibration. The case of the cracked continuous rotor is examined by introducing suitable complex boundary conditions. The shaft rotates on two journal bearings that are simulated as forces acting on it and the boundary conditions are expressed accordingly. When the angular velocity passes through critical speeds, these forces become highly nonlinear. Identifications of cracking and wear of the bearing are separately investigated. The current challenge for design engineers is to provide lighter, quieter, more efficient, compact, and stable, as well as less expensive and ecologically friendly, rotating machines, operating even in severe conditions. In other words, new targets must be seen from the following three points of view: (a) analysis and design, (b) new material technology, and (c) new production techniques.


Rotor Shaft Crack Bearing Wear Nonlinear 


  1. 1.
    Eshleman, R.L., Eubanks, R.A.: On critical speeds of continuous rotor. ASME-Paper 69-Vibr-52 (1969)Google Scholar
  2. 2.
    Papadopoulos, C.A.: The strain energy release approach for modeling cracks in rotors: A state of the art review. Mech. Syst. Signal Process. 22(4), 763–789 (2008)CrossRefGoogle Scholar
  3. 3.
    Chasalevris, A.C., Papadopoulos, C.A.: Crack identification using external excitation and coupled response of a continuously modeled rotor with internal damping. In: The Ninth International Conference on Computational Structures Technology, Civil Comp Press, Athens, Greece, 2–5 September 2008Google Scholar
  4. 4.
    Dufrane, K.F., Kannel, J.W., McCloskey, T.H.: Wear of steam turbine journal bearings at low operating speeds. J. Lubr. Technol. 105(3), 313–317 (1983)CrossRefGoogle Scholar
  5. 5.
    Chasalevris, A.C., Papadopoulos, C.A.: A continuous model approach for cross-coupled bending vibrations of a rotor-bearing system with a transverse breathing crack. Mech.Mach. Theor. 44(6), 1176–1191 (2009)CrossRefzbMATHGoogle Scholar
  6. 6.
    Lee, C.: Vibration Analysis of Rotors. Springer, The Netherlands (1993)Google Scholar
  7. 7.
    Dimarogonas, A.D., Paipetis, S.A.: Analytical Methods in Rotor Dynamics. Applied Science Publishers, London (1983)Google Scholar
  8. 8.
    Chasalevris, A.C., Papadopoulos, C.A.: Identification of multiple cracks in beams under bending. Mech. Syst. Signal Process. 20(7), 1631–1673 (2006/10)CrossRefGoogle Scholar
  9. 9.
    Childs, D.: Turbomachinery Rotordynamics: Phenomena, Modeling, & Analysis. Wiley-Interscience (1993)Google Scholar
  10. 10.
    Vance, J.M.: Rotordynamics of Turbomachinery. Wiley-Interscience (1988)Google Scholar
  11. 11.
    Gertzos, K.P., Nikolakopoulos, P.G., Papadopoulos, C.A.: CFD analysis of journal bearing hydrodynamic lubrication by Bingham lubricant. Tribol. Int. 41(12), 1190–1204 (2008)CrossRefGoogle Scholar
  12. 12.
    Gertzos, K.P., Nikolakopoulos, P.G., Chasalevris, A.C., Papadopoulos, C.A.: Wear identification in rotor-bearing systems by volumetric and bearing performance characteristics measurements. In: The Nineth International Conference on Computational Structures Technology, Civil Comp Press, Athens, Greece, 2–5 September 2008Google Scholar
  13. 13.
    Lees, A.W., Sinha, J.K., Friswell, M.I.: Model-based identification of rotating machines. Mech. Syst. Signal Process. 23(6), 1884–1893 (2009)CrossRefGoogle Scholar
  14. 14.
    Saridakis, K.M., Nikolakopoulos, P.G., Papadopoulos, C.A., Dentsoras, A.J.: Fault diagnosis of journal bearings based on artificial neural networks and measurements of bearing performance characteristics. In: Proceedings of the Ninth International Conference on Computational Structures Technology, Civil-Comp Press, Athens, Greece, 2–5 September 2008Google Scholar
  15. 15.
    Nikolakopoulos, P.G., Chasalevris, A.C., Papadopoulos, C.A.: Applying external excitation to a rotor for wear identification of the non-linear fluid-film bearings. Civil Comp Press, Athens, Greece, 2–5 September 2008Google Scholar
  16. 16.
    Nikolakopoulos, P.G., Papadopoulos, C.A.: A study of friction in worn misaligned journal bearings under severe hydrodynamic lubrication. Tribol. Int. 41(6), 461–472 (2008)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • C. A. Papadopoulos
    • 1
    Email author
  • A. C. Chasalevris
    • 1
  • P. G. Nikolakopoulos
    • 1
  1. 1.Department of Mechanical Engineering & AeronauticsUniversity of PatrasPatrasGreece

Personalised recommendations