Nonparametric stochastic modeling of uncertainty in rotordynamics—Part II: Applications

Raghavendra Murthy, Marc Mignolet, Aly El-Shafei

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

In the first part of this series, a comprehensive methodology was proposed for the consideration of uncertainty in rotordynamic systems. This second part focuses on the application of this approach to a simple, yet representative, symmetric rotor supported by two journal bearings exhibiting linear, asymmetric properties. The effects of uncertainty in rotor properties (i.e., mass, gyroscopic, and stiffness matrices) that maintain the symmetry of the rotor are first considered. The parameter λ that specifies the level of uncertainty in the simulation of stiffness and mass uncertain properties (the latter with algorithm I) is obtained by imposing a standard deviation of the first nonzero natural frequency of the free nonrotating rotor. Then, the effects of these uncertainties on the Campbell diagram, eigenvalues and eigenvectors of the rotating rotor on its bearings, forced unbalance response, and oil whip instability threshold are predicted and discussed. A similar effort is also carried out for uncertainties in the bearing stiffness and damping matrices. Next, uncertainties that violate the asymmetry of the present rotor are considered to exemplify the simulation of uncertain asymmetric rotors. A comparison of the effects of symmetric and asymmetric uncertainties on the eigenvalues and eigenvectors of the rotating rotor on symmetric bearings is finally performed to provide a first perspective on the importance of uncertainty-born asymmetry in the response of rotordynamic systems.

Original languageEnglish (US)
Pages (from-to)92502-1-92502-11
JournalJournal of Engineering for Gas Turbines and Power
Volume132
Issue number9
DOIs
StatePublished - 2010

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Rotors
Bearings (structural)
Eigenvalues and eigenfunctions
Stiffness
Uncertainty
Journal bearings
Stiffness matrix
Natural frequencies
Damping

ASJC Scopus subject areas

  • Nuclear Energy and Engineering
  • Fuel Technology
  • Aerospace Engineering
  • Energy Engineering and Power Technology
  • Mechanical Engineering

Cite this

Nonparametric stochastic modeling of uncertainty in rotordynamics—Part II : Applications. / Murthy, Raghavendra; Mignolet, Marc; El-Shafei, Aly.

In: Journal of Engineering for Gas Turbines and Power, Vol. 132, No. 9, 2010, p. 92502-1-92502-11.

Research output: Contribution to journalArticle

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