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International Journal of Rotating Machinery
Volume 2012, Article ID 378565, 10 pages
http://dx.doi.org/10.1155/2012/378565
Research Article

A Continuous Model for the Dynamical Analysis of Mistuned Bladed Rotors

1Department of Civil Engineering, University of Rome Tor Vergata, Via Politecnico 1, 00133 Rome, Italy
2Construction Technologies Institute, National Research Council, Via Salaria Km 29,300, 00016 Monterotondo Stazione, Rome, Italy

Received 26 October 2011; Revised 23 January 2012; Accepted 12 February 2012

Academic Editor: Meinhard Taher Schobeiri

Copyright © 2012 Paolo Bisegna and Giovanni Caruso. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Ideal bladed rotors are rotationally symmetric, as a consequence they exhibit couples of degenerate eigenmodes at coinciding frequencies. When even small imperfections are present destroying the periodicity of the structure (disorder or mistuning), each couple of degenerate eigenfrequencies splits into two distinct values (frequency split) and the corresponding modal shapes exhibit vibration amplitude peaks concentrated around few blades (localization phenomenon). In this paper a continuous model describing the in-plane vibrations of a mistuned bladed rotor is derived via the homogenization theory. Imperfections are accounted for as deviations of the mass and/or stiffness of some blades from the design value; a perturbation approach is adopted in order to investigate the frequency split and localization phenomena arising in the imperfect structure. Numerical simulations show the effectiveness of the proposed model, requiring much lower computational effort than classical finite element schemes.