Open Access

ABSTRACT

Stability Analysis of Beams Rotating on an Elastic Ring Application to Turbo machinery Rotor-Stator Contacts

N. Lesaffre¹, J-J. Sinou¹, F. Thouverez¹

1 Ecole Centrale de Lyon; Laboratoire de Tribologie et Dynamique des Systèmes, UMR CNRS
2 513; Equipe Dynamique des Systèmes et des Structures; 36 avenue Guy de Collongue, 69134 Ecully Cedex, FRANCE; e-mail: nicolas.lesaffre@ec-lyon.fr

The International Conference on Computational & Experimental Engineering and Sciences 2007, 2(4), 101-110. https://doi.org/10.3970/icces.2007.002.101

Abstract

This paper presents a model of flexible beams rotating on the inner surface of an elastic stationary ring. The beams possesses two degrees of freedom, traction/compression and flexure. The in-plane deformations of the ring are considered and a single mode approximation is used. The model has been developed within the rotating frame by use of an energetic method. To better understand the phenomena occurring, the degrees of freedom of the beams can first be treated separately then together. Stability analysis show that even without rubbing, the radial degree of freedom of a beam rotating on an elastic ring can create divergence instabilities as well as mode couplings of the circular structure. When rubbing is considered, the system is unstable as soon as the rotational speed is non null. Moreover rubbing can couple the beams and the ring giving rise to mode coupling instabilities and locus veering phenomena. Finally, a comparison to a more complicated model of a flexible bladed-rotor in contact with an elastic casing shows a very good accordance with the phenomena occurring.

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Keywords

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