Engineering Mechanics

Proceedings Vol. 9 (2003)

ENGINEERING MECHANICS 2003

Copyright © 2003 Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, v.v.i., Prague

 

Ballo I., Chmúrny R.
pages 18 - +9p., full text

The contribution deals with a mathematical model of bending vibrations of a slender flexible rotor, excited by unbalance when passing the critical speed. The analysed rotor is supported by two short bearings on flexible supports; the influence of hydrodynamic forces is neglected. The rotor is assumed being of constant circular cross-section in his whole length and driven by an engine of limited power. The bending vibrations of the rotor are analysed assuming that the transversal displacement limitation during passage trough the critical speeds is facilitated by one of following three possibilities: A/ Increase of driving engine power output and so speed up the passage trough critical speed. B/ Decrease of rotor natural frequency just before reaching the critical speed C/ Inclusion of a non-linear element into flexible rotor supports. The aim of this contribution is to compare the time course and magnitude of rotor transversal displacement in the transient vibrations caused by passing critical speed by one of the three approaches mentioned.

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