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NATURAL FREQUENCIES OF TUNED AND MISTUNED BLADED DISCS ON A SHAFT

Abstract

The dynamic behaviour of a rotor consisting of two tuned and mistuned bladed discs on a solid shaft is considered. The effect of the shaft’s flexibility on the dynamic characteristics of the bladed discs and the coupling effects between the shaft and bladed disc modes are investigated. Results show clearly the coupling effects in a bladed disc-shaft system. Interference diagrams are developed, from which the dynamic behaviour of a bladed disc can be predicted for varying flexibility relationships between solid shafts and bladed discs.

The global rotating mode shapes of flexible tuned and mistuned bladed disc-shaft assemblies are calculated. Rotational effects, such as centrifugal stiffening, are accounted for and all the possible couplings between the flexible parts are allowed. Calculated natural frequencies obtained from the blade, the bladed disc and the shaft with two discs are checked to discover resonance conditions and coupling effects. It is shown that blade mistuning strongly affects the interaction between flexible bladed discs and a flexible shaft. This interaction affects the flexible bladed disc modes and is not restricted to the modes with zero, one and two nodal diameters. The torsional frequency of the shaft with two bladed discs is coupled with the zero nodal diameter modes of the single bladed discs. It is shown that including the shaft in the bladed discs model is important from the designer’s point of view and may alter the spectrum of frequencies considerably.

Keywords:

blade, bladed disc, mistuning

Details

Issue
Vol. 10 No. 3 (2006)
Section
Research article
Published
2006-09-30
Licencja:
Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Author Biographies

ROMUALD RZĄDKOWSKI,
Polish Academy of Sciences, Institute of Fluid-Flow Machinery



MARCIN DREWCZYŃSKI,
Polish Academy of Sciences, Institute of Fluid-Flow Machinery



Authors

  • ROMUALD RZĄDKOWSKI

    Polish Academy of Sciences, Institute of Fluid-Flow Machinery
  • MARCIN DREWCZYŃSKI

    Polish Academy of Sciences, Institute of Fluid-Flow Machinery
  • LESZEK KUBITZ

    Polish Naval Academy

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