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The non-linear modelling of squeeze film damped rotor-dynamic systems : an efficient integrated approach

The non-linear modelling of squeeze film damped rotor-dynamic systems : an efficient integrated approach
The non-linear modelling of squeeze film damped rotor-dynamic systems : an efficient integrated approach

Squeeze film dampers (SFDs) are non-linear elements used in rotor assemblies such as aero-engines to attenuate vibrations and transmitted forces, and to improve stability. However, undesirable non-linear side effects under rotating unbalance excitation necessitate in effective predictive tool for the resulting dynamics. The main contribution of this thesis is the development of an efficient integrated non-linear modelling technique for the solution of the unbalance response problem. It consists of the following three complementary blocks, each of which is tractable to practical systems with many degrees of freedom:

(1) A Receptance Harmonic Balance method for the determination of periodic solutions. In this method, the receptance functions of the rotating linear part of the system are used in the non-linear analysis of the complete system.

(2) Stability analysis of these periodic solutions. This is done by applying Floquet theory to a limited number of the perturbed modal equations of the system.

(3) Numerical integration of the modal equations, when necessary.

With such an approach, linear rotor-dynamic software packages used in industry can be used to analyse the linear subsystem for receptance functions and modal parameters. The latter quantities can then be used in a detailed non-linear analysis of the whole system that can be implemented using standard mathematical software. The integrated model is tested on three squeeze film damped rotor-dynamic systems, of increasing complexity. The SFD forces are obtained from an extant model for the SFD that assumes a short incompressible film that cavitates at absolute zero pressure. In each case studied, excellent correlations between the results from the above mentioned modelling blocks is achieved.

University of Southampton
Bonello, Philip
a990612b-0024-4858-b910-b185414b5e00
Bonello, Philip
a990612b-0024-4858-b910-b185414b5e00

Bonello, Philip (2002) The non-linear modelling of squeeze film damped rotor-dynamic systems : an efficient integrated approach. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

Squeeze film dampers (SFDs) are non-linear elements used in rotor assemblies such as aero-engines to attenuate vibrations and transmitted forces, and to improve stability. However, undesirable non-linear side effects under rotating unbalance excitation necessitate in effective predictive tool for the resulting dynamics. The main contribution of this thesis is the development of an efficient integrated non-linear modelling technique for the solution of the unbalance response problem. It consists of the following three complementary blocks, each of which is tractable to practical systems with many degrees of freedom:

(1) A Receptance Harmonic Balance method for the determination of periodic solutions. In this method, the receptance functions of the rotating linear part of the system are used in the non-linear analysis of the complete system.

(2) Stability analysis of these periodic solutions. This is done by applying Floquet theory to a limited number of the perturbed modal equations of the system.

(3) Numerical integration of the modal equations, when necessary.

With such an approach, linear rotor-dynamic software packages used in industry can be used to analyse the linear subsystem for receptance functions and modal parameters. The latter quantities can then be used in a detailed non-linear analysis of the whole system that can be implemented using standard mathematical software. The integrated model is tested on three squeeze film damped rotor-dynamic systems, of increasing complexity. The SFD forces are obtained from an extant model for the SFD that assumes a short incompressible film that cavitates at absolute zero pressure. In each case studied, excellent correlations between the results from the above mentioned modelling blocks is achieved.

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Published date: 2002

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Local EPrints ID: 464854
URI: http://eprints.soton.ac.uk/id/eprint/464854
PURE UUID: 944dd91b-2c3c-4711-b378-e3f2beeeafee

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Date deposited: 05 Jul 2022 00:05
Last modified: 05 Jul 2022 03:22

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Author: Philip Bonello

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