Vibration due to non-circularity of a rotating ring having discrete radial supports - With application to thin-walled rotor/magnetic bearing systems

© 2018 Elsevier Ltd This paper investigates the vibration arising in a thin-walled cylindrical rotor subject to small non-circularity and coupled to discrete space-fixed radial bearing supports. A Fourier series description of rotor non-circularity is incorporated within a mathematical model for vib...

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Main Authors: Wichaphon Fakkaew, Matthew O.T. Cole
Format: Journal
Published: 2018
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Online Access:https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85045732583&origin=inward
http://cmuir.cmu.ac.th/jspui/handle/6653943832/58673
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Institution: Chiang Mai University
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spelling th-cmuir.6653943832-586732018-09-05T04:39:05Z Vibration due to non-circularity of a rotating ring having discrete radial supports - With application to thin-walled rotor/magnetic bearing systems Wichaphon Fakkaew Matthew O.T. Cole Engineering Physics and Astronomy © 2018 Elsevier Ltd This paper investigates the vibration arising in a thin-walled cylindrical rotor subject to small non-circularity and coupled to discrete space-fixed radial bearing supports. A Fourier series description of rotor non-circularity is incorporated within a mathematical model for vibration of a rotating annulus. This model predicts the multi-harmonic excitation of the rotor wall due to bearing interactions. For each non-circularity harmonic there is a set of distinct critical speeds at which resonance can potentially arise due to flexural mode excitation within the rotor wall. It is shown that whether each potential resonance occurs depends on the multiplicity and symmetry of the bearing supports. Also, a sufficient number of evenly spaced identical supports will eliminate low order resonances. The considered problem is pertinent to the design and operation of thin-walled rotors with active magnetic bearing (AMB) supports, for which small clearances exist between the rotor and bearing and so vibration excitation must be limited to avoid contacts. With this motivation, the mathematical model is further developed for the case of a distributed array of electromagnetic actuators controlled by feedback of measured rotor wall displacements. A case study involving an experimental system with short cylindrical rotor and a single radial AMB support is presented. The results show that flexural mode resonance is largely avoided for the considered design topology. Moreover, numerical predictions based on measured non-circularity show good agreement with measurements of rotor wall vibration, thereby confirming the validity and utility of the theoretical model. 2018-09-05T04:28:09Z 2018-09-05T04:28:09Z 2018-06-09 Journal 10958568 0022460X 2-s2.0-85045732583 10.1016/j.jsv.2018.02.055 https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85045732583&origin=inward http://cmuir.cmu.ac.th/jspui/handle/6653943832/58673
institution Chiang Mai University
building Chiang Mai University Library
country Thailand
collection CMU Intellectual Repository
topic Engineering
Physics and Astronomy
spellingShingle Engineering
Physics and Astronomy
Wichaphon Fakkaew
Matthew O.T. Cole
Vibration due to non-circularity of a rotating ring having discrete radial supports - With application to thin-walled rotor/magnetic bearing systems
description © 2018 Elsevier Ltd This paper investigates the vibration arising in a thin-walled cylindrical rotor subject to small non-circularity and coupled to discrete space-fixed radial bearing supports. A Fourier series description of rotor non-circularity is incorporated within a mathematical model for vibration of a rotating annulus. This model predicts the multi-harmonic excitation of the rotor wall due to bearing interactions. For each non-circularity harmonic there is a set of distinct critical speeds at which resonance can potentially arise due to flexural mode excitation within the rotor wall. It is shown that whether each potential resonance occurs depends on the multiplicity and symmetry of the bearing supports. Also, a sufficient number of evenly spaced identical supports will eliminate low order resonances. The considered problem is pertinent to the design and operation of thin-walled rotors with active magnetic bearing (AMB) supports, for which small clearances exist between the rotor and bearing and so vibration excitation must be limited to avoid contacts. With this motivation, the mathematical model is further developed for the case of a distributed array of electromagnetic actuators controlled by feedback of measured rotor wall displacements. A case study involving an experimental system with short cylindrical rotor and a single radial AMB support is presented. The results show that flexural mode resonance is largely avoided for the considered design topology. Moreover, numerical predictions based on measured non-circularity show good agreement with measurements of rotor wall vibration, thereby confirming the validity and utility of the theoretical model.
format Journal
author Wichaphon Fakkaew
Matthew O.T. Cole
author_facet Wichaphon Fakkaew
Matthew O.T. Cole
author_sort Wichaphon Fakkaew
title Vibration due to non-circularity of a rotating ring having discrete radial supports - With application to thin-walled rotor/magnetic bearing systems
title_short Vibration due to non-circularity of a rotating ring having discrete radial supports - With application to thin-walled rotor/magnetic bearing systems
title_full Vibration due to non-circularity of a rotating ring having discrete radial supports - With application to thin-walled rotor/magnetic bearing systems
title_fullStr Vibration due to non-circularity of a rotating ring having discrete radial supports - With application to thin-walled rotor/magnetic bearing systems
title_full_unstemmed Vibration due to non-circularity of a rotating ring having discrete radial supports - With application to thin-walled rotor/magnetic bearing systems
title_sort vibration due to non-circularity of a rotating ring having discrete radial supports - with application to thin-walled rotor/magnetic bearing systems
publishDate 2018
url https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85045732583&origin=inward
http://cmuir.cmu.ac.th/jspui/handle/6653943832/58673
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