Approximated Stiffness Coefficients in Rotor Systems Supported by Bearings with Clearance

Many kinds of rotating machinery are supported by bearings with clearance, which are further clamped in a supporting structure. When designing such machinery it is important to be able to predict dynamics and hence valid models are needed. Due to gravity, the shaft often vibrates close to a static e...

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Main Author: Magnus Karlberg
Format: Article
Language:English
Published: Wiley 2010-01-01
Series:International Journal of Rotating Machinery
Online Access:http://dx.doi.org/10.1155/2010/540101
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author Magnus Karlberg
author_facet Magnus Karlberg
author_sort Magnus Karlberg
collection DOAJ
description Many kinds of rotating machinery are supported by bearings with clearance, which are further clamped in a supporting structure. When designing such machinery it is important to be able to predict dynamics and hence valid models are needed. Due to gravity, the shaft often vibrates close to a static equilibrium position leading to a possibility to linearise the equation of motion. Although several studies on bearings with clearance exist, there are still no reports on how such clearances affects the stiffness coefficients close to a static equilibrium position. Therefore, analytical expressions for such approximated pedestal stiffness coefficients have been derived in this paper. By using such approximated pedestals in simple rotordynamical models, it was found that the eigenfrequencies decrease significantly with clearance. It is further shown that the approximated pedestal stiffness coefficients only will be valid for vibrations close to the static equilibrium position.
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institution Kabale University
issn 1023-621X
1542-3034
language English
publishDate 2010-01-01
publisher Wiley
record_format Article
series International Journal of Rotating Machinery
spelling doaj-art-bfbc797a91e049aab12d2f00da80f7c92025-02-03T01:27:47ZengWileyInternational Journal of Rotating Machinery1023-621X1542-30342010-01-01201010.1155/2010/540101540101Approximated Stiffness Coefficients in Rotor Systems Supported by Bearings with ClearanceMagnus Karlberg0Division of Computer Aided Design, Department of Applied Physics and Mechanical Engineering, Luleå University of Technology, 971 87 Luleå, SwedenMany kinds of rotating machinery are supported by bearings with clearance, which are further clamped in a supporting structure. When designing such machinery it is important to be able to predict dynamics and hence valid models are needed. Due to gravity, the shaft often vibrates close to a static equilibrium position leading to a possibility to linearise the equation of motion. Although several studies on bearings with clearance exist, there are still no reports on how such clearances affects the stiffness coefficients close to a static equilibrium position. Therefore, analytical expressions for such approximated pedestal stiffness coefficients have been derived in this paper. By using such approximated pedestals in simple rotordynamical models, it was found that the eigenfrequencies decrease significantly with clearance. It is further shown that the approximated pedestal stiffness coefficients only will be valid for vibrations close to the static equilibrium position.http://dx.doi.org/10.1155/2010/540101
spellingShingle Magnus Karlberg
Approximated Stiffness Coefficients in Rotor Systems Supported by Bearings with Clearance
International Journal of Rotating Machinery
title Approximated Stiffness Coefficients in Rotor Systems Supported by Bearings with Clearance
title_full Approximated Stiffness Coefficients in Rotor Systems Supported by Bearings with Clearance
title_fullStr Approximated Stiffness Coefficients in Rotor Systems Supported by Bearings with Clearance
title_full_unstemmed Approximated Stiffness Coefficients in Rotor Systems Supported by Bearings with Clearance
title_short Approximated Stiffness Coefficients in Rotor Systems Supported by Bearings with Clearance
title_sort approximated stiffness coefficients in rotor systems supported by bearings with clearance
url http://dx.doi.org/10.1155/2010/540101
work_keys_str_mv AT magnuskarlberg approximatedstiffnesscoefficientsinrotorsystemssupportedbybearingswithclearance