Unbalance Response Prediction for Rotors on Ball Bearings Using Speed- and Load-Dependent Nonlinear Bearing Stiffness

<p>Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus, an accurate rotordynamic analysis requires that bearing forces corresponding to the actual bearing deflection be utilized. For this work, bearing forces were calculated by COBRA-AHS, a recently developed rolling-...

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Main Authors: Fleming David P., Poplawski J. V.
Format: Article
Language:English
Published: Wiley 2005-01-01
Series:International Journal of Rotating Machinery
Subjects:
Online Access:http://www.hindawi.net/access/get.aspx?journal=ijrm&volume=2005&pii=S1023621X03502111
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author Fleming David P.
Poplawski J. V.
author_facet Fleming David P.
Poplawski J. V.
author_sort Fleming David P.
collection DOAJ
description <p>Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus, an accurate rotordynamic analysis requires that bearing forces corresponding to the actual bearing deflection be utilized. For this work, bearing forces were calculated by COBRA-AHS, a recently developed rolling-element bearing analysis code. Bearing stiffness was found to be a strong function of bearing deflection, with higher deflection producing markedly higher stiffness. Curves fitted to the bearing data for a range of speeds and loads were supplied to a flexible rotor unbalance response analysis. The rotordynamic analysis showed that vibration response varied nonlinearly with the amount of rotor imbalance. Moreover, the increase in stiffness as critical speeds were approached caused a large increase in rotor and bearing vibration amplitude over part of the speed range compared to the case of constant-stiffness bearings. Regions of bistable operation were possible, in which the amplitude at a given speed was much larger during rotor acceleration than during deceleration. A moderate amount of damping will eliminate the bistable region, but this damping is not inherent in ball bearings.</p>
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spelling doaj-art-51706f423b6647e5b78bc0d02878529b2025-02-03T07:25:15ZengWileyInternational Journal of Rotating Machinery1023-621X2005-01-01200515359Unbalance Response Prediction for Rotors on Ball Bearings Using Speed- and Load-Dependent Nonlinear Bearing StiffnessFleming David P.Poplawski J. V.<p>Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus, an accurate rotordynamic analysis requires that bearing forces corresponding to the actual bearing deflection be utilized. For this work, bearing forces were calculated by COBRA-AHS, a recently developed rolling-element bearing analysis code. Bearing stiffness was found to be a strong function of bearing deflection, with higher deflection producing markedly higher stiffness. Curves fitted to the bearing data for a range of speeds and loads were supplied to a flexible rotor unbalance response analysis. The rotordynamic analysis showed that vibration response varied nonlinearly with the amount of rotor imbalance. Moreover, the increase in stiffness as critical speeds were approached caused a large increase in rotor and bearing vibration amplitude over part of the speed range compared to the case of constant-stiffness bearings. Regions of bistable operation were possible, in which the amplitude at a given speed was much larger during rotor acceleration than during deceleration. A moderate amount of damping will eliminate the bistable region, but this damping is not inherent in ball bearings.</p>http://www.hindawi.net/access/get.aspx?journal=ijrm&volume=2005&pii=S1023621X03502111rotordynamicsrolling-element bearing stiffnessdynamic analysisrolling-element bearingsbistable operation
spellingShingle Fleming David P.
Poplawski J. V.
Unbalance Response Prediction for Rotors on Ball Bearings Using Speed- and Load-Dependent Nonlinear Bearing Stiffness
International Journal of Rotating Machinery
rotordynamics
rolling-element bearing stiffness
dynamic analysis
rolling-element bearings
bistable operation
title Unbalance Response Prediction for Rotors on Ball Bearings Using Speed- and Load-Dependent Nonlinear Bearing Stiffness
title_full Unbalance Response Prediction for Rotors on Ball Bearings Using Speed- and Load-Dependent Nonlinear Bearing Stiffness
title_fullStr Unbalance Response Prediction for Rotors on Ball Bearings Using Speed- and Load-Dependent Nonlinear Bearing Stiffness
title_full_unstemmed Unbalance Response Prediction for Rotors on Ball Bearings Using Speed- and Load-Dependent Nonlinear Bearing Stiffness
title_short Unbalance Response Prediction for Rotors on Ball Bearings Using Speed- and Load-Dependent Nonlinear Bearing Stiffness
title_sort unbalance response prediction for rotors on ball bearings using speed and load dependent nonlinear bearing stiffness
topic rotordynamics
rolling-element bearing stiffness
dynamic analysis
rolling-element bearings
bistable operation
url http://www.hindawi.net/access/get.aspx?journal=ijrm&volume=2005&pii=S1023621X03502111
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