Stability of rigid rotors supported by air foil bearings: Comparison of two fundamental approaches

Jon Steffen Larsen; Ilmar Santos; Alexander Sebastian von Osmanski

doi:10.1016/j.jsv.2016.06.022

Stability of rigid rotors supported by air foil bearings: Comparison of two fundamental approaches

Jon Steffen Larsen, Ilmar Santos, Alexander Sebastian von Osmanski

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Abstract

High speed direct drive motors enable the use of Air Foil Bearings (AFB) in a wide range of applications due to the elimination of gear forces. Unfortunately, AFB supported rotors are lightly damped, and an accurate prediction of their Onset Speed of Instability (OSI) is therefore important. This paper compares two fundamental methods for predicting the OSI. One is based on a nonlinear time domain simulation and another is based on a linearised frequency domain method and a perturbation of the Reynolds equation. Both methods are based on equivalent models and should predict similar results. Significant discrepancies are observed leading to the question, is the classical frequency domain method sufficiently accurate? The discrepancies and possible explanations are discussed in detail. (C) 2016 Elsevier Ltd. All rights reserved.

Original language	English
Journal	Journal of Sound and Vibration
Volume	381
Pages (from-to)	179-191
ISSN	0022-460X
DOIs	https://doi.org/10.1016/j.jsv.2016.06.022
Publication status	Published - 2016

Keywords

Air foil bearing
Rigid rotor
Transient simulation
Nonlinear analysis
Stability

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title = "Stability of rigid rotors supported by air foil bearings: Comparison of two fundamental approaches",

abstract = "High speed direct drive motors enable the use of Air Foil Bearings (AFB) in a wide range of applications due to the elimination of gear forces. Unfortunately, AFB supported rotors are lightly damped, and an accurate prediction of their Onset Speed of Instability (OSI) is therefore important. This paper compares two fundamental methods for predicting the OSI. One is based on a nonlinear time domain simulation and another is based on a linearised frequency domain method and a perturbation of the Reynolds equation. Both methods are based on equivalent models and should predict similar results. Significant discrepancies are observed leading to the question, is the classical frequency domain method sufficiently accurate? The discrepancies and possible explanations are discussed in detail. (C) 2016 Elsevier Ltd. All rights reserved.",

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author = "Larsen, {Jon Steffen} and Ilmar Santos and {von Osmanski}, {Alexander Sebastian}",

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journal = "Journal of Sound and Vibration",

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T1 - Stability of rigid rotors supported by air foil bearings: Comparison of two fundamental approaches

AU - Larsen, Jon Steffen

AU - Santos, Ilmar

AU - von Osmanski, Alexander Sebastian

PY - 2016

Y1 - 2016

N2 - High speed direct drive motors enable the use of Air Foil Bearings (AFB) in a wide range of applications due to the elimination of gear forces. Unfortunately, AFB supported rotors are lightly damped, and an accurate prediction of their Onset Speed of Instability (OSI) is therefore important. This paper compares two fundamental methods for predicting the OSI. One is based on a nonlinear time domain simulation and another is based on a linearised frequency domain method and a perturbation of the Reynolds equation. Both methods are based on equivalent models and should predict similar results. Significant discrepancies are observed leading to the question, is the classical frequency domain method sufficiently accurate? The discrepancies and possible explanations are discussed in detail. (C) 2016 Elsevier Ltd. All rights reserved.

AB - High speed direct drive motors enable the use of Air Foil Bearings (AFB) in a wide range of applications due to the elimination of gear forces. Unfortunately, AFB supported rotors are lightly damped, and an accurate prediction of their Onset Speed of Instability (OSI) is therefore important. This paper compares two fundamental methods for predicting the OSI. One is based on a nonlinear time domain simulation and another is based on a linearised frequency domain method and a perturbation of the Reynolds equation. Both methods are based on equivalent models and should predict similar results. Significant discrepancies are observed leading to the question, is the classical frequency domain method sufficiently accurate? The discrepancies and possible explanations are discussed in detail. (C) 2016 Elsevier Ltd. All rights reserved.

KW - Air foil bearing

KW - Rigid rotor

KW - Transient simulation

KW - Nonlinear analysis

KW - Stability

U2 - 10.1016/j.jsv.2016.06.022

DO - 10.1016/j.jsv.2016.06.022

M3 - Journal article

SN - 0022-460X

VL - 381

SP - 179

EP - 191

JO - Journal of Sound and Vibration

JF - Journal of Sound and Vibration

ER -

Stability of rigid rotors supported by air foil bearings: Comparison of two fundamental approaches

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Keywords

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