Combination Resonance of a Rotor Supported by a High-Tc Superconducting Bearing

Toshihiko Sugiura, Keniti Matsunaga, Takuo Kugiya, Masatsugu Yoshizawa

研究成果: Article

抄録

This research deals with nonlinear dynamics of a rotating rigid magnet levitated above a high Tc superconducting (HTSC) bulk. Motion of the rotating magnet in the radial and axial directions were investigated theoretically by using analytical expression of electromagnetic force obtained by “the advanced mirror image method”. Analytical and numerical results show existence of combination resonance due to nonlinear coupling between whirling and vertical motion of the magnet. The resonant frequency of rotation is given as the sum of the natural frequency in the horizontal and vertical directions. At this resonance, the whirling motion becomes quasi-periodic, having the harmonics with both the driving and natural frequencies, while periodic motion at the natural frequency appears in the vertical direction. Stability analysis shows that this resonance occurs if the eccentricity of the magnet is larger than a certain critical value. Experiments for spinning motion of the magnet were carried out, and combination resonance predicted in the theory was clearly observed. Nonlinearity in forces can thus have significant effects on dynamics in application of HTSC bearings.

元の言語English
ページ(範囲)3568-3575
ページ数8
ジャーナルNihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C
66
発行部数651
DOI
出版物ステータスPublished - 2000

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Bearings (structural)
Magnets
Rotors
Natural frequencies
Mirrors

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering

これを引用

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title = "Combination Resonance of a Rotor Supported by a High-Tc Superconducting Bearing",
abstract = "This research deals with nonlinear dynamics of a rotating rigid magnet levitated above a high Tc superconducting (HTSC) bulk. Motion of the rotating magnet in the radial and axial directions were investigated theoretically by using analytical expression of electromagnetic force obtained by “the advanced mirror image method”. Analytical and numerical results show existence of combination resonance due to nonlinear coupling between whirling and vertical motion of the magnet. The resonant frequency of rotation is given as the sum of the natural frequency in the horizontal and vertical directions. At this resonance, the whirling motion becomes quasi-periodic, having the harmonics with both the driving and natural frequencies, while periodic motion at the natural frequency appears in the vertical direction. Stability analysis shows that this resonance occurs if the eccentricity of the magnet is larger than a certain critical value. Experiments for spinning motion of the magnet were carried out, and combination resonance predicted in the theory was clearly observed. Nonlinearity in forces can thus have significant effects on dynamics in application of HTSC bearings.",
keywords = "Combination Resonance, Coupled Vibration, Electromagnetic Force, High-Tc Superconducting Bearing, Nonlinear Vibration, Vibration of Rotating Body",
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T1 - Combination Resonance of a Rotor Supported by a High-Tc Superconducting Bearing

AU - Sugiura, Toshihiko

AU - Matsunaga, Keniti

AU - Kugiya, Takuo

AU - Yoshizawa, Masatsugu

PY - 2000

Y1 - 2000

N2 - This research deals with nonlinear dynamics of a rotating rigid magnet levitated above a high Tc superconducting (HTSC) bulk. Motion of the rotating magnet in the radial and axial directions were investigated theoretically by using analytical expression of electromagnetic force obtained by “the advanced mirror image method”. Analytical and numerical results show existence of combination resonance due to nonlinear coupling between whirling and vertical motion of the magnet. The resonant frequency of rotation is given as the sum of the natural frequency in the horizontal and vertical directions. At this resonance, the whirling motion becomes quasi-periodic, having the harmonics with both the driving and natural frequencies, while periodic motion at the natural frequency appears in the vertical direction. Stability analysis shows that this resonance occurs if the eccentricity of the magnet is larger than a certain critical value. Experiments for spinning motion of the magnet were carried out, and combination resonance predicted in the theory was clearly observed. Nonlinearity in forces can thus have significant effects on dynamics in application of HTSC bearings.

AB - This research deals with nonlinear dynamics of a rotating rigid magnet levitated above a high Tc superconducting (HTSC) bulk. Motion of the rotating magnet in the radial and axial directions were investigated theoretically by using analytical expression of electromagnetic force obtained by “the advanced mirror image method”. Analytical and numerical results show existence of combination resonance due to nonlinear coupling between whirling and vertical motion of the magnet. The resonant frequency of rotation is given as the sum of the natural frequency in the horizontal and vertical directions. At this resonance, the whirling motion becomes quasi-periodic, having the harmonics with both the driving and natural frequencies, while periodic motion at the natural frequency appears in the vertical direction. Stability analysis shows that this resonance occurs if the eccentricity of the magnet is larger than a certain critical value. Experiments for spinning motion of the magnet were carried out, and combination resonance predicted in the theory was clearly observed. Nonlinearity in forces can thus have significant effects on dynamics in application of HTSC bearings.

KW - Combination Resonance

KW - Coupled Vibration

KW - Electromagnetic Force

KW - High-Tc Superconducting Bearing

KW - Nonlinear Vibration

KW - Vibration of Rotating Body

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