Abstract
Nonlinear forced oscillations of a rotating shaft with nonlinear spring characteristics and internal damping are studied. In particular, entrainment phenomena at the critical speeds of 1/2 order subharmonic oscillations of forward and backward whirling modes are investigated. A self-excited oscillation appears in the wide range above the major critical speed. The amplitude of this oscillation reaches a limit value and then a self-sustained oscillation occurs. In the vicinity of a 1/2 order subharmonic oscillation of a forward whirling mode, a self-excited oscillation is entrained by a subharmonic oscillation. In the vicinity of a 1/2 order subharmonic oscillation of a backward whirling mode, either a self-excited oscillation or a subharmonic oscillation occurs.
Experiments were made by an elastic rotating shaft with a disc. Nonlinearity in its restoring force was due to an angular clearance of a bearing and internal damping was due to friction between the shaft and an inner ring of the bearing. A self-excited oscillation was observed in the range above the major critical speed and this self-excited oscillation was entrained by a 1/2 order subharmonic oscillation of a forward whirling mode.
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Abbreviations
- O−xyz :
-
rectangular coordinate system
- θ, θx, θy :
-
inclination angle of a shaft and its projections on the xz- and yz-planes
- θ′x, θ′y :
-
inclination angles in rotating coordinates
- θ, ϕ:
-
polar coordinates
- I p :
-
polar moment of inertia of a rotor
- I :
-
diametral moment of inertia of a rotor
- i p :
-
ratio of I p to I
- τ:
-
dynamic unbalance of a rotor
- ω:
-
rotating speed (angular velocity)
- F :
-
magnitude of a dynamic unbalance force, F = (1 − i p )τω2
- c :
-
external damping coefficient
- h :
-
internal damping coefficient
- t :
-
time
- D θx , D θy :
-
internal damping terms in stationary coordinates
- D θx , D θy :
-
internal damping terms in rotating coordinates
- N θx , N θy :
-
nonlinear terms in restoring forces
References
Yamamoto, T., ‘On the critical speed of a shaft of subharmonic oscillation’, Transactions of JSME (in Japanese) 21, 1955, 853–858. (English Translation: Yamamoto, T., ‘On the vibrations of a rotating shaft’, Memoirs of the Faculty of Engineering, Nagoya University 9, 1957, 25–39).
Yamamoto, T., ‘On the critical speeds with peculiar modes of vibration’, Transactions of JSME (in Japanese) 22, 1956, 172–177. (English translation: Yamamoto, T., ‘On the vibration of a rotating shaft’, Memoirs of the Faculty of Engineering, Nagoya University 9, 1957, 43–53).
Yamamoto, T., ‘Response curves at the critical speeds of sub-harmonic and “summed and differential harmonic” oscillations’, Bulletin of JSME 3, 1960, 397–403.
Yamamoto, T., Ishida, Y., and Kawasumi, J., ‘Oscillations of a rotating shaft with symmetrical nonlinear spring characteristics’, Bulletin of JSME 18, 1975, 965–975.
Yamamoto, T., ‘On sub-harmonic oscillations and on vibrations of peculiar modes in non-linear systems having multiple degrees of freedom’, Transactions of JSME (in Japanese) 22, 1956, 868–875. (English Translation: Yamamoto, T, ‘On the vibrations of a rotating shaft’, Memoirs of the Faculty of Engineering, Nagoya University 9, 1957, 53–71).
Yamamoto, T., ‘On sub-harmonic and “summed and differential harmonic” oscillations of a rotating shaft’, Bulletin of JSME 4, 1961, 51–58.
Yamamoto, T. and Ishida, Y., ‘Theoretical discussions of vibrations of a rotating shaft with nonlinear spring characteristics’, Ingenieur-Archiv 46, 1977, 125–135.
Ishida, Y., Ikeda, T., and Yamamoto, T., ‘Nonlinear forced oscillations caused by quartic nonlinearity in a rotating shaft system’, Transactions of the ASME, Journal of Vibration and Acoustics 112, 1990, 288–297.
Ehrich, F. F., ‘Subharmonic vibration of rotors in bearing clearance’, ASME Paper No. 66-MD-1.
Bently, D., ‘Forced subrotative speed dynamic action of rotating machinery’, ASME Paper No. 74-PET-16.
Childs, D., ‘Fractional-frequency rotor motion due to nonsymmetric clearance effects’, Transactions of the ASME, Journal of Engineering for Power 104, 1982, 533–541.
Kim, Y. B. and Noah, S. T., ‘Steady-state analysis of a nonlinear rotor-housing system’, Transactions of the ASME, Journal of Engineering for Gas Turbines and Power 113, 1991, 550–556.
Newkirk, B. L., ‘Shaft whipping’, General Electric Review 27, 1924, 169–178.
Kimball, A. L., ‘Internal friction theory of shaft whirling’, General Electric Review 27, 1924, 244–251.
Van derPol, B., ‘Forced oscillations in a system with non-linear resistance’, Philosophical Magazine 3, 1927, 65.
Shaw, J. and Shaw, S. W., ‘Instabilities and bifurcations in a rotating shaft’, Journal of Sound and Vibration 132, 1989, 227–244.
Shaw, J. and Shaw, S. W., ‘Non-linear resonance of an unbalanced shaft with internal damping’, Journal of Sound and Vibration 147, 1991, 435–451.
Tondl, A., Some Problems of Rotor Dynamics, Publishing House of the Czechoslovak Academy of Science, Prague, 1965, Chapter 1.
Ishida, Y., Ikeda, T., Yamamoto, T., and Murakami, S., ‘Nonstationary vibration of a rotating shaft with nonlinear spring characteristics during acceleration through a critical speed (A critical speed of a 1/2-order subharmonic oscillation)’, JSME International Journal, Series III 32, 1989, 575–584.
Ishida, Y., Ikeda, T., and Yamamoto, T., ‘Effects of quartic nonlinear restoring forces on 1/2-order subharmonic and summed-and-differential harmonic oscillations of a rotating shaft (Variations of resonance curves and occurrence of unstable vibrations)’, Bulletin of JSME 29, 1986, 4326–4333.
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Ishida, Y., Yamamoto, T. Forced oscillations of a rotating shaft with nonlinear spring characteristics and internal damping (1/2 order subharmonic oscillations and entrainment). Nonlinear Dyn 4, 413–431 (1993). https://doi.org/10.1007/BF00053689
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DOI: https://doi.org/10.1007/BF00053689