Abstract
Nonstationary vibration of a flexible rotating shaft with nonlinear spring characteristics during acceleration through a critical speed of a summed-and-differential harmonic oscillation was investigated. In numerical simulations, we investigated the influence of the angular acceleration λ, the initial angular position of the unbalance ψn and the initial rotating speed ω on the maximum amplitude. We also performed experiments with various angular accelerations. The following results were obtained: (1) the maximum amplitude depends not only on λ but also on ψn and ω: (2) when the initial angular position ψn changes. the maximum amplitude varies between two values. The upper and lower bounds of the maximum amplitude do not change monotonously for the angular acceleration: (3) In order to always pass the critical speed with finite amplitude during acceleration. the value of λ must exceed a certain critical value.
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Abbreviations
- O-xyz :
-
rectangular coordinate system
- θ, θ1, θ1 :
-
inclination angle of rotor and its projections to thexy- andyz-planes
- I r :
-
polar moment of inertia of rotor
- I :
-
diametral moment of inertia of rotor
- i r :
-
ratio ofI r toI
- τ:
-
dynamic unbalance of rotor
- Ψ:
-
directional angle of τ fromx-axis
- c :
-
damping coefficient
- δ:
-
spring constant of shaft
- N nt ,N nt :
-
nonlinear terms in restoring forees in θ1 and θ1 directions
- τ4 :
-
representative angle
- ε:
-
a small quantity
- V. V u .V N :
-
potential energy and its components corresponding to linear and nonlinear terms in the restoring forees
- ϕ:
-
directional angle
- ɛn :
-
coefficients of asymmetrical nonlinear terms
- βn :
-
coefficients of symmetrical nonlinear terms
- ɛ:
-
coefficients of asymmetrical nonlinear terms experessed in polar coordinates
- β:
-
coefficients of symmetrical nonlinear terms expressed in polar coordinates
- ω:
-
rotating speed of shaft
- t :
-
time
- ψn :
-
initial angular position of τ att=0
- p :
-
natural frequency
- p 1.p t :
-
natural frequencies of forward and backward precessions
- θω, θ1, θ1 :
-
total phases of harmonic, forward precession and backward precession components in summed-and-differential harmonic oscillation
- β, δ1, δ1 :
-
phases of harmonic, forward precession and backward precession components in summed-and-differential harmonic oscillation
- P, R t ,R b :
-
amplitudes of harmonic, forward precession and backward precession components in summed-and-differential harmonic oscillation
- ψ:
-
difference between phases (ψ = δf − δu)
- λ:
-
acceleration of rotor
- ω:
-
initial rotating speed
- t ′ t ,r ′ b :
-
amplitudes of nonstationary oscillation during acceleration
- (r ′ t )max, (r ′b )max :
-
maximum amplitudes of nonstationary oscillation during acceleration
- (r 11 )max, (r 1b )max :
-
maximum value of angular acceleration of non-passable case
- λ0 :
-
critical value over which the rotor can always pass the critical speed
- p 1,p 2,p 3,p 4 :
-
natural frequencies of experimental apparatus
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Ishida, Y., Yamamoto, T., Ikeda, T. et al. Nonstationary vibration of a rotating shaft with nonlinear spring characteristics during acceleration through a critical speed (A critical speed of a summed-and-differential harmonic oscillation). Nonlinear Dyn 1, 341–358 (1990). https://doi.org/10.1007/BF01893168
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DOI: https://doi.org/10.1007/BF01893168