Beneficial Effects of Parametric Excitation in Rotor Systems
For a long time parametric excitation in rotor systems was associated only with the gravity effect on the bending vibration of rotors with anisotropic shafts. Parametric excitation seemed to have only negative effects on the dynamics of rotating systems and therefore the focus of research studies was on how to avoid or at least minimize the adverse consequences of parametric excitation.
However, recent research results have shown that parametric excitation may not only cause harmful instabilities in a dynamical system but can also improve the capability of a system to suppress vibrations. In particular it is possible to avoid the onset of an instability by introducing parametric excitation to the system. These findings are quite new and the numerous possibilities of making use of it still need to be explored and discussed.
This article presents the basics of parametric excitation as a means to suppress vibrations in rotating machines. Several theoretical and experimental studies are reviewed. The potential of this novel design concept is discussed and directions for further research and future practical applications are outlined.
KeywordsRotor instability Vibration damping Time-periodic stiffness variation
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