Vibration Suppression of Rotating Machinery Utilizing Discontinuous Spring Characteristics

In rotating machinery, resonance phenomena occur with large amplitude in the vicinities of the major critical speeds. In this paper, a new vibration suppression method utilizing a discontinuous spring characteristic is proposed. This spring characteristic is made by additional springs with preload. This method has the following advantages: In designing these additional springs, we need not adjust their parameter values to the rotor stiffness and the system damping. The amplitude of vibration can be suppressed to any desired level. Although this method has a disadvantage that an almost periodic motion occurs above the major critical speed, two countermeasures are proposed to diminish it. We clarified these phenomena theoretically and experimentally.

Almost periodic motion in complete space

It is interesting that in a complete space an almost periodic motion is periodic if the null setϕis closed and ifϕis not closed then every point of its trajectory is a limit point.

StablePand distal dynamical systems

In this paper we study the behavior of dynamical systems in uniform space which are Poisson stable and distal. The main results are that the trajectories of such motions are closed and every almost periodic motion is stablePand distal. In complete uniform space, this motion is periodic, Lagrange stable and recurrent.