Analysis of a Rotating Machine Flexibly Supported by Vibration Isolating Materials

When diagnosing the vibration of a rotating machine flexibly supported by vibration isolating material, the natural frequency of the rigid body mode of the machine must be considered, in addition to the natural frequency of the rotating shaft. There are two kinds of vibration isolating materials; one has a fixed spring constant, giving it the characteristic of a linear spring, and the other has nonlinear characteristics in which the spring constant varies with the mass of the machine. When the machine is supported by a linear spring, since the natural frequency varies depending on the mass of the machine, avoiding resonance requires optimal setting of the rotation speed or selection of an appropriate vibration isolating material for the equipment to be used. Meanwhile, some nonlinear springs have constant natural frequencies even if the mass of the machine changes. As the mass of the machine increases, the spring constant also increases. Selection of such a vibration isolating material is easy, because the resonance frequency is known in advance. In this study, we analyze the vibration of a rotating machine flexibly supported by vibration isolating material. Vibration analysis was carried out on a simple model of a rotating machine supported by a linear spring or a nonlinear spring. Subsequently, the experimental equipment was manufactured and numerical calculations were performed by using the derived numerical model.