ER Fluid Squeeze Film Damper for Semi-Active Vibration Control Device: A Parametric Study

This paper deals with a successful application of Electro-Rheological (ER) fluid to a squeeze film damper which enables a flexible rotor to reduce whirling amplitude by adjusting the damping property at each rotating speed. An experimental small scale model composed of a flexible shaft and a controllable ER squeeze film damper was constructed and its performance was studied under various electric field strengths. The ER fluid used in the present experiment was a colloidal suspension of silica powder in mineral oil. Furthermore, a theoretical approach to the performance of ER squeeze film damper was made in which the short bearing approximation of a journal bearing with Bingham plastic fluid was introduced. It is shown that the natural frequencies of a flexible shaft was increased continuously as the applied electric field was strengthened in the experiment, which was caused by the mode change due to supporting damping variation, and that the optimum damping for the flexible rotor in each rotating speed can always be applied by changing the applied voltage to the ER fluid squeeze film damper. It is also shown that the simplified theory introduced in this paper shows good agreement with the present experimental results.