Research on improved magnetorheological damper for wide-band vibration control

Magnetorheological (MR) damper is a new smart device utilized in semi-active vibration control, which has less response time, greater damping force and is easy to control. But common MR damper can't be used in cases of high-frequency vibrations because of stiffness hardening, which leads to increase of displacement transmissibility at high frequencies. For this reason a new MR damper with decoupling mechanism is designed by adding decoupling mechanism into the common MR damper. The decoupling mechanism made the damper sensitive to vibration. This means that the damper has different stiffness and damping in case of different amplitude. Based on the Bingham fluid theory, model of present MR damper has been built, and transmissibility expression of the isolation system has been proposed. Dynamic characteristics have been emulated. The results show that the decoupling sheet doesn't work in case of low frequency and large amplitude vibration, and the damper presents high damping. In case of high frequency and small amplitude vibration, the decoupling sheet works and the damper presents small damping and stiffness. As a result, transmissibility at high frequencies decreased.