Active vibration control of a shaft bracket-plate coupled system

Active vibration control of a shaft bracket-plate coupled system is investigated. The vibration of the plate is controlled with electromagnetic vibration absorbers (EVAs), which are mounted around the feet of the shaft bracket to impede the transmission of vibration from the bracket apex to the plate. A dynamic model is established on the Timoshenko beam theory and the Kirchhoff thin plate theory to reveal the mechanism of vibration transmission. It is exhibited that all the induced forces and moments at the coupling points contribute much to the transverse responses of the plate. The feasibility of active control with the EVAs is evaluated numerically based on the controllability of the plate vibration. It is demonstrated that the two-point in-plane control is able to attenuate the plate vibration under the excitation of in-plane disturbance forces, while the multi-point control is effective in reducing the plate vibration regardless of the directions of disturbance forces. An experimental system is built to verify the performance of the two-point in-plane control. The results have shown that with the help of adaptive control, the two-point in-plane control is capable of suppressing the vibration of the foundation induced by the in-plane forces acting on the shaft bracket.