Considering the low-frequency and large-amplitude vibration characteristics of the high-rise structure, a tuned magnetic fluid rolling-ball damper is proposed to suppress the vibration of the structure. By adjusting the external magnetic field to control the natural rolling frequency of the ball, the purpose of tuning vibration reduction is achieved. Firstly, the working principle of the damper is theoretically analysed, a three-dimensional (3D) magnetic-fluid-solid multiphysical field coupling mathematical model of the damper is established and the governing equations of multiphysical field coupling are derived. Secondly, the magnetic field distribution and operating characteristics of the damper are simulated and analysed. Finally, the effectiveness of the model is verified by experiments, and the damping performance of the damper with two kinds of magnetic fluid is tested and compared. The results show that the magnetic-fluid-solid multiphysical field coupling model can accurately simulate the working characteristics of the damper. The maximum damping force of the damper is about 12% of the elastic force of the structure, which can increase the damping ratio of the structure by about two times, effectively reduce the vibration response time, and suppress the vibration of the high-rise structure.

Energy dissipation of tall building structures suffering frequent violent shaking under strong excitation is a key research topic for the safety of such buildings. In this paper, a new-type tuned magnetic fluid damper with copper balls immersed is proposed to reduce the vibration under different excitation frequencies. First, the natural frequency of the damper was deduced by the Kinetic equations of magnetic fluid, and the sizes of the copper balls in the damper were determined by constructing the equivalent damping ratio model. Meanwhile, the viscosity changes of the magnetic fluid with different magnetic fields were obtained by establishing the finite element simulation of the magnetic field and carrying out the magnetic-viscous experiment about the magnetic fluid. The kinetic energy of magnetic fluid and copper balls were obtained by constructing dynamic finite element simulation model. The vibration experiment was carried out to verify the damping effect of the damper. Finally, the conversion of dissipated energy in the process of energy dissipation was analyzed by building fitting functions, and then analyzed in combination with the simulation results. The experimental results showed that the amplitude attenuation of horizontal vibration was obvious under the action of the damper when the excitation frequency was close to the natural frequency of the damper. In addition, most dissipated energy was converted into the kinetic energy of magnetic fluid and copper balls.