Vibration characteristics of a rotating sandwich beam with magnetorheological fluid

In order to investigate the vibration characteristics of a rotating sandwich beam with magnetorheological (MR) fluid, the MR fluid can be simplified as linear and viscoelastic material. The finite element theory was applied to establish the finite element model of a two-node element with eight degrees of freedom for the rotating sandwich beam with MR fluid. Then the unit mass matrix and the unit stiffness matrix of the upper and lower surface elastic layers and the MR fluid of the middle layer were formed separately. And then, the equation of motion of the rotating MR fluid sandwich beams can be derived based on the Hamilton’s principle. The simulation provided the vibration characteristics of the sandwich beam under different magnetic field intensity and different rotating speeds. The result showed that the natural frequency and modal loss factor of the rotating MR fluid sandwich beam will increase with the increasing of magnetic field intensity. With the increasing of the rotating speed, the natural frequency of the rotating MR fluid sandwich beam will increase significantly and modal loss factor will reduce to some extent. So under the action of magnetic field, the MR fluid material can significantly influence the vibration characteristics of the rotating flexible beam