Design and geometric parameter optimization of hybrid magnetorheological fluid damper

A hybrid type magneto-rheological (MR) fluid damper based on electromagnet and two permanent magnets apart from electromagnet was designed and its characteristics were analyzed numerically. In the proposed MR damper, the magnetic field is generated by the permanent magnet and raised by the additional electromagnet. This combination provides a larger amount of damping force with lower consumption of electric energy. The proposed model has an additional advantage of providing a moderate damping force in case of electromagnet failure. The magnetic circuit of a hybrid MR valve was analyzed by applying Kirchhoff’s law and magnetic flux conservation rule. A 2D axisymmetric model of the proposed hybrid MR damper was developed in commercial software where magnetic field properties are analyzed by finite element method. The optimization process was developed to optimize the geometric parameters and generated damping force using design of experiment (DoE) technique. The damping force of the MR damper was selected as an objective function. The optimal solution to the optimization problem of the hybrid MR valve structure was evaluated and compared with the solution obtained from the initial parameters. It is demonstrated that the novel hybrid type provides higher damping force than the previous model.