FEM Simulation And Model Parameter Identification For MR Damper

Magnetorheological fluid (MR) damper is a type of excellent semi active control device with large output force, long adjustable range, wide temperature adaptability, fast response speed and low power consumption. Overcoming high cost, high power consumption and structural complexity, the shortcomings of active control device, MR damper can generate large force under little power input, which is very suitable for civil engineering application.In order to study the relationship between physical dimensions, current intensity and magnetic induction intensity in the fluid gap of damper, two dimension model of MR damper is established based on FEM method. The magnetic induction intensity of fluid gap was measured without MR fluid in the damper. The nicety of magnetic FEM method was verified by comparing the results of FEM method and experiment.The intelligent MR damper with large force is necessary to be developed first in order to be applied in actual structural vibration control, since engineering structure is often huge. A 200kN MR damper was designed according to magnetic FEM method, the performance of which was then estimated by simulation. A new full scale pole-fixed MR damper was designed with 200kN maximal output force. Because the position of coil and fluid gap is fixed, the performance of the damper is more stable than traditional shear value mode damper. Under the same performance index, the new MR damper is smaller and lighter than which was designed by Lord Corporation, so it will have a rather large practicality value and extensive application prospect.For the sake of simulating the dynamic behavior of MR damper and laying a foundation for vibration control emulation and further civil engineering application, the dynamic model parameters of a home-made 500kN MR damper was identified with nonlinear least square method. The quasi-static experiment of this damper was carried out to test its output force under variant currents and excitations. Based on the test result of sine wave excitation, the modified Bingham model of the MR damper was identified using nonlinear damped least square method. The comparison of model theoretical values and experimental values indicates that they can achieve good fit, which has verified the effectivity of the parameter identification method.