Abstract:A double coil magnetorheological (MR) damper was designed,and its structure and working principle were introduced. The dynamic characteristics of the proposeed MR damper were tested using the INSTRON stretching machine, and dynamic characteristics of the double coil magnetorheological damper were analyzed with the current applied to double coil in the test conditions including: applied currents with same direction, applied current with reverse direction, one coils current fixed while another coils current changed. Meanwhile, the relation of changes of damping force versus displacements and the damping force versus velocity were compared and analyzed under the different stretching displacement and loading frequency of the tested machine. The results show that the damping force equals 120 N under zero applied current of the damper. The influences of the changing frequency on the damping force are obvious while the loading frequency and the stretching displacements changed. Moreover, the damping force under the applied current with reverse direction in the double coil is bigger than that of under the applied currents with same direction, and the maximum damping force can reach 121 kN under the applied current with reverse direction. When one coils current is fixed and another coils current is changed, the damping force can keep stable if the total applied currents equal each other, which reveal that the magnetic flux density of the designed double coil is also identical, with rather good symmetry.