Design And Experiment Of MR Damper With Full-length Effective Damping Path

Magnetorheological(MR) fluid is a kind of new smart material. MR damper is the ideal measurement for semi-active control of civil engineering structures with magnetorheological fluid as actuating medium. Magnetic coils ought to be winded around pistons of the conventional MR dampers, and hence, above half of the damping path is ineffective, which greatly decreases the maximum force of the MR damper.In order to overcome this disadvantage, this paper proposes a new type MR damper with full-length effective damping path. The main works in this paper are shown as follows:(1)The effective length of the dampers is increased by making use of magnetism leading lantern ring and then the damping path of the dampers is full-length effective. Combining with finite element analysis of the magnetic field, the structural design and the magnetic circuit design of two new dampers are completed.(2)The magnetic field of the MR damper is tested, and the results indicate that the magnetic field is stable along the whole damping path and reaches the designed value, which proves the design of the magnetic circuits to be correct and feasible.(3)The performance experiment of the new MR damper is performed on MTS servo test machine, and the hysteresis loops are obtained.The experimental results indicate that the proposed magnetic circuit can realize the design idea of the full-length effective damping path. And thus the maximum damping forces of these dampers are increased by 40%~70% compared with traditional MR damper of the same size.The study in this paper demonstrates the superior damping performance of the proposed MR damper with Full-length Effective Damping Path, and it also provides a reliable theoretical basis for the application of this kind of damper to the semi-active control of practical civil engineering structures.