This article presents the design and multi-physics coupling analysis of a shear-valve-mode magnetorheological fluid damper with different piston configurations. The finite element model is built to study the effects of the shape of the piston slot and magnetism-insulators at both ends of the piston yoke on the performance of the magnetorheological damper. Particle swarm optimization and finite element simulation are combined to optimize the structural parameters of the magnetorheological damper. The influences of different piston configurations on the magnetic flux density in the working gap, the shear stress, the viscous stress, and the dynamic range are investigated. The simulation results reveal that the magnetorheological damper, in which the corners of the piston slot are chamfered and the edges of the magnetism-insulators are filleted, exhibits a better damping performance. Furthermore, magnetorheological dampers with and without magnetism-insulators are fabricated. The influences of control current, displacement, and velocity on the mechanical performance of the magnetorheological dampers are experimentally investigated, and the experiment results are in accordance with the theoretical derivation and finite element simulation results.

Magnetorheological fluid (MRF) damper is one of the most promising semiactive devices for vibration control. In this paper, a shear-valve mode MRF damper for pipeline vibration control is proposed. The dynamic model and the state equation of the pipeline are established and the linear quadratic regulator (LQR) is used to generate the optimal damping force of MRF damper. The design concept considering the structure and the electromagnetic properties simultaneously is discussed in detail. A mathematical model of the relation between shear stress and control current based on interpolation method is established. Finite element analysis (FEA) software COMSOL is selected to simulate the magnetic field and electromagnetism-thermal field of the MRF damper. A computational method based on the simulation model is established to calculate the shear stress. In order to reduce the magnetic leakage, a method of adding magnetism-insulators at both ends of the piston head is presented. The influence of control current, displacement, and velocity on mechanical performance of the proposed MRF damper is experimentally investigated. The test results show that the performance of the MRF damper is basically identical with the theoretical prospective and the simulation conclusions, which proves the correctness and feasibility of this design concept.