Theoretical design and experimental study of magnetic circuit for magnetorheological (MR) damper of shear-valve mode

According to the analysis of shear flow and pressure difference flow of MR fluids, the damping force of MR shear-valve damping force was analysed and calculated, and a magnetic circuit of Magnetorheological (MR) damper was designed. Based on the designed magnetic circuit, the degree of magnetic saturation and the dynamic characteristics of MR fluid damper, such as impedance, current, velocity and frequency were investigated. Magnetic induction testing of damping clearance was conducted, the test results show that when the coil current is 1.4A, the magnetic induction intensity reaches 0.55T.The bench test results show that when the piston speed is constant and the current is less than 1.36A, the variation range of damping force increases significantly. However, when the current is greater than 1.36A, the damping force tends to be stable and the coil reaches magnetic saturation, and energy indication characteristic of MR damper also show the same trend, which are consistent with the theoretical results. The results of this study can provide useful guidance for the magnetic circuit design of shear-valve MR fluid damper.