Design, experiment and modeling of a damper based on magnetic gradient pinch mode MR valve

In this study, a novel magnetorheological (MR) damper designed based on the magnetic gradient pinch mode MR (MGPMR) valve, is investigated analytically and experimentally. The prototype and experimental platform are designed and established to characterize the dynamic force-displacement/velocity properties under board ranges of excitation and current conditions with the consideration of the effect of design parameters, which mainly includes the number of the non-magnetic rings and the diameter of the flow channel. The experimental data shows that the tunable damping range is positive correlation with the number of non-magnetic rings and negative correlation with the diameter of flow channel. Therefore, an analytical model, which considers the hysteresis damping model of the MGPMR valve, ideal gas model, and the hysteresis friction of seals, is established to describes the dynamic force-displacement/velocity properties of the MGPMR damper with 4 non-magnetic rings and 7 mm diameter of the MGPMR valve. The proposed hysteresis damping model of the MGPMR valve consists of the tangential hyperbolic hysteresis model, tunable viscous damping, and fluid inertial together with the identified model parameters. The validity of the proposed model of MGPMR damper is demonstrated through a comparison between the simulation and experiment results showing good agreement of the hysteresis loops and output force-displacement/velocity characteristics under wide range of excitation and currents conditions.