Magnetorheological fluid

About: Magnetorheological fluid is a research topic. Over the lifetime, 8538 publications have been published within this topic receiving 131502 citations. The topic is also known as: MRF & MR fluid.

A Magnetorheological Damper with Bifold Valves for Shock and Vibration Mitigation

Abstract: This study presents the design and fabrication of a flow-mode bifold magnetorheological (MR) damper for shock and vibration mitigation for high piston velocity (15mph or 6.75m/s) as well as an evaluation of its performance at low speed. Based on a Bingham-plastic (BP) model, as well as a BP model coupled with a low speed hysteresis model, two theoretical MR damper models for flow-mode MR dampers are constructed. Using the design strategy associated with the Bingham-model based damper model, two MR damper designs for achieving the performance requirement with a limited space are considered: first, the conventional MR damper that has an MR valve inside the piston head and second, the bifold MR damper that has MR valves at each end of the damper. After numerically comparing the damping performances of the two MR damper designs, the bifold MR damper has been chosen because its dynamic range is better at high speed. The bifold MR damper was tested at a relatively low piston velocity using an MTS testing machine under sinusoidal loading. Experimental data compare well with the results predicted by the theoretical models.

Parameter optimization and analysis of a vehicle suspension system controlled by magnetorheological fluid dampers

Abstract: This paper presents the parameter optimization and simulation analysis of a new type of vehicle suspension system controlled by recently developed magnetorheological fluid dampers. First, the differential equations of motion for a vehicle suspension system considering two degrees of freedom corresponding to vertical vibration and rocking vibration are formulated. Then, the non-controlled and optimally controlled response of the suspension system under six sets of measured road surface excitation is simulated, which shows the effectiveness of full-state feedback LQR control for the vibration suppression of the suspension system. Furthermore, the influence of the control algorithm parameters is analyzed, and the results show that active control can be fully realized by semi-active control technology, due to the intrinsic variable damping behavior of LQR control. Finally, the simulation of semi-active magnetorheological fluid damper control using a limited optimal Hrovat control algorithm is carried out, and the results are compared with LQR control results. The numerical results show that using magnetorheological fluid dampers to replace active actuators in vibration control of vehicle suspension system is quite feasible. Copyright © 2005 John Wiley & Sons, Ltd.

Magnetorheological Elastomers and Their Applications

Abstract: Magnetorheological elastomers (MRE) are smart materials whose modulus or mechanical performances can be controlled by an external magnetic field. In this chapter, the current research on the MRE materials fabrication, performance characterisation, modelling and applications is reviewed and discussed. Either anistropic or isotropic or MRE materials are fabricated by different curing conditions where magnetic field is applied or not. Anistropic MREs exhibit higher MR effects than isotropic MREs. Both steady-state and dynamic performances were studied through both experimental and theoretical approaches. The modelling approaches were developed to predict mechanical performances of MREs with both simple and complex structures. The sensing capabilities of MREs under different loading conditions were also investigated. The review also includes recent representative MRE applications such as adaptive tuned vibration absorbers and novel force sensors.

Bouc–Wen model-based real-time force tracking scheme for MR dampers

Abstract: A Bouc–Wen model-based control scheme is presented which allows tracking the desired control force in real-time with magnetorheological (MR) dampers without feedback from a force sensor. The control scheme estimates the MR damper force by parallel computing of several Bouc–Wen models with different constant currents as inputs and for the actual MR damper displacement and velocity, respectively. Based on the estimated forces and the desired control force the MR damper current is determined by a piecewise linear interpolation scheme. The model-based feed-forward control scheme is numerically and experimentally validated. If the desired control force is not constrained by the pre-yield region, residual force at 0 A and force at maximum current, the very small force tracking error ≤0.0015 in the simulation is caused by the control-oriented simplification of the linear interpolation scheme. The tests reveal that the real-time control scheme is numerically stable and the force tracking error of ≤0.078 represents an acceptable accuracy.