Feasibility study on the use of Magnetorheological fluids to provide active roll stiffness and damping

Michelle Lennon

Abstract


The development of new technologies, in particular smart materials, creates opportunities for active control methods. Magnetorheological fluids are a class of smart materials commonly used in active vibration control due to their favourable energy dissipation properties. Within the expanding field of active suspension systems magnetorheological fluids are being extensively applied in shock absorbers in race vehicles, where the ability to optimize suspension for a range of race conditions is often limited. The magnetorheological fluid can in that case be used to extend the operational envelope of the suspension system. This paper conducts a feasibility study of the use of a magnetorheological fluid MRF-132DG from the LORDâ„¢ Corporation for use in active roll stiffness and damping in an anti roll bar. The ranges of stiffness and damping are identified through vehicle dynamics calculations. Rheometry testing identified a Herschel Bulkey model for fluid behaviour with decoupled magnetic field strength and shear rate terms. This model applies over low field strengths which are possible to generate in a race vehicle. From the rheometry results it was determined that it was not possible to achieve sufficient roll stiffness, however it was feasible to achieve a useful amount of variable roll damping.

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