A model of the behaviour of magnetorheological materials

Abstract

Magnetorheological materials are a class of smart materials whose rheological properties may be rapidly varied by application of a magnetic field. These materials typically consist of micron-sized ferrous particles dispersed in a fluid or an elastomer. A quasi-static, one-dimensional model is developed that examines the mechanical and magnetic properties of magnetorheological materials. This model attempts to account for magnetic non-linearities and saturation by establishing a mechanism by which magnetic flux density is distributed within the composite material. Experimental evidence of the viscoelastic behaviour and magnetic properties of magnetorheological fluids and elastomers suggests that the assumptions made in the model development are reasonable. It is shown that the model is semi-empirical in that it must be fit to the experimental data by adjusting a parameter that accounts for unmodelled magnetic interactions.