Magnetorheological elastomers are smart, field-responsive composite materials that are of increasing interest in numerous industries, with much work being conducted to characterise them. They exhibit microstructural changes under the influence of a magnetic field, namely due to inter-particle and particle-matrix interaction. If it is applied during curing, the migration of the magnetisable particles causes the formation of chain-like structures leading to anisotropic properties of the cured media.
Numerous challenges exist with respect to the characterisation and simulation of such materials. The material behaviour is highly non-linear at both the macro-scale and micro- scale, and the response due to magnetic induction is complex. The polymer composite exhibits incompressible and rate-dependent material behaviour, and due to the embedded particles has a dependency on the alignment of the particles and the magnetic induction.
In this talk I will present various aspects of work performed to fabricate and characterise these composites in a repeatable and reliable manner. Robust methods that may be used to perform parameter identification studies based on experimental data, with its associated uncertainties, will be presented. Some aspects of computational homogenisation and microstructural studies, including for determination of magnetic forces acting on individual particles and the influence of the microstructure on macroscopic material response will be shown. Lastly I will focus on the modelling magnetorheological elastomers from the macroscopic viewpoint. This discussion will include an efficient method to incorporate the influence of the free space surrounding the solid composite. Using this framework, several numerical examples will be explored, including one highlighting a novel constitutive law that takes into consideration the dispersed anisotropy of materials cured under a magnetic field.