Multiscale modeling of magnetorheological elastomers with a twist

Magnetorheological elastomers (MREs) are polymers with embedded micron or submicron ferromagnets. MREs are a promising platform for studying cell responses to dynamic mechanical changes in their environment, as the shear modulus is tunable via an applied magnetic field [1]. MREs deform under applied magnetic fields, including visible twisting. In this work, we used a multi-scale approach to model the magnetic reversal and field-dependent deformations. Ferromagnetic particles in the polymer interact via dipolar coupling, but are also permitted to move; the balance of dipole, elastic energies, and Zeeman energy dictates the deformations of MREs. A point-dipole based model was used to study the behavior of a collection of particles in an elastomer matrix, and micromagnetic simulation results for a ferromagnetic sphere provided the susceptibilities used as input parameters. Volume-preserving in- and out-of-plane deformations were incorporated in the model, as well as, twisting of the matrix as observed in experiments. Modelling results will be presented and compared to experimental hysteresis measurements.
References
[1] Cantera, M Asun, et al., Smart Materials and Structures 26, 023001 (2017).