Magnetorheological elastomers (MRE) are composites which can alter their macroscopic properties if a magnetic field is applied. Typically, these materials represent a two-component system, in which micron-sized magnetizable particles are embedded in a cross-linked polymer matrix. The spatial distribution of these particles can be either anisotropic or isotropic depending on whether the particles have been aligned by an applied magnetic field before the cross-linking of the polymer. Since the effective material behavior of MRE is essentially determined by the constitutive properties of the individual components and their geometrical arrangement within the composite, this contribution will apply a microscopic modeling approach for strongly coupled magneto-mechanical problems. Starting from the properties of the magnetizable particles and the elastomer matrix, a coupled model based on a continuum formulation of the problem is presented.
Experiments published recently by Danas et al. indicate a strong dependence of the magnetostrictive effect on applied preloeads for MRE with chain-like particle structures. These findings motivate the incorporation of finite deformations into the model. For finite element calculations, a monolithic solution scheme is developed in order to account for the strong coupling of the magnetic and mechanical fields. Numerical results presented in this contribution show a good agreement with the qualitative behavior which is observed in the experiments. Further investigations on possible deformation mechanisms based on simulations with simplified specimens provide a better understanding of the underlying effects.
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