Large-strain behaviour of Magneto-Rheological Elastomers tested under uniaxial compression and tension, and pure shear deformations

The large-strain behaviour of Magneto-Rheological Elastomers (MREs) is characterised experimentally under uniaxial compression, uniaxial tension and pure shear deformation, in the absence and in the presence of magnetic fields. MREs are 'smart' materials that can alter their properties instantaneously by the application of external stimuli. They hold great potential for use in adaptive stiffness devices. So far, the large-strain behaviour of MREs has not been well explored, and their behaviour under pure shear deformation has not been characterised. Tests on silicone rubber based isotropic and anisotropic MREs, with and without the application of an external magnetic field have been performed in this investigation. The MR effect, defined as the increase in tangent moduli, is studied versus large engineering strain. Strains were measured optically using a Digital Image Correlation (DIC) system. Relative MR effects up to 284% were found under uniaxial tension, when a magnetic field strength of 290 mT was applied with the loading direction parallel to the direction of particle alignment.