On the shear test of a MR elastomer under magnetic field applied at various angles

Abstract

In this paper the influence of the angle between the applied external magnetic field and the mechanical shear direction on the measured elasticity of a magnetorheological (MR) elastomer is addressed. The whole range of magnetic field angles from 0∘ to 90∘ is analyzed in steps of 5∘. Though this dependence is of highest importance for practical applications this issue is rather neglected in previous studies. The work uses MR elastomer specimens based on a silicone rubber matrix containing iron powder in weight fractions of 82 and 89 wt.%. It has been shown that the measured modulus of elasticity of such composites decreases as the angle between an external magnetic field and applied shear deformation increases. As the framework for the discussion of the findings a macroscopic explanation associated with the magneto-deformation effect as well as an influence of the demagnetizing factor are considered.