Measurement of single three-dimensional moduli to evaluate the effect of a uniform magnetic field on magnetorheological fluids

Magnetorheological fluids (MRF) are usually evaluated in shear mode on a plane that is perpendicular to a magnetic field. The measurements thus obtained are perpendicular to the magnetic field. However, to better choose and design possible applications, a complete three-dimensional characterization would be needed. In the present work the rheological behavior of a MRF is evaluated in the three directions of the space while subjected to a uniform magnetic field and different mechanical stresses or deformations. The anisotropy developed in the material as a consequence of the application of a unidimensional magnetic field originates that different compression and shear moduli are obtained depending of the directions of the stresses with respect to the magnetic field. The experimental setups used here were carefully chosen to perform oscillatory measurements in different directions with respect to the applied magnetic field.