Shear properties of a magnetorheological elastomer

This paper presents an experiment testing the damped free vibration of a system composed of a magnetorheological elastomer and a mass. The goal of this experiment was to obtain the dependence of the natural frequency and the damping ratio of the structure on the applied magnetic field. The shear properties, including the shear storage modulus and the damping factor, were therefore determined. The experimental results revealed that the shear storage modulus could reach a value of 60% of the zero-field modulus and was dominated by the magnetic field, but the change in the damping factor could be neglected. Furthermore, when the field was moderate and saturation did not occur, the shear storage modulus increased proportionally with the applied field. This interesting phenomenon was analysed, and it is suggested that the subquadratic field dependence, which arises from the saturation of the magnetization near the poles of closely spaced pairs of spheres, must be taken into consideration.