ABSTRACT
To maximize the magnetic permeability of the composite, the filler particles in the MRE should be aligned in the direction of the applied magnetic field (Carlson, 2000). The particles alignment is effected by an external magnetic field applied during the cross-linking of the MRE, the particles form columnar structures and become locked in place upon final cure. It is stated that to obtain the maximal MR effect while retaining the mechanical properties of the composite the optimum filler fraction should not exceed 30 vol% (Lokander & Stenberg, 2003). The matrix materials commonly used for MREs are natural rubber, silicon rubbers, vulcanized rubbers filled by carbon black or by silica. The MR effect is increased by choosing the material of the particles with high permeability and high saturation magnetization. Iron or carbonyl iron spherical particles with a diameter of 1-10 μm are commonly used (Lokander & Stenberg, 2003). Engineering applications of MREs are in general very recent and involve, for example, tuned vibration absorbers, stiffness-tunable mounts and suspensions and automotive bushings. In particular, vibration isolators made of MS rubber are shown to be more effective than traditional rubber isolators (Blom & Kari, 2003), (Alberdi-Muniain et al., 2013), (Tian et al., 2013), (Vlach et al., 2009).
