Abstract:
To provide adaptability to passive seismic isolation devices the magneto-rheological
elastomers are used. In this research, the synergistic behavior of magnetorheological
elastomers containing nickel and cobalt along with iron particles as magnetically
polarizable fillers is examined experimentally under dynamic shear loading. Two
different types of magnetorheological elastomer were fabricated having equal proportions
of iron and nickel in one kind, and iron and cobalt in the other. The concentrations of
magnetic particles in each type are varied from 10% to 40% and investigated for several
frequencies, displacement amplitude, and magnetic field values. A test assembly with
moveable permanent magnets was used to vary magnetic field density. Force
displacement hysteresis loops were studied for the dynamic response of MREs. It was
observed that MREs showed a linear behavior at low strains while nonlinearity increased
with increasing strain. The percentage filler content and frequency increased the MRE
stiffness whereas it decreased with displacement amplitude. The computed maximum MR
effect was 55.56 percent. While MRE with iron and cobalt gave the highest effective
stiffness, MRE with iron and nickel gave the highest MR effect.
