Dynamic compression testing of a tunable spring element consisting of a magnetorheologicalelastomer

Abstract

Magnetorheological elastomers (MRE) are interesting candidates for active vibration control ofstructural systems. In this study, spring elements consisting of magnetorheologicalelastomer were prepared and tested in dynamic compression to study the changes in theirstiffness and vibration damping characteristics under the influence of a magnetic field.Aligned and isotropic magnetorheological elastomer composites were preparedusing room temperature vulcanizing silicone elastomer as the matrix material andcarbonyl iron as the magnetizable filler. Aligned MREs were prepared by curing thematerial under an external magnetic field. Aligned MREs were tested and theresults were compared with isotropic composites with no preferred orientation.The mechanical properties of the MREs were tested in cyclic compression passively andwith increasing magnetic flux density. The influence of the testing frequency and strainamplitude on the dynamic stiffness and damping properties was studied. It was noted thatwhen measured in a magnetic field both the dynamic spring constants and the loss factorvalues of aligned MREs were increased compared to the zero-field values. Thedynamic stiffness of aligned MREs increased with increasing testing frequency and itwas tunable with magnetic flux density in the studied frequency range. The lossfactor of aligned MREs was also tunable with the magnetic flux density but theabsolute values also depend on the testing frequency. The dynamic stiffness of thealigned MREs measured in compression decreased with increasing strain amplitude,but the damping properties were not affected similarly. On the basis of theseresults, MREs are applicable as tunable spring elements for active vibration control.