Effect of shape factor on compression mode dynamic properties of magnetorheological elastomers

The present study investigates the effects of shape factor (SF) on compression mode properties of cylindrical isotropic and anisotropic MREs. MRE samples with different SFs were fabricated and an experimental set up was designed to measure their magneto-mechanical responses. Extensive experimental characterizations of both kinds of MREs under wide ranges of excitation (strain-rate and amplitude) and applied magnetic field were conducted to realize the effect of SF on their compression mode dynamic properties, and also to identify the coupling effect between SF and loading conditions. Moreover, practical models have been proposed to accurately predict compression elastic and loss moduli of both MREs as a function of SF, strain-rate, amplitude and magnetic flux density. Results revealed maximum SF-stiffening effect of up to 77% and 111% for the compression elastic modulus of the isotropic and anisotropic MREs, respectively, when SF was increased from 0.375 to 0.75. The respective maximum SF effects on the loss factor were obtained as 120% and 49%. Results also generally show nonlinear effects of the SF on both the off- and on-state MRE properties and increasing the SF can enhance the relative MR effect in terms of both the elastic modulus and the loss factor of both MREs.