The preparation of natural rubber based isotropic thick magnetorheological elastomers (MRE) was focused on by varying the percentage volume concentration of carbonyl iron powder and developing a test set up to test the dynamic properties. Effect of magnetic field on the damping ratio was studied on the amplification region of the transmissibility curve. The viscoelastic dynamic damping nature of the elastomer was also studied by analyzing the force-displacement hysteresis graphs. The results show that MR effect increases with the increase in magnetic field as well as carbonyl iron powder particle concentration. It is observed that softer matrix material produces more MR effect. A maximum of 125% improvement in the loss factor is observed for the MRE with 25% carbonyl iron volume concentration. FEMM simulation shows that as carbonyl iron particle distribution becomes denser, MR effect is improved. FEMM analysis also reveals that if the distance between the adjacent iron particles are reduced from 20 μm to 10 μm, a 40% increase in stored energy is observed.

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In the present study, a modeling approach to estimate the parameters of the MRE isolator model with respect to the frequency-response curve is presented. To concur the response of the isolator over wide frequency range, fractional order based Kelvin Voigt model comprised of three parameters and the fractional Zener model having four parameters are proposed. An isolator operating in shear-mode is developed, and its performance is evaluated through the transmissibility tests. The parameters of the model are identified by minimizing the error between the transmissibility response from the MRE isolator model and the experimental results. A polynomial function is used to generalize the variation of these parameters with respect to the input current. The response predicted by the MRE isolator models confirms that both fractional Kelvin Voigt and fractional Zener modeling approaches are effective in portraying the transmissibility response. The fractional Zener MRE isolator model is more accurate and can reproduce the experimentally determined magnitude and phase response of the transmissibility with an accuracy greater than 91.5% and 84.87% respectively. On the contrary, the fractional Kelvin Voigt model is simpler in form, and it effectively reproduced the magnitude of the transmissibility response with an accuracy higher than 86.35% and the phase response greater than 83.77%.

The ability to mitigate the vibrations by a magnetorheological elastomer (MRE) isolator varies with the amplitude of the excitation and the magnetic field. To implement semi-active vibration control, a mathematical model representing the dynamic response over a wide frequency range is crucial. In the present study, an attempt was made to develop a mathematical model for the designed MRE isolator over a wide frequency range under different operating conditions. A model-based fuzzy controller was developed to implement semi-active control attributes over a broadband frequency. The methodology entails that the MRE isolator operating in shear mode was designed. The performance of the isolator was evaluated over a frequency range of 15–80 Hz with varying input currents and excitation amplitudes. The transmissibility response of MRE isolator was mathematically represented using viscoelastic constitutive relations. The isolator system was represented in state-space form, and its parameters were determined by minimizing the mean square error between experimental and model responses. A polynomial function was used to generalize variations in viscoelastic model parameters with respect to the input current. Based on the controller stopping frequency, a relationship was established between the current input to the MRE isolator and the excitation amplitude. Using the mathematical equations, a model-based fuzzy controller was developed and tested in simulation and real-time conditions. The results show that the controller effectively isolates the vibration amplitude at various excitation amplitudes and frequencies.

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