The present study aims at the development of a magnetorheological elastomer (MRE) based semi-active seat suspension isolator and its adaptive control using a neural network (NN) control scheme. Isotropic MRE samples with 25% volume fraction of iron particles have been fabricated and then characterized under shear mode using a rotary magneto-rheometer to obtain MRE's viscoelastic properties (shear storage and loss moduli) under different levels of applied magnetic flux density. Results reveal a significant change in the storage and loss moduli with respect to the varied magnetic field. The viscoelastic properties of the MRE are then utilized to design an MRE-based seat suspension isolator in order to attenuate the transmitted vibration to the driver. For this purpose, the modeling of the seat incorporated with the MRE-based isolator is derived and subsequently, a novel NN control scheme is proposed for the semi-active control of the MRE-based isolator. The convergence and stability of the proposed control strategy have been mathematically verified using the Lyapunov method. Finally, the performance of the proposed control strategy is compared with those obtained using passive and widely used sky-hook controllers under different types of excitation including harmonic motion, road bump, and random profile. It is shown that the proposed NN controller considerably mitigates the vibration of the driver seat and outperforms the passive and skyhook controllers over the frequency range of interest.

The temperature dependency of the viscoelastic properties of magnetorheological elastomers (MREs) operating in the shear mode was experimentally investigated under broad ranges of strain amplitude, excitation frequency, and applied magnetic field. Experiments were performed with isotropic MRE samples with 25 % volume fraction of carbonyl iron particles dispersed in the silicone rubber matrix under controlled temperature, ranging from − 10 ∘ C to 50 ∘ C together with different levels of magnetic field density ( 0 to 1.0 T ). The results revealed significant effect of temperature on the linear and nonlinear viscoelastic properties of MREs, in addition to the effects of strain amplitude, rate, and applied magnetic flux density. The temperature dependency of mechanical properties of an unfilled rubber matrix was also measured, which served as a reference. The shear properties of the MRE revealed reductions in both the storage and loss moduli with increasing temperature. The temperature dependency of the MRE, however, diminished under shear strain in excess of the critical strain. The results also revealed more pronounced temperature effect at higher temperatures and excitation frequencies, while it was relatively lesser with increasing magnetic field. Increase in temperature resulted in enhanced magnetorheological effect, while a clear trend with regard to the excitation frequency could not be established. Finally, a phenomenological model has been developed to predict the storage and loss moduli of the MRE as a function of excitation frequency, applied magnetic flux density, and temperature. The superb performance of the proposed model in predicting viscoelastic moduli under various operating and environmental conditions has been demonstrated through comparison of the experimental and simulation results.

The present study aims to investigate the dynamic performance and design optimization of a novel magnetorheological elastomer based adaptive tuned vibration absorber (MRE-ATVA). The proposed MRE-ATVA consists of a light-weight sandwich beam treated with an MRE core layer and two electromagnets installed at both free ends. Three different design configurations for electromagnets are proposed. The finite element (FE) model of the proposed MRE-ATVA and magnetic model of the electromagnets are developed and combined to evaluate the frequency range of the absorber under varying magnetic field intensity. The results of the developed model are validated in multiple stages with available analytical and simulation data. A multidisciplinary design optimization strategy has been formulated to maximize the frequency range of the proposed MRE-based ATVA while respecting constraints of weight, size, mechanical stress, and sandwich beam deflection. The optimal solution is obtained and compared for the three proposed ATVA configurations. The optimal ATVA with a U-shaped electromagnet shows more than 40% increase in the natural frequency while having a total mass of 596 g.