Employing vibration isolation can avoid the detrimental effects of unattenuated torsional vibrations on rotary mechanical equipment. Semi-active vibration isolators can effectively reduce the vibration levels in mechanical systems. Magnetorheological elastomers (MREs) are a class of smart materials whose mechanical and rheological properties can be reversibly altered under an applied magnetic field. With their inherent property-change characteristics, MREs have been successfully employed in semi-active isolators to improve their operating frequency range. This study develops an MRE-based coupling with variable stiffness to attenuate torsional vibrations. MRE sample with 10% magnetic particles volume fraction is fabricated and attached within the electromagnetic coupling. A sine sweep vibration test is conducted to examine the torsional transmissibility of the MRE-based coupling at different current levels. The results reveal that the natural frequency is shifted from 8.8 to 10.4 as the current increased from 1A (4.83 mT) to 3A (14.10 mT), respectively. The shift in the natural frequency indicates the increase of the MRE stiffness. The findings of this study demonstrate the potential of isolating torsional vibrations using the MRE-based coupling.

This work was supported by Qatar University Graduate Assistantship Grant.

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