Magnetically Tunable Transmissibility for Magneto-Responsive Elastomers Consisting of Magnetic and Nonmagnetic Particles

Vibration experiments were performed for a bimodal magneto-responsive elastomer containing magnetic and nonmagnetic particles with thicknesses of 5 and 10 mm to investigate the effect of nonmagnetic particles on the natural frequency and the vibration transmissibility. The vibration experiments were carried out in a frequency range of 50-400 Hz at magnetic fields up to 80 mT. The frequency spectra of transmissibility at 0 mT for the bimodal elastomer showed a natural frequency in a frequency range of 50-150 Hz. The natural frequency shifted to higher frequencies as the magnetic field was raised. The maximum change in the natural frequency for the bimodal elastomer was 224 Hz, which was twice that for a monomodal elastomer filled only with magnetic particles (112 Hz). A proportional relationship was found between the change in natural frequency and the change in storage modulus in the linear viscoelastic regime for both monomodal and bimodal elastomers. A proportional relationship was also found between the natural frequency and the value of (G/m)(1/2). It was found that the proportionality constant for the magnetic elastomer with a sample thickness of 10 mm was close to the calculated value. Furthermore, a demonstration of the electrical vibration control using the bimodal elastomer was presented.