Enhancement of magnetoelastic behavior of bimodal magnetic elastomers by stress transfer via nonmagnetic particles

Abstract

The magnetoelastic behavior of bimodal magnetic elastomers consisting of magnetic particles, carbonyl iron, and nonmagnetic particles, zinc oxide, has been investigated by dynamic viscoelastic measurements. The storage modulus of bimodal magnetic elastomers increased under a magnetic field of 500 mT. The change in the storage modulus was enhanced by adding nonmagnetic particles at volume fractions above a certain volume fraction of 0.02, indicating the occurrence of stress transfer by a chain structure of magnetic particles via nonmagnetic particles. The critical volume fraction at 500 mT determined by percolation analysis was nearly independent of the diameter of nonmagnetic particles. However, at low magnetic fields below 160 mT, the critical volume fraction was found to decrease with the particle diameter. Substituting magnetic particles with nonmagnetic ones, the change in the storage modulus of bimodal magnetic elastomers monotonically decreased with the substitution ratio of magnetic particles. The mechanism of the enhanced magnetoelastic response for bimodal magnetic elastomers is discussed.

Recent Progress on Magnetorheological Solids: Materials, Fabrication, Testing, and Applications

“…In practical, it is represented by a) Change modulus as function of strain amplitude; flux density; frequency excitation, and filler volume fraction [40,47,49,98,99,164,179,258] the ratio of change of modulus (Young modulus and shear modulus) with off-state modulus. [146,147,255] The main influencing factor of MR effect is the response of MREs due to the external magnetic field. This means that the attractive force within particle will often make positive sign in MR effect.…”

“…According to the size-based mapping, the investigations involving magnetizable particles above 100 mm have wide potential for future opportunities. [146,147] Particle distribution in the MRE element also affects the MR effect, in which an anisotropic arrangement gives better performance than an isotropic arrangement. Spherical shaped iron particles have attracted the most interest, which is about 91.9% since they are widely commercialized.…”

“…The reduction of Young modulus is caused by the network between particle and matrix is destroyed by the transitory magnetic field. [146,147,255] The main influencing factor of MR effect is the response of MREs due to the external magnetic field. [183] It can be in the form of tensile or compression forces, complex modulus, shear modulus, or even shifting frequency.…”

“…A heterogeneous dispersion of particles (particle network) barricades the MR effect, while a random dispersion leads to drastic changes in the dynamic modulus. [146,147] Particle distribution in the MRE element also affects the MR effect, in which an anisotropic arrangement gives better performance than an isotropic arrangement. So far, the volume fraction of iron particles aligned within the matrix to reach a good MR effect is about 30%.…”

Recent progress on the magnetorheological plastomers

“…Moreover, the influence of stepwise magnetic field on the storage modulus of MRPs has also been systematically studied. These results have demonstrated that the MR effect and magnetic response velocity are highly dependent on the aggregation structure of the magnetic particles [45,50,67,80]. The MRP exhibits unique nonlinear dynamic properties by loading harmonic strain.…”