The field-dependent surface roughness of magnetorheological elastomer: numerical simulation and experimental verification

Uncertainty about the effect of magnetic field on the surface of a magnetorheological elastomer (MRE) results in difficulty in controlling the surface change effectively. Thus, a mesoscopic model based on magneto-mechanical coupling analysis is proposed to investigate how a magnetic field induces interaction of the ferromagnetic particles inside a MRE, and consequently how the surface microstructures of the MRE are changed. The results show that when a magnetic field is applied, the ferromagnetic particles are magnetized and there are interactions between particles; this leads to a change in the microstructure of the MRE surface, which accounts for the controllable tribological properties of the MRE. The influence of the initial surface profile, the particle volume fraction, the magnetic field strength and the modulus of the matrix on the surface roughness are also discussed. Based on the results of simulations, the mechanism of roughness change under a magnetic field is analyzed in combination with magnetic dipole theory. Further, a roughness measuring platform is developed and samples with different initial surface profiles and particle volume fractions are tested with and without a magnetic field; the results are consistent with simulations. (paper)