Analysis of quasistatic squeeze behavior of magnetorheological fluid from the microstructure variations

Magnetorheological fluid is a novel functional material, of which quasistatic squeeze behavior needs to be quantitatively controlled in industrial applications. Since the quasistatic squeeze behavior has a close relation with microstructure variations, thus it is modeled from a microscopic approach. By analyzing compression of single chains, aggregation from single chains to BCT structure and compression of BCT structure, the initial stress sigma(0) , yield stress sigma(y) , yield strain epsilon(y) , and stress in post-yield stage sigma are respectively modeled. It is found that they have an exponential dependence on magnetic field strength H and particle volume concentration xi , including sigma(0) proportional to xi H-2 , sigma(y) proportional to H-2 , and (sigma(y) - sigma(0)) proportional to xi(2) , etc. By comparing predicted results with measured results, the micro-macro stress model on quasistatic squeeze behavior is well validated. This model can be used to design, manufacture, and control industrial magnetorheological devices.