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

Abstract

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 ${\sigma }_0\propto \xi H^2$ , ${\sigma }_y\propto H^2$ , and $({\sigma }_y-{\sigma }_0)\propto {\xi }^2$ , 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.