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 σ 0 , yield stress σ y , yield strain ε y , and stress in post-yield stage σ are respectively modeled. It is found that they have an exponential dependence on magnetic field strength H and particle volume concentration ξ , including σ 0 ∝ ξ H 2 , σ y ∝ H 2 , and ( σ y − σ 0 ) ∝ ξ 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.