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.