Deformation and rupture mechanisms of ER and MR fluids

In this paper, we discuss the different modelisations of the rupture of aggregates in ER or MR fluids. In particular, we show that microstructural models which take into account the separation between the particles inside tha aggregates give predictions very different from those based on a continuum approach. Some experimental results help us to discuss the reliability of each approach. Creep measurements were made on TiO2 particles dispersed in silicon oil. They give information on the critical deformation at which the aggregates break. An experimental model consisting of millimetric steel spheres in a magnetic field allows us to understand the different possible mechanisms of rupture.