Dynamic elastic properties of magneto-rheological slurries

We study the propagation of elastic perturbations in magneto-rheological sl urries of iron particles dispersed in glycerine. The complexity of these sy stems is revealed in the fibrillar structure acquired under the application of a magnetic field, Recently, it has been reported the observation of two different low frequency modes of propagation. One of these modes has been associated to the propagation of the perturbation through the fluid medium, The other one has been qualitatively explained as the propagation of the e lastic perturbation through the suspended particles. This second mode appea rs when a magnetic field is applied to the slurry. The propagation speed fo r both modes depends on the field intensity and on the properties of the ma gnetic particles, Theoretically, we analyze these modes and calculate the s ound velocity, We obtain a quantitative good agreement with the experimenta l results. (C) 2001 Elsevier Science B,V, All rights reserved,