THE ROLE OF SUSPENSION STRUCTURE IN THE DYNAMIC-RESPONSE OF ELECTRORHEOLOGICAL SUSPENSIONS

The dynamic response of electrorheological (ER) suspensions has receiv ed little attention relative to the effort devoted to the study of the steady shear response. We report on simulation and experimental inves tigations of the dynamic oscillatory response of ER suspensions, in pa rticular focusing on the relationship between suspension structure and the rheological response. We consider the response of monodisperse an d polydisperse suspensions under linear deformation, as well as the re sponse in the nonlinear regime. Dimensional analysis of the equations of motion predict that the linear rheological response obeys a time-fi eld strength superposition principle, which is confirmed by experiment . The response is found to exhibit a sharp dispersion that is only bro adened slightly by polydispersity. Nonlinear deformation is found to s ignificantly broaden the observed dispersion.