The effective magnetic properties of magnetorheological fluids

Magnetorheological (MR) fluids represent a class of smart materials whose r heological properties change in response to the application of a magnetic f ield. These fluids typically consist of small (mum) magnetizable particles dispersed in a nonmagnetic carrier fluid that generally contains additives such as surfactants and antiwear agents [1]. Due to such additives, there i s an outer nonmagnetic layer on the particles that keeps them from touching . The god of this paper is to study the effective magnetic behavior of an M R composite as a function of the interparticle distance. To this end, we pr esent and employ a model for the effective magnetic properties of MR fluids with periodic microstructure that; is based on the theory of homogenizatio n. Finally, we discuss an interpolating formula for the effective permeabil ity of MR fluids as an extension of the work of Keller [2] and Doyle [3]. ( C) 2001 Elsevier Science Ltd. All rights reserved.