Indirect measurements of microstructure development in magnetorheological fluids

Magneto-induction experiments have been devised to measure the microstructu re response of quiescent magnetorheological (MR) fluids to an applied magne tic field. Unlike many previous techniques this measurement technique is we ll: suited for MR fluids of high iron loading. Two distinct time scales of microstructure formation have been observed within the range of 10(-3) to 1 0(-1) seconds. These two time constants are thought to be associated with f lee or chain formation and chain growth and migration. The dependency of th e time response upon volume fraction, carrier viscosity and applied field i s in partial agreement with contemporary theories and models of particle ag gregation.