Viscoelastic behavior at high volume fraction of magnetorheological suspensions in the presence of discontinuous shear thickening

Abstract

This paper presents a study of the viscoelastic behavior of suspensions of carbonyl iron particles coated with a superplastifier molecule and dispersed in ethylene glycol. The experiments were done in plate-plate configuration with the rheometer MCR502 of Anton Paar. The discontinuous shear thickening (DST) transition manifests by a large jump of the storage and loss modulus. For low magnetic fields (H < 50 kA/m) the increase of moduli is at least of two orders of magnitude compared to the one induced by the magnetic field in the absence of DST. The behavior of the critical strain and the critical stress where the transition happens are presented for different frequencies and fields and a qualitative interpretation of the observed behavior is presented.