Rheological and creep and recovery behavior of carbonyl iron water-based magnetorheological gel using laponite as an additive and oleic acid as a surfactant

Abstract

This study investigates rheological properties under different operating modes and creep and recovery behaviors at a different constant stress level of a flake-shaped carbonyl iron microparticles water-based MR gel where laponite is used as an additive and oleic acid as a surfactant. The results showed that static yield stress in the shear stress sweep mode has a larger value than the shear strain sweep mode. The transient shear stress measurement of MR gel showed that there was a rapid increase in shear stress after applying a magnetic field and complete reversibility occurred after removing the magnetic field. Creep and recovery behaviors help understand the deformation mechanism of the MR fluid flow under applied constant level, and magnetic field. The results showed that at lower stress, instantaneous strains are equal to instantaneous recovery strain and MR gel behaves like a linear viscoelastic material. As the stress level increases, plastic flow of gel comes into play with increasing the instantaneous creep strain and the contribution of retardation strain and vicious strain decreases and MR gel behaves like nonlinear viscoelastic material. The MR gel becomes stiffer with increment in magnetic flux density, and the elastic energy storage capacity of MR gel increases and as a result, the instantaneous creep strain decreases sharply, and elastic recovery strain increases with an increasing magnetic field.