Title: Magnetorheological fluids modelling: without the no-slip boundary condition

Authors: X.Q. Peng, F. Shi, Y.F. Dai

Addresses: School of Mechatronics Engineering and Automation, The National University of Defence Technology, Changsha, 410073, China. ' School of Mechatronics Engineering and Automation, The National University of Defence Technology, Changsha, 410073, China. ' School of Mechatronics Engineering and Automation, The National University of Defence Technology, Changsha, 410073, China

Abstract: In this work, we have developed a new Micro-Mechanic-Hydrodynamic Model (MMH Model) to predict the yield stress of MagnetoRheological (MR) fluids, which is also applicable without the no-slip boundary condition. We first determine the storage modulus of a MR fluid with a three-dimensional chain structure model taking into account the field concentration between the particles inside the aggregates and the effect of saturation magnetisation of the particles. Then we determine the apparent viscosity of a MR fluid by using the balance between the magnetic torque and the hydrodynamic torque. The magnetic interaction between the particles and the wall, as well as the static coefficient of friction, are considered. Experiments are conducted to measure the magnetic properties of two MR fluids with core-shell particles. The predictions of the model are compared to preliminary experimental data obtained in a controlled stress plate–plate rheometer and other theoretical predictions. It is found that the model gives almost the correct yield stress for the MRFs in the magnetic fields lower than the saturation field, but underestimates the experimental results obtained in the magnetic fields higher than the saturation field.

Keywords: magnetorheological fluids; modelling; rheology; viscoelasticity; micromechanics; hydrodynamics; yield stress; no-slip boundary condition; saturation magnetisation; static coefficient of friction; magnetic interaction; core-shell particles.

DOI: 10.1504/IJMPT.2008.015892

International Journal of Materials and Product Technology, 2008 Vol.31 No.1, pp.27 - 35

Available online: 02 Dec 2007 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article