Electronic edition ISSN 1574-0579

Normal force of micro magnetorheological fluid mixed nano ferromagnetic particles

X. H. Liu , W. L. Wang , Y. G. Fu , X. B. Han , Z. D. Ma , Y. Wu

School of Mechanical Engineering, Shanghai Institute of Technology, Shanghai, People's Republic of China

Abstract
In this paper, a new type of micro-nano-sized magnetorheological (MR) fluid is studied. Nanoparticles with different mass fractions (0%, 4%, 7%, 11%, 14%) are added to micro-sized magnetorheological fluid, and its effect on the normal force of MR fluid is analyzed. A microscopic magnetic dipole model of micro-nano-sized MR fluid is analyzed theoretically by the finite element software ANSYS. Different magnetic flux densities and magnetic field intensities in micro-sized magnetorheological fluid are obtained. Different active currents (0.2 A, 0.4 A, 0.6 A, 0.8 A and 1.0 A) are applied to investigate the effect of different mass fractions (nano-sized magnetic particles) on micro-nano-sized magnetic dipoles. The experimental results indicate that with increasing mass fraction of nano-sized magnetic particles, the structure of the magnetic dipole chain becomes tighter. Additionally, the magnetic flux density of the micro-nano-sized magnetic dipole enlarges with increasing excited current. In the static magnetic field, the increasing of the mass fraction of nano-sized magnetic particles will also lead to gradual increase of the normal force of the micro-nano-sized magneto-dipole. Tables 2, Figs 11, Refs 16.