Smart magnetorheological fluids

S. Verma
New Jersey Institute of Technology, New Jersey, United States

Poster stand number: W141

Keywords: Smart fluids, dampers, magnetorheological fluids, materials with direction-dependent material properties

This work describes the rheological behavior of magnetorheological (MR) fluids formed using mixtures of iron and glass particles in a ferrofluid. The measurements show that the yield stress of an MR fluid containing iron and glass particles can be several times greater than that of an MR fluid with only iron particles. The increase in the yield stress is due to the formation of a cross-linked structure that resists shear more effectively. If the MR fluid contains only iron or glass particles, the particle chains repel sideways, creating regions with no particles. The yield stress varies with the magnetic permeabilities of the particles and the suspending liquid, their sizes, and proportions of iron and glass particles, the total volume fraction of particles, and the applied magnetic field strength. The yield stress is maximum when the proportions of iron and glass particles are about 0.55 and 0.45, corresponding to an arrangement where particles attract their neighbors.