Ferrofluids for Active Shock Absorbers

Abstract

This paper deals with synthesis and characterization of a ferrofluid and examining its suitability for developing a damper whose damping behavior can be controlled by applying magnetic field. In particular, ferrofluids, consisting of oleic acid coated Fe3O4 nanoparticles dispersed in kerosene, have been synthesized and characterized. Oleic acid coated nanoparticles of Fe3O4 have been characterized using XRD, TEM and FTIR. These studies show that sizes of particles are in range of 6 to17 nm and oleic acid is adsorbed on the surface of above particles. The role of damping medium on the damping behavior of a damper has been studied by carrying out studies with several different liquids. The effect of magnetic field on the damping behavior of ferrofluid based damper has also been studied. It is seen that damping ratio depends on the viscosity of damping medium. In particular, it is seen that damping ratio of a ferrofluid based damper increases on application of magnetic field. However, the sensitivity of damping ratio to the magnetic field has been found to be different for different ferrofluids. It seems, magnetic moment or size of the particle plays an important role in deciding the sensitivity of the damper. No attempt has been made to improve the sensitivity of the damper by optimizing various parameters. All the same, present studies provide a proof of concept for smart shock absorber.