Investigation of the fundamental property of a magnetorheological compound

Abstract

Magnetorheological compound (MR compound) was developed and its typical properties were investigated experimentally by using a rotational viscometer specially designed for MR suspensions. Magnetorheological fluid (MR fluid) is composed of magnetic particles and carrier oil. It is known as one of functional fluids, whose rheological properties can be controlled by the applied magnetic field strength. Utilizing these properties, brakes, clutches, dampers and various engineering applications have been studied. However, the sedimentation of the magnetic particles of MR fluid will result in unsteady dynamic behaviors of the MR devices. In order to reduce or avoid the sedimentation of the magnetic particles in MR fluid, Magnetorheological elastomer (MR elastomer) which is a functional solid material was developed. But, the amount of the property change decreased because the binding of the magnetic particles was too strong. As a new material for solving these problems, MR compound is proposed. This is adjusted the degree of crosslinking in the process of the addition of additives and molding after mixing the elastomer stock and the magnetic particles. The basic properties of MR compound haven’t yet been clearly elucidated because it is located in the region between the liquid and the solid. In this paper, it is the purpose to elucidate the magnetic field response properties of MR compound. The relationship of the strength of the magnetic field applied to MR compound, the shear rate, and the viscosity change were investigated experimentally. Also, states of sedimentation of MR compound and MR fluid were compared.