Study on the mechanism of the squeeze-strengthen effect in magnetorheological fluids

Current magnetorheological (MR) fluids have the limitation that their yield stresses are not strong enough to meet some industrial requirements. X. Tang, X. Zhang, and R. Tao [J. App. Phys 87, 2634 (2000)] proposed a method to achieve high-efficiency MR fluids by study of squeeze-strengthen effect. But there is little report on its mechanism. This paper aims to investigate this effect through experimental and theoretical approaches. For this purpose, an apparatus is designed to experimentally study the mechanism of this squeeze-strengthen effect. Taking account of a modified magnetic dipole model and the friction effect, a semiempirical model is proposed to explain this effect. In addition, this model is expected to study the squeeze-strengthen effect in electrorheological fluids. (C) 2004 American Institute of Physics.