A review of the state of the art in magnetorheological fluid technologies - Part I: MR fluid and MR fluid models

This paper presents a review of the state of the art in magnetorheological technology. As magnetorheological fluids continue to gain attention, the research and development of these fluids must keep pace. Since their invention in 1948, MR fluid development has made significant advancements. Throughout this time, MR fluids have been faced with many challenges and today, after many years of development, MR fluid formulations appear to have overcome many of these challenges. The fluids have proven to be commercially viable and well suited for many applications. The intent of this study is to provide a review of the state of the art in MR fluid technologies. To limit the scope, this study will focus on three common concerns associated with MR fluids; namely the strength of the fluid (i.e., the achievable yield stress), the stability of the fluid, and the durability of the fluid. When considering the use of a MR fluid in a particular application, it is these three areas that fall under the greatest scrutiny. The literature is rich in works devoted to addressing these concerns. Furthermore, with the great success of MR fluids and MR fluid devices, a number of the models used to describe the behavior of the fluid are also reviewed; specifically, works related to the visco-plastic modeling of MR fluids are reviewed. Models used to describe the physics behind the formation of the field induced yield stress are also reviewed.