[Phenomena]
A fluid that consists of a synthetic hydrocarbon or silicone base coupled with a suspension of magnetically soft particles. In the off state, the particles disperse randomly and the fluid exhibits Newtonian behavior. But in the On State – when an applied magnetic field aligns the metal particles into fibrous structures – the rheological behavior changes from Newtonian to Bingham plastic, which makes the fluid act as though it’s more viscous. The iron particles form links that resist being broken. By changing the magnetic field, we can control the amount of torque transmitted through the device.
<Magnetic Behavior of MR Fluid>
[History]
Inventor Jacob Rabinow received the first patent for MR fluid in the 1940s. A laboratory curiosity with little practical use for decades, researchers began to get serious about it in the late 1980s and 1990s, when other technologies began to converge that made practical use of MR fluid a real possibility.
Still, new technologies aside, moving this new material from lab to commercialization faced huge hurdles. Cary, N.C.-based Lord Corporation holds the world’s most extensive patent portfolio on MR fluid formulations, which became key to successful commercialization. Lord engineers invented their own MR devices to demonstrate how the material functioned and how it would look in a real application.
[Applications]
MR fluids have been used commercially since the mid 1990s. In 1998, small, real-time controlled MR fluid damper systems were introduced commercially for heavy-duty trucks, tractors and construction vehicles for operator seat shock absorbers. The same year, a controllable MR fluid-based primary suspension shock absorber for NASCAR race cars was introduced by Carrera.
Today, the greatest driving force behind MR fluid technology is the commercial auto industry, particularly controllable primary suspensions systems. In January of 2002, the Cadillac Seville STS automobile was introduced with a MagneRide suspension system having real-time controllable MR fluid shock absorbers and struts as standard equipment. The MagneRide shock absorbers are made by Delphi Corporation. Lord supplies the MR fluid. Since the initial introduction, GM has integrated the new technology into more car models. Other car makers are looking to do the same.
• Research Fields
SSSLab (Smart Structure and System Laboratory) have researched for design and control of automotive, robotic and precision machine utilizing MR fluids.
Design for MR fluid hysteresis model
Optimal design for MR Shock Absorber
Vibration Control utilizing MR Shock Absorber
Reduction of Sound and Noise utilizing MR Insert
Consideration the hysteresis characteristics of MR fluid utilizing Preisach Model
Shock Control in Vehicle utilizing MR Shock Damper
Design the controllable MR Haptic Knob for vehicle device
Stability Analysis of Railway Vehicle Featuring MR Damper
Advanced Control Algorithm for controlling MR
HILS(Hardware In the Loop System) for developing MR Shock Absorber
