Magnetorheological Fluids

Jaime Niño Jr.

MEEN 3344

FALL 2005

Functions of MR Fluids These are liquids that change their properties

when we apply a magnetic field to them. When the magnet is in place the MR Fluid

turns into solid. When the magnet is removed the solid

instantly reverts to liquid

What is MR fluid? Soft magnetic material in a carrier oil.

Silicon oil or even corn syrup is mixed with the MRF to prevent rust.

Typical MR fluid contains 20-40% by volume of relatively pure, soft iron particles.

Rheology or to the phenomena of flowing matter Is type of rheological fluids whose yield stress can

be varied by an applied magnetic field. A typical MR fluid consists of micron sized

magnetizable iron/ferrous particles suspended in a base fluid like silicone oil or water.

Applications of MR Fluid Vehicle Suspension

Dampers

The MR damper has a built-in MR valve across which the MR fluid is forced. The piston of the MR damper acts as an electromagnet with the required number of coils to produce the appropriate magnetic field. Also the MR damper has a run-through shaft to avoid an accumulator.

Cont’ Applications MR Transmission Clutches

They are used in automotive power train to transmit torque from the engine to the transmission and the vehicle. The MR sponge clutch may be used to provide launch control of an automobile thereby achieving smooth vehicle launch.The MRF clutch thus may replace the existing torque converters and therefore help increase the fuel economy.

Advantages Of MR Fluid Easy to control

As magnetic fields can be precisely controlled by current driven electromagnets

Have higher magnitude of yield stress Compared to ER fluids the simple construction of

devices, low power requirements for control, fast response

References http://rclsgi.eng.ohio-state.edu/~gnwashin/par

ts/MR_1.html http://rclsgi.eng.ohio-state.edu/~gnwashin/par

ts/MR.html http://rclsgi.eng.ohio-state.edu/~gnwashin/par

ts/MR_3.html http://www.sciencentral.com/articles/view.ph

p3?article_id=218392121&language=english