31-05-2012, 11:36 AM
Magneto-Rheological Fluid
Magneto-Rheological Fluid.ppt (Size: 1,006.5 KB / Downloads: 63)
WHAT ARE ‘MR’ FLUIDS?
Dispersions of Particles made of a soft magnetic material in a carrier oil.
Responds to magnetic field with change in rheological properties.
Forms semi-solid with controllable yield strength.
Material behavior
Tiny Iron Particles align with Magnetic Field.
Fluid turns pasty and feels very stiff.
Reverts to liquid when Magnetic Field is removed.
The weight and space required by the coils to produce magnetic field is a setback.
Surfactants are additives that reduce the effect of particle settling.
Operation principle
Suspension of magnetically polarizable particles in a carrier fluid.
Alignment of the polarized particles along the lines of magnetic flux due to interaction of the dipoles.
Reversible solidification in only a few milliseconds.
Applications of MR Fluid in 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.