Definitions and application of MR fluid in modern days

1. MAGNETO AND ELECTRO
RHEOLOGICAL FLUID
Name : M.Mouvlieswaran
Roll No : 17M909
Department : 2nd year BE SW Mechanical

2. Magneto and Electro Rheological
What is a magneto-rheological (MR) fluid?
 Magneto rheological fluid (MR fluid) - type of smart fluid
(properties which can be changed by applying magnetic field)
 (subjected to a magnetic field) fluid greatly increases its apparent
viscosity.

3. Flow modes
Types of flow modes:
Depending on the fluid flow and the rheological stress there are
three different modes of MRF operation:
1. Valve mode,
2. Shear mode, and
3. Squeeze mode.

4. Valve mode
Valve mode: It is the most widely used of three modes. Here the two
reservoirs of MR fluid are used and magnetic field is used to impede the flow
of MR fluid from one reservoir to another. Here the flow can be achieved by
pressure drop between reservoirs and flow resistance can be controlled by
magnetic field. The valve mode as an operational mode is used in dampers,
shock absorbers.

5. APPLICATION
Shock absorbers:
In aero plane, the vibration damping is high, while landings.
So the MR fluid is used to high efficiency of damping vibrations.

6. Shear mode
The second operational mode is the direct shear mode.
The direct shear mode is used in brakes and clutches.

7. Features
Shear mode : It differs in operation from squeeze mode due to
moving paramagnetic sliding or rotating surfaces. It has thin
layer( 0.015 in.) of MR fluid sandwiched between paramagnetic
surfaces.
1. Magnetic field is perpendicular to the
direction of motion of these moving surfaces.
2. Examples of shear mode include clutches, breaks, chucking
and locking devices, dampers and structural composites.
3. Suitable for relatively small force applications.

8. Application
Braking system:
The MR fluid system is used in this brake system for the
effective control of braking.

9. Points
 Using this simple mechanical principle the damping
arrangement becomes controllable and the vibration
transmission and excitation frequency for a suspended seat can
be adjusted accordingly.
 Other possible MRF applications using this mode are dampers
for knee prosthesis, vibration dampers, seismic dampers for
civil industry, active engine mounts and propeller shaft
mounts.

10. Real time applications