Magnetorheological fluid
Overview
Smart fluid
A smart fluid is a fluid whose properties can be changed by applying an electric field or a magnetic field.The most developed smart fluids today are fluids whose viscosity increases when a magnetic field is applied...
in a carrier fluid, usually a type of oil. When subjected to a magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
, the fluid greatly increases its apparent viscosity
Apparent viscosity
Apparent viscosity is a rheological property calculated from rheometer readings performed by a Mud engineer on drilling fluid. It is normally abbreviated as AV. It is expressed in cP . Centipoise is the amount of force required to move one layer of fluid in relation to another...
, to the point of becoming a viscoelastic solid. Importantly, the yield stress of the fluid when in its active ("on") state can be controlled very accurately by varying the magnetic field intensity. The upshot of this is that the fluid's ability to transmit force can be controlled with an electromagnet
Electromagnet
An electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current. The magnetic field disappears when the current is turned off...
, which gives rise to its many possible control-based applications.
MR fluid is different from a ferrofluid
Ferrofluid
A ferrofluid is a liquid which becomes strongly magnetized in the presence of a magnetic field.Ferrofluids are colloidal liquids made of nanoscale ferromagnetic, or ferrimagnetic, particles suspended in a carrier fluid . Each tiny particle is thoroughly coated with a surfactant to inhibit clumping...
which has smaller particles.
Unanswered Questions
