Magnetorheological elastomers (MREs) (also called magnetosensitive elastomers) are a class of solids that consist of polymeric matrix with embedded micro- or nano-sized ferromagnetic particles such as carbonyl iron. As a result of this composite microstructure, the mechanical properties of these materials can be controlled by the application of magnetic field.
Contents
Fabrication
MREs are typically prepared by curing process for polymers. The polymeric material (e.g. silicone rubber) in its liquid state is mixed with iron powder and several other additives to enhance their mechanical properties. The entire mixture is then cured at high temperature. Curing in the presence of a magnetic field causes the iron particles to arrange in chain like structures resulting in an anisotropic material. If magnetic field is not applied, then iron-particles are randomly distributed in the solid resulting in an isotropic material. Recently, an advanced technology, 3D printing has also been used to configure the magnetic particles inside the polymer matrix.
Classification
MREs can be classified according to several parameters like: particles type, matrix, structure and distribution of particles:
Particles magnetic properties
Matrix structure
Matrix electrical properties
Distribution of particles
Theoretical Studies
In order to understand magneto-mechanical behaviour of MREs, theoretical studies need to be performed which couple the theories of electromagnetism with mechanics. Such theories are called theories of magneto-mechanics. A parallel branch of theoretical study is performed in the case of electro-mechanics.
Applications
MREs have been used for vibration isolation applications since their stiffness changes within a magnetic field