Magnetorheological elastomer
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.[1][2]
Fabrication
[edit | edit source]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.[3] 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, in 2017, an advanced technology, 3D printing has also been used to configure the magnetic particles inside the polymer matrix. [4]
Classification
[edit | edit source]MREs can be classified according to several parameters like: particles type, matrix, structure and distribution of particles:[citation needed]
Particles magnetic properties
[edit | edit source]- Soft magnetic particles
- Hard magnetic particles
- Magnetostrictive particles
- Magnetic shape-memory particles
Matrix structure
[edit | edit source]- Solid matrix
- Porous matrix
Matrix electrical properties
[edit | edit source]- Isolating matrix
- Conductive matrix
Distribution of particles
[edit | edit source]- Isotropic
- Anisotropic
Theoretical Studies
[edit | edit source]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.[5][6]
Programmable magnetopolymers
[edit | edit source]Magnetopolymers with large remanence are typically formed by combining hard-magnetic particles with a polymer matrix. The orientation of the magnetic particles is typically controlled with an external magnetic field during the polymerization process, and then mechanically fixed after the material is synthesized. Because the Curie temperature of these magnetopolymers exceeds the temperature at which the polymer matrix would break down, they must be degaussed in order to be remagnetized. This means that the functionality of these magnetopolymers is limited and they can only be permanently programmed during manufacturing.
Programmable magnetopolymers embed athermal ferromagnetic particles in droplets of low melting point materials in polymer matrices.[7][8][9] Above the droplet melting point, the particles have rotational freedom. The uniqueness of these composites exists in their easily reprogrammable magnetization profiles. This behaviour follows from the fact that particles (1) are athermal, (2) have Curie temperatures above the droplet melting point, and (3) are fixated in solid droplets while possessing full rotational freedom in molten droplets. This easy reprogramming is a critical characteristic for such materials to be used in a wide range of applications.[8]
Applications
[edit | edit source]MREs have been used for vibration isolation applications since their stiffness changes within a magnetic field [10][11]
References
[edit | edit source]- ^ Magnetorheology, Editor: Norman M Wereley, Royal Society of Chemistry, Cambridge 2014, https://pubs.rsc.org/en/content/ebook/978-1-84973-754-8
- ^ Rigbi, Z. and Jilkén, L. The response of an elastomer filled with soft ferrite to mechanical and magnetic influences. J. Magnetism and Magn. Mat. 37 267-276 (1983)
- ^ Jolly, M. R., Carlson, J. D. & Muñoz, B. C. A model of the behaviour of magnetorheological materials. Smart Mater. Struct. 5, 607–614 (1996).
- ^ A.K. Bastola, V.T Hoang, L. Lin. A novel hybrid magnetorheological elastomer developed by 3D printing. Materials and Design 114, 391–397 (2017) [link].
- ^ Kankanala, S. V. & Triantafyllidis, N. On finitely strained magnetorheological elastomers. J. Mech. Phys. Solids 52, 2869–2908 (2004).
- ^ Dorfmann, A. & Ogden, R. W. Magnetoelastic modelling of elastomers. Eur. J. Mech. - A/Solids 22, 497–507 (2003).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).File:Creative Commons by small.svg This article incorporates text from this source, which is available under the CC BY 4.0 license.
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Deng, H. X., Gong, X. L. & Wang, L. H. Development of an adaptive tuned vibration absorber with magnetorheological elastomer. Smart Mater. Struct. 15, N111-N116 (2006) [link].
- ^ Behrooz, M., Wang, X. & Gordaninejad, F. Performance of a new magnetorheological elastomer isolation system. Smart Mater. Struct. 23, 045014 (2014) [link].
Further reading
[edit | edit source]- Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).