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]
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.[2] 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. [3]
Classification
MREs can be classified according to several parameters like: particles type, matrix, structure and distribution of particles:
Particles magnetic properties
- Soft magnetic particles
- Hard magnetic particles
- Magnetostrictive particles
- Magnetic shape-memory particles
Matrix structure
- Solid matrix
- Porous matrix
Matrix electrical properties
- Isolating matrix
- Conductive matrix
Distribution of particles
- Isotropic
- Anisotropic
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.[4][5]
Applications
MREs have been used for vibration isolation applications since their stiffness changes within a magnetic field [6][7]
References
- Magnetorheology, Editor: Norman M Wereley, Royal Society of Chemistry, Cambridge 2014, https://pubs.rsc.org/en/content/ebook/978-1-84973-754-8
- 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).
- 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].