Modeling of particle interactions in magnetorheological elastomers

Biller, A. M.; Столбов, О. В.; Raǐkher, Yu. L.

doi:10.1063/1.4895980

Cited by 90 publications

(76 citation statements)

References 28 publications

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“…1a). For initialization, we arrange the particles in straight linear chain-like aggregates: each chain is one particle in diameter, but several equi-distanced particles in length that are separated by finite gaps filled with elastic material 22,49,[55][56][57] . The chains are initially aligned parallel to each other, but otherwise placed in a random non-overlapping way 53 .…”

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confidence: 99%

Tailoring superelasticity of soft magnetic materials

Cremer

Löwen

Menzel

2015

Applied Physics Letters

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Embedding magnetic colloidal particles in an elastic polymer matrix leads to smart soft materials that can reversibly be addressed from outside by external magnetic fields. We discover a pronounced nonlinear superelastic stress-strain behavior of such materials using numerical simulations. This behavior results from a combination of two stress-induced mechanisms: a detachment mechanism of embedded particle aggregates as well as a reorientation mechanism of magnetic moments. The superelastic regime can be reversibly tuned or even be switched on and off by external magnetic fields and thus be tailored during operation. Similarities to the superelastic behavior of shape-memory alloys suggest analogous applications, with the additional benefit of reversible switchability and a higher biocompatibility of soft materials.The term "superelasticity" expresses the capability of certain materials to perform huge elastic deformations that are completely reversible 1,2 . It was initially introduced in the context of shape-memory alloys 3-5 . These metallic materials can perform large recoverable deformations due to stress-induced phase transitions. A transition to a more elongated lattice structure accommodates an externally imposed extension. Typically, this transition shows up as a pronounced "plateau-like" regime on the corresponding stress-strain curve. On this plateau, the samples are heterogeneous with domains of already transitioned material. Then, only relatively small additional stress induces a huge additional deformation. Smart material properties are observed 6-9 : upon stress release, shape-memory alloys can reversibly find back to their initial state. They self-reliantly adapt their appearance to changed environmental conditions.In the present letter, we demonstrate that an analogous phenomenological behavior can be realized for a very different class of materials, exploiting different underlying mechanisms. Moreover, we show that during operation the behavior can be reversibly tailored from outside by external magnetic fields. All of this is achieved by employing soft magnetic gels as working materials: colloidal magnetic particles embedded in a possibly swollen elastic polymer matrix 10 . Similarly to magnetic fluids 11-18 , magnetic gels allow to reversibly adjust their material properties by external magnetic fields. In this way, switching the elastic properties 19-23 offers a route to construct readily tunable dampers 24 or vibration absorbers 25 , while the possibility to switch the shape 19,26-28 allows application as soft actuators [29][30][31] . Here, we show that magnetic gels due to the interplay between magnetic and elastic interactions likewise feature superelastic behavior: it is enabled by a detachment mechanism of embedded magnetic particle aggregates and by a reorientation mechanism of magnetic moments. Both mechanisms are stress-induced and rea) Electronic mail: pcremer@thphy.uni-duesseldorf.de b) Electronic mail: menzel@thphy.uni-duesseldorf.de spond to external magnetic fields. Therefore, su...

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confidence: 99%

Tailoring superelasticity of soft magnetic materials

Cremer

Löwen

Menzel

2015

Applied Physics Letters

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“…[7,8] was specialized to describe the inner deformations which occur in MREs, which are free of external mechanical In particular, we show that a pure mechanical load is able to produce a strain hysteresis in a 2P element that otherwise dwells in an equilibrium magnetized state. In a qualitative way this proves that clustering of the particles (occurrence of "magnetic staples"), which changes so much the macroscopic properties of the MREs, could be provoked by mechanical loads as well as by magnetization as such.…”

Section: Resultsmentioning

confidence: 99%

“…To clarify the above-mentioned points, in our works [7,8] we considered a system consisting of a pair of spherical magnetizable particles embedded in an elastomer matrix. Such a mesoscopic system is the smallest representative entity that displays basic magnetomechanical effects inherent to MREs.…”

Section: Mesoscopic Elementmentioning

confidence: 99%

Elastic properties of magnetorheological elastomer: description with the two-particle mesoscopic model

Biller

Столбов

Raǐkher

2017

IOP Conf. Ser.: Mater. Sci. Eng.

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View the article online for updates and enhancements. Abstract. A pair of magnetizable solid particles embedded in a cylinder made of highelasticity material is considered as a model of a mesoscopic structure element of a magnetorheological elastomer. An applied magnetic field induces ponderomotive interaction of the particles making them to move relative to one another so as to balance the counteracting magnetic and elastic forces. In a certain parameter range, the system exhibits bistability due to which under the increase / decrease of the field, the interparticle distance changes in a hysteretic manner. This behavior has a significant effect on the ability of the mesoscopic element to resist external load. Using the developed two-particle model prone to the magnetomechanical hysteresis, we extend it to the case of a virtually macroscopic sample presenting the latter as a superposition of such elements with distributed interparticle distances. In spite of its simplicity, this scheme in a generally correct way describes the field-induced changes of the internal structure and elastic modulus of the magnetorheological composites. IntroductionMagnetorheological elastomers (MREs) are a special type of smart composites distinguished by their ability for significant shape and elastic properties changes in response to applied magnetic field. Under magnetization, the microparticles of the ferromagnet filler are got coupled by ponderomotive forces that entails a number of interesting effects: magnetically induced deformation and stiffening of MREs, the magnetic shape memory, and others, all of which possessing a substantial practical potential. At the qualitative level, the picture is simple. The applied external field magnetizes the particles and imparts magnetic moments to them. The arising ponderomotive interaction strives to arrange the particles into a spatial structure that corresponds to the minimum of magnetostatic energy. For the particles embedded in a polymer, this tendency is opposed by the elastic restoring forces, which turn up in the MRE matrix as soon as any particle shifts from its initial position. Both experiment [1,2,3] and theory [4,5,6] show that such changes can strongly modify the properties of simulated MRE samples, thus entailing their qualitatively different behavior. The key issue underlying these peculiarities is the magneto-elastic interaction of the particles in a magnetorheological elastomer at the mesoscopic level, i.e., at the scale of the particle size and the interparticle distance.

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“…[8]. In the here adopted units the result of [8] for the magnetic attraction force per particle writes as…”

Section: Time-dependent Formulationmentioning

confidence: 99%

“…[8,9]. In that modelling, nonuniform deformation of a nonlinearly elastic elastomer matrix and nonuniform and nonlinear magnetisation of the particles were taken into account as well.…”

Section: Introductionmentioning

confidence: 99%