Modelling of locomotion systems using deformable magnetizable media

Zimmermann, Klaus; Налетова, В.А.; Zeidis, Igor; Böhm, Valter; Kolev, E.

doi:10.1088/0953-8984/18/38/s30

Cited by 27 publications

(37 citation statements)

References 9 publications

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“…Similarly to magnetic fluids [11][12][13][14][15][16][17][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][27][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.…”

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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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mentioning

confidence: 99%

Tailoring superelasticity of soft magnetic materials

Cremer

Löwen

Menzel

2015

Applied Physics Letters

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“…All of these questions are of high practical relevance in view of the dynamic applications. For instance, response and relaxation times determine the range of usability of ferrogels as the basis of the above-mentioned novel damping devices [10], vibrational absorbers [11], or soft actuators [5,17].…”

Section: Discussionmentioning

confidence: 99%

Tunable dynamic response of magnetic gels: Impact of structural properties and magnetic fields

et al. 2014

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Ferrogels and magnetic elastomers feature mechanical properties that can be reversibly tuned from outside through magnetic fields. Here we concentrate on the question how their dynamic response can be adjusted. The influence of three factors on the dynamic behavior is demonstrated using appropriate minimal models: first, the orientational memory imprinted into one class of the materials during their synthesis; second, the structural arrangement of the magnetic particles in the materials; and third, the strength of an external magnetic field. To illustrate the latter point, structural data are extracted from a real experimental sample and analyzed. Understanding how internal structural properties and external influences impact the dominant dynamical properties helps to design materials that optimize the requested behavior.

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“…11 by the blue filled circles. Also the oscillation amplitude ∆h shows 23 In contrast, the theoretical value, estimated according to (8) at G ′ (1 Hz), increases drastically under decrease of θ, as shown in Fig.12. Only for high temperatures, the experimental and theoretical values are close to each other.…”

Section: Comparison Of the Thresholds With Predictionsmentioning

confidence: 90%

“…For lower temperatures, the gap between them increases drastically. According to (8) it even diverges at a critical shear modulus of…”

Section: Comparison Of the Thresholds With Predictionsmentioning

confidence: 99%

Surface instabilities and magnetic soft matter

et al. 2009

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We report on the formation of surface instabilities in a layer of thermoreversible ferrogel when exposed to a vertical magnetic field. Both static and time dependent magnetic fields are employed. Under variations of temperature, the viscoelastic properties of our soft magnetic matter can be tuned. Stress relaxation experiments unveil a stretched exponential scaling of the shear modulus, with an exponent of β = 1/3. The resulting magnetic threshold for the formation of Rosensweig-cusps is measured for different temperatures, and compared with theoretical predictions by Bohlius et. al. in

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Modelling of locomotion systems using deformable magnetizable media

Cited by 27 publications

References 9 publications

Tailoring superelasticity of soft magnetic materials

Tailoring superelasticity of soft magnetic materials

Tunable dynamic response of magnetic gels: Impact of structural properties and magnetic fields

Surface instabilities and magnetic soft matter

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