Influence of the particle size on the rheology of magnetorheological fluids

Lemaire, Élisabeth; Meunier, Alain; Bossis, Georges; Liu, J.; Felt, D.; Bashtovoi, P.; Matoussevitch, Nina

doi:10.1122/1.550614

Cited by 116 publications

(72 citation statements)

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“…An MR effect can be measured if the magnetic field is completely homogeneous, but it is much smaller than for MR fluids [21]. The dependence of the yield stress of fluids on particle size is very large up to 1 µm in diameter [25]. However, even for particles with diameters of several micrometers, the yield stress of MR fluids increases with increasing particle size [26].…”

Section: Particlesmentioning

confidence: 99%

Performance of isotropic magnetorheological rubber materials

2003

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Magnetorheological (MR) rubber materials are controllable composites that consist of magnetically polarisable particles in a rubber matrix. They belong to a group of socalled "smart materials" that have seen an increased interest recently. These materials have rheological properties that can be changed continuously, rapidly and reversibly by an applied magnetic field. With suitable control algorithms and solid state electronics, they can respond to changes in their environment. Although few applications of these materials have yet been reported in the literature, the possibilities for materials with controllable stiffness are numerous. Examples of potential applications are tuned vibration absorbers, and stiffness-tuneable mounts and suspensions.The purpose of this work is to increase our knowledge relating to magnetorheological materials for damping applications, using construction rubber as the matrix. The materials should exhibit large responses to an applied magnetic field and have good mechanical properties. In order to simplify their manufacture, the use of a magnetic field during production should, if possible, be avoided.MR rubber materials were made from nitrile and natural rubber, and irregularly shaped iron particles several micrometers in size. The particles were not aligned by a magnetic field prior to the vulcanisation; hence, the materials can be considered to be isotropic. These materials show a large MR effect, e.g. an increase in the shear modulus when a magnetic field is applied, although the particles are not aligned within the material. This is explained by the low critical particle volume concentration (CPVC) of such particles. Similar behaviour can be obtained with materials containing carbonyl iron, if the particles are aggregated and thereby behave like large irregular particles. The iron particle concentration has to be very close to the CPVC in order to obtain a large MR effect.The absolute MR effect in isotropic MR rubber materials with large irregular iron particles is independent of the matrix material, and the relative MR effect can thus be increased by the addition of plasticisers. Other ways of increasing the MR effect are to increase the strength of the magnetic field, although the materials saturate magnetically at high field strengths, or to use small strain amplitudes. The strong strain amplitude dependence of the MR effect suggests that isotropic MR rubber materials are most suitable for low amplitude applications, such as sound and vibration insulation. Measurements at frequencies within the audible frequency range show that this is a promising application for isotropic MR rubber materials.

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Section: Particlesmentioning

confidence: 99%

Performance of isotropic magnetorheological rubber materials

2003

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“…For example, taken as the reference the value of sample S1, at H = 297 kA/m the static and dynamic yield stress are respectively: 94 % and 98 % for sample S2; 82 % and 89 % for sample S3; 65 % and 78 % for sample S4. The reason for this decrement could be the Brownian motion, which is able to generate fluctuations on a large scale and promote the presence of gaps between the particles, which will decrease the strength of the columnar structures under strain and, consequently, the strength of the MR effect (Lemaire et al 1995). Nevertheless, considering that, even for the smallest diameter, we have λ > 1000 for H = 297 kA/m it is not obvious that such a low Brownian motion can explain this size dependence; furthermore, this decrease should be less pronounced at the largest fields, which corresponds to the highest values of λ and actually we observe the contrary.…”

Section: Magnetorheologymentioning

confidence: 99%

“…Finally, some investigation of the effect of particle sizes were conducted on suspensions of non magnetic particles in a ferrofluid by de Gans et al (2000) and Saldivar-Guerrero et al (2006) They found an important effect of particle size on these properties for particle diameters of the order of 100 nm. but due to the low permeability of the ferrofluid the magnetic forces are much lower than in classical MR suspensions and Brownian motion could still be efficient to break the chains of particles (Lemaire et al 1995). The difficultness of performing a rigorous experimental study about the influence of particle size on the MR properties lies in obtaining monodisperse spherical particles with different average particle diameter.…”

Section: Introductionmentioning

confidence: 99%

“…From the experimental viewpoint, little is known about the effect of particle size on the MR properties of suspensions intermediate between FF and MR fluids. Lemaire et al (1995) reported some experimental data on the influence of particle size on the MR properties of suspensions of magnetisable particles. These authors measured the shear stress as a function of the shear rate for three different suspensions' sizes, made of polystyrene particles containing inclusions of magnetite, under the presence of an applied magnetic field of approximately 10 kA/m.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis and magnetorheology of suspensions of submicron-sized cobalt particles with tunable particle size

López–López¹,

Kuzhir²,

Meunier³

et al. 2010

J. Phys.: Condens. Matter

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. Synthesis and magnetorheology of suspensions of submicronsized cobalt particles with tunable particle size. Journal of Physics: Condensed Matter, IOP Publishing, 2010, 22, pp.324106 Abstract. Different samples of cobalt powder were synthesized. Particle size and shape were characterized by electron microscopy and light scattering. These measurements showed that the synthesized powders consisted of monodisperse spheres with average diameters ranging between 63 and 760 nm. These powders were used for the preparation of magnetorheological (MR) fluids by dispersing them in silicone oil. The MR properties of these MR fluids were investigated. It was found that particle size did not have much influence on the MR response of MR fluids, for average particle diameters larger than 100 nm. On the other hand, the MR response decreased appreciably when average particle diameter was diminished below 100 nm; a theory based on the change of the aggregates'shape with the size of the particles could explain these observations. IntroductionSuspensions of colloidal magnetic particles are complex fluids that exhibit magnetic field-dependent rheological (flow) properties. This feature is known as magnetorheological (MR) effect. According to the size of the dispersed particles, these suspensions can be divided in: (i) ferrofluids (FF), which are dispersions of ferro-or ferrimagnetic nanoparticles (approx. 10 nm in diameter) in a carrier liquid (Odenbach 2006); and (ii) MR fluids, which are dispersions of micron-sized particles of magnetizable materials in a carrier liquid (Bossis et al 2002). Upon magnetic field application, particles of FF and MR fluids experience attractive magnetostatic forces, which lead to the formation of particle structures aligned in the field direction. The formation of these structures, which strengthen the suspension and oppose to the flow, is the basic phenomenon underlying the MR effect. The formation of field-induced particle aggregates, i.e. the intensity of the MR effect, will depend on the ratio of the magnetic interaction energy to the thermal energy. For two magnetic dipoles this ratio is given by:

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“…MRFs with high permeability magnetic particles were researched by Bossis and the positive relationship between yield stress and MRFs volume fraction was investigated [10]. The phenomenon was found by Lemaire that the yield stress increases with the increase of particle diameter when the particle diameter was quite small and yield stress had nothing to do with particle size when the particle diameter was quite big [11]. The lord magnetic field of MRF and its circuit design are mainly expounded [12].…”

Section: Introductionmentioning

confidence: 99%

Study on the Saturation Properties of Silicone Oil-Based Magnetorheological Fluids in Mechanical Engineering

Wang¹,

Liu²,

Wang³

et al. 2015

TOMEJ

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Abstract:In this paper some saturation properties of silicone oil-based magnetorheological fluids in mechanical engineering were researched and discussed by theoretical analysis and experiments. Firstly, experiment materials and preparation process of silicone oil-based magnetorheological fluids were presented. Secondly, magnetic-field saturation, particles saturation and added nano-particles saturation were elaborated. Finally, the influence of these properties on magnetorheological fluids properties were discussed to provide references for parameter design of magnetorheological fluids preparation and mechanical engineering.

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Influence of the particle size on the rheology of magnetorheological fluids

Cited by 116 publications

References 0 publications

Performance of isotropic magnetorheological rubber materials

Performance of isotropic magnetorheological rubber materials

Synthesis and magnetorheology of suspensions of submicron-sized cobalt particles with tunable particle size

Study on the Saturation Properties of Silicone Oil-Based Magnetorheological Fluids in Mechanical Engineering

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