scholarly journals Magnetorheological Hybrid Elastomers Based on Silicone Rubber and Magnetorheological Suspensions with Graphene Nanoparticles: Effects of the Magnetic Field on the Relative Dielectric Permittivity and Electric Conductivity

2019 ◽  
Vol 20 (17) ◽  
pp. 4201 ◽  
Author(s):  
Bica ◽  
Bunoiu
Keyword(s):  
Magnetic Field ◽  
Dielectric Permittivity ◽  
Silicone Rubber ◽  
Silicone Oil ◽  
Relative Dielectric Permittivity ◽  
Magnetorheological Elastomers ◽  
Magnetorheological Suspensions ◽  
Alternating Electric Field ◽  
Graphene Nanoparticles ◽  
The Magnetic Field

Hybrid magnetorheological elastomers (hMREs) were manufactured based on silicone rubber, silicone oil, carbonyl iron microparticles, graphene nanoparticles and cotton fabric. Using the hMREs, flat capacitors (FCs) were made. Using the installation described in this paper, the electrical capacitance and the coefficient of dielectric losses of the hMREs were measured as a function of the intensity of the magnetic field superimposed over an alternating electric field. From the data obtained, the electrical conductivity, the relative dielectric permittivity and magnetodielectric effects are determined. It is observed that the obtained quantities are significantly influenced by the intensity of the magnetic field and the amount of graphene used.

Experimental and Theoretical Study of the Field Induced Phase Separation in Electro- and Magnetorheological Suspensions

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1791-1797 ◽  
Author(s):  
S. Cutillas ◽  
G. Bossis ◽  
E. Lemaire ◽  
A. Meunier ◽  
A. Cebers
Keyword(s):  
Magnetic Field ◽  
Phase Separation ◽  
Theoretical Study ◽  
Silicone Oil ◽  
The Other ◽  
Regular Pattern ◽  
Normal Stresses ◽  
Dense Phase ◽  
Magnetorheological Suspensions ◽  
The Magnetic Field

We present here the study of field induced phase separation in E.R. and M.R. fluids. Two thermodynamic models — one for the formation of chais of particles and the other for phase separation are presented and compared with experimental results obtained with two kinds of suspensions. One was made of silica particles in silicone oil and the other was made of magnetic polystyrene particles in water. In the presence of a flow the phase separation occurs with the dense phase forming a regular pattern of stripes. The dependence of the period of these stripes on the intensity of the magnetic field is well reproduced by the same kind of thermodynamic model if we add the effect of normal stresses induced by the shear flow.

scholarly journals Magnetodielectric Effects in Magnetorheological Elastomers Based on Polymer Fabric, Silicone Rubber, and Magnetorheological Suspension

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
A. M. Gavrilovici ◽  
E. M. Anitas ◽  
L. Chirigiu ◽  
I. Bica ◽  
M. L. Negrutiu
Keyword(s):  
Dielectric Permittivity ◽  
Silicone Rubber ◽  
Biomedical Applications ◽  
Physical Mechanism ◽  
Magnetic Flux Density ◽  
Relative Dielectric Permittivity ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Copper Electrodes ◽  
Magnetorheological Suspension

We fabricate a hybrid magnetorheological elastomer (hMRE) based on a microfiber cloth soaked with a mixture containing magnetorheological suspension (MRS) and silicone rubber (SR). Two parallel copper electrodes are attached to the hMRE and the capacitance C is measured as a function of time t, for fixed values of magnetic flux density B. We show that C is stable in time and is sensibly influenced by B, while the relative dielectric permittivity increases up to two orders of magnitude when B reaches 340 mT. We explain the physical mechanism which leads to the observed magnetodielectric effects. The obtained results can be used for various biomedical applications such as in fabrication of active biomagnetic membranes used in dental implantology.

Experimental and modeling investigations on the quasi-static compression properties of isotropic silicone rubber-based magnetorheological elastomers under the magnetic fields ranging from zero to saturation field

2021 ◽  
Vol 31 (1) ◽  
pp. 015029
Author(s):  
Yanliang Qiao ◽  
Jiangtao Zhang ◽  
Mei Zhang ◽  
Pengcheng Zhai ◽  
Xiang Guo
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Silicone Rubber ◽  
Static Compression ◽  
Saturation Field ◽  
Magnetorheological Elastomers ◽  
Compression Properties ◽  
Deformation Stress ◽  
The Magnetic Field ◽  
Quasi Static Compression

Abstract The isotropic magnetorheological elastomers (MREs) containing three different contents of carbonyl iron particles (CIPs) based on silicone rubber were prepared, and their quasi-static compression properties under various magnetic fields were characterized by a material testing machine with specialized electromagnet. The magneto-induced actuation stress at zero strain condition as well as the deformation stress during compression process of MREs were tested. According to the magnetization model and demagnetizing energy theory, a magneto-induced actuation model of isotropic MREs was proposed. Meanwhile, a magneto-hyperelastic model was established for calculating the magnetic field- and strain-dependent deformation stress of MREs via combining the Neo–Hookean model, the magnetization model, and the magnetic dipole theory. Therefore, a new constitutive model was established to describe compression properties of isotropic MREs by considering the magneto-induced actuation and the magneto-hyperelastic behaviors. Finally, the effect of CIP content and model applicability were analyzed. It is verified that the developed compression model was able to exactly predict the compression properties of isotropic MREs with various CIP contents over the magnetic field range varying from zero field to saturation field by adopting a set of unified model parameters.

HEXAGON-STRIPE TRANSITION AT THE MAGNETIC FIELD INDUCED PHASE TRANSFORMATIONS OF THE MAGNETORHEOLOGICAL SUSPENSIONS

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2345-2351 ◽  
Author(s):  
A. CEBERS
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Physical Parameters ◽  
Phase Boundaries ◽  
Modulated Phases ◽  
Magnetorheological Suspensions ◽  
Perturbed State ◽  
Magnetorheological Suspension ◽  
The Magnetic Field ◽  
Hele Shaw Cell

The phase diagram of the magnetorheological suspension allowing for the modulated phases in the Hele-Shaw cell under the action of the normal field is calculated. The phase boundaries between the stripe, the hexagonal and the unmodulated phases in dependence on the layer thickness and the magnetic field strength are found. The existence of the transitions between the stripe and the hexagonal phases at the corresponding variation of the physical parameters is illustrated by the numerical simulation of the concentration dynamics in the Hele-Shaw cell. It is remarked that those transitions in the case of the magnetorheological suspensions can be caused by the compression or the expansion of the layer. Among the features noticed at the numerical simulation of the concentration dynamics in the Hele-Shaw cell are: the stripe patterns formed from the preexisting hexagonal structures are more ordered than arising from the initial randomly perturbed state; at the slightly perturbed boundary between the concentrated and diluted phases the hexagonal and the inverted hexagonal phases are formed and others.

MRE Damping Characteristics Evaluation

2016 ◽  
Vol 699 ◽  
pp. 31-36 ◽  
Author(s):  
Eduard Chirila ◽  
Ionel Chirica ◽  
Doina Boazu ◽  
Elena Felicia Beznea
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Smart Materials ◽  
Magnetorheological Elastomers ◽  
Damping Characteristics ◽  
The Subject ◽  
Energy Absorbing ◽  
The Magnetic Field ◽  
Material Form

The paper addresses the study of the damping characteristics estimation and behaviour of the magnetorheological elastomers (MREs) in the absence of magnetic field. This type of material actively changes the size, internal structure and viscoelastic characteristics under the external influences. These particular composite materials whose characteristics can vary in the presence of a magnetic fields are known as smart materials. The feature which causes the variation of properties in magnetic fields is explained by the existence of polarized particles which change the material form by energy absorbing. Damping is a special characteristic that influences the vibratory of the mechanical system. As an effect of this property is the reducing of the vibration amplitudes by dissipating the energy stored during the vibratory moving. The main characteristic that is based on the determination of the damping coefficient is the energy loss, which is the subject of the present paper. Before to start the characteristics determination in the presence of the magnetic field, it is necessary to study these characteristics in the absence of magnetic field. The MRE specimens have been manufactured and tested under the light conditions (non magnetic field). A special experimental test rig was built to investigate the response of the MRE specimens under the charging force. The experimental results show that the loss energy of the MRE specimen can be determined from the charging-discharging curves versus displacement. The results of the MRE specimen are presented in this paper: MRE with feromagnetic particles not exposed in magnetic field during fabrication.

Anisotropic Silicone Rubber Based Magnetorheological Elastomer with Oil Silicone and Iron Microparticles

2012 ◽  
Vol 190 ◽  
pp. 645-648 ◽  
Author(s):  
I. Bica ◽  
Maria Balasoiu ◽  
A.I. Kuklin
Keyword(s):  
Magnetic Field ◽  
Elastic Properties ◽  
Silicone Rubber ◽  
Longitudinal Magnetic Field ◽  
Dipole Approximation ◽  
Continuous Linear ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Young Module ◽  
Linear Body

Results on anisotropic magnetorheological elastomers magnetoelasticity are presented and discussed. In the dipole approximation, and considering the MRE as a continuous linear body, the effects of magnetic field on its main elastic properties (linear deformations and Young module) are investigated. Experimental evidences that the compression of the cylindrical bar is influenced by the intensity of the longitudinal magnetic field and the Young module of the MRE sample increases with the intensity H of the longitudinal magnetic field are obtained and the results discussed.

Tuning Active Magnetorheological Elastomers for Damping Applications

2010 ◽  
Vol 636-637 ◽  
pp. 766-771 ◽  
Author(s):  
Anna Boczkowska ◽  
Stefan F. Awietjan
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Volume Fraction ◽  
Iron Particles ◽  
Magnetorheological Elastomers ◽  
Ferromagnetic Component ◽  
Electron And Light Microscopy ◽  
Tan Δ ◽  
Microscopy Techniques ◽  
The Magnetic Field

Magnetorheological elastomers (MREs) were obtained by mixing soft polyurethane and carbonyl-iron particles. The effect of the volume fraction of the ferromagnetic particles on the MREs microstructure and properties, as well as their arrangement in relation to the external magnetic field were investigated. As a ferromagnetic component carbonyl–iron powder, with particle size from 6-9µm, was used. The amount of the carbonyl iron particles was varied from 1.5 to 33.0 %(v/v). The samples were produced with randomly dispersed and aligned carbonyl iron particles. Scanning electron and light microscopy techniques were used for the MRE microstructure observations. The rheological properties (G’, G’’ and tan δ) of the MRE were tested without and with the application of the magnetic field. It was found that the microstructure of MREs, particularly the amount and arrangement of the carbonyl-iron particles, has a significant influence on their rheological and damping properties.

Viscoelastic Responses of Silicone-Rubber-Based Magnetorheological Elastomers Under Compressive and Shear Loadings

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Rui Li ◽  
L. Z. Sun
Keyword(s):  
Magnetic Field ◽  
Silicone Rubber ◽  
Viscoelastic Properties ◽  
Mechanical Performance ◽  
Dynamic Stiffness ◽  
Zero Magnetic Field ◽  
Dynamic Strain ◽  
Loading Frequency ◽  
Magnetorheological Elastomers ◽  
Mr Effect

Magnetorheological elastomers (MREs) are adaptive composite materials in the sense that their mechanical properties are tailored by the applied magnetic field. In this paper we developed both isotropic and anisotropic silicone-rubber-based MREs. We examined the zero-magnetic-field dynamic stiffness and damping along with the magnetic field induced changes (the magnetorheological (MR) effect) for the viscoelastic properties of the MREs by conducting both compression and shear investigations. While the anisotropic MREs exhibited substantial magnetic-field-dependent viscoelastic properties at a medium magnetic field, the isotropic ones showed a negligible MR effect. The magnetic filler structure and concentration, loading frequency, and dynamic strain amplitude were all confirmed to play significant roles in the dynamic mechanical performance of the MREs.

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