scholarly journals Simulation Study on the Motion of Magnetic Particles in Silicone Rubber-Based Magnetorheological Elastomers

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Zhiqiang Xu ◽  
Heng Wu ◽  
Qiuliang Wang ◽  
Liyin Yi ◽  
Jun Wang
Keyword(s):  
Magnetic Field ◽  
Silicone Rubber ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Equations Of Motion ◽  
Viscous Force ◽  
The Finite Element Method ◽  
Magnetic Field Model ◽  
Magnetorheological Effect

Magnetorheological elastomer (MRE) is an intelligent composite material and has been widely used in various fields such as vibration reduction and sensing. MRE has an excellent magnetorheological effect through the chaining of its internal magnetic particles. Current studies on MREs mainly focus on the preparation of materials and characterization of mechanical properties. However, very few studies have been conducted on the mechanism of magnetic particle motion during MRE curing. Based on the silicone rubber-based MRE, the motion mechanism of magnetic particles during curing was explored through numerical simulation. First, we analyzed the magnetic force and viscous force of magnetic particles in MRE and discussed the equations of motion of magnetic particles under applied magnetic field. Further, we established a uniform magnetic field model through the finite element method and simulated the motion of two magnetic particles under the magnetic field. Finally, we discussed the effects of particle distribution angles, particle radii, applied magnetic field strength, and distance between particles on particle velocity and displacement. The results show that the distance between particles has the greatest influence on the motion of magnetic particles, and the size of the distance between particles will affect the contact time of the particles, thus affecting the chain formation of magnetic particles in the MRE.

Characterization of the Magnetostriction of Magnetorheological Elastomers

2008 ◽  
Author(s):  
Zelalem Aga ◽  
LeAnn Faidley
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Matrix Material ◽  
Capacitive Sensor ◽  
Solenoid Coil ◽  
Mass Percentage ◽  
Magnetorheological Elastomers ◽  
Filler Particles

Magnetorheological Elastomers (MREs) are polymer composites comprised of an elastomer matrix material with a filler of magnetic particles. The interaction of the filler particles when exposed to a magnetic field can result in a change in stiffness and a strain. However, the main focus of previous research has been on field induced change in stiffness. The goal of this study is therefore to characterize the magnetostriction (field induced strain) of these materials. The measurement of the magnetostriction of MRE was carried out by placing the specimens in a magnetic field produced by a solenoid coil and measuring the resulting strain using a capacitive sensor. A one cycle sinusoidal voltage was input to the solenoid coil that surrounded the MRE specimen to produce the magnetic field. In order to study the effect of mass percentage of iron filler particles on magnetostriction, specimens with different iron filler composition varying from 10 to 30% were produced. The effect of bulk stiffness of the specimen and the magnitude of applied magnetic field on magnetostriction properties has also been studied. The results reveal that increasing the mass percentage of iron in the specimen increases the magnitude of the magnetostriction. In addition, the magnetostriction of MRE showed dependence on the level of applied magnetic field and on the bulk stiffness of the MRE specimens.

scholarly journals Tunable Adhesion of a Bio-Inspired Micropillar Arrayed Surface Actuated by a Magnetic Field

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Xingji Li ◽  
Zhilong Peng ◽  
Yazheng Yang ◽  
Shaohua Chen
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Rotation Angle ◽  
Adhesion Force ◽  
Practical Applications ◽  
Section Shape ◽  
Theoretical Predictions ◽  
Large Elastic Deformation ◽  
The Difference

Bio-inspired functional surfaces attract many research interests due to the promising applications. In this paper, tunable adhesion of a bio-inspired micropillar arrayed surface actuated by a magnetic field is investigated theoretically in order to disclose the mechanical mechanism of changeable adhesion and the influencing factors. Each polydimethylsiloxane (PDMS) micropillar reinforced by uniformly distributed magnetic particles is assumed to be a cantilever beam. The beam's large elastic deformation is obtained under an externally magnetic field. Specially, the rotation angle of the pillar's end is predicted, which shows an essential effect on the changeable adhesion of the micropillar arrayed surface. The larger the strength of the applied magnetic field, the larger the rotation angle of the pillar's end will be, yielding a decreasing adhesion force of the micropillar arrayed surface. The difference of adhesion force tuned by the applied magnetic field can be a few orders of magnitude, which leads to controllable adhesion of such a micropillar arrayed surface. Influences of each pillar's cross section shape, size, intervals between neighboring pillars, and the distribution pattern on the adhesion force are further analyzed. The theoretical predictions are qualitatively well consistent with the experimental measurements. The present theoretical results should be helpful not only for the understanding of mechanical mechanism of tunable adhesion of micropillar arrayed surface under a magnetic field but also for further precise and optimal design of such an adhesion-controllable bio-inspired surface in future practical applications.

Patterned Magnetorheological Elastomer Developed by 3D Printing

2018 ◽  
Vol 939 ◽  
pp. 147-152 ◽  
Author(s):  
Anil K. Bastola ◽  
Milan Paudel ◽  
Lin Li
Keyword(s):  
Magnetic Field ◽  
3D Printing ◽  
Magnetic Particles ◽  
Layer By Layer ◽  
Carrier Fluid ◽  
Vibration Technique ◽  
Mode Of Operation ◽  
3D Printed ◽  
Mr Effect

This article delineates the characterization of the 3D printed MR elastomer through a forced vibration technique in the squeeze mode of operation. An anisotropic hybrid magnetorheological (MR) elastomer is developed via 3D printing. The 3D printed MR elastomer consists of three different materials; magnetic particles, magnetic particles carrier fluid, and an elastomer. MR fluid filaments are encapsulated layer-by-layer within the elastomer matrix using a 3D printer. When a moderately strong magnetic field is applied, the 3D printed MR elastomer changes its elastic and damping properties. The hybrid 3D printed MR elastomer also shows an anisotropic behavior when the direction of the magnetic field is changed with respect to the orientation of the printed filaments. The relative MR effect is higher when the applied magnetic field is parallel to the orientation of the printed filaments. The maximum change in the stiffness is observed to be 65.2% when a magnetic field of 500 mT is applied to the MR elastomer system. This result shows that the new method, 3D printing could produce anisotropic hybrid MR elastomers or possibly other types.

scholarly journals Quantifying the motion of magnetic particles in excised tissue: Effect of particle properties and applied magnetic field

2015 ◽  
Vol 393 ◽  
pp. 243-252 ◽  
Author(s):  
Sandip Kulkarni ◽  
Bharath Ramaswamy ◽  
Emily Horton ◽  
Sruthi Gangapuram ◽  
Alek Nacev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Particle Properties ◽  
Excised Tissue ◽  
Tissue Effect

ASTROID CURVES FOR A SYNTHETIC ANTIFERROMAGNETIC STACK IN AN APPLIED MAGNETIC FIELD

2009 ◽  
Vol 23 (20n21) ◽  
pp. 4021-4040
Author(s):  
D. M. FORRESTER ◽  
E. KOVACS ◽  
K. E. KÜRTEN ◽  
F. V. KUSMARTSEV
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Single Particle ◽  
Material Properties ◽  
Magnetic Particles ◽  
Particle System ◽  
Energy Landscape ◽  
Metastable States ◽  
Field Plane ◽  
The Magnetic Field

The interaction of two magnetic particles separated by an interlayer is illustrated through the "astroid" curves that represent regions in the magnetic field plane where different numbers of minima associated with stable or metastable states may exist. For a single particle, we describe the astroid curves of the Stoner-Wohlfarth model. The case of two particles is then examined and found to be much more complicated. The energy landscape of the two-particle system contains ferromagnetic, antiferromagnetic and canting states that emerge in response to the level of applied magnetic field. Because of this, up to four energy minima can exist in the system, depending upon the strength of the magnetic field and the material properties of the particles.

Classical spin dynamics of anisotropic Heisenberg dimmers

Open Physics ◽  
2013 ◽  
Vol 11 (12) ◽  
Author(s):  
Laura Pérez ◽  
Omar Suarez ◽  
David Laroze ◽  
Hector Mancini
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Spin Dynamics ◽  
Dynamical Behavior ◽  
Exchange Constant ◽  
Largest Lyapunov Exponent ◽  
Lifshitz Equation ◽  
Dissipative Case ◽  
Complicated Topology

AbstractIn the present work we study the deterministic spin dynamics of two interacting anisotropic magnetic particles in the presence of an external magnetic field using the Landau-Lifshitz equation. The interaction between particles is through the exchange energy. We study both conservative and dissipative cases. In the first one, we characterize the dynamical behavior of the system by monitoring the Lyapunov exponents and bifurcation diagrams. In particular, we explore the dependence of the largest Lyapunov exponent respect to the magnitude of applied magnetic field and exchange constant. We find that the system presents multiple transitions between regular and chaotic behaviors. We show that the dynamical phases display a very complicated topology of intricately intermingled chaotic and regular regions. In the dissipative case, we calculate the final saturation states as a function of the magnitude of the applied magnetic field, exchange constant as well as the anisotropy constants.

Non-Equilibrium Magnetization of a Dilute Suspension of Magnetic Particles

2009 ◽  
Vol 152-153 ◽  
pp. 167-170 ◽  
Author(s):  
Alexander Tyatyushkin
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Heat Generation ◽  
Applied Magnetic Field ◽  
Single Particle ◽  
Uniform Magnetic Field ◽  
Magnetic Particles ◽  
Equilibrium Magnetization ◽  
Dilute Suspension ◽  
Generation Power

A suspension of magnetic particles in a viscous liquid magnetized in an alternating uniform magnetic field is theoretically studied. The suspension is regarded as so dilute that interaction of a single particle with the applied magnetic field can be considered without taking into account the influence of other particles. The complex magnetic susceptibility of the suspension is found as a function of the frequency of the applied magnetic field. The heat generation power density averaged over the period of the oscillations is calculated.

Visco-elastic control of elastomer with magnetic particles by applied magnetic field

2016 ◽  
Vol 2016 (0) ◽  
pp. J2230204
Author(s):  
Daiki MAEDE ◽  
Fujio TSUMORI ◽  
Kentaro KUDO ◽  
Toshiko OSADA
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles

scholarly journals Development of a continuum model for ferrogels

2016 ◽  
Vol 28 (10) ◽  
pp. 1358-1375 ◽  
Author(s):  
Abdolhamid Attaran ◽  
Jörg Brummund ◽  
Thomas Wallmersperger
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Angular Momentum ◽  
Continuum Model ◽  
Magnetic Particles ◽  
Polymer Network ◽  
Reduced Model ◽  
Specific Magnetization ◽  
The Finite Element Method ◽  
Theory Of Mixtures

A systematic development of a continuum model is presented, which is capable of describing the magneto-mechanical behavior of magnetic polymer gels commonly referred to as “ferrogels”. In the present research, ferrogels are treated as multicomponent, multiphase materials. They consist of a polymer network (P), fixed magnetic particles (f), mobile magnetic particles (m), and liquid (L). By considering ferrogels as multicomponent materials, interaction among constituents of ferrogels can be captured. This helps in understanding the process occurring inside ferrogels under the influence of external stimuli, such as magnetic fields. In our modeling approach, the field equations of ferrogels are derived within the framework of the theory of mixtures. The basic equations include Maxwell’s equations, balance of mass, linear momentum, angular momentum, energy, and entropy. In the framework of the theory of mixtures, balance relations are first presented at the constituent level also referred to as partial balance relations. By summing partial balance relations over all constituents and imposing the restrictions of theory of mixtures, balance relations of mixture (for the ferrogel) are obtained. In the current work the specific magnetization (magnetization per density) is considered as an evolving variable. It is demonstrated that balance of angular momentum is satisfied using the evolution equation of specific magnetization and constitutive laws. In the process of modeling, a suitable free energy function is introduced and thermodynamically consistent constitutive laws are formulated. Introducing certain assumptions, a reduced model of the ferrogel, a coupled magneto-mechanical formulation, is subsequently presented. The reduced model consists only of a polymer network (P) and fixed magnetic particles (f). It is concluded that the reduced model compares well to the existing ones in the literature. The magneto-mechanical problem based on the reduced model is solved in 2D using the finite element method. The only unknowns for the finite element method implementation are mechanical displacement and magnetic potential. Deformation of a ferrogel in a magnetic field is subsequently investigated. Elongation and contraction of a ferrogel are observed when a magnetic field is applied in the x- and y-directions, respectively. The numerical results were compared with existing experimental work in the literature. A good qualitative agreement was found between numerical and experimental results.

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