Sensing Behavior of Magnetorheological Elastomers

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
Xiaojie Wang ◽  
Faramarz Gordaninejad ◽  
Mert Calgar ◽  
Yanming Liu ◽  
Joko Sutrisno ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Properties ◽  
Magnetic Particles ◽  
External Stimulus ◽  
Magnetorheological Elastomer ◽  
Polymer Medium ◽  
Mechanical Loads ◽  
Magnetorheological Elastomers ◽  
Impedance Response ◽  
Ferromagnetic Particles

A magnetorheological elastomer (MRE) is comprised of ferromagnetic particles aligned in a polymer medium by exposure to a magnetic field. The structures of the magnetic particles within elastomers are very sensitive to the external stimulus of either mechanical force or magnetic field, which result in multiresponse behaviors in a MRE. In this study, the sensing properties of MREs are investigated through experimentally characterizing the electrical properties of MRE materials and their interfaces with external stimulus (magnetic field or stress/strain). A phenomenological model is proposed to understand the impedance response of MREs under mechanical loads and magnetic fields. Results show that MRE samples exhibit significant changes in measured values of impedance and resistance in response to compressive deformation, as well as the applied magnetic field.

Electrical Properties of Magneto-Rheological Elastomers

2008 ◽  
Author(s):  
Xiaojie Wang ◽  
Faramarz Gordaninejad ◽  
Mert Calgar ◽  
Yanming Liu ◽  
Joko Sutrisno ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Properties ◽  
Magnetic Particles ◽  
External Stimulus ◽  
Magnetorheological Elastomer ◽  
Polymer Medium ◽  
Impedance Response ◽  
Properties Of Materials ◽  
Magneto Rheological ◽  
Ferromagnetic Particles

A magnetorheological elastomer (MRE) is comprised of ferromagnetic particles aligned in a polymer medium by exposure to a magnetic field. The structures of the magnetic particles within elastomers are very sensitive to the external stimulus of either mechanical force or magnetic field, which result in multi-response behaviors in MRE. In this study, sensing properties of MREs through experimentally characterizing the electrical properties of materials and theirs interfaces with external stimulus (magnetic field or stress/strain) are investigated. A phenomenological model is proposed to model the impedance response of MREs. Results show that MRE samples exhibit significant changes in measured values of impedance and resistance in response to compressive deformation, as well as applied magnetic field.

MONITORING INTERPARTICLE DISTANCE IN MAGNETORHEOLOGICAL COMPOSITES

2007 ◽  
Vol 21 (28n29) ◽  
pp. 4868-4874
Author(s):  
G. BOSSIS ◽  
E. COQUELLE ◽  
C. NOEL ◽  
F. GIULIERI ◽  
A. M. CHAZE
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Energy Dissipation ◽  
Viscoelastic Properties ◽  
Magnetic Particles ◽  
Interparticle Distance ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Magnetic Spheres ◽  
The Creation

We describe two different systems, the first one based on a magnetorheological elastomer and the second one on magnetic particles inside a liquid crystal. In both system we manage to have chain structures with particles that are not in contact. The effect of the gap between particles on the viscoelastic properties are studied. We show in particular how in magnetorheological elastomers, the energy dissipation is closely related to the creation and the motion of cavities in the gap between the particles. In liquid crystal chaining of particles can occur without applying a magnetic field. This happens if the anchoring of liquid crystal on the surface of the particles is homeotropic. We demonstrate how the combination of elastic defects and of a magnetic field allow to obtain microscopic springs made of a pair of magnetic spheres.

Smart Materials Based on Magnetorheological Composites

2012 ◽  
Vol 714 ◽  
pp. 167-173 ◽  
Author(s):  
Marcin Masłowski ◽  
Marian Zaborski
Keyword(s):  
Magnetic Field ◽  
Smart Materials ◽  
Magnetic Field Effect ◽  
Cross Linking ◽  
Vibrating Sample Magnetometer ◽  
Magnetorheological Elastomer ◽  
Gamma Iron ◽  
Magnetorheological Elastomers ◽  
Elastomer Composites ◽  
Ferromagnetic Particles

Magnetorheological elastomer composites (MREs) based on different magnetoactive fillers such as: carbonyl iron powder (CIP), gamma iron oxide (γ-Fe2O3), micro-and nanosize Fe3O4 are reported and studied. MREs were obtained from various elastomer matrixes such as: ethylene propylene, acrylonitrile butadiene, silicone, ethylene-octene and polyoctenamer rubbers. To align particles in elastomer, cross-linking process took place in magnetic field. Effect of the amount of ferromagnetic particles and their arrangement on the microstructure and properties in relation to the external magnetic field was examined. The microstructure, magnetic and magnetoreological properties of compositions were investigated with scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and ARES Rheometer with magnetic device. Cross-linking density and mechanical properties of the composites were also studied. It was found that microstructure anisotropy has significant effect on the properties of magnetorheological elastomers. Moreover, different amount of magnetoactive fillers influence mechanical and magnetic properties of the vulcanizates. Many essential conclusions occur after application the wide variety of elastomer matrixes filled with different ferromagnetic particles in the context of preparation process of smart materials based on magnetorheological elastomer composites.

Soft magnetorheological elastomers as new actuators for valves

2012 ◽  
Vol 23 (9) ◽  
pp. 989-994 ◽  
Author(s):  
Holger Böse ◽  
Raman Rabindranath ◽  
Johannes Ehrlich
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Air Flow ◽  
Inhomogeneous Magnetic Field ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Type Device ◽  
New Type ◽  
Flow Through ◽  
The Magnetic Field

The actuation behavior of soft silicone-based magnetorheological elastomers in magnetic fields of variable strength was investigated. An inhomogeneous magnetic field gives rise to a reversible actuation effect, which is the result of the competition between magnetic and elastic forces in the material. Magnetorheological elastomers are capable of performing more pronounced deformations than known rigid actuator materials. In this article, the actuation behavior of magnetorheological elastomer ring-shaped bodies in a valve-type device for the control of an air flow is demonstrated. For this purpose, magnetorheological elastomer rings with different Shore hardness were prepared and used in the valve. In addition to the common isotropic magnetorheological elastomer samples, rings with an anisotropic arrangement of the magnetic particles were also prepared. The actuation of these anisotropic magnetorheological elastomers was compared with that of the isotropic samples. Based on simulations, the inhomogeneity of the magnetic field at the magnetorheological elastomer material which is required for the actuation could be strongly affected by the shape in the design of the magnetic yoke. In this study, the closing characteristics of the valve with different yoke shapes and magnetorheological elastomer materials were evaluated by measuring the dependence of the air flow rate on the magnetic field strength. It is demonstrated that the air flow through the valve can be controlled by the current in the field-generating coil, which yields the base for a new type of magnetic valve.

scholarly journals Effect of Magnetic Field and Aggregation on Electrical Characteristics of Magnetically Responsive Suspensions for Novel Hybrid Liquid Capacitor

2019 ◽  
Vol 5 (2) ◽  
pp. 38 ◽  
Author(s):  
Kunio Shimada
Keyword(s):  
Magnetic Field ◽  
Electrical Properties ◽  
Natural Rubber ◽  
Applied Voltage ◽  
Nonlinear Response ◽  
Magnetic Particles ◽  
Particle Aggregation ◽  
Electrical Characteristics ◽  
Rubber Latex ◽  
Wide Range

Magnetically responsive fluid based on polymers of natural rubber (NR-latex) involves a magnetic compound fluid (MCF) rubber liquid. For a wide range of engineering applications of suspensions or liquids with particles, their electrical characteristics of fluidic suspensions are investigated to obtain useful results that might be important in the study of devices, such as fluidic sensors and capacitors. The author of the present paper proposes that MCF rubber liquid can be produced by combining MCF and rubber latex. The influence of the aggregation of magnetic particles and rubber molecules on electrical characteristics under a magnetic field was investigated by measuring electrical properties under an applied voltage. The electrical characteristics change with a linear or a nonlinear response, based on conditions of particle aggregation. The capacity of the electric charge also changes with the conditions of particle aggregation. These results show that MCF rubber liquid is a novel hybrid capacitor.

Coupled Magneto-mechanical Modeling of Composites Containing Aligned Ferromagnetic Particles

2003 ◽  
Vol 785 ◽  
Author(s):  
Huiming Yin ◽  
Lizhi Sun
Keyword(s):  
Magnetic Field ◽  
Elastic Interaction ◽  
Mechanical Modeling ◽  
Mechanical Loads ◽  
Elastic Fields ◽  
Particle Chain ◽  
Proposed Model ◽  
Fully Coupled ◽  
Ferromagnetic Particles ◽  
Soft Elastomer

ABSTRACTThe objective of this paper is to investigate effective magneto-mechanical behavior of composites containing aligned ferromagnetic particles. The effective magneto-elastic properties and the overall magnetostriction of the composites are derived by considering the pair-wise interaction between ferromagnetic particles. For the composites with soft elastomer matrix, the microstructural configuration rapidly changes with the magnetic and mechanical loads so that the local magnetic and elastic fields are fully coupled. This model accounts for the coupled magneto-elastic interaction and pair-wise interaction between particles. The results show that the Young's modulus along the particle-chain direction is reduced and the shear modulus is increased under the applied magnetic field. Predictions from the proposed model are compared with available experimental data and other models.

scholarly journals Experiments and Numerical Implementation of a Boundary Value Problem Involving a Magnetorheological Elastomer Layer Subjected to a Nonuniform Magnetic Field

2021 ◽  
Vol 88 (7) ◽  
Author(s):  
Charles Dorn ◽  
Laurence Bodelot ◽  
Kostas Danas
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Boundary Value Problem ◽  
Magnetic Particles ◽  
Boundary Value ◽  
Energetic Efficiency ◽  
Iron Core ◽  
Isotropic Layer ◽  
Magnetorheological Elastomer ◽  
Electromagnetic Coil

Abstract This study investigates experimentally and numerically the response of a magnetorheological elastomer (MRE) layer placed atop an electromagnetic coil. The MRE layer is deflected upon application of a current in the coil, which creates highly nonuniform magnetic fields. Isotropic and transversely isotropic layers (i.e., containing chains of magnetic particles) are tested experimentally, and the isotropic layer exhibits the largest deflection. To enhance the energetic efficiency of the model device, an iron core is introduced inside the electromagnetic coil, thereby leading to an increase in the resulting magnetic field near the center of the MRE layer. In parallel, the boundary value problem —including the MRE layer, the coil, the core (if present) and the surrounding air—is modeled numerically. For this, a magneto-mechanical, vector potential-based variational formulation is implemented in a standard three-dimensional finite element model at finite strains. For the material description, a recently proposed analytical homogenization-guided model is used to analyze the MRE in the “coil-only” configuration. It is then employed to predict the response of the layer in the “coil plus core” configuration, thus circumventing the need for a separate material characterization procedure. The proposed numerical simulation strategy provides a deeper understanding of the underlying complexity of the magnetic fields and of their interaction with the MRE layer. This study also reveals the importance of modeling the entire setup for predicting the response of MRE materials and, as a result, constitutes a step toward designing more efficient MRE-based devices.

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.

Folding Actuation and Locomotion of Novel Magneto-Active Elastomer (MAE) Composites

2013 ◽  
Author(s):  
Paris von Lockette ◽  
Robert Sheridan
Keyword(s):  
Magnetic Field ◽  
Barium Ferrite ◽  
Magnetic Particles ◽  
Flat Surface ◽  
Iron Particles ◽  
Soft Magnetic ◽  
Magnetorheological Elastomers ◽  
Vibration Attenuation ◽  
Magnetically Aligned ◽  
Mechanical Actuation

Magneto-active elastomers (also called magnetorheological elastomers) are most often used in vibration attenuation application due to their ability to increase in shear modulus under a magnetic field. These shear-stiffening materials are generally comprised of soft-magnetic iron particles embedded in a rubbery elastomer matrix. More recently researchers have begun fabricating MAEs using hard-magnetic particles such as barium ferrite. Under the influence of uniform magnetic fields these hard-magnetic MAEs have shown large deformation bending behaviors resulting from magnetic torques acting on the distributed particles and consequently highlight their ability for use as remotely powered actuators. Using the magnetic-torque-driven hard-magnetic MAE materials and an unfilled silicone elastomer, this work develops novel composite geometries for actuation and locomotion. MAE materials are fabricated using 30% v/v 325 mesh barium ferrite particles in Dow Corning HS II silicone elastomers. MAE materials are cured in a 2T magnetic field to create magnetically aligned (anisotropic) materials as confirmed by vibrating sample magnetometry (VSM). Gelest optical encapsulant is used as the uniflled elastomer material. Mechanical actuation tests of cantilevers in bending and of accordion folding structures highlight the ability of the material to perform work in moderate, uniform fields of μ0H = 150 mT. Computational simulations are developed for comparison. Folding structures are also investigated as a means to produce untethered locomotion across a flat surface when subjected to an alternating field similar to scratch drive actuators; geometries investigated show promising results.

Urethane Magnetorheological Elastomers - Manufacturing, Microstructure and Properties

2009 ◽  
Vol 154 ◽  
pp. 107-112 ◽  
Author(s):  
Anna Boczkowska ◽  
Stefan F. Awietjan
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Vibrating Sample Magnetometer ◽  
Iron Particles ◽  
Magnetorheological Elastomers ◽  
Microstructure And Properties ◽  
Ferromagnetic Particles ◽  
Scanning Electron

In this paper studies on urethane magnetorheological elastomers (MREs) microstructure in respect to their magnetic and mechanical properties are reported. MREs were obtained from a mixture of polyurethane gel and carbonyl-iron particles cured in a magnetic field of 100 and 300 mT. The amount of particles was varied from 1.5 to 33 vol. %. Samples with different arrangements of particles were produced. Effect of the amount of ferromagnetic particles and their arrangement on microstructure and properties in relation to the external magnetic field was investigated. The microstructure was studied using scanning electron microscopy. Magnetic properties were measured using vibrating sample magnetometer. Rheological and mechanical properties under compression were also examined.

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