scholarly journals Testing the magnetoactive elastomer sample for compression with the test machine

2021 ◽  
Vol 2094 (4) ◽  
pp. 042064
Author(s):  
Andrey Minaev
Keyword(s):  
Magnetic Field ◽  
Testing Machine ◽  
Compression Modulus ◽  
Test Machine ◽  
Self Healing ◽  
Compression Force ◽  
Linear And Nonlinear ◽  
The Magnetic Field ◽  
Nonlinear Nature ◽  
Magnetoactive Elastomer

Abstract A sample of a magnetoactive silicone composite with ferromagnetic fillers is examined on a testing machine. The dependences of the change in the values of the moduli of longitudinal elasticity on deformation are plotted for various modes of compression of the sample. The characteristics of the linear and nonlinear dynamics of changes in the moduli of longitudinal elasticity are given as a function of the magnitudes of the deformations of the material during compression. Within the limits of deformation of the sample, which is 24% of its height, the moduli of longitudinal elasticity are linear. The nonlinear nature of the change in the compression modulus occurs when the sample is deformed over 40%. When the compression ratio of the sample was up to 72%, the compression modulus increased by a factor of 9 without the action of a magnetic field and by a factor of 22 under the action of a magnetic field. The influence of the magnetic field on the growth of the compression moduli with the increase in the compression force ranges is shown. The property of the material to self-healing (“shape memory”) was established after testing in the mode of maximum compression of ultimate loads.

scholarly journals Feasibility of Probing the Filler Restructuring in Magnetoactive Elastomers by Ultra-Small-Angle Neutron Scattering

2021 ◽  
Vol 11 (10) ◽  
pp. 4470
Author(s):  
Inna A. Belyaeva ◽  
Jürgen Klepp ◽  
Hartmut Lemmel ◽  
Mikhail Shamonin
Keyword(s):  
Magnetic Field ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Iron Particles ◽  
Filler Particles ◽  
The Magnetic Field ◽  
Magnetoactive Elastomer

Ultra-small-angle neutron scattering (USANS) experiments are reported on isotropic magnetoactive elastomer (MAE) samples with different concentrations of micrometer-sized iron particles in the presence of an in-plane magnetic field up to 350 mT. The effect of the magnetic field on the scattering curves is observed in the scattering vector range between 2.5 × 10−5 and 1.85 × 10−4 Å−1. It is found that the neutron scattering depends on the magnetization history (hysteresis). The relation of the observed changes to the magnetic-field-induced restructuring of the filler particles is discussed. The perspectives of employing USANS for investigations of the internal microstructure and its changes in magnetic field are considered.

Synthesis of magnetorheological fluid and its application in a twin-tube valve mode automotive damper

2020 ◽  
Vol 234 (7) ◽  
pp. 1001-1016 ◽  
Author(s):  
Rangaraj Madhavrao Desai ◽  
Subash Acharya ◽  
Mohibb-e-Hussain Jamadar ◽  
Hemantha Kumar ◽  
Sharnappa Joladarashi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Rheological Properties ◽  
Smart Materials ◽  
Dynamic Range ◽  
Experimental Testing ◽  
Testing Machine ◽  
Magnetorheological Fluid ◽  
Magnetorheological Damper ◽  
Geometrical Parameters ◽  
The Magnetic Field

The change in rheological properties of smart materials like magnetorheological fluid when brought under the influence of a magnetic field can be utilized to develop magnetorheological devices where the output has to be continuously and quickly varied using electronic control interface. In the present study, magnetorheological fluid is synthesized and used as a smart fluid in a twin-tube magnetorheological damper operating in valve mode. The behavior of the magnetorheological fluid is experimentally characterized in a rheometer and mathematically modeled using Herschel–Bulkley model. The parameters of the Herschel–Bulkley model are expressed as polynomial functions of strength of the magnetic field in order to find the shear stress developed by the magnetorheological fluid at any given strength of the magnetic field applied. The magnetorheological damper, which was designed for application in a passenger van, is tested in the damper testing machine. The performance of the damper at different damper velocities and current supplied is studied. The range of values for the parameters of the experimental testing are chosen to emulate the actual conditions of operation in its intended application. Nondimensional analysis is performed, which links magnetorheological fluid rheological properties and geometrical parameters of magnetorheological damper design with the force developed by the damper. Finite element method magnetics is used to find the strength of the magnetic field at the fluid flow gap. Analytical methods are used to calculate the damper force developed due to the field-dependent yield stress and compared with experimental force values. The resulting dynamic range of the magnetorheological damper is also assessed.

Magnetophoretic assembly of flexible nanoparticles/lipid microfilaments

2015 ◽  
Vol 181 ◽  
pp. 437-448 ◽  
Author(s):  
Bhuvnesh Bharti ◽  
Anne-Laure Fameau ◽  
Orlin D. Velev
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticle ◽  
Colloidal Particles ◽  
Practical Importance ◽  
Directed Assembly ◽  
Lipid Binding ◽  
Self Healing ◽  
New Class ◽  
Linear Chains ◽  
The Magnetic Field

The directed assembly of colloidal particles into linear chains and clusters is of fundamental and practical importance. In this study we characterize and analyse the mechanism of the magnetic field driven assembly of lipid-coated iron oxide nanoparticles into flexible microfilaments. Recently we showed that nanocapillary lipid binding can form a new class of magnetic nanoparticle-lipid microfilaments with unprecedented flexibility and self-healing properties. In the presence of a uniform magnetic field, the magnetophoretic attraction of the particles combined with interparticle dipole–dipole attraction drives the microfilament assembly. The fluid like lipid layer on the particles leads to stickiness on the surface of the filaments and the magnetic field concentration overcomes the potential electrostatic repulsion in the water phase. The lipid capillary bridges formed between the particles facilitate their permanent binding and sustain the flexible microfilament structure. We demonstrate that this surface stickiness combined with the magnetic response of the filaments can be used further to twist, bend and bundle the microfilaments into unusual structures.

scholarly journals Magnetoelectric Response of Laminated Cantilevers Comprising a Magnetoactive Elastomer and a Piezoelectric Polymer, in Pulsed Uniform Magnetic Fields

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6390
Author(s):  
Gašper Glavan ◽  
Inna A. Belyaeva ◽  
Kevin Ruwisch ◽  
Joachim Wollschläger ◽  
Mikhail Shamonin
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Voltage Response ◽  
Peak Voltage ◽  
Magnetic Field Sensors ◽  
Voltage Coefficient ◽  
Piezoelectric Polymer ◽  
Laminated Structures ◽  
The Magnetic Field ◽  
Magnetoactive Elastomer

The voltage response to pulsed uniform magnetic fields and the accompanying bending deformations of laminated cantilever structures are investigated experimentally in detail. The structures comprise a magnetoactive elastomer (MAE) slab and a commercially available piezoelectric polymer multilayer. The magnetic field is applied vertically and the laminated structures are customarily fixed in the horizontal plane or, alternatively, slightly tilted upwards or downwards. Six different MAE compositions incorporating three concentrations of carbonyl iron particles (70 wt%, 75 wt% and 80 wt%) and two elastomer matrices of different stiffness are used. The dependences of the generated voltage and the cantilever’s deflection on the composition of the MAE layer and its thickness are obtained. The appearance of the voltage between the electrodes of a piezoelectric material upon application of a magnetic field is considered as a manifestation of the direct magnetoelectric (ME) effect in a composite laminated structure. The ME voltage response increases with the increasing total quantity of the soft-magnetic filler in the MAE layer. The relationship between the generated voltage and the cantilever’s deflection is established. The highest observed peak voltage around 5.5 V is about 8.5-fold higher than previously reported values. The quasi-static ME voltage coefficient for this type of ME heterostructures is about 50 V/A in the magnetic field of ≈100 kA/m, obtained for the first time. The results could be useful for the development of magnetic field sensors and energy harvesting devices relying on these novel polymer composites.

scholarly journals Remotely Self-Healable, Shapeable and pH-Sensitive Dual Cross-Linked Polysaccharide Hydrogels with Fast Response to Magnetic Field

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1271
Author(s):  
Andrey V. Shibaev ◽  
Maria E. Smirnova ◽  
Darya E. Kessel ◽  
Sergey A. Bedin ◽  
Irina V. Razumovskaya ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Cobalt Ferrite ◽  
Fast Response ◽  
Ferrite Nanoparticles ◽  
Polymer Chains ◽  
Self Healing ◽  
Cobalt Ferrite Nanoparticles ◽  
Hydroxypropyl Guar ◽  
Cross Links ◽  
The Magnetic Field

The development of actuators with remote control is important for the construction of devices for soft robotics. The present paper describes a responsive hydrogel of nontoxic, biocompatible, and biodegradable polymer carboxymethyl hydroxypropyl guar with dynamic covalent cross-links and embedded cobalt ferrite nanoparticles. The nanoparticles significantly enhance the mechanical properties of the gel, acting as additional multifunctional non-covalent linkages between the polymer chains. High magnetization of the cobalt ferrite nanoparticles provides to the gel a strong responsiveness to the magnetic field, even at rather small content of nanoparticles. It is demonstrated that labile cross-links in the polymer matrix impart to the hydrogel the ability of self-healing and reshaping as well as a fast response to the magnetic field. In addition, the gel shows pronounced pH sensitivity due to pH-cleavable cross-links. The possibility to use the multiresponsive gel as a magnetic-field-triggered actuator is demonstrated.

Preparation and characterization of magnetorheological elastic polishing composites

2019 ◽  
Vol 30 (10) ◽  
pp. 1481-1492 ◽  
Author(s):  
Zhiqiang Xu ◽  
Qiuliang Wang ◽  
Kejun Zhu ◽  
Shengqiang Jiang ◽  
Heng Wu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Testing Machine ◽  
Optical Microscope ◽  
Scratch Resistance ◽  
Machining Process ◽  
X Ray Diffraction ◽  
Processing Efficiency ◽  
New Type ◽  
The Magnetic Field

Magnetorheological elastic polishing composites, a new type of polishing material using magnetorheological elastomers as a binder, were developed to solve the problems of low processing efficiency and difficulty controlling the machining process in current polishing technology. A set of heat–magnet–force-coupled devices was designed and used to prepare isotropic and anisotropic silicon rubber–based magnetorheological elastic polishing composites by magnetic field–assisted compression molding technology. Then, the microstructure and properties of magnetorheological elastic polishing composites were characterized by X-ray diffraction, optical microscope, electronic universal testing machine, and microscratch tester. The results show that magnetorheological elastic polishing composite is a polymer-based composite composed of rubber and micro/nanoparticles, and the magnetic field applied during the preparation process causes the interior of the magnetorheological elastic polishing composites to appear as chains and columns formed by iron particles. The compressive elastic modulus and scratch resistance of magnetorheological elastic polishing composites increase with the increase in the surrounding magnetic field strength. The main reason for the above phenomena is related to the change in the microstructure of magnetorheological elastic polishing composites induced by an external magnetic field. Finally, a simple application of magnetorheological elastic polishing composites in polishing proves that magnetorheological elastic polishing composites can be applied to mechanical processing to achieve magnetically controlled polishing.

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