scholarly journals Field-Induced Transversely Isotropic Shear Response of Ellipsoidal Magnetoactive Elastomers

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3958
Author(s):  
Sanket Chougale ◽  
Dirk Romeis ◽  
Marina Saphiannikova
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Shear Deformation ◽  
Transversely Isotropic ◽  
Field Direction ◽  
Mechanical Anisotropy ◽  
Cauchy Stress ◽  
Strain Behavior ◽  
Dipole Interactions ◽  
Magneto Rheological

Magnetoactive elastomers (MAEs) claim a vital place in the class of field-controllable materials due to their tunable stiffness and the ability to change their macroscopic shape in the presence of an external magnetic field. In the present work, three principal geometries of shear deformation were investigated with respect to the applied magnetic field. The physical model that considers dipole-dipole interactions between magnetized particles was used to study the stress-strain behavior of ellipsoidal MAEs. The magneto-rheological effect for different shapes of the MAE sample ranging from disc-like (highly oblate) to rod-like (highly prolate) samples was investigated along and transverse to the field direction. The rotation of the MAE during the shear deformation leads to a non-symmetric Cauchy stress tensor due to a field-induced magnetic torque. We show that the external magnetic field induces a mechanical anisotropy along the field direction by determining the distinct magneto-mechanical behavior of MAEs with respect to the orientation of the magnetic field to shear deformation.

Study of the Performance of Practical Magneto-Rheological Elastomers

2012 ◽  
Vol 430-432 ◽  
pp. 1979-1983
Author(s):  
Wei Bang Feng ◽  
Xue Yang ◽  
Zhi Qiang Lv
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Magnetic Properties ◽  
External Magnetic Field ◽  
Magnetic Particles ◽  
Poor Performance ◽  
Electrical And Magnetic Properties ◽  
Intelligent Material ◽  
Magneto Rheological

Magneto-rheological elastomer( MR elastomer) is an emerging intelligent material made up of macromolecule polymer and magnetic particles. While a promising wide application it has in the fields of warships vibration controlling for its controllable mechanical, electrical and magnetic properties by external magnetic field, design and application of devices based on it are facing great limitations imposed by its poor performance in mechanical properties and magneto effect. Aiming at developing a practical MR elastomer, a new confecting method was proposed in this paper. Then, following this new method and using a specificly designed solidifying matrix, an amido- polyester MR elastomer was developed with its mechanical property systemically explored.

Influence of low external magnetic field on electric field induced strain behavior of 9/70/30, 9/65/35 and 9/60/40 PLZT ceramics

2016 ◽  
Vol 42 (11) ◽  
pp. 13223-13231 ◽  
Author(s):  
Siripong Somwan ◽  
Narit Funsueb ◽  
Apichart Limpichaipanit ◽  
Athipong Ngamjarurojana
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Electric Field ◽  
Strain Behavior ◽  
Electric Field Induced Strain

scholarly journals Analysis of a Compact Squeeze Film Damper with Magneto Rheological Fluid

2020 ◽  
Vol 70 (2) ◽  
pp. 122-130
Author(s):  
Rahul Kumar Singh ◽  
Mayank Tiwari ◽  
Anpeksh Ambreesh Saksena ◽  
Aman Srivastava
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Squeeze Film ◽  
Vibration Level ◽  
Mr Fluid ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Jeffcott Rotor ◽  
Magneto Rheological ◽  
Control Feedback

Rotor systems play vital role in many modern day machinery such as turbines, pumps, aeroengines, gyroscopes, to name a few. Due to unavoidable unbalance in the rotor systems, there are lateral and torsional vibrations. Ignoring these effects may cause the system serious damages, which sometimes lead to catastrophic failures. Vibration level in rotor systems is acceptable within a range. Focus in this work is to minimize the vibration level to the acceptable range. One of the ways vibration level can be minimised is by means of providing damping. To accomplish this task in this work a new concept squeeze film damper is made by electro discharge machining which is compact in configuration, is filled with magneto-rheological (MR) fluid and tested out on one support of a Jeffcott rotor. This compact squeeze film damper (SFD) produces damping in a compact volume of the device compared to a conventional SFD. MR fluid is a smart fluid, for which apparent viscosity changes with the application of external magnetic field. This compact damper with MR fluid provides the variable damping force, controlled by an external magnetic field. In this work, proportional controller has been used for providing the control feedback. This MR damper is seen to reduce vibrations in steady state and transient input to the Jeffcott rotor. Parametric study for important design parameters has been done with the help of the simulation model. These controlled dampers can be used for reducing vibrations under different operating conditions and also crossing critical speed.

scholarly journals Exstraordinary and planar Hall effects in thin permalloy films

2021 ◽  
pp. 53-60
Author(s):  
Victoryia I. Halauchyk ◽  
Michail G. Lukashevich
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Film Plane ◽  
Field Direction ◽  
Hall Resistance ◽  
Magnetic Field Direction ◽  
Full Width ◽  
Half Maximum ◽  
Hall Effects ◽  
The Magnetic Field

The Hall resistance hysteresis loops in thin (d = 80 –280 nm) magnetically ordered permalloy films (Ni0.8 Fe0.2) were studied at room temperature at different angles between the film plane and the magnetic field direction (φ = 0 –360°) (extraordinary and ordinary Hall effects), at different angles (θ = 0 – 90°) between the magnetic field direction and the flowing current (planar Hall effect at φ = 0°) in a magnetic field up to B = 1.25 T. The thin films were obtained on sitall dielectric substrate by ion beam sputtering. Sharp peaks of the Hall resistance were observed in the extraordinary and planar Hall effects during the magnetisation reversal of the films due to a change of the magnetisation direction with respect to the sampling current direction. In the extraordinary Hall effect the position and full width at half maximum of a peak is determined by the angle between the magnetic field direction and the film plane. It has been shown that as the direction of the external magnetic field approaches the spontaneous magnetisation direction, both the peak magnetic field position Bp and the full width at half maximum of the peak Δ Bp increase. In the angles range of φ = 0 – 90° Bp and Δ  Bp varies in the magnetic field range from Δ  В ≈ 0.2 to 5.0 mT. A non-monotonic dependence of the planar Hall resistance and its peak position on the angle between the flowing current and the magnetic field direction was detected. It is related to the change of the longitudinal and transverse components the resistance of the magnetically ordered solids by an external magnetic field. The values of the ordinary and extraordinary Hall effects coefficients have been determined: RH0 = 6 ⋅ 10–9 m3/C and RH1 = 3.2 ⋅ 10–8 m3/C, respectively.

Anisotropic Thermal Transport in Magnetic Fluids

2009 ◽  
Author(s):  
Xiaopeng Fang ◽  
Yimin Xuan ◽  
Qiang Li
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
External Magnetic Field ◽  
Magnetic Fluid ◽  
Thermal Transport ◽  
Present Method ◽  
Field Direction ◽  
Magnetic Field Direction ◽  
The Magnetic Field ◽  
Anisotropic Feature

The inhomogeneous morphology of magnetic fluid may appear in the presence of an external magnetic field, which shows the structure controllability of magnetic fluid and will lead to anisotropic thermal transport inside the magnetic fluid. Based on the microstructure of magnetic fluid and considering the effect of nanolayer, a model for the thermal conductivity of the magnetic fluid has been developed. The anisotropic thermal transport inside the magnetic fluid is investigated by the present method. The results show that in the presence of an external magnetic field the particles form chainlike clusters along the magnetic field direction, which leads to an increment in the thermal conductivity along the field direction and little change in the thermal conductivity perpendicular to the magnetic field direction. The thermal conductivity of magnetic fluid presents an anisotropic feature. With the increase of the magnetic field strength the chainlike clusters in the magnetic fluid becomes more obvious and the anisotropic feature of heat conduction in the fluids becomes more evident. Comparisons show that the results predicted by the present method are well coincident with the experimental data.

Tunable friction performance of magneto-rheological elastomer induced by external magnetic field

2017 ◽  
Vol 29 (2) ◽  
pp. 160-170 ◽  
Author(s):  
Rui Li ◽  
Dejun Ren ◽  
Xiaojie Wang ◽  
Xiang Chen ◽  
Shiwei Chen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Friction Performance ◽  
Magneto Rheological

The Electro-Hydraulic Control Directional Valve Based on Magneto-Rheological Fluid

2013 ◽  
Vol 567 ◽  
pp. 139-142
Author(s):  
D.D. Liu ◽  
C.R. Tang ◽  
C. Zhao
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Control Valve ◽  
Piping System ◽  
Manufacturing Cost ◽  
Hydraulic Control ◽  
Hydraulic Support ◽  
Excitation Coil ◽  
Magneto Rheological

The electro-hydraulic control directional valve based on magneto-rheological fluid using in hydraulic support is proposed. The magneto-rheological fluid represents favorable flow liquid state without external magnetic field, but it can represent mechanics quality of similarity solid in strong magnetic field. The magneto-rheological fluid may become solid within milliseconds under the action of an external magnetic field, which can realize intelligent control of hydraulic system and overcome shortcoming of traditional hydraulic valve. The electro-hydraulic control directional valve uses magneto-rheological fluid as controlling fluid, and adjusts pressure difference of action main control valve between left end and right end though changing excitation coil current of magneto-rheological valve. The electro-hydraulic control directional valve based on magneto-rheological fluid can satisfy the self-feeding hydraulic support using requirements and has low manufacturing cost. The installation and using of the electro-hydraulic control valve is more convenient and fast. It reduces the point of failure of the hydraulic supports piping system and makes hydraulic support more secure and reliable.

Formation of chainlike structures in an Mn-89.7 wt%Sb alloy during isothermal annealing process in the semisolid state in a high magnetic field

2009 ◽  
Vol 24 (7) ◽  
pp. 2321-2330 ◽  
Author(s):  
Tie Liu ◽  
Qiang Wang ◽  
Chao Zhang ◽  
Ao Gao ◽  
Donggang Li ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Isothermal Annealing ◽  
Structural Evolution ◽  
Field Direction ◽  
Semisolid State ◽  
Average Characteristic ◽  
Dipole Interactions ◽  
Characteristic Radius ◽  
The Magnetic Field

This study is concerned with the investigation of the structural evolution occurring during isothermal annealing of an Mn-89.7 wt%Sb alloy in a high magnetic field in the semisolid state. The alloy specimens were isothermally annealed without and with an 11.5-T magnetic field for various annealing times. With the application of the magnetic field, the average characteristic radius of the primary MnSb particles increased with increasing annealing time. The primary MnSb particles were oriented with their c-plane parallel to the imposed field direction. Furthermore, the primary MnSb particles were found to align along the field direction and form chainlike structures eventually. These phenomena were attributed to the attraction and coalescence of the particles induced by the dipole–dipole interactions among them.

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