scholarly journals THEORETICAL QUESTIONS OF APPLYING SMART MATERIALS FOR MICROACTUATORS / TEORINIAI IŠMANIOJO SKYSČIO TAIKYMO MIKROPAVAROMS KLAUSIMAI

2013 ◽  
Vol 6 (4) ◽  
pp. 541-545
Author(s):  
Andrius Klevinskis ◽  
Vytautas Bučinskas ◽  
Lukas Daujotas
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Materials ◽  
Smart Materials ◽  
Theoretical Calculations ◽  
Magnetorheological Fluid ◽  
Magnetic Liquid ◽  
Operating Modes ◽  
Essential Properties ◽  
Main Operating

The article provides an overview of smart magnetic materials, including the essential properties of smart magnetic liquid materials and discusses the main operating modes of these materials. Theoretical calculations have disclosed changes in the behavior of the magnetorheological fluid determined under the influence of an external magnetic field of the microactuator. Finally, the paper presents the results and conclusions of the conduced experiments. Santrauka Darbe apžvelgtos išmaniosios magnetinės medžiagos, pateiktos pagrindinės išmaniųjų magnetinių skysčių charakteristikos, aptarti pagrindiniai šių medžiagų darbo režimai. Teoriniais skaičiavimais nustatyta mikropavaroje veikiančio magnetoreologinio skysčio savybių kitimo priklausomybė nuo išorinio magnetinio lauko. Darbe pateikti tyrimo metu gautų rezultatų grafikai ir išvados.

Wear Behavior of Rotary Lip Seal Operating in a Magnetorheological Fluid Under Magnetic Field Conditions

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Peng Zhang ◽  
Kwang-Hee Lee ◽  
Chul-Hee Lee
Keyword(s):  
Magnetic Field ◽  
Smart Materials ◽  
Wear Behavior ◽  
High Volume ◽  
Magnetorheological Fluid ◽  
Engine Oil ◽  
Wear Properties ◽  
Lip Seal ◽  
Sealing Performance ◽  
Stiffness And Damping

A magnetorheological fluid (MRF) is one of many smart materials that can be changed their rheological properties. The stiffness and damping characteristics of MRF can be changed when a magnetic field is applied. This technology has been successfully employed in various low and high volume applications, such as dampers, clutches, and active bearings, which are already in the market or are approaching production. As a result, the sealing performance of MRF has become increasingly important. In this study, the wear properties of seals with MRFs were evaluated by a rotary-type lip seal wear tester. The test was performed with and without a magnetic field. The leakage time was monitored during the tests in typical engine oil conditions. The results showed that the wear resistance of the seal with MRF was decreased under the magnetic field.

Influence of Permanent Magnets Installation Approach on the Torque of а Magneto-Rheological Disk Brake

2021 ◽  
Vol 105 ◽  
pp. 184-193
Author(s):  
Ilya Aleksandrovich Frolov ◽  
Andrei Aleksandrovich Vorotnikov ◽  
Semyon Viktorovich Bushuev ◽  
Elena Alekseevna Melnichenko ◽  
Yuri Viktorovich Poduraev
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Materials ◽  
Permanent Magnets ◽  
Magnetorheological Fluid ◽  
Simulation Modelling ◽  
Disc Brake ◽  
Large Area ◽  
Braking Torque ◽  
The Magnetic Field

Magnetorheological braking devices function due to the organization of domain structures between liquid and solid magnetic materials under the action of an electromagnetic or magnetic field. The disc is most widely used as a rotating braking element that made of a solid magnetic material due to the large area of contact with a magnetorheological fluid. Many factors affect the braking characteristics of the magnetorheological disc brake. Specifically, the value of the magnetic field and how the field is distributed across the work element is significantly affected at the braking torque. There are different ways to generate a magnetic field. In this study, the method of installation of permanent magnets into the construction, allowing to increase the braking torque of the magnetorheological disc brake is proposed. Simulation modelling showing the distribution of the magnetic field across the disk depending on the installation of permanent magnets with different pole orientations were carried out. The model takes into account the possibility of increasing the gap between solid magnetic materials of the structure, inside them which the magnetorheological fluid is placed. Comparative estimation of the distribution of the magnetic fields depending on the chosen method of installation of permanent magnets with different orientations of their poles is carried out. Further research is planned to focus on a comparative assessment of the distribution of magnetic fields depending on the selected material of the braking chamber.

The colloidal nanocrystal deposition process: an advanced method to prepare high performance hematite photoanodes for water splitting

2014 ◽  
Vol 7 (7) ◽  
pp. 2250-2254 ◽  
Author(s):  
Ricardo H. Gonçalves ◽  
Edson R. Leite
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Water Splitting ◽  
High Performance ◽  
Magnetorheological Fluid ◽  
Deposition Process ◽  
Sintering Process ◽  
Advanced Method ◽  
Colloidal Deposition

The association of colloidal deposition of magnetorheological fluid in the presence of an external magnetic field with a sintering process facilitates the attainment of hematite photoanodes with high performance for water splitting.

Study of Microwave Reflection Behaviour in Fe3O4 Magnetorheological Fluids

2011 ◽  
Vol 287-290 ◽  
pp. 2785-2788
Author(s):  
Nan Hui Yu ◽  
Ji Jun Fan
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
External Magnetic Field ◽  
Field Strength ◽  
Smart Materials ◽  
Particle Concentration ◽  
Critical Concentration ◽  
Microwave Frequency ◽  
Magnetorheological Fluids ◽  
Microwave Reflection

Owing to its unique properties and wide engineering applications, magnetorheological fluids (MRF) has become a hot study area in the field of smart materials. In this paper experimental study of the microwave reflection behavior in MRF was carried out. The results indicated that at the same frequency the microwave reflectivity of MRF decreased with the increasing of magnetic field strength; and with the particle concentration increasing, microwave reflectivity first increased, then decreased, there is a critical concentration of 15%. Under the same magnetic field, with the increasing of microwave frequency, it first decreased, there is a lowest point at 9.2GHz, and then it increased. Usually, it is considered that the change of internal structure of MRF under external magnetic field is the main reason for the regulation behavior of microwave reflectivity.

Manipulation of Non-Magnetic Materials in Ferrofluid Containing Media

2005 ◽  
Vol 877 ◽  
Author(s):  
Derek Halverson ◽  
Ben Yellen ◽  
Gary Friedman
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
External Magnetic Field ◽  
Magnetic Materials ◽  
Time Varying ◽  
Magnetic Islands ◽  
Iron Oxide Particles ◽  
Novel Method ◽  
Oxide Particles

AbstractA novel method is proposed whereby non-magnetic objects can be moved along a surface at the microscale and nanoscale. It uses a negative magnetophoretic force, explained in the caption for figure one, on the non-magnetic objects which results from stabilized 10nm diameter iron oxide particles (ferrofluid) being attracted to regions of field maxima around magnetic islands on a surface, which pushes the non-magnetic objects to regions of field minima. By varying an external magnetic field we can control where these minima are and thus control how objects will position themselves with static fields and by using rotating time varying fields we can control how they move across the surface. This method does not require the objects to be initially in contact with the surface, as they will be pulled down to the surface from solution. While this paper deals with beads, any arbitrarily shaped object should be manipuable using this method. Additionally, while we address non-magnetic objects in this work similar methods could easily manipulate objects that are magnetic.

Theoretical calculations of shallow acceptor states in GaAs/AlxGa1−xAs quantum wells in the presence of an external magnetic field

1994 ◽  
Vol 50 (4) ◽  
pp. 2393-2398 ◽  
Author(s):  
Q. X. Zhao ◽  
P. O. Holtz ◽  
Alfredo Pasquarello ◽  
B. Monemar ◽  
M. Willander
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Quantum Wells ◽  
Theoretical Calculations ◽  
Shallow Acceptor

Theoretical Study of Transmissivity of Electromagnetic Wave in Magnetorheological Fluids

2012 ◽  
Vol 605-607 ◽  
pp. 1356-1359
Author(s):  
Yong Qing Wan ◽  
Ji Jun Fan ◽  
Nan Hui Yu
Keyword(s):  
Magnetic Field ◽  
Dielectric Constant ◽  
Magnetic Properties ◽  
Electromagnetic Wave ◽  
External Magnetic Field ◽  
Electromagnetic Wave Propagation ◽  
Theoretical Study ◽  
Magnetorheological Fluid ◽  
Theoretical Simulation ◽  
Mr Fluids

The internal structure of magnetorheological fluid could change under external magnetic field, as well as its dielectric constant and magnetic conductance. A theoretical model of electromagnetic wave propagation in MRF was established and the basic formula of transmissivity was deduced. Theoretical simulation shows that the electromagnetic wave transmissivity decreases with the increasing of dielectric constant of magnetorheological fluid, and increases with the magnetic permeability. Theoretical analysis indicates that the change of its structure and dielectric magnetic properties of MR fluids is the main cause for the fact that the transmittance could be adjusted under external magnetic field.

Research progress of field-induced soft smart materials

2018 ◽  
Vol 32 (18) ◽  
pp. 1840010 ◽  
Author(s):  
Han Wu ◽  
Zhi Chao Xu ◽  
Jin Bo Wu ◽  
Wei Jia Wen
Keyword(s):  
Magnetic Field ◽  
Smart Materials ◽  
Soft Matter ◽  
Soft Materials ◽  
Magnetorheological Fluid ◽  
Electrorheological Fluid ◽  
Research Area ◽  
Research Progress ◽  
Polymer Gel ◽  
Field Temperature

The field-induced soft smart materials are a kind of soft matter whose macroscopic properties (mechanical, or optical) can be significantly and actively controlled and manipulated by external fields such as magnetic field, electric field, temperature or light. In this paper, we briefly review the research and application progress of the field-induced soft smart materials in recent years and discuss the development problems and trend in this research area. In particular, we focus on three typical field-induced soft materials of smart materials: magnetorheological fluid, electrorheological fluid, and temperature and light sensitive polymer gel.

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.

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