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Dissertations / Theses on the topic 'Magnetorheological Fluids'
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1
Rashid, Abu S. "Compressible magnetorheological fluids." abstract and full text PDF (UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1456488.
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Ocalan, Murat. "Magnetorheological fluids for extreme environments : stronger, lighter, hotter." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67592.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 270-275).
The controllable properties of magnetorheological (MR) fluids offer reliable and efficient actuation means to a number of far-ranging engineering applications. In this thesis we are motivated by the applications of MR fluids in oil & gas exploration and production. These applications also bring about a number of operational requirements for the fluid such as generating large magnetically induced shift in rheological properties with tolerance to elevated temperatures and low fluid density in order to maintain manageable hydrostatic downhole pressures. In this thesis we investigate a number of these fluid design constraints. Firstly, the evolution of the rheological properties of MR fluids over a wide range of magnetic field and temperature was investigated. A magnetorheometry fixture with a unique combination of high-field and high-temperature capability was manufactured. With the experimental measurements and the results from a numerical model of interparticle magnetic interaction, a scaling law was identified between the applied magnetic field and the resulting MR yield stress. The aggregation phenomena and the evolution of fluid microstructure were also investigated in microfluidic geometries with strong particle-wall interactions. The results of this study highlighted design features and operational techniques that can improve the performance of MR fluid valves. Investigation of fluid flow in non-uniform magnetic fields showed that in these regions the motion of the particle phase is governed by a balance between hydrodynamic and magnetophoretic forces. Finally, the flow of MR fluids in spatially-inhomogeneous magnetic and deformation fields was studied. A slit-flow magnetorheometer was manufactured to measure the bulk MR response of the fluid under non-uniform fields. In order to understand the parameters governing these flows and to develop a predictive tool for further investigations, a two-fluid suspension-balance constitutive model was developed which captures the key features of multi-phase flow and fluid anisotropy. The model was numerically implemented using the finite element method and was used to study the transport of MR fluids in spatially-inhomogeneous flows such as those encountered in contraction and expansion channels. This model provides insight into the design and optimization of MR fluid devices that can enhance the magnetically-controlled gain in flow resistance under downhole conditions.
by Murat Ocalan.
Ph.D.
3
Hu, Ben. "Nano-structured and surface polymerized magnetorheological fluid /." abstract and full text PDF (free order & download UNR users only), 2005. http://0-wwwlib.umi.com.innopac.library.unr.edu/dissertations/fullcit/3209226.
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Thesis (Ph. D.)--University of Nevada, Reno, 2005."December 2005." Includes bibliographical references (leaves 155-166). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2005]. 1 microfilm reel ; 35 mm.
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moles, nathaniel caleb. "Actively Controllable Hydrodynamic Journal Bearing Design Using Magnetorheological Fluids." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1444899327.
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York, David J. "A novel magnetorheological fluid-elastomer vibration isolator /." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1448335.
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Thesis (M.S.)--University of Nevada, Reno, 2007."August, 2007." Includes bibliographical references (leaves 83-86). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2007]. 1 microfilm reel ; 35 mm.
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Liang, Youzhi Ph D. Massachusetts Institute of Technology. "Design and optimization of micropumps using electrorheological and magnetorheological fluids." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101479.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 71-75).
Micropumps have rapidly expanded microhydraulic systems into a wider range of applications, such as drug delivery, chemical analysis and biological sensing. Empirical research has shown that micropumps suffer most from their extremely low efficiency. To improve the efficiency of micropumps, we propose to employ electrorheological (ER) and magnetorheological (MR) fluids as the hydraulic fluids. This thesis presents two methods: one is a dynamic sealing method to be applied on current micro-scale gear pumps using MR fluids, and the other is a novel design method of micropumps using ER fluids. Using MR fluid with applied magnetic field as a substitute for industrial hydraulic fluids, magnetic chains are aligned within the channel. The parameters, such as magnetic field, viscosity and volume fraction of MR fluid can be balanced to provide optimal sealing performance. Darcy flow through porous media and Bingham flow in a curved channel with a rectangular cross section have been used to model the MR fluid flow exposed to certain magnetic field intensity. Static and dynamic magnetic sealing performance is investigated theoretically and experimentally, which is evaluated by Mason numbers and friction factor. To achieve a higher efficiency and faster dynamic response, a novel design for micropumps driven by ER fluid is demonstrated. Moving mechanical parts are eliminated by applying a periodic voltage gradient. The approach involves exerting electric forces on particles distributed within the fluid and exploiting drag or entrainment forces to drive flow. Variables are explored, such as the dimension and layout of the channel and electrodes. Experiments are also designed to observe the performance of the solid state pump. In addition, a method of characterizing the efficiency of chamber pump is introduced and applied on screw-chamber pump and solenoid-chamber pump with check valve and ER valve.
by Youzhi Liang.
S.M.
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Chooi, W. W. "Experimental characterisation of the properties of magnetorheological (MR) fluids and MR damper." Thesis, University of Manchester, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502588.
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Getzie, Travis David. "Mangeto-Optical and Rheological Behaviors of Oil-Based Ferrofluids and Magnetorheological Fluids." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1333823536.
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Goncalves, Fernando D. "Characterizing the Behavior of Magnetorheological Fluids at High Velocities and High Shear Rates." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/26142.
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Magnetorheological (MR) fluids offer solutions to many engineering challenges. The success of MR fluid is apparent in many disciplines, ranging from the automotive and civil engineering communities to the biomedical engineering community. This well documented success of MR fluids continues to motivate current and future applications of MR fluid.
One such application that has been considered recently is MR fluid devices for use in impact and other high velocity applications. In such applications, the fluid environment within the device may be well beyond the scope of our understanding for these fluids. To date, little has been done to explore the suitability of MR fluids in such high velocity and high shear applications.
While future applications may expose the fluid to adverse flow conditions, we must also consider current and existing applications which expose the fluid to extreme flow environments. Consider, for example, an MR damper intended for automotive primary suspensions, in which shear rates may exceed 10^5 s^-1. Flow conditions within these dampers far exceed existing fluid behavior characterization.
The aim of the current study is to identify the behavior of the fluid under these extreme operating conditions. Specifically, this study intends to identify the behavior of MR fluid subject to high rates of shear and high flow velocities. A high shear rheometer is built which allows for the high velocity testing of MR fluids. The rheometer is capable of fluid velocities ranging from 1 m/s to 37 m/s, with corresponding shear rates ranging from 0.14x10^5 s^-1 to 2.5x10^5 s^-1. Fluid behavior is characterized in both the off-state and the on-state.
The off-state testing was conducted in order to identify the high shear viscosity of the fluid. Because the high shear behavior of MR fluid is largely governed by the behavior of the carrier fluid, the carrier fluid behavior was also identified at high shear. Experiments were conducted using the high shear rheometer and the MR fluid was shown to exhibit nearly Newtonian post-yield behavior. A slight thickening was observed for growing shear rates. This slight thickening can be attributed to the behavior of the carrier fluid, which exhibited considerable thickening at high shear.
The purpose of the on-state testing was to characterize the MR effect at high flow velocities. As such, the MR fluid was run through the rheometer at various flow velocities and a number of magnetic field strengths. The term â dwell timeâ is introduced and defined as the amount of time the fluid spends in the presence of a magnetic field. Two active valve lengths were considered, which when coupled to the fluid velocities, generated dwell times ranging from 12 ms to 0.18 ms. The yield stress was found from the experimental measurements and the results indicate that the magnitude of the yield stress is sensitive to fluid dwell time. As fluid dwell times decrease, the yield stress developed in the fluid decreases. The results from the on-state testing clearly demonstrate a need to consider fluid dwell times in high velocity applications. Should the dwell time fall below the response time of the fluid, the yield stress developed in the fluid may only achieve a fraction of the expected value. These results imply that high velocity applications may be subject to diminished controllability for falling dwell times.
Results from this study may serve to aid in the design of MR fluid devices intended for high velocity applications. Furthermore, the identified behavior may lead to further developments in MR fluid technology. In particular, the identified behavior may be used to develop or identify an MR fluid well suited for high velocity and high shear applications.Ph. D.
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Mahboob, Monon. "Characterization and Microstructural Modeling of Composites: Carbon Nanofiber Polymer Nanocomposites and Magnetorheological Fluids." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1265262504.
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Lagger, Hanna [Verfasser], and Jan G. [Akademischer Betreuer] Korvink. "Particle-based simulation of sheared magnetorheological fluids = Partikelbasierte Simulation von magnetorheologischen Flüssigkeiten unter Scherung." Freiburg : Universität, 2014. http://d-nb.info/1123481946/34.
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Norris, James Alexander. "Behavior of Magneto-Rheological Fluids Subject to Impact and Shock Loading." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/33865.
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Investigations on the design of controllable magnetorheological (MR) fluid devices have focused heavily on low velocity and low frequency applications. The extensive work in this area has led to a good understanding of MR fluid properties at low velocities and frequencies. However, the issues concerning MR fluid behavior in impact and shock applications are relatively unknown.
To investigate MR fluid properties in this regime, MR dampers were subjected to impulsive loads. A drop-tower test facility was developed to simulate the impact events. The design includes a guided drop-mass released from variable heights to achieve different impact energies. Five drop-heights and two fundamental MR damper configurations were tested. The two configurations were a double-ended piston and a mono-tube with nitrogen accumulator. To separate the dynamics of the MR fluid from the dynamics of the current source, each damper received a constant supply current before the impact event. A total of five supply currents were investigated for each impact velocity.
After reviewing the results, it was concluded that the effect of energizing the MR fluid only leads to â controllabilityâ below a certain fluid velocity for the double-ended design. In other words, until the fluid velocity dropped below some threshold, the MR fluid behaved as if it was not energized, regardless of the strength of the magnetic field. Controllability was defined when greater supply currents yielded larger damping forces.
For the mono-tube design, it was shown that the MR fluid was unable to travel through the gap fast enough during the initial impact. Consequently, the damper piston and accumulator piston traveled in unison until the accumulator bottomed out. After which, the fluid was forced through the gap.
In conclusion, the two designs were compared and general recommendations on designing MR dampers for impulsive loading were made. Possible directions for future research were presented as well.Master of Science
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Sahin, Huseyin. "Theoretical and experimental studies of magnetorheological (MR) fluids and MR greases/gels from rheology to system application /." abstract and full text PDF (UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3339143.
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Nika, Grigor. "Multiscale analysis of emulsions and suspensions with surface effects." Digital WPI, 2016. https://digitalcommons.wpi.edu/etd-dissertations/146.
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The better understanding of the behavior of emulsions and suspensions is important in many applications. In general, emulsions allow the delivery of insoluble agents to be uniformly distributed in a more efficient way. At the same time suspensions of rigid particles are used as “smart materialsâ€� as their properties can be changed by the interaction with a magnetic or electric field. In the first part of the talk we consider a periodic emulsion formed by two Newtonian fluids in which one fluid is dispersed under the form of droplets of arbitrary shape, in the presence of surface tension. We assume the droplets have fixed centers of mass and are only allowed to rotate. We are interested in the time-dependent, dilute case when the characteristic size of the droplets aε, of arbitrary shape, is much smaller than the period length ε. We obtain a Brinkman type of fluid flow for the critical size aε = O(ε3) as a replacement of the Stokes flow of the emulsion. Additionally, using Mosco convergence and semigroup theory we extend the convergence to the parabolic case. For the case when the droplets convect with the flow, it can be shown again using Mosco-convergence that, as the size of the droplets converges to zero faster than the distance between the droplets, the emulsion behaves in the limit like the continuous phase and no “strangeâ€� term appears. Moreover, we determine the rate of convergence of the velocity field for the emulsion to that of the velocity for the one fluid problem in both the H1 and L2 norms. Additionally, a second order approximation is determined in terms of the bulk and surface polarization tensors for the cases of uniform and non-uniform surface tension. The second part of the talk is devoted to the study of MR fluids. We consider a suspension of rigid magnetizable particles in a non-conducting, viscous fluid with an applied external magnetic field. Thus, we use the quasi-static Maxwell equations coupled with the Stokes equations to capture the magnetorheological effect. We upscale using two scale asymptotic expansions to obtain the effective equations consisting of a coupled nonlinear system in a connected phase domain as well as the new constitutive laws. The proposed model generalizes the model of Rosenweig by coupling the velocity of the fluid and the magnetic field intensity. Using the finite element method we compute the effective coefficients for the MR fluid. We analyze the resulting MR model for Poiseuille and Couette flows and compare with experimental data for validation.
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Potisk, Tilen [Verfasser], and Helmut [Akademischer Betreuer] Brand. "Macroscopic aspects of ferromagnetic nematic phases, tetrahedral order in ferrogels, and magnetorheological fluids / Tilen Potisk ; Betreuer: Helmut Brand." Bayreuth : Universität Bayreuth, 2019. http://d-nb.info/1194059929/34.
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Berka, Pavel. "Studium sedimentace MR kapalin." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318390.
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This diploma thesis investigates the accelerated sedimentation of the magnetorheological fuids (MRFs) using centrifuge. Experiments are carried out at room temperature as well as at higher temperatures (40°C, 60°C and 80°C). The development of the new improved measuring device for the sedimentation evaulation is described. Magnetic components of the device were designed using FEM analysis. Newly designed device is verified. To accomplish the experiments at the high temperatures the new heated chamber for experimental centrifuge is designed and constructed. In the next part of the work full experiment of the accelerated sedimentation is performed. At final the empirical model of the sedimetation velocity for various accelerations and temperatures is synthesized.
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Pierson, Harry A. "Tunable Dynamic Support for Resonance Avoidance in Bar Feeders." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1342811163.
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Dvořáček, Ondřej. "Studium stability bidisperzní MR kapaliny a jejího magnetoreologického efektu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-377875.
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The diploma thesis deals with the study of the behaviour of bidisperse MR fluids. The introduction gives brief research and analysis of previously published studies. In the main part of this thesis, the sedimentation properties of monodispersions and bidispersions are investigated influencing on the primary and secondary particles size, the ratio between the fractions, the total concentration of the particles dispersed in the MR fluid and the carrier fluid viscosity. The initialization sedimentation rate is used to assess sediment stability. Subsequently, MR samples are tested on a slit-flow rheometer, and flow curves are measured at different temperatures and in the presence of various magnetic fields intensities. The MR effect is evaluated by the yield stress. The study contains results describing the behaviour of investigated MR fluid samples.
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Pavlíček, Dušan. "Studium magnetoreologického hřídelového těsnění." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318684.
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This thesis deals with the experimental study of magnetorheological shaft seal. The purpose of this diploma thesis is to describe the operating parameters of rotational magnetoreological shaft seal. In thesis, the effects of magnetic field and shaft speed on the pressure resistance and braking torque are described. Operating parameters were measured by an experimental device. Research has shown that the magnetoreological seal is characterized by a high pressure resistant. Disadvantages are the high braking torque and leakage of carrier oil from the magnetorheological fluid. These problems have been solved by a new design of magnetic circuit, that has been identified as a magnetoreological gradient pinch seal (MRGPS).
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Skalski, Pawell. "Analyse des propriétés viscoplastiques du fluide magnétorhéologique dans des conditions de travail d'un amortisseur." Thesis, Orléans, 2011. http://www.theses.fr/2011ORLE2003/document.
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Le but principal de ce travail est la présentation de la formulation mathématique et l’analyse des propriétés viscoplastiques du fluide magnétorhéologique dans des conditions d’exploitation d’amortisseur ainsi que la détermination des dimensions optimum de l’orifice d’écoulement du fluide MR dans le dispositif de ce type. Une analyse particulière de la littérature a été effectuée. Nous nous sommes limités à deux types d’amortisseurs: l’amortisseur LORD RD 1005-3 et le prototype d’amortisseur T-MR SiMR 132 DG. Les résultats expérimentaux ont permis de déterminer la limite élastique et la contrainte maximale de cisaillement du fluide MR sous tension en fonction de différentes vitesses de cisaillement, différentes intensités du courant, températures et hauteurs d’orifice d’écoulement. Les modèles viscoplastiques identifiés ont permis de simuler le comportement du fluide MR et de comparer les résultats numériques avec ceux obtenus par des mesures. On a constaté une bonne concordance des courbes tracées dans ces deux cas, ce qui permet de conclure qu’il est possible d’utiliser les modèles viscoplastiques des métaux pour décrire le comportement du fluide magnétorhéologiqueThe main goal of this dissertation is a mathematical description and an analysis of viscoplasticproperties of magnetorheological fluid, in operational conditions of the damper’s work, as well as the determining the optimum, in view of indicated values of parameters, size of the gap for the MR fluid to flow, in these devices. A detailed analysis of literature was made. The scope of research work has been limited to two types of magnetorheological devices: the shock absorber LORD RD 1005-3 and the MR damper prototype T-MR SiMR -132 DG. On the basis of performed experiments, it has been estimated i.e.: conventional yield point and the maximum shear stress of analyzed MR fluid, including variable shear rate, intensity of current flowing in a solenoid, liquid’s temperature and the gap height. Identified viscoplastic models were used to develop a simulation that verifies the proposed mathematical model which describes the behaviour of MR fluid in operating gap of machine’s head, with data derived from performed experiments
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Spinks, Joseph Michael. "Dynamic simulation of particles in a magnetorheological fluid." Thesis, Monterey, Calif. : Naval Postgraduate School, 2008. http://handle.dtic.mil/100.2/ADA483755.
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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2008.Thesis Advisor(s): Lloyd, John. "June 2008." Description based on title screen as viewed on September 2, 2008. Includes bibliographical references (p.63). Also available in print.
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Wiltsie, Nicholas Eric. "A controllably adhesive climbing robot using magnetorheological fluid." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78191.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 67-69).
In this thesis, the novel adhesive effects of magnetorheological fluid for use in climbing robotics were experimentally measured and compared to existing cohesive failure fluid models of yield stress adhesion. These models were found to correlate with experimental results at yield stresses below 1.12 kPa. MR fluid samples activated to have yield stresses above 1.12 kPa were limited to an adhesive stress of approximately 25-30 kPa regardless of inital fluid thickness or yield stress. A climbing robot capable of utilizing MR fluid adhesion was constructed and shown to be capable of adhering to surfaces of any orientation and climbing rough surfaces with a 45° slope. The robot was capable of controllably adhering to rough sandpaper and smooth glass with an adhesive stress of 7.3 kPa, demonstrating a novel form of adhesion on a wide range of surface roughnesses and orientations.
by Nicholas Eric Wiltsie.
S.M.
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Reese, Owein. "Homogenization of acoustic wave propagation in a magnetorheological fluid." Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-0430104-101629.
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Lefèvre, Xavier. "Grafting of ‘push-pull’ systems on germanium : towards the electric passivation." Palaiseau, Ecole polytechnique, 2012. https://theses.hal.science/tel-00782709.
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Les excellentes propriétés électroniques du germanium limitées par la faible qualité isolante de son oxyde rendent le développement de nouveaux matériaux diélectriques nécessaires. En outre, la sensibilité du germanium requiert la création d'une couche passivante de surface pour le protéger. Bien que de nombreuses études soient réalisées pour le développement de nouveaux diélectriques inorganiques, ce projet de recherche en rupture concerne la conception, la réalisation et le développement de film mince diélectrique organique passivant sur le germanium pour des applications en nanoélectronique. Le travail réalisé porte principalement sur la synthèse de nouvelles molécules " push-pull " (systèmes conjugués linéaires portant de part et d'autres un groupe donneur et un groupe accepteur) et sur la fonctionnalisation du germanium. Plusieurs nouveaux systèmes donneur-accepteur ainsi que des systèmes conjugués linéaires contenant une fonction d'ancrage ont été synthétisés selon de nouvelles voies. En particulier, une série de dérivés azobenzène contenant différents accepteurs (groupes fluorés, pyridinium, nitro) et donneurs (amines, alcoxyl) ainsi que des fonctions d'ancrage variées (thiol, acide carboxylique, sel de diazonium, triazene) a été obtenue. En parallèle, la préparation et la fonctionnalisation de surfaces de germanium ont été étudiées. Un nouveau procédé permettant d'enlever l'oxyde natif de la surface et d'obtenir des surfaces halogénées de faible rugosité a été développé. Les substrats de germanium ont été fonctionnalisés par des thiols mais également par des sels de diazonium. Ce nouveau processus de greffage spontané a permis d'abaisser considérablement le temps de réaction (15 minutes de greffage spontané des sels de diazonium contre 3 jours pour la formation de monocouches auto-assemblées de thiols) tout en travaillant dans des conditions douces. Les films minces ainsi obtenus présentent une stabilité comparable à celles des monocouches de thiols. Des systèmes conjugués linéaires ont été greffés à la fois sous forme de thiol et sous forme de sels de diazonium afin de déterminer l'influence du noyau aromatique sur la formation du film et sur ses propriétés. Enfin, les systèmes " push-pull " ont également été greffés. Des premières études électroniques sur or avec les systèmes conjugués linéaires ont été réalisées. Ces études ont été étendues au germanium et laissent envisager des résultats significatifs avec les molécules " push-pull "Despite its excellent electronic properties, germanium is limited by the low passivation of its oxide. Therefore, new dielectrics must be developed. Furthermore, germanium sensitivity requires the creation of a passivation layer on the surface. Even if numerous studies were carried out on new inorganic dielectrics, this research project concerns the design, the realization and the development of thin passivating organic dielectric films on germanium for nanoelectronics applications. This work principally involves the synthesis of new push-pull molecules (π-conjugated systems bearing a donor and an acceptor part) and germanium functionalization. New donor-acceptor systems and π-conjugated linear systems containing an anchoring group were synthesized through new ways. In particular, a series of azobenzene derivatives with different acceptors (fluorinated groups, pyridinium, nitro) and donors (amines, alkoxyl) and various anchoring groups (thiol, carboxylic acid, diazonium salt, triazene) was obtained. Meanwhile, preparation and functionalization of germanium surfaces was studied. A new process to etch the native oxide and obtain halogenated surfaces with low roughness was developed. Germanium substrates were then functionalized with thiol but also with diazonium salts. This new spontaneous grafting process considerably decreased the reaction time (15 minutes spontaneous grafting of diazonium salts against 3 days for self-assembled monolayers of thiol formation) in mild conditions. Thin films obtained present stability similar to the one of thiol monolayers. Π-conjugated linear systems were grafted both as thiol and diazonium salt to probe the influence of the aromatic core on the film formation and properties. Finally, push-pull systems were also grafted. Electronic studies on gold with π-conjugated systems were realized. These studies were extended to germanium and allow expecting significant results with push-pull molecules
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Hu, Wei. "Development of magnetorheological fluid elastomeric dampers for helicopter stability augmentation." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3211.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Kubík, Michal. "Magnetorheological Suspension Damper for Space Application." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-371779.
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Disertační se práce se zabývala vývojem magnetoreologického (MR) tlumiče odpružení pro kosmonautiku. Dle současného stavu poznání jsou důležitými parametry pro semi-aktivně řízený tlumič pro kosmonautiku hermetické oddělení pracovní kapaliny od zbytku nosiče a krátká časová odezva tlumícího elementu. Těmto požadavkům vyhovuje magnetoreologický tlumič s vlnovcovou jednotkou. Magnetický obvod MR tlumiče pro kosmonautiku byl vyroben z feritového materiálu, který umožnil výrazně snížit časovou odezvu. Hermetičnost byla zajištěna použitím vlnovcové jednotky. Konstrukce takového typu tlumiče ovšem přináší celou řadu problémů. Vyvinutý MR tlumič s feritovým magnetickým obvodem dosahoval časové odezvy 4.1 ms a dynamického rozsahu 8. Během konstrukčních prací na MR tlumiči pro kosmonautiku byly hledány nové metody pro konstrukci semi-aktivně řízeného MR tlumiče s krátkou časovou odezvou. Konkrétně se jednalo o metodu eliminace vířivých proudů v magnetickém obvodu MR tlumiče, magnetostatický a transietní magnetický model, CFD model obtokové štěrbiny, hydraulický model MR tlumiče a jejich experimentální verifikace. Tyto nové metody umožní konstrukci MR tlumiče pro kosmonautiku lehčí, s nižší časovou odezvou a vyšším dynamickým rozsahem.
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Liu, Yanqing. "Variable damping and stiffness semi-active vibration isolation control using magnetorheological fluid dampers." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144553.
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Kubík, Michal. "Návrh testovacího standu pro stanovení provozních parametrů magnetického hřídelového těsnění." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230462.
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This thesis deals with design of testing stand for operating parameters magnetic seal. In this thesis was done analysis of construction magnetic circuit and analysis of operating parameters. This work contains FEM analysis of magnetic circuit and experimental tune up. The results of this analysis will be used for design magnetic circuit and geometric sensitivity analysis in test stand.
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Wang, Shuo. "Control of a Uni-Axial Magnetorheological Vibration Isolator." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302200947.
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Ngatu, Grum T. "Development of a snubber type magnetorheological fluid elastomeric lag damper for helicopter stability augmentation." College Park, Md.: University of Maryland, 2009. http://hdl.handle.net/1903/9326.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2009.Thesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Ahmadkhanlou, Farzad. "Design, Modeling And Control Of Magnetorheological Fluid-Based Force Feedback Dampers For Telerobotic Systems." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1212419874.
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Richards, Russell Joseph. "Comparison of Linear, Nonlinear, Hysteretic, and Probabilistic MR Damper Models." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31447.
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Magnetorheolgical (MR) fluid dampers have the capability of changing their effective damping force depending on the current input to the damper. A number of factors in the construction of the damper, as well as the properties of the fluid and the electromagnet, create a dynamic response of the damper that cannot be fully described with a static model dependent on current and velocity. This study will compare different techniques for modeling the force response of the damper in the current-velocity space.
To ensure that all the dynamic response characteristics of the damper are captured in data collection, random input signals were used for velocity and current inputs. By providing a normally distributed random signal for velocity to a shock dynamometer and a uniformly distributed random signal for current to a Lord rheonetic seat damper, the force response could be measured.
The data from this test is analyzed as a two dimensional signal, a three dimensional force plot in the current velocity plane, and as a probability density function. Four models are created to fit the data. The first is a linear model dependent solely on current. The second is a nonlinear model dependent on both current and velocity. The third model takes the nonlinear model and includes a filter that affects the force response of the model with time. Each of these three approaches are compared based on the total error in the force response and the models? ability to match the PDF of the data. Finally, a fourth model is created for the damper that improves the nonlinear model by making one parameter a probability parameter defined by a PDF calculated from the data. However, because it is a probability model, the error cannot be found through comparison to the data.Master of Science
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Nguyen, The Minh. "A Novel Semi-Active Magnetorheological Mount for Vibration Isolation." University of Toledo / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1250008519.
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STELZER, GREGORY JON. "A MAGNETORHEOLOGIC SEMI-ACTIVE ISOLATOR TO REDUCE NOISE AND VIBRATION TRANSMISSIBILITY IN AUTOMOBILES." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1029363540.
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Deshmukh, Suraj Sharadchandra 1978. "Development, characterization and applications of magnetorheological fluid based "smart" materials on the macro-to-micro scale." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38697.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2007.Includes bibliographical references (p. 193-208).
Magnetorheological fluids belong to the class of field-responsive fluids that undergo large, reversible and fast changes in their rheological properties when acted upon by an external magnetic field. 'Smart' or controllable composite materials have been obtained by doping polymers, foams, fabrics etc. with these field-responsive fluids. The resulting composite materials have potential applications in numerous fields ranging from adaptive energy absorption, automotive crash protection to microfluidic valves, mixers and separation devices. A series of stable magnetorheological (MR) fluids have been systematically characterized under steady shearing, creep and large amplitude oscillatory shear (LAOS) flow conditions. A rheometer fixture for applying nearly uniform magnetic fields up to 0.4 T has been fabricated to measure both steady-state and transient changes in the fluid properties under applied fields. Stable MR fluids with a markedly improved dynamic response (yield stress as a function of magnetic field) compared to commercial fluids have been formulated by increasing the constituent particle size and by stabilizing the system against sedimentation. A new "soft-glassy rheology" model has been used to model the fluid response time and visco-elasto-plastic response under creep conditions and oscillatory loadings.
(cont.) The experiments and model show that the evolution of chain structure and plastic collapse in these suspensions exhibits a universal scaling with the dimensionless stress s = [sigma]/[sigma]y. Structure evolution, pattern formation and dynamics of MR fluid flow in microchannel geometries has been analyzed using high-speed digital video microscopy. In order to elucidate the mechanisms that control MR structure formation, experiments have been performed while varying the magnetic field, particle size, channel geometry, concentration and fluid composition. Excellent qualitative agreement has been obtained with Brownian Dynamics simulations and useful scalings based on interplay of magnetostatic & viscous forces have been extracted to understand the field-dependent fluid response on the macro & micro scale. Novel MR elastomeric materials and microparticles have been synthesized by doping photo-curable or thermo-curable polymers with field-responsive fluids. A high-throughput micromolding technique for synthesis of controllable particles of anisotropic shapes and sizes has been developed. Flexible and permanent chain-like structures have also been synthesized using amidation chemistry. Potential microfluidic applications such as field-responsive valves, mixers and separation devices using these 'smart' materials have also been investigated.
by Suraj Sharadchandra Deshmukh.
Ph.D.
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Lazar, Jaroslav. "Magnetoreologický tlumič kmitání." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229399.
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This master's thesis deals with an engineering design of an external reservoir for hydraulic shock absorbers with combined filling of oil and magnetorheological fluid. The first part describes existing designes of magnetorheological shock absorbers and characteristics of magnetorheological fluid. Next part describes a design of an experimental external reservoir and a test of its functionality on a prototype. This is followed by an optimalized engineering design of the experimental external reservoir.
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Büssing, Tobias. "Conception d'un simulateur mécatronique à propriétés variables pour l'apprentissage du geste en kinésithérapie respiratoire." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENA015.
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En France, 460000 nourrissons âgés d’un moins à deux ans, sont affectés par la bronchiolite aiguë chaque hiver. Cette infection virale, qui a pour conséquence une inflammation des voies respiratoires, est généralement traitée par des séances de kinésithérapie respiratoire (KR). Afin d’améliorer l’apprentissage des techniques de KR pédiatriques, un simulateur, représentatif d’un nourrisson de six mois présentant un encombrement moyen, a été réalisé au laboratoire SYMME. Ce premier simulateur permet aux kinésithérapeutes novices d’apprendre les gestes de base de la KR dans un environnement didactique et protégé. Ce travail s’inscrit dans la continuité de cette étude, et devra permettre à terme d’améliorer la formation, en proposant des situations didactiques variées. Dans un premier temps, un système permettant de reproduire sur le simulateur le mouvement de respiration du nourrisson a été réalisé. Puis nous avons travaillé sur la conception d’un mécanisme permettant d’obtenir un comportement mécanique variable au niveau du thorax, afin de permettre à l’apprenant de s’entrainer sur différents cas cliniques. Pour la réalisation d’un tel dispositif, nous nous sommes orientés vers des systèmes classiquement utilisés pour dissiper de l’énergie en modifiant la raideur et/ou l’amortissement de la structure. Deux dispositifs semi-actifs basés sur l’utilisation d’un vérin hydraulique ont été principalement étudiés. Ils se différencient par la façon dont l’écoulement du fluide entre les deux chambres du vérin est modifié : le premier par un changement de section de la canalisation, le deuxième par une modification des propriétés d’écoulement d’un fluide magnétorhéologique. La première solution a été validée partiellement par un kinésithérapeute référent mais n’est pas tout à fait satisfaisante. La seconde a été testée sur un banc d’essai spécifique et semble être une voie prometteuse pour la réalisation du simulateur à propriétés variablesIn France, 460000 infants between one month and two years are affected by the acute bronchiolitis each winter. This viral infection which leads to an inflammation of the respiratory tract is generally treated during a respiratory physiotherapy(RP) session. In order to improve the technical learning of the paediatric RP, a simulator which represents a six month old infant with an average type of bronchiolitis was developed in the laboratory SYMME. This first simulator allows the physiotherapist students to learn the basic gestures of the RP in a didactic and safe environment. This research work follows the frame work of this study and should allow an improvement of the training by proposing various didactic situations. As a first step, a system that allows reproducing the breathing movement of an infant on the simulator was developed. Then we worked on the design of a mechanism that allows obtaining a variable mechanical behaviour of the thorax in order to enable the student to practice on different clinical cases. For the realisation of such a device, we focused on systems which are conventionally used to dissipate energy by modifying the stiffness and/or the damping of the structure. Two semi-active devices based on the usage of a cylinder/piston system were examined. They differ in the way the pressure difference between the two chambers of the cylinder is generated : first, by changing the flow geometry and second, by a modification of the fluid flow characteristics of a magnetorheological fluid. The first solution was partially validated by a physiotherapist but was not completly satisfying. The second solution was tested on a specific test bench and seems to be a promising way to realise a simulator with variable properties
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Kagarise, Christopher D. "Rheological Characterization and Modeling of Micro- and Nano-Scale Particle Suspensions." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259699454.
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Southern, Brian Mitchell. "Design and Characterization of Tunable Magneto-Rheological Fluid-Elastic Mounts." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/32654.
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This study of adaptable vibration isolating mounts sets out to capture the uniqueness of magnetorheological (MR) fluidâ s variable viscosity rate, and to physically alter the damping and stiffness when used inside an elastomeric mount. Apparent variable viscosity or rheology of the MR fluid has dependency on the application of a magnetic field. Therefore, this study also intends to look at the design of a compact magnetic field generator which magnetizes the MR fluid to activate different stiffness and damping levels within the isolator to create an adaptable and tunable feature.
To achieve this adaptable isolator mount, a mold will be fabricated to construct the mounts. A process will then be devised to manufacture the mounts and place MR fluid inside the mount for later compatibility with the magnetic field generator. This process will then produce an MR fluid-elastic mount. Additionally for comparative purposes, passive mounts will be manufactured with a soft rubber casing and an assortment of metal and non-metal inserts. Next, the design of the magnetic field generator will be modeled using FEA magnetic software and then constructed.
Stiffness or force/displacement measurements will then be analyzed from testing the isolator mount and magnetic field generator on a state-of-the-art vibration dynamometer. To vary the magnetic flux through the mount, an electro-magnet is used. To analyze the results, a frequency method of the stiffness will be used to show the isolators adaptation to various increments of magnetic flux over the sinusoidal input displacement frequencies. This frequency response of the stiffness will then be converted into a modeling technique to capture the essence of the dynamics from activating the MR fluid within the isolator mount.
With this methodology for studying the adaptability of an MR fluid-elastic mount, the stiffness increases are dependent on the level of magnetic field intensity provided from the supplied electro-magnet. When the electro-magnet current supply is increased from 0.0 to 2.0 Amps, the mount stiffness magnitude increase is 78% in one of the MR fluid-elastic mounts. Through comparison, this MR fluid-elastic mount at off-state with zero magnetic field is similar to a mount made of solid rubber with a hardness of 30 Shore A. With 2 Amps of current, however, the MR fluid-elastic mount has a higher stiffness magnitude than a rubber mount and resembles a rubber casing with a steel insert.
Moreover, when the current in the electro-magnet is increased from 0.0 to 2.0 Amps the equivalent damping coefficient in a MR fluid-elastic mount increases over 500% of the value at 0 Amps at low frequency. Through damping comparisons, the MR fluid-elastic mount with no current is similar to that of a mount made of solid rubber with a hardness of 30 Shore A. At full current in the electromagnet, however, the damping in the MR fluid-elastic mount is greater than any of the comparative mounts in this study.
Therefore, the results show that the MR fluid-elastic mount can provide a wide range of stiffness and damping variation for real-time embedded applications. Since many aerospace and automotive applications use passive isolators as engine mounts in secondary suspensions to reduce transmitted forces at cruise speed, the MR fluid-elastic mount could be substituted to reduce transmitted forces over a wider range of speeds. Additionally, this compact MR fluid-elastic mount system could be easily adapted to many packaging constraints in those applications.Master of Science
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Mesquita, Neto Camilo. "Proposta de construção de um amortecedor de vibração ajustável, TVA, utilizando fluido magnetoreológico /." Ilha Solteira : [s.n.], 2008. http://hdl.handle.net/11449/94508.
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Resumo: Neste trabalho é apresentado uma proposta de absorvedor de vibrações ajustável tipo viga sanduíche utilizando fluido Magnetoreológico no centro. Para o desenvolvimento deste projeto foi realizada uma revisão sobre os vários tipos de absorvedores e algumas aplicações. Em seguida foi realizado um estudo sobre o comportamento do fluido magnetoreológico, mostrando como este material inteligente varia suas propriedades quando submetido a um campo magnético. O objetivo do estudo foi verificar as propriedades do sistema para realização de um futuro controle, que é realizado através da variação do campo magnético. Avaliou-se, também, a relação com a corrente elétrica, quais os parâmetros que o influenciam e como podemos produzir um campo magnético com a intensidade desejada. Para avaliar as características do sistema foi utilizado o modelo no programa Ansys, com o objetivo de se verificar o comportamento do sistema. Para encontrar as características reais do sistema foi utilizado o modelo na forma de espaço de estados modais, identificado através do método PEM, Método de Predição de Erros (do inglês Prediction Error Methods ���� PEM). Os testes experimentais foram realizados para se adquirir conhecimento do comportamento dinâmico deste tipo de fluido e, verificar se há repetibilidade nas medidasAbstract: This work presents a proposal of a tunable vibrations absorber type sandwich beam, using the Magnetorheologic fluid in the intermediate layer. For the development of this study a revision of some types of absorber with some applications was carried out. After that, a study of the behavior of the magnetorheologic fluid was carried through, showing as this intelligent material tunable its properties when submitted to a magnetic field. The objective of this analysis was to verify the properties of the system for implementation of a future control, which is based on the variation of the magnetic field. It was realized an analysis of the relation of the electric current and the parameters that influence it, in order to produce a magnetic field with the desired intensity. The characteristics of the system were verified through a mathematical model obtained with the software Ansys. The real characteristics of the system were found through the identification method PEM, Prediction Error Methods, using modal space states formulation. Experimental tests were carried out in order to obtain know how of the dynamic behavior of this type of material
Orientador: Vicente Lopes Junior
Coorientador: Michael J. Brennan
Banca: Hermes Adolfo de Aquino
Banca: Edson Antonio Capello Sousa
Mestre
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Žáček, Jiří. "Výzkum opotřebení materiálů v kontaktu s MR kapalinou." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443230.
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This paper is focused on MR dampers and its critical parts in term of damper`s durability, which seems to be a piston-rod seals, and it should find an ideal material combination of seal and MR fluid for increasing the damper`s life. The tests were conducted in modified pin-on-flat configuration, which was supposed to be more suitable for laboratory testing. There was tested and compared a suitable material for seals, like PTFE, NBR, SBR of polyurethanes. The article is also focused on MR fluids and its contribution to seal`s wear. The impact of particle concentration, wear of MR fluid and effect of modification of MR fluid was tested. It showed up, that the best material for seal is H-PU95FDA. The effect of particle concentration is negligible on seal`s wear, while effect of modification and wear of MR fluids are significantly higher.
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Mesquita, Neto Camilo [UNESP]. "Proposta de construção de um amortecedor de vibração ajustável, TVA, utilizando fluido magnetoreológico." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/94508.
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Neste trabalho é apresentado uma proposta de absorvedor de vibrações ajustável tipo viga sanduíche utilizando fluido Magnetoreológico no centro. Para o desenvolvimento deste projeto foi realizada uma revisão sobre os vários tipos de absorvedores e algumas aplicações. Em seguida foi realizado um estudo sobre o comportamento do fluido magnetoreológico, mostrando como este material inteligente varia suas propriedades quando submetido a um campo magnético. O objetivo do estudo foi verificar as propriedades do sistema para realização de um futuro controle, que é realizado através da variação do campo magnético. Avaliou-se, também, a relação com a corrente elétrica, quais os parâmetros que o influenciam e como podemos produzir um campo magnético com a intensidade desejada. Para avaliar as características do sistema foi utilizado o modelo no programa Ansys, com o objetivo de se verificar o comportamento do sistema. Para encontrar as características reais do sistema foi utilizado o modelo na forma de espaço de estados modais, identificado através do método PEM, Método de Predição de Erros (do inglês Prediction Error Methods PEM). Os testes experimentais foram realizados para se adquirir conhecimento do comportamento dinâmico deste tipo de fluido e, verificar se há repetibilidade nas medidas
This work presents a proposal of a tunable vibrations absorber type sandwich beam, using the Magnetorheologic fluid in the intermediate layer. For the development of this study a revision of some types of absorber with some applications was carried out. After that, a study of the behavior of the magnetorheologic fluid was carried through, showing as this intelligent material tunable its properties when submitted to a magnetic field. The objective of this analysis was to verify the properties of the system for implementation of a future control, which is based on the variation of the magnetic field. It was realized an analysis of the relation of the electric current and the parameters that influence it, in order to produce a magnetic field with the desired intensity. The characteristics of the system were verified through a mathematical model obtained with the software Ansys. The real characteristics of the system were found through the identification method PEM, Prediction Error Methods, using modal space states formulation. Experimental tests were carried out in order to obtain know how of the dynamic behavior of this type of material
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Železník, Tomáš. "Slit-flow reometr pro magnetické i nemagnetické kapaliny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417518.
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In this thesis was designed, manufactured and tested the fourth evolution of a slit-flow rheometer with another necessary parts, eg. rheometer`s holder, drive frame and important jig tools. The rheometer is able to measure rheological properties of magnetic and non-magnetic fluids at very high shear rates, which commercial rheometers can not reach. It is designed for 200 bar pressure and maximum load 15 kN. The construction of the slit-flow rheometer with it`s holder and drive frame improves user friendliness, accelerates change of the fluid sample and expands research opportunities thanks to a big space for additional adjustments. It is possible to use different length of the slit and thanks to a changeable inserts it is possible to change parameters of the slit (roughness of the walls, wall material, thickness of the slit). A part of this thesis was focused on illation of necessary equations for planning calibration measurements. Aim of these measurements is to obtain minor pressure losses dependence on Reynolds number for specific slit.
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Roupec, Jakub. "Mezní a degradační procesy magnetoreologických tlumičů odpružení." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-233963.
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This work deals with the research of degradation of magnetorheological (MR) fluid during long-term loading under conditions that correspond to the real load in the linear MR devices such as dampers. The behaviour of MR fluid is described by a Bingham model of viscoplastic fluid. The parameters of this model are the yield stress and viscosity. Their values are determined by the shear rate from 1 to 2,8104 s-1. Results of durability tests show a significant decrease in viscosity of MR fluid, a gradual increase in yield stress in the off-state and a significant decrease in MR effect. The paper also described the effect of temperature on these parameters and there is also designed a method of non-assembly diagnostic of the MR fluid state in the damper using the "rate of pulsation."
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Kao, Chen-Yu, and 高震宇. "Research on the Mesoscopic Theory of Magnetorheological Fluids." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/52m3uh.
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碩士國立暨南國際大學
土木工程學系
92
The mesoscopic concept, which was originally developed in the theory of liquid crystals, is introduced for the description of magnetorheological (MR) materials. This mesoscopic theory is constructed based on the mixture concept of continuum mechanics. The idea of the mesoscopic theory is that the configuration space is augmented to the mesoscopic space which includes the newly-introduced mesoscopic variable characterizing the arrangement of the particles. On account of the contribution of magnetic field, the mesoscopic and macroscopic balance equations are formulated and the relationship between the mesoscopic and macroscopic quantities are established. By the concept of multipole expansion we derive the mesoscopic-based macroscopic evolution equations of the internal variables. In virtue of simple constitutive equations for the velocity of the mesoscopic variable, two equations for the second moment of the distribution function are also given.
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"Self-powered, self-sensing magnetorheological dampers." 2012. http://library.cuhk.edu.hk/record=b5549609.
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磁流變阻尼器可用於各種動態系統的半主動振動控制，非常有前景。在當前的磁流變阻尼器系統中，需要使用外加并分離的電源和動態傳感器。本論文提出并探索了自供能自傳感磁流變阻尼器。它將能源採集、動態傳感和磁流變阻尼三種技術集成到同一器件中，具有內置的發電機制，和速度/位移傳感能力。此多功能的集成可以對當前的磁流變阻尼器系統帶來眾多的益處，如更節能、更高的可靠性、尺寸及重量的減少、較低的成本、以及更少的維護需求。該研究成果可以促進各種動態系統，如懸架系統和義肢的發展。在論文中，作者對自供能自傳感磁流變阻尼器的概念、原理、設計方法、設計難點及解決方案進行了探討，設計製作了兩件原型，並對原型進行了性能測試。作者提出并探索了幾種可與磁流變阻尼器集成的發電機制，和動態傳感的方法。對發電、動態傳感和阻尼力三種性能，進行了建模、理論分析、以及實驗驗證。作者提出并驗證了自供能自傳感磁流變阻尼器的數學模型，該模型考慮了單獨的功能以及多功能間的相互作用。本論文對自供能磁流變阻尼器系統進行了探討分析，包括能源產生與磁流變阻尼的相互作用、自供能判據、工作範圍和設計指引。還提出并探索了一個自供能控制器，以及一種複合的磁場隔離方法。
Magnetorheological (MR) dampers are promising for semi-active vibration control of various dynamic systems. In the current MR damper system, separate power supply and dynamic sensor are required. This research is aimed to propose and investigate self-powered, self-sensing (SPSS) MR dampers, which integrate energy harvesting, sensing and MR damping technologies into one device. SPSS MR damper has self-contained power generation and velocity/displacement sensing capabilities. This multifunctional integration will bring great benefits such as energy saving, higher reliability, size and weight reduction, lower cost, and less maintenance for the use of MR damper systems. It will advance the technology of various dynamic systems such as suspensions and prostheses.
Concepts, principles, design methodology, key issues and solutions of SPSS MR dampers are studied. Two prototypes of the SPSS MR dampers are designed, fabricated, and tested. Several integrated power generation and sensing methods for MR dampers are proposed and investigated. Modeling, theoretical analyses, and experimental studies on power generation ability, sensing capability and damping force performances are conducted. Models of SPSS MR dampers considering individual functions and interactions are developed and validated experimentally. Systematic studies on the self-powered MR damper system are performed, including interaction between the power generation and MR damping, self-powered criterion, working range and design guidelines. Moreover, a self-powered controller and combined magnetic-field isolation method are proposed and investigated.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Chen, Chao.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references (leaves 163-172).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
ABSTRACT --- p.i
摘要 --- p.iii
TABLE OF CONTENTS --- p.vii
LIST OF FIGURES --- p.xi
LIST OF TABLES --- p.xvii
Chapter 1 --- INTRODUCTION --- p.1
Chapter 1.1 --- Background and Motivation --- p.2
Chapter 1.1.1 --- MR fluids --- p.2
Chapter 1.1.2 --- MR dampers --- p.3
Chapter 1.1.3 --- Previous research on functional integration of MR dampers --- p.7
Chapter 1.2 --- Research Objective --- p.10
Chapter 1.3 --- Thesis Organization --- p.12
Chapter 2 --- DESIGN OF SELF-POWERED, SELF-SENSING MR DAMPERS --- p.13
Chapter 2.1 --- Concept and Key Issues of Multifunctional Integration --- p.14
Chapter 2.2 --- Configurations of Different Methods of Multiple Functions --- p.17
Chapter 2.3 --- Principles of SPSS MR Dampers --- p.18
Chapter 2.3.1 --- Structure and operation principle of the first prototype --- p.18
Chapter 2.3.2 --- Structure and operation principle of the second prototype --- p.21
Chapter 2.3.3 --- Energy flow of SPSS MR damper --- p.25
Chapter 2.4 --- Materials Used in Design --- p.27
Chapter 2.5 --- Fabrication of Prototypes --- p.32
Chapter 2.6 --- Experimental Setup --- p.35
Chapter 2.7 --- Chapter Summary --- p.37
Chapter 3 --- POWER GENERATION OF SELF-POWERED, SELF-SENSING MR DAMPERS --- p.39
Chapter 3.1 --- Introduction to Electromagnetic Energy Harvesting --- p.40
Chapter 3.2 --- Finite Element Method --- p.42
Chapter 3.3 --- Slotted Power Generation Method --- p.44
Chapter 3.3.1 --- Modeling and analysis of slotted power generation --- p.44
Chapter 3.3.2 --- Experimental results of slotted power generation --- p.52
Chapter 3.4 --- Slotless Power Generation Method --- p.56
Chapter 3.4.1 --- Design considerations --- p.56
Chapter 3.4.2 --- Modeling and analysis of slotless power generation --- p.57
Chapter 3.4.3 --- Experimental results of slotless power generation --- p.62
Chapter 3.5 --- Frequency Multiplication Effect of Generated Voltage --- p.65
Chapter 3.6 --- Chapter Summary --- p.67
Chapter 4 --- SENSING OF SELF-POWERED, SELF-SENSING MR DAMPERS --- p.69
Chapter 4.1 --- Introduction to Self-sensing Ability --- p.70
Chapter 4.1.1 --- Self-sensing for vibration control --- p.70
Chapter 4.1.2 --- Self-sensing of SPSS MR damper --- p.71
Chapter 4.2 --- Moving-spacer Velocity Sensing Method --- p.73
Chapter 4.3 --- Velocity-extraction Method from Slotted Power Generator --- p.80
Chapter 4.4 --- Velocity-extraction Method from Slotless Power Generator --- p.86
Chapter 4.5 --- Chapter Summary --- p.90
Chapter 5 --- DAMPING FORCE OF SELF-POWERED, SELF-SENSING MR DAMPERS --- p.93
Chapter 5.1 --- Design of MR Damping Part --- p.94
Chapter 5.2 --- Testing Results of MR Damping Force of the First Prototype --- p.97
Chapter 5.3 --- Testing Results of Damping Force of the Improved Prototype --- p.101
Chapter 5.4 --- Damping Force Modeling and Identification --- p.105
Chapter 5.5 --- Chapter Summary --- p.110
Chapter 6 --- INTERACTION ANALYSIS --- p.111
Chapter 6.1 --- Modeling Summary and Magnetic Field Interactions of SPSS MRD --- p.112
Chapter 6.1.1 --- Modeling summary of SPSS MR dampers --- p.112
Chapter 6.1.2 --- Magnetic field interactions --- p.114
Chapter 6.2 --- Analysis of a Versatile Self-powered MR Damper System --- p.122
Chapter 6.3 --- Application to Vehicle Suspension Systems --- p.130
Chapter 6.3.1 --- Modeling of suspension system --- p.131
Chapter 6.3.2 --- Working range and vibration control efficiency under on-off controller --- p.133
Chapter 6.4 --- Design Guidelines of Self-powered Working Range --- p.141
Chapter 6.5 --- A Proposed Self-powered Controller --- p.146
Chapter 6.6 --- Chapter Summary --- p.153
Chapter 7 --- CONCLUSION AND FUTURE WORK --- p.155
Chapter 7.1 --- Conclusion --- p.155
Chapter 7.2 --- Future Work --- p.160
Chapter 8 --- BIBLIOGRAPHY --- p.163
Chapter 9 --- APPENDIX --- p.173
Chapter A. --- MR Fluid Datasheet --- p.173
Chapter B. --- Sectional Views of Prototypes --- p.175
47
Von, Pfeil Karl. "A two-fluid continuum model for structure evolution in electro- and magnetorheological fluids." 2002. http://catalog.hathitrust.org/api/volumes/oclc/50264137.html.
Full textAbstract:
Thesis (M.S.)--University of Wisconsin--Madison, 2002.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 107-116).
48
CHO, SAN-HUI, and 卓三暉. "Preparation of magnetorheological fluids of modified carbonyl iron powders with different silane coupling agents and discussion of their magnetorheological properties." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/772j69.
Full textAbstract:
碩士國立臺北科技大學
分子科學與工程系有機高分子碩士班
107
Magnetorheological fluids are intelligent fluids that can be widely used in industry by increasing the magnetic field to change their state. The magnetorheological fluid composed of carbonyl iron differs from the oil in density and therefore has a very serious problem of sedimentation and redispersibility. In this paper, the carbonyl iron surface layer produces hydroxyl groups by hydrochloric acid, and then the two silane coupling agents APTES and PTMS are hydrolyzed in different acid-base conditions to form functional groups on the surface of the carbonyl iron powder, which can improve its sedimentation and redispersion. In this experiment, FTIR, TEM and EDS results were used to support the grafting of iron powder and silane coupling agent. The vibrating sample magnetometer was used to analyze the saturation magnetization of the modified iron powder, The sedimentation condition was observed by using a laser transmittance meter. And using physica to understand the magnetorheological behavior of a non-settling magnetorheological fluid. The experimental results show that the two siliane coupling agents have better modification effect under acidic conditions, and the sedimentation condition is obviously improved, after the addition of appropriate silica. And discuss its Shear stress and viscosity.
49
"Continuous variable transmission and regenerative braking devices in bicycles utilizing magnetorheological fluids." 2013. http://library.cuhk.edu.hk/record=b5884378.
Full textAbstract:
Cheung, Wai Ming Edwin.Thesis (Ph.D.)--Chinese University of Hong Kong, 2013.
Includes bibliographical references (leaves 107-112).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts also in Chinese.
50
"Design and analysis of magnetorheological dampers for train suspension." 2004. http://library.cuhk.edu.hk/record=b5891975.
Full textAbstract:
Lau Yiu Kee.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.
Includes bibliographical references (leaves 142-146).
Abstracts in English and Chinese.
LIST OF TABLES --- p.viii
LIST OF FIGURES --- p.x
Chapter 1. --- INTRODUCTION --- p.1
Chapter 1.1 --- Motivation --- p.1
Chapter 1.2 --- Railway Vehicle Suspension --- p.2
Chapter 1.3 --- Semi-Active Magnetorheological Fluid Damper --- p.3
Chapter 1.4 --- Research Objectives --- p.4
Chapter 1.5 --- Thesis Outline --- p.5
Chapter 2. --- BACKGROUND --- p.7
Chapter 2.1 --- MR Fluids --- p.7
Chapter 2.1.1 --- Composition of MR fluids --- p.7
Chapter 2.1.2 --- Properties and characteristics of MR fluids --- p.8
Chapter 2.1.3 --- Literature review --- p.13
Chapter 2.2 --- MR Devices --- p.13
Chapter 2.2.1 --- Advantages of MR devices --- p.13
Chapter 2.2.2 --- Common device geometries --- p.14
Chapter 2.2.3 --- MR fluid based applications --- p.15
Chapter 2.2.4 --- Literature review --- p.19
Chapter 2.3 --- Overview of Railway Vehicles --- p.21
Chapter 2.3.1 --- "Passive, active and semi-active suspensions" --- p.21
Chapter 2.3.2 --- Basic railway vehicle structure --- p.23
Chapter 2.3.3 --- Literature review --- p.25
Chapter 2.4 --- Railway Vehicle Suspension Systems --- p.25
Chapter 2.4.1 --- Primary vertical suspension --- p.25
Chapter 2.4.2 --- Secondary vertical suspension --- p.27
Chapter 2.4.3 --- Secondary lateral suspension --- p.27
Chapter 2.4.4 --- Yaw suspension --- p.28
Chapter 3. --- DESIGN CONSIDERATIONS FOR MR DAMPERS --- p.29
Chapter 3.1 --- Overview of Existing MR Dampers --- p.29
Chapter 3.1.1 --- Monotube MR fluid damper --- p.29
Chapter 3.1.2 --- Double-ended MR damper --- p.31
Chapter 3.1.3 --- Bellow type MR damper --- p.35
Chapter 3.2 --- Optimal Design and Configuration of Magnetic Circuit --- p.35
Chapter 3.2.1 --- Magnetic circuit and magnetic field orientation --- p.35
Chapter 3.2.2 --- Physical dimension of MR damper --- p.38
Chapter 3.2.3 --- Connection polarity of electromagnetic circuit --- p.40
Chapter 3.3 --- Basic Geometry Design Considerations --- p.43
Chapter 3.3.1 --- Controllable force and dynamic range --- p.43
Chapter 3.3.2 --- Geometry constraints --- p.45
Chapter 3.3.3 --- Magnetic circuit design --- p.47
Chapter 4. --- DEVELOPMENT AND FABRICATION OF MR DAMPERS --- p.51
Chapter 4.1 --- Pneumatic Air Cylinder --- p.51
Chapter 4.2 --- Fabrication Process of Double-Ended MR Dampers --- p.55
Chapter 4.2.1 --- Modifications on the pneumatic air cylinder --- p.55
Chapter 4.2.2 --- Manufacturing processes of the piston sleeve --- p.56
Chapter 4.2.3 --- Modification processes of the original piston rod --- p.59
Chapter 4.2.4 --- Modification of the piston staging area --- p.60
Chapter 4.2.5 --- Copper wire wrapping and damper assembling --- p.63
Chapter 5. --- EXPERIMENTAL SETUP AND RESULTS --- p.66
Chapter 5.1 --- Experimental Setup for the Double-Ended MR Damper --- p.66
Chapter 5.1.1 --- Instron 8801 loading machine --- p.66
Chapter 5.1.2 --- Experimental setup for testing the MR damper --- p.67
Chapter 5.2 --- Force-Lag Phenomenon of MR Damper --- p.70
Chapter 5.2.1 --- Force-lag phenomenon --- p.70
Chapter 5.2.2 --- Reasons of the force-lag phenomenon --- p.73
Chapter 5.2.3 --- Methods to eliminate the force-lag phenomenon --- p.76
Chapter 5.2.4 --- Setup for hydraulic pump system --- p.77
Chapter 5.2.5 --- Results and effects of the pressurized MR damper --- p.79
Chapter 5.3 --- Experimental Results for Testing the MR Damper --- p.83
Chapter 6. --- SIMULATION RESULTS OF SEMI-ACTIVE TRAIN SUSPENSION --- p.87
Chapter 6.1 --- MR Damper Model --- p.87
Chapter 6.2 --- Rail Vehicle Model --- p.92
Chapter 6.3 --- Semi-Active Railway Suspension --- p.94
Chapter 6.3.1 --- Lateral vibration on the train --- p.94
Chapter 6.3.2 --- Semi-active control strategy --- p.95
Chapter 6.4 --- Simulation Results --- p.98
Chapter 6.4.1 --- Lower sway mode excitation --- p.99
Chapter 6.4.2 --- Upper sway mode excitation --- p.105
Chapter 6.4.3 --- Mixed sway mode excitation --- p.110
Chapter 6.4.4 --- BR high speed assault course --- p.116
Chapter 6.4.5 --- Discussions --- p.124
Chapter 6.5 --- Effects of Vibration on Ride Comfort --- p.128
Chapter 7. --- CONCLUSIONS --- p.134
APPENDIX --- p.136
BIBLIOGRAPHY --- p.142