Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 28

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  MR fluid
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
PL
Artykuł jest poswięcony sprzęgłom magnetoreologicznym i w centrum uwagi stawia problem kompleksowego porównania rozwiązania konstrukcyjnego 1- i 2- tarczowego z punktu widzenia róznych kryteriów: masy, objękosci, charakterystycznych wspóczynników Tc/m i Tc/V (gdzie: Tc - moment sprzęgającym - masa sprzęgła, V - objętość sprzęgła), poboru mocy elektrycznej (niezbędnej do podtrzymania stanu sprzęzenia), strat ˙ w miedzi cewki wzbudzenia oraz maksymalnego wzrostu temparatury cieczy magnetoreologicznej w strefie roboczej sprzęgła. Porównania dokonano na przykładzie 6 zaprojektowanych sprzęgieł dla wybranego ciągu momentów sprzęgających: Tc= 20, 35 i 50Nm. Wskazano, ze rekomendowanym ˙ rozwiązaniem konstrukcyjnym jest sprzęgło 2-tarczowe.
EN
The article is devoted to magnetorheological clutches and focuses on the problem of a comprehensive comparison of a 1- and 2-disc design solution from the point of view of various criteria: mass, volume, characteristic factors Tc/m and Tc/V (where: Tc - clutch torque, m - clutch mass, V - clutch volume), electrical power consumption (necessary to maintain the clutching state), copper losses in the excitation coil and the maximum temperature increase of the magnetorheological fluid in the clutch working region. The comparison was made on the example of 6 designed clutches for a selected sequence of clutching torques: Tc = 20, 35 and 50 Nm. It was indicated that the recommended constructional solution is a 2-disc clutch.
EN
The unique properties of magnetic fluids result from their ability to undergo reversible, almost immediate, changes in their rheological properties under the influence of magnetic fields as well as the possibility to position them by magnetic field forces. It is also possible to control the direction and flow rate of such fluids. These properties provide an efficient way to develop new types of controllable machines and devices, such as brakes, clutches and bearings. The objective of the study was to examine the axial force and torque friction of a magnetorheological (MR) fluid working in the shear flow mode (parallel plate system) subjected to different magnetic induction ramp profiles. The rotation speed and working gap height were also taken into account. Determining the response of the tested system to magnetic induction change in different working conditions was of particular interest.
EN
The study deals with the pinch mode of magnetorheological (MR) fluids’ operation and its application in MR valves. By applying the principle in MR valves a highly non-uniform magnetic field can be generated in flow channels in such a way to solidify the portion of the material that is the nearest to the flow channel’s walls. This is in contrary to well-known MR flow mode valves. The authors investigate a basic pinch mode valve in several fundamental configurations, and then examine their magnetic circuits through magnetostatic finiteelement (FE) analysis. Flux density contour maps are revealed and basic performance figures calculated and analysed. The FE analysis results yield confidence in that the performance of MR pinch mode devices can be effectively controlled through electromagnetic means.
EN
In this study, the vibration analysis of fully and partially treated laminated composite Magnetorheological (MR) fluid sandwich plates has been investigated experimentally. The natural frequencies of fully and partially treated laminated composite MR fluid sandwich plates have been measured at various magnetic field intensities under two different boundary conditions. The variations of natural frequencies with applied magnetic field, boundary conditions and location of MR fluid pocket have been explored. Further, a comparison of natural frequencies of fully and partially treated MR fluid sandwich structure has been made at various magnetic field intensities.
PL
W pracy przedstawiono studium eksperymentalne analizy wibracji płyty warstwowej z warstwą laminatu całkowicie lub częściowo wypełnioną ferropłynem reologicznym (MR). Częstotliwości drgań własnych warstwowej płyty z warstwą całkowicie lub częściowo zmodyfikowaną płynem MR mierzono przy różnych natężeniach pola magnetycznego i dla dwu różnych warunków brzegowych. Badano zmiany częstotliwości drgań własnych pod wpływem pola magnetycznego i wpływ warunków brzegowych i usytuowania kieszonek z płynem reologicznym. Ponadto, porównano częstotliwości drgań własnych struktur laminatu z częściową lub pełną warstwą płynu reologicznego przy różnych natężeniach pola magnetycznego.
EN
The study summarises the results of quasi-static experimental tests of an MR squeeze-mode damper prototype (MRSQD) performed at the MTS testing machine. Of particular interests was the influence of MR fluid clumping behaviour in the MRSQD working gap on the force output of the device. The MRSQD tests were assessed by measuring the damping force output at prescribed sinusoidal displacement inputs and at various (fixed) voltage levels resulting in the respective average current levels in the control coil. The influence of piston position offset on the damping force was also investigated. The collected data were shown in the form of damping force time histories and damping force-piston displacements loops and discussed with respect to MR fluid clumping behaviour.
PL
W pracy przeprowadzono analizę siły wytwarzanej przez wibroizolator z cieczą magnetoreologiczną (MR) działającą w trybie ściskania w stanach quasi-statycznych. Opisano budowę wibroizolatora i model ściskania cienkiej warstwy cieczy MR. Wyznaczono charakterystyki wibroizolatora. Te charakterystyki obrazują przebiegi czasowe siły wibroizolatora i jej składowych oraz zależności siły od przemieszczenia i prędkości tłoka przy stałych wartościach natężenia prądu w cewce sterującej oraz sinusoidalnych przemieszczeniach tłoka.
EN
The study summarises the quasi-static analysis of the damping force generated by a vibration isolator with magnetorheological (MR) fluid in the squeeze mode. The isolator’s structure is described and the model of a simple squeeze-film device is outlined. Force characteristics of the isolator were obtained, plotting, the time patterns of the force and its components determined under sine piston displacements and constant levels of input current in the control coil, as well as force-displacement and force-velocity loops.
PL
Obiektem analizy był wibroizolator z cieczą magnetoreologiczną (MR) pracującą w trybie ściskania. Przedstawiono budowę i działanie wibroizolatora oraz wyniki obliczeń numerycznych pola magnetycznego w urządzeniu. Celem obliczeń było wyznaczenie rozkładu pola dla rozważanych wariantów konstrukcyjnych wibroizolatora, zależności składowej osiowej indukcji magnetycznej oraz indukcyjności cewki sterującej od wysokości szczeliny roboczej. Obliczenia przeprowadzono przy użyciu programu program Opera-2d.
EN
The present study investigates the behaviour of a magnetorheological (MR) vibroisolator operated in the squeeze mode. The structure design and operating principles of the vibroisolator are outlined and the results of numerical calculations of the magnetic field in the device are provided. The purpose of the numerical procedure was to find the magnetic field distribution for all considered design options of the device and to establish the dependence of the axial component of magnetic flux density and the inductance of the control coil on the slit height.
8
Content available Viscoplastic properties of an MR fluid in a damper
EN
The aim of this paper is to mathematically describe and analyze the viscoplastic properties of a magnetorehological (MR) fluid. The scope of the discussed research has been limited to the T-MR SiMR 132 DG damper prototype. Laboratory tests have been performed on a specially developed experimental stand with a kinematic excitation rule. On the basis of the experimental data, conventional yield points and maximum shear stresses for the analyzedMR fluid, including variable shear rate, current intensity flowing through a solenoid, liquid temperature and gap height have been analyzed. Basing on the acquired results, the parameters of Bodner-Partom constitutive equations have been estimated. The identified viscoplastic model has been used to carry out simulation tests that enabled verification of the numerical results and real experimental data.
EN
The paper summarises the results of laboratory testing of three commercially available magnetorheological (MR) fluids operated in the oscillatory squeeze mode. Tested fluids include the Basonetic 204 and Basonetic 4035 (BASF) and MRF-122EG (Lord Corporation). The oscillatory squeeze mode produces large forces at small displacements. This feature may be well utilised in fabrication of new MR de-vices. The purpose of the experiments was to evaluate the suitability of MR fluids for applications in MR vibration dampers being devel-oped under the current research project. The results enable a comparative analysis of investigated fluids and verification of phenomena encountered in the oscillatory squeeze mode and reported in the literature.
10
EN
The study briefly outlines a CFD model of a magnetorheological (MR) fluid operated in squeeze mode with a constant interface area using the CFD (Computational Fluid Dynamics) approach. The underlying assumption is that the MR fluid is placed between two surfaces of which at least one can be subject to a prescribed displacement or a force input. The widely employed Bingham model, which fails to take into account the yield stress variations depending on the height of the gap, has been modified. Computation data obtained in the ANSYS CFX environment are compared with experimental results.
EN
The subject of the paper is vibration control of a cantilever beam with magnetorheological (MR) fluid. Based on the results of identification and energy analysis, a control algorithm for free vibrations damping of the beam was proposed. The algorithm was realized by controlling the current supplying the electromagnet. The free vibrations of beam were investigated for constant current and current varied according to the assumed control algorithm.
EN
This study briefly outlines the structure of the test facility for investigating the behaviour of a sandwich plate filled with magnetorheological (MR) fluid. The plate has two outer layers made of aluminium and the space between them is filled with MR fluid. The test facility is engineered within the framework of the research project focused on vibration reduction in beams and plates using MR fluids. The paper outlines the design of the test facility and the measurement equipment. Measurement data are summarised, including the free and forced vibration of the plate.
PL
W artykule przedstawiono stanowisko laboratoryjne do badania płyt z cieczą magnetoreologiczną (MR). Badana płyta jest płytą trójwarstwową, w której dwie zewnętrzne warstwy są wykonane z aluminium, a przestrzeń między nimi jest wypełniona cieczą MR. Stanowisko zbudowano w ramach projektu badawczego dotyczącego redukcji drgań belek i płyt przy wykorzystaniu cieczy MR. W pracy przedstawiono strukturę stanowiska oraz oprzyrządowanie układu pomiarowego. Zamieszczono wyniki pomiarów drgań własnych i wymuszonych płyty.
EN
In the article, drive-load system with magnetorheological clutch as a connection element is presented. Research results of this clutch, working as a mechanical fuse are shown. During the experiment, there was performed check out of clutch response to gradually increasing load up to the level higher than safe for the system value. This was performed to show the possibility of this clutch to protect the drive against load disturbances. Atter that, research results for predetermined value of clutch control voltage are shown. Two diagrams present values of such parameters as output torque, input, and output rotary speed for varying load. At the end of the article discussion on obtained results is presented.
EN
The paper investigates a magnetic field acting on a three-layer sandwich beam filled with MR fluid, the field being generated by an electromagnet. The FEM approach is applied to determine the magnetic field strength and magnetic flux density in the area between the poles and in the MR fluid layer. The results are utilised to establish the relationship between the magnetic flux density and parameters of the assumed model of the MR fluid layer.
EN
The study presents the results of laboratory studies on free vibrations of sandwich beams filled with magnetorheological (MR) fluids characterised by various proportions of ferromagnetic particles by weight. Based on the obtained results, it was possible to determine the impact of the content of the particles in question on the natural frequency of free vibrations and the dimensionless damping coefficient of beam.
PL
W pracy przedstawiono wyniki badań laboratoryjnych drgań swobodnych trójwarstwowych belek wypełnionych cieczami magnetoreologicznymi (MR) o różnej zawartości wagowej cząstek ferromagnetycznych. Na podstawie uzyskanych wyników określono wpływ zawartości tych cząstek na podstawową częstotliwość drgań własnych i bezwymiarowy współczynnik tłumienia belki.
16
Content available remote Design, Analysis and Research of the Prototype Linear Magnetorheological Damper
EN
The paper issues the basic problems connected with the design, fabrication and analysis the linear magnetorheological (MR) dampers. Basic information concerning characteristics of typical MR fluids and dampers were presented. The prototype MR damper was designed, fabricated and tested under variety of working conditions. The performance calculations of the prototype were verified with the experimental results and evaluated. The numerical Bouc-Wen model of the damper was computed with the PeXsim software and its properties were widely examined.
17
PL
W artykule przedstawiono wyniki badań drgań wymuszonych trójwarstwowej belki wspornikowej z cieczą magnetoreologiczną (MR). Ruch belki wywoływano sinusoidalnie zmiennym przemieszczeniem uchwytu mocującego jeden koniec belki. Rejestrowano wymuszenie (przemieszczenie utwierdzenia) i odpowiedź (przemieszczenie swobodnego końca belki). Na podstawie otrzymanych wyników wyznaczono charakterystyki amplitudowo-częstotliwościowe.
EN
The study covers the identification of model parameters of a three-layered cantilever beam with a magnetorheological (MR) fluid. The beam's motion was induced by applying sinusoidal variable displacements of the beam's fixture on one end. The excitation signal (displacement of the fixture) and the response signal (displacement of the beam's free end) were registered. The results were utilised to obtain the time and frequency characteristics of the investigated plant.
PL
Praca dotyczy analizy rozpraszania energii drgań w trójwarstwowej belce z cieczą MR. Belka składa się z dwóch zewnętrznych warstw aluminiowych oraz warstwy wewnętrznej, którą stanowi ciecz MR. W pracy wykorzystano model rozkładu cząstek ferromagnetycznych w warstwie MR znajdującej się w jednorodnym polu magnetycznym. Przedstawiono pewną metodę oszacowania zespolonego modułu sztywności poprzecznej warstwy MR oraz zaproponowano metodę wyznaczania energii rozpraszanej w poszczególnych fragmentach belki. Wykonano obliczenia rozpraszania energii wzdłuż całej długości belki. Wyniki obliczeń przedstawiono w formie wykresów.
EN
In the work a three-layered beam incorporating a magnetorheological (MR) fluid was considered. The beam consists of two outer layers made of aluminium and a MR fluid layer placed in between. The estimation of complex shear modulus was proposed based on body-centred-tetragonal model of distribution of magnetic particles. Using finite element model the dissipation of energy along the beam was determined. Results of calculations were presented in graphs.
19
Content available remote Symulacja drgań belki kompozytowej z cieczą magnetyczną
PL
Przedstawiono obliczenia numeryczne wykonane za pomocą programu ANSYS 11.0, dotyczące wpływu natężenia pola magnetycznego na częstotliwość i amplitudę drgań wymuszonych belki kompozytowej z cieczą magnetyczną. Na podstawie wyników obliczeń stwierdzono, że aktywacja cieczy magnetycznej spowodowała 10-krotne zmniejszenie amplitudy drgań, przy której występuje amplituda maksymalna.
EN
In the paper harmonic analysis of a sandwich beam with magnetic fluid (MR) is undertaken with the ANSYS program. The purpose of this analysis is to simulate a MR sandwich beam to obtain its natural frequency and vibration amplitude with and without magnetic field. The beam is made out of the polyethylene terephthalate and the used MR fluid is AL 458, produced by Fraunhofer-ISC. The viscoelastic properties of the fluid, needed for calculations, were obtained with a plate-plate Anton Paar rheometer which has an adapted MR fluid device to generate a uniform and controlled magnetic field up to 1 Tesla in the fluid gap. From these measurements, the complex shear modulus G* was inputted in the ANSYS program to model the fluid as a viscoelastic solid. This parameter was introduced as frequency-dependent properties. For the harmonic analysis, a sinusoidal load of 13N was applied to the beam in the vertical direction. Then, the plot response vs. frequency was obtained. It have been noted that application of magnetic field caused significant influence on amplitude decreasing. In conclusion it was stated that MR fluid can be successfully applied in sandwich beams, but results of numerical calculation should be verified experimentally before practical application.
20
Content available remote MR Fluid Analysis in a Magnetorheological Damper
EN
The main focus of this paper is the analysis of MR fluid in the damper during work. The impact of the temperature, the current intensity, the shear rate on the shear stress in MR fluid in the prototype damper during work has been described. For the investigation, a prototype of the MR damper has been manufactured and tested.
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.