bluuebunny/crossref_metadata_2025 huggingface dataset:
BASIC PROPERTIES OF GEL-STRUCTURED ELECTRO-RHEOLOGICAL FLUIDS
Authors: KAKINUMA Y. , AOYAMA T. , ANZAI H. , ISOBE K. , TANAKA K.
Published: June 2005

Electra-rheological fluids (ERFs) are composed of a functional fluid and colloidal suspension. Their rheological properties vary rapidly and reversibly with the applied electric field intensity. ERFs are mixtures of nonconductive silicone oil and inorganic/organic composite electro-rheological particles. Investigations into the properties of ERFs have led to remarkable advances in their performance in recent years. However, ERFs exhibit an undesirable property that obstructs the long-term use of ERF devices, namely the sedimentation and separation of ER particles from the silicone oil. The sedimentation of ER particles reduces the electro-rheological effect. In order to suppress the sedimentation and thereby improve the performance of ERF devices, a new functional material called Gel Structured ERF (ERG) is developed and its basic properties are analyzed in this study. The ER particles are sustained in the gel component, and thus will not precipitate out. This suppresses the decrease in ER effect associated with precipitation. The developed ERG shows large shear stress variation in response to the applied electric field. This high performance of ERGs involves a different mechanism than that observed in ERFs. In order to elucidate the mechanism in ERGs, the behavior of ER particles was observed under an electric field. Conditions at the interface between the electrode and ERG were found to change rapidly in response to the applied electric field, resulting in the variation of shear force.
FLOW CHARACTERISTICS OF A LIQUID CRYSTAL MIXTURE IN A CIRCULAR PIPE ELECTRODE
Authors: TSUKIJI TETSUHIRO , KOYABU EITARO
Published: June 2005

A circular pipe electrode was developed to control the pressure and the flow rate of the ER(Electro-rheological) fluids by one of the authors. The shape of the electrode is a circular pipe and some parts of the inner surface of the pipe are the electrode. The diameter of the tube is 1mm and the four pairs of the electrode are used. In the present study a liquid crystal mixture is selected for a homogeneous ER fluid and the pressure drop of the circular pipe electrode is measured for the constant flow rates under application of the voltages. The voltages are added in the peripheral direction. The director which is the average direction of the molecular of the liquid crystal is perpendicular to the flow direction. On the other hands, numerical analysis of the electric fields and the flow in the circular pipe electrode is conducted and the relations between the flow rate and the pressure are obtained for various electric field intensities, which almost agree with experimental results. The emphasized point of the present flow analysis is assuming that the viscosity of a liquid crystal mixture distributes in the flow field. Furthermore the pulse-wave voltages are added to the electrodes to control the pressure drop using the pulse width modulation. It is found that the pressure can be controlled using the pulse width modulation in the some range of the parameters.
A NEW DEVICE FOR THE FULL RHEOLOGICAL CHARACTERIZATION OF MAGNETO-RHEOLOGICAL FLUIDS
Authors: LAEUGER JOERG , WOLLNY KLAUS , STETTIN HEIKO , HUCK SIEGFRIED
Published: June 2005

A new magneto-rheology device (MRD) was constructed, which can be used in combination with a Physica MCR roational rheometer form Anton Paar. The MRD is build around a parallel-plate measuring geometry. Maximum magnetic flux densities of up to 1 Tesla in the air gap between the two plates are possible. The distribution of the magnetic flux density in the measuring gap has been evaluated with the help of a three-dimensional Hall sensor. The MRD system allows simultaneous software controlled setting of the magnetic field strength and the use of all possible rheological test modes of the rheometer. In the past mostly flow curves based on purely rotational measurements have been used to investigate the rheological behavior of MRFs giving only limited information. A measuring method is introduced, which is based on oscillatory measurements and thus allowing an exact determination of a substance's visco-elastic properties as a function of the magnetic field strength. In addition to structure investigations at various magnetic field strength with standard oscillatory strains sweeps an oscillation measurement with constant amplitude and constant frequency was performed while changing the magnetic field strength in a logarithmic ramp (magneto-sweep). On a typical MRF significant transition points are observed which distinguish different regions. These transitions can directly be correlated to corresponding changes in the material's structure resulting from the increase in the magnetic flux density.
GRAVITATIONAL AND MAGNETIC CONVECTION IN MAGNETIC FLUID
Authors: BOZHKO A. A. , PUTIN G. F.
Published: June 2005

Experiments were performed to examine the influence of external homogeneous magnetic field on ferrofluid convection in thin cylindrical layer heated from one wide sidewall and cooled from another. Gravitational and magnetic mechanisms of convection as well as the influence of gravitational sedimentation of particles and their aggregates on stability and structure of fluid flows are studied. The integral and local temperature sensors were used for measurement of heat transport across the layer. Visualization of flow patterns was provided by a temperature-sensitive liquid crystal sheet. The results indicate that with the help of a magnetic field it is possible to control the stability and the form of convection motions. Besides, the concentration gradients of solid phase can have material role to convection instability and heat transfer.
SUBSTITUTION OF MICRON BY NANOMETER SCALE POWDERS IN MAGNETORHEOLOGICAL FLUIDS
Authors: CHAUDHURI A. , WANG G. , WERELEY N. M. , TASOVKSI VASIL , RADHAKRISHNAN R.
Published: June 2005

The effects of substitution of micron size powder by nanometer size powder in magnetorheological (MR) fluids are investigated in this study. Three MR fluid samples containing iron powder with 45% weight fraction in a carrier fluid were made by Materials Modification Inc. The difference among these three fluids is size of the magnetic particles. The first MR fluid sample contained only micron size iron powder with 10μm particle size. In the second sample, 5% micron iron was substituted with nano powders having 30~40nm mean diameter, while the third sample had 37.5% micron powder and 7.5% nano powder. Rheological tests were conducted on the three samples using a parallel disk rheometer. Highest yield stress was observed in the second MR fluid sample containing 40% micron and 5% nano iron powder. By replacing only 5% micron iron powder with nanoparticles, we achieved substantial increment in yield stress. However, when nano powder content is increased to 7.5%, the yield stress decreases and is lower than that in the all micron MR fluid. Thus, by doping a reasonable percent of nano iron powder in the MR fluid, a substantial change in the rheological characteristics is obtainable. Further investigations of effects of nano iron powder in MR fluids for higher weight fraction MR fluids will be carried out in future.
HALF CAR MAGNETORHEOLOGICAL SUSPENSION SYSTEM ACCOUNTING FOR NONLINEARITY AND TIME DELAY
Authors: DONG X. M. , YU MIAO , HUANG S. L. , LI ZUSHU , CHEN W. M.
Published: June 2005

MR suspension systems have significant non-linearity and time-delay characteristics. For this reason, linear feedback control of an MR suspension has limited vibration control performance. To address this problem, a four DOF half car suspension model with two MR dampers was adopted. Having analyzed non-linearity and time-delay of the MR suspension, a Human-Simulation Intelligent Control (HSIC) law with three levels was designed. Simulation verified effects of HSIC in solving the problem of non-linearity and time-delay of MR dampers. In comparison, simulation of linear-quadratic gaussian (LQG) without considering the non-linearity and time-delay of MR suspension is also made. The simulation results show that the HSIC controller is faster than LQG controller under bump input and has better stability and accuracy, and it can achieve smaller acceleration peak value and root mean square (RMS) and better ride comfort compared with LQG controller under random input.
PECULIARITIES OF SHOWING CAPILLARY EFFECTS BY ELECTRORHEOLOGICAL FLUIDS
Authors: KOROBKO E. V. , GORODKIN R. G. , MARDOSEVICH M. I. , MARDOSEVICH E. I. , KOROBKO A. O.
Published: June 2005

Experimentally the filling of a single capillary-condenser in the transverse to the gradient of electrical field current was studied. ERF on the basis of polymethyloxane fluids or mineral oil that consist of activated particles of SiO 2 with the weight concentration 5-30% were observed. The dependence of position of meniscus, its crookedness and the height of near-wall layer on the tension of electrical influence and time were measured. The variants of usage of homogeneous and gradient on the axis of the capillary electrical fields were studied. In the experiments consolidation of the middle area of meniscus and lengthening of its near-wall area and also the change of the speed of its filling while the intensity of electrical influence increased was found.
BEHAVIOR OF MR FLUIDS AT HIGH VELOCITIES AND HIGH SHEAR RATES
Authors: GONCALVES F. D. , AHMADIAN M. , CARLSON J. D.
Published: June 2005

The objective of this work is to characterize the performance of MR fluid at high shear rates and high velocities. A slit-flow rheometer has been built which allows for high speed testing of MR fluid under varying field strengths. Fluid velocities range from 3.9 m/s to 27 m/s with resulting shear rates ranging from 0.23×105 s -1 to 1.6×105 s -1. In order to evaluate the performance of the fluid, the force required to drive the fluid through the slit is measured and force-velocity characteristics are generated. The zero-field viscosity is found and results indicate that shear thinning is still present even at these high shear rates. Two magnetic field strengths were considered for the field testing (50 kA/m and 100 kA/m). Results indicate that a yield stress is still being developed in the fluid. However, as fluid velocity increases, the yield stress being developed in the fluid decreases. This reduction in the yield stress could be attributed to the dwell time, or the amount of time the fluid spends in the presence of a magnetic field.
THE INFLUENCE OF FERROMAGNETIC PARTICLES COATING ON RHEOLOGICAL PROPERTIES OF MAGNETOELECTRORHEOLOGICAL FLUIDS (MERFS)
Authors: MEDVEDEVA E. V.
Published: June 2005

The influence of the type and concentration of activator (substance used to provide sensitivity of ferromagnetic particles to electric field) on the electrorheological (ER), magnetoelectrorheological (MER) and dielectric properties of MERFs have been investigated. Non-colloidal particles of -iron oxide or magnetite are used as a dispersed phase. An organic acid activator and two types of amine-based activators have been studied. MERFs with amine-based activators exhibit stronger ER effect. It has been found that the minima in the dependencies of dielectric constant on the activator concentration are strongly correlated with maxima in the correspondent dependencies of MER and ER effects.
ELECTRORHEOLOGICAL BEHAVIOR OF MECHANOCHEMICALLY ACTIVATED KAOLINITE/TITANIUM OXIDE COMPOSITE
Authors: WANG BAOXIANG , ZHAO XIAOPENG
Published: June 2005

By means of the combination of mechanochemical method and sol-gel technique the modified kaolinite/titanium oxide composite was prepared. The structure analyses XRD, EDS showed that composite was consisted of the mechanochemically activated kaolinite/ NaCl complex coating with titanium oxide. A distinct enhancement in the electrorheological effect under DC electric field was found by using such particles dispersed in silicone oil. The shear stresses of modified kaolinite/titanium oxide suspension were about 9.5 kPa at 4kV/mm, which are 11.5 times of that of pure kaolinite ERF and 2.2 times of that of kaolinite/ TiO 2 ERF reported previous respectively.
INFLUENCE OF PARTICLE SIZE ON THE RHEOLOGICAL PROPERTIES OF MAGNETORHEOLOGICAL SUSPENSIONS
Authors: TRENDLER A.-M. , BÖSE H.
Published: June 2005

Magnetorheological suspensions with different particle sizes including bimodal particle size distributions have been rheologically investigated. The results show a continuous decrease in the base viscosity without magnetic field when increasing the ratio of coarse to fine particles, which is in accordance with the observed trend of sedimentation stability of the samples. However, measurements of the shear stress with a rising magnetic flux density demonstrate higher values for MR suspensions with special mixtures of coarse and fine particles indicating a strengthening of the particle interactions in the magnetic field. The change of the viscoelastic properties of the MR suspensions in dependence on the field strength and shear load (amplitude) have been studied with oscillatory experiments. As expected, at low field strengths, the viscous behavior dominates and, at high field strengths, the elastic behavior, but differences in the crossover field strengths between the two regimes occur for the different particle size distributions. The shear load variation also shows differences between the various MR suspensions indicating the highest yield stress for the sample with only fine particles without magnetic field, but the lowest yield stress at moderate field strengths.
THE CONDUCTIVITY AND TEMPERATURE DEPENDENCE OF BATIO3 COATED- PAN BASED ELECTRORHEOLOGICAL FLUIDS
Authors: WEI J. H. , SHI J. , LIU Z. Y. , GUAN J. G. , YUAN R. Z.
Published: June 2005

Coated-PAn particles consisting of polyaniline(PAn) core and barium titanate ( BaTiO 3) shell were synthesized by modified sol-gel processing. The shear stress and current density of the suspensions of Coated-PAn particles and pure PAn particles in silicone oil with a 20vol% were investigated at different conductivity and environment temperature. The dielectric and the conductance behavior of coated PAn particles as a function of temperature we also investigated. The results showed that the ER effect of BaTiO 3 coated PAn particles was far stronger than that of pure polyaniline synthesized by the same method. Meanwhile, the BaTiO 3 coated-PAn particles also showed favorable temperature stability and low current loss at the high electric field, which is rather important for the ER fluids application.
MR FLUID OF LIQUID GALLIUM DISPERSING MAGNETIC PARTICLES
Authors: ITO RYOJI , DODBIBA GJERGJ , FUJITA TOYOHISA
Published: June 2005

The heat convection, which can be provided from a magneto-rheological (MR) fluid, is a useful process in converting heat from high to low temperature and vice versa. In this work, the property and preparation of liquid gallium-based MR fluid is presented. The prepared MR fluid disperses micron-sized iron or nicked metal powders in liquid gallium ( Ga ). In this experiment, supercooling of MR fluid was investigated in order to obtain the condition under which the liquid state can be kept below the melting point. Moreover, the viscosity and elasticity of the prepared MR liquid were measured as a function of magnetic flux density. Finally, it was demonstrated that liquid Ga is a useful base for preparing a new type MR fluid.
EVALUATIONS OF CLUSTER STRUCTURE AND MAGNETO-RHEOLOGY OF MR SUSPENSIONS
Authors: NISHIYAMA HIDEYA , KATAGIRI KAZUNARI , HAMADA KATSUHISA , KIKUCHI KAZUTO , HATA KATSUHIKO , PARK SANG-KYU , NAKANO MASAMI
Published: June 2005

In the present study, we sysnthesize two types of MR fluids with different particle shapes and sizes. The magnetic functions are evaluated circulatingly by the analysis of cluster formation, rheological properties in the applied magnetic field and damping characteristics in the MR damper, comparing with those of commercial MR fluids. Final objective is to provide the fundamental data for the development of newly advanced MR fluids. The main topics consist of geographycal cluster formation depending on particle shapes and sizes, relating to the apparent viscosity and yield stress with magnetic flux density and further equivalent damping coefficient of two newly sysnthesised MR fluids comparing with those of LORD MR fluid.
THE RESPONSE OF STARCH/GELATIN/GLYCERIN AQUEOUS ELECTRORHEOLOGICAL ELASTOMER TO APPLIED ELECTRIC FIELD
Authors: GAO LINGXIANG , ZHAO XIAOPENG
Published: June 2005

The aqueous ER elastomers, containing crude organic starch particles which dispersed in gelatin/glycerin/water matrix, were prepared with or without the applied DC electric field. The responses of the composite systems to the electric field were tested by the compression modulus and resistance of the elastomers. The result shows that they are enhanced and controlled evidently under an applied DC electric field. The strongest responses appear at 25% weight fraction of starch. In addition, the increment modulus of the elastomer increases with the strength of the applied field within 0.5~1.5 kV/mm, while after the field is stronger than 1.5 kV/mm it doesn't increase with field, appearing "saturation".
THE STRESS-STRAIN RELATIONSHIP AND THE DYNAMIC YIELD STRESS IN ELECTRORHEOLOGICAL FLUID UNDER A MODIFIED CONDUCTION MODEL
Authors: LUO CHUNRONG , TANG HONG , GAO XIANGYANG , YIN JIANBO , ZHAO XIAOPENG
Published: June 2005

By using a modified conduction model and the dipole approximation model respectively, we simulate the stress-strain curve and evaluate the dynamic yield stress through an ideal microstructure model of electrorheological fluid. The static yield strain is larger in our modified conduction model than in the dipole approximation model. Besides, the dynamic yield stress and static yield stress nearly linearly vary as volume fraction in the dipole model, while in our modified model they both exhibit a maximum at about volume fraction ϕ=0.45. Interpretation about these results is associated with the conduction effect and the inter-chain interactions.
MR FLUIDS AND DEVICES IN THE REAL WORLD
Authors: CARLSON J. DAVID
Published: June 2005

Magnetorheological (MR) fluids are now well established as one of the leading materials for use in controllable structures and systems. Commercial application of MR fluids, particularly in the automotive industry, has grown rapidly over the past few years. Today, MR fluid devices can be found in tens of thousands of vehicles. Experience in developing commercially successful MR fluids and devices has led to the creation of a series of figures-of-merit, design guidelines and empirical equations for describing MR fluids. Such experience-based guidelines have proven to be invaluable tools in all phases of MR fluid device development from initial concept feasibility to production engineering. These tools are easily integrated into design spreadsheets that enable the simultaneous optimization of MR fluid, device geometry, device size, device materials and electromagnet parameters.
MAGNETORHEOLOGICAL FLUID AND ELASTOMERIC LAG DAMPER FOR HELICOPTER STABILITY AUGMENTATION
Authors: HU WEI , WERELEY NORMAN M.
Published: June 2005

The feasibility of utilizing a composite magnetorheological fluid plus elastomeric (MRFE) damper is assessed. To emulate the loading conditions for a helicopter lag damper, the MRFE damper emulation was subjected to single frequency (lag/rev) and dual frequency (lag/rev and 1/rev) sinusoidal loading, and equivalent viscous damping was used to compare the MRFE damping characteristics with a conventional elastomeric damper. The preliminary MRFE damper showed nonlinear behavior: damping was reduced as displacement amplitude increased. Upon application of a magnetic field, the damping level was controlled according to a specific damping objective as a function of the excitation amplitude. Under dual frequency conditions, damping degradation at lag frequency due to 1/rev motion was also mitigated by magnetic field input to the MR damper.
DEVELOPMENT OF AN INTERACTIVE MR FLUID EXPERIMENT FOR SMART MATERIALS CURRICULA
Authors: BANNEROT R. , SONG G.
Published: June 2005

This paper presents the development of an interactive MR (Magneto-Rheological) fluid experiment. The hands-on experiment is developed to introduce MR fluids to students who are interested in this smart fluid. This apparatus is also used as a teaching tool for courses in smart materials. The experiment is designed to show students the basic operations of MR fluids and some common applications. This interactive experiment includes three devices with associated control buttons and all the devices are housed in a clear display case for easy visualization. 1) MR fluid morphing device, which clearly shows the morphing of MR material between fluid and semi-solid with the control of the electromagnet. 2) MR brake, which allow a user clearly feel the change of resistance level of the crank shaft with increasing of current to the electromagnets. 3) Vibration damping using MR fluid damper, which shows that the vibration of a platform induced by a rotating motor with an imbalanced mass can be suppressed by a simple MR fluid damper. This interactive experiment is fully autonomous and has been used in University of Houston. It has been demonstrated that it is an effective tool to assist student to learn MR fluids.
DEVELOPMENT OF HIGH-PERFORMANCE MR ACTUATOR AND ITS APPLICATION TO 2-D FORCE DISPLAY
Authors: YAMAGUCHI Y. , FURUSHO J. , KIMURA S. , KOYANAGI K.
Published: June 2005

Force display systems are a kind of robot systems, which share the space with people while they are working, and which directly touch and display force-senses to their users. For such a robot system, it is important to estimate safety quantitatively and to assure mechanically safety. The safety can be assured by using MR actuator because MR actuator is one of clutch type actuators. And, the features of MR actuator are very preferable to those of ER actuator and other clutch type actuators, to improve the performance of force display systems. In this study, we developed an MR actuator with low inertia, high torque/inertia ratio and high responsibility. Then, a 2-D force display system using the MR actuator was developed. The characteristics of the MR actuator that are low inertia, high torque/inertia ratio and high responsibility contribute to improve the performance of force display systems.
PRELIMINARY DESIGN PROCEDURE OF MR DAMPERS FOR CONTROLLING SEISMIC RESPONSE OF BUILDING STRUCTURES
Authors: LEE SANG-HYUN , MIN KYUNG-WON , LEE ROOJEE , LEE HO-GUEN , SUNG KUM-GIL , KIM DAE-KON
Published: June 2005

In this paper, a preliminary design procedure of magnetorheological (MR) dampers is developed for controlling building response induced by seismic excitation. Hysteretic biviscous model which is simple and can describe the hysteretic characteristics of MR damper, is used for parametric studies. The capacity of MR damper is determined as a portion of not the building weight but the lateral restoring force. A method is proposed for the optimal placement and number of MR dampers, and its effectiveness is verified by comparing it with the simplified sequential search algorithm. Numerical results indicate that capacity, number and placement can be reasonably determined using the proposed design procedure.
SUGGESTION OF THE MAGNET SOLIDIFICATION FLUID (MSF), AND APPLICATION TO A BASE-ISOLATION SYSTEM
Authors: SUGIMOTO NOBORU , KIYOTA TAKANORI , SASAKI TAKUMI
Published: June 2005

In this paper, we suggest the new intelligent fluid applying MR fluid, and new base-isolation system using that new intelligent fluid. At first, new intelligent fluid suggested in this paper as MSF (Magnet Solidification Fluid) consist of some magnetic fluid and special particles. The most remarkable characteristic of the MSF is that this fluid gives stable and optional yield sharing stress by gathering the properties of containing materials.

By the way, in the region where the earthquake often occurs, buildings and industrial equipments must be provided for earthquakes. Then, fuse property is considered as the most anticipative idea for base-isolation system at present. That is, base-isolation system holds an upper structure by stable holding force at usual condition or slight earthquake. On the other hand, when a severe earthquake occurs, it releases holding force and insulates transfer of excitation force of earthquake at the isolation layer of system by yielding relative displacement between ground and an upper structure. According to such idea, we developed new base-isolation system utilizing characteristic of MSF.
THE RESPONSE TIME OF A ROTOR SYSTEM WITH A DISK-TYPE MAGNETORHEOLOGICAL FLUID DAMPER
Authors: ZHU CHANGSHENG
Published: June 2005

The response time of a rotor system supported upon a disk-type magnetorheological fluid damper operating on shear mode is measured experimentally. The effects of rotating speed, step current and magnetic particle volume fraction, on the response time are dealt with. It is shown that the dynamic response can be described by first 10% response time and rapid response time. Generally, the first 10% response time and the rapid response time are in order of less than 0.1 second and 0.1~0.4 second. The magnetic field strength, magnetic particle volume fraction and power supply have a great effect on the response time. The response time in dropping step current is several times longer than that in applying step current. There is a zero initial delay time at either applying or dropping the current, which is caused by the magnetizing or de-magnetizing process.
OPTIMAL FUZZY CONTROL OF A SEMI-ACTIVE SUSPENSION OF A FULL-VEHICLE MODEL USING MR DAMPERS
Authors: WANG HAO , HU HAIYAN
Published: June 2005

MR (Magneto-Rheological) dampers have turned out to be a promising device for improving the ride comfort of ground vehicles. However, the current control algorithms for MR dampers, including on-off control and clipped-optimal control, are not sufficiently effective. This paper presents a fuzzy control strategy for an MR damper in order to determine the input voltage according to the desired restoring force. It then goes on using this new strategy to reduce the suspension vibration of a full-vehicle model equipped with 4 MR dampers, where the desired restoring forces are determined through the optimal control of suspension system. The numerical simulations indicate that the optimal fuzzy control can effectively reduce the suspension vibration of the full-vehicle model, especially the pitch angular acceleration and the roll angular acceleration of the sprung mass, and offers better ride comfort, running safety and handling stability than the clipped-optimal control. The design of the fuzzy controller is independent of the control system. Furthermore, fuzzy controller can also be extended to other applications of MR dampers, together with other control strategies.
VIBRATION CHARACTERISTICS OF THE DAMPER ELEMENT COMPOSED OF ANNULAR MAGNETS AND MAGNETIC FLUID
Authors: SUDO S. , NAKAGAWA A.
Published: June 2005

This paper is concerned with the development of a damper with excellent characteristics. The vibration characteristics of the damper element composed of two annular permanent magnets and magnetic fluid are studied experimentally using a vibration testing system. The vibration amplitude of the upper magnet-magnetic fluid system is measured with an optical displacement detector system. It was found that the element of two annular permanent magnets adsorbed magnetic fluid is very effective over the wide frequency range.
PAYLOAD/LAUNCHER VIBRATION ISOLATION: MR DAMPERS MODELING WITH FLUID COMPRESSIBILITY AND INERTIA EFFECTS THROUGH CONTINUITY AND MOMENTUM EQUATIONS
Authors: JEAN PIERRICK , OHAYON ROGER , LE BIHAN DOMINIQUE
Published: June 2005

During launching, a payload is submitted to large vibrations, which may damage it. To get rid of the problem, a solution would be to put an appropriate vibration isolator at the payload/launcher interface. Thus, a soft Isolating Payload Attach Fitting (IPAF) using Magneto-Rheological (MR) dampers is envisaged. In a pre-design phase for the launcher application, a preliminary study of the behaviour of a commercial MR damper (RD-1005-3) and its use in a 1-dof vibration isolator is carried out. In this paper, we report the MR damper behaviour analysis based on fluid and solid mechanics equations. In particular, we investigate chambers fluid compressibility and inertia effects. Then the damper model is used to evaluate the performance of a MR isolator in terms of equivalent transmissibility in passive mode and using skyhook control. The theoretical results will be soon compared to those from an experimental bench in construction.
EVALUATION OF DYNAMIC PERFORMANCE OF MAGENETO-RHEOLOGICAL DAMPER BY VIRTUAL PROTOTYPE TECHNOLOGY
Authors: HOU BAOLIN , WANG JIONAG
Published: June 2005

Numerical dynamic simulation of a full vehicle incorporating a magneto-rheological damper in the primary suspension is studied using the package ADAMS and SIMULINK. The full vehicle model is built under ADAMS. The interaction between the tire and the road profile is simulated using the ADAMS/TIRE capabilities. The UA tire model is used to model the dynamic characteristics of the tires. A 3-D road profile model is built based on the spatial power spectrum density of a random road profile. In order to model the dynamic characteristics of the primary suspension MR damper, a non-parametric model of an MR damper is proposed which can conveniently be incorporated into the vehicle dynamic model. Two kinds of control policies, a common skyhook and the so-called non-jerk skyhook, are adopted to control the current applied to the MR damper. The simulation results imply that either one of the two skyhook control policies can obtain a good compromise between so-called "soft damping" and "hard damping", and non-jerk skyhook control policy can curb some higher frequency components which are observed in the acceleration response of the chassis. This study demonstrates that virtual prototype technology is an effective approach for investigating the dynamic behavior of MR dampers for complex systems.
DESIGN AND TESTING OF A COMPACT MAGNETORHEOLOGICAL DAMPER FOR HIGH IMPULSIVE LOADS
Authors: FACEY WILLIAM B. , ROSENFELD NICHOLAS C. , CHOI YOUNG-TAI , WERELEY NORMAN M. , CHOI SEUNG BOK , CHEN PETER
Published: June 2005

Magnetorheological (MR) based semi-active dampers for the protection of sensitive devices against high shock and impact is examined from design considerations to characterization testing. Shock and impact dampers should be able to produce a high damping force at high velocities. However, a specification requiring high damping force generally causes an increase in the size of shock and impact dampers, which motivates the study of MR dampers to retrofit existing or conventional passive shock and impact dampers. A novel MR damper design was developed in this study for achieving both design goals: high force and compactness. The novel MR damper design increases the number of magnetically active volumes through which fluid to passes while minimizing damper length. Through FEM (Finite Element Method) analysis, the magnetic properties of the proposed design are investigated prior to actual fabrication. In addition to the unique magnetic circuit, other considerations stemming from the high pressures and velocities expected in this device are addressed. Characterization testing was performed up to 12 Hz with 1 inch sinusoidal stroke on a servo-hydraulic testing machine. These tests demonstrate that the MR damper is able to provide a high damping force at high velocity.
PERFORMANCE COMPARISON OF MR DAMPERS WITH THREE DIFFERENT WORKING MODES: SHEAR, FLOW AND MIXED MODE
Authors: SUNG KUM-GIL , CHOI SEUNG-BOK , LEE HO-GUEN , MIN KYUNG-WON , LEE SANG-HYUN
Published: June 2005

In this work, three different magneto-rheological(MR) dampers, which are applicable for vibration control of a multi-story structure, are devised and their performance characteristics are compared. As a first step, the schematic configurations of the shear, flow, and mixed mode MR dampers are described with design constraints. The analytical models to predict the field-dependent damping forces are derived for each type and their damping forces are evaluated. The field-dependent damping forces are compared in terms of the damping force magnitude and the mixed-mode type of MR damper is chosen as an optimal candidate for the vibration control of the multi-story structure. An appropriate size of the mixed mode MR damper is manufactured and its field-dependent damping characteristics are evaluated in time domain. In addition, the displacement vs. damping force cycles of the piston are observed at various field intensities.
STUDY ON POWER TRANSMISSION TECHNOLOGY BASED-ON MRF
Authors: TIAN LING , WANG YANYU
Published: June 2005

According to Bingham rheological model, the paper describes the technique of hydraulic power transmission based on the Magnetorheological fluid (MRF). As we all know, the MRF is an intelligent material, and it is used as the medium by which the power and signal can pass. Therefore, utilizing rheological behavior of MRF, the rheological state and viscosity of MRF can be directly modulated by electromagnetism field to control the speed, move direction and pressure of hydraulic system. We can gain an intermediate drive -control mode, which possesses many advantages such as: super stability, accurate precision, fine reliability, cheap cost and quick response and so on. It can overcome a series of disadvantages of the traditional hydraulic power transmission system. In addition, the paper introduces the operation principle of MRF power transmission, and researches the working performance and the fundamental factors that affect the properties of MRF by modeling and simulation. Finally, the paper explores theory and method of optimum design for MRF power transmission.
MAGNETIC SUPPORT OF MAGNETIC FLUID DROPLET AGAINST FLOW
Authors: YAMANE R. , SAKIYAMA N. , PARK M. K.
Published: June 2005

The magnetic droplet should be held in position against the flow of the blood for the magnetic drug targeting. In the present research, as the basis of this problem three types of experiments were conducted. In the first and the second experiments, a two-dimensional and a three-dimensional droplet are placed on the inclined flat plate and are supported by the magnetic force against the gravity. The maximum inclination for the droplet to flow down is measured. In the third experiment, a two-dimensional droplet is placed on the floor of the channel and is held in position by the magnetic force against the flow of the water. The droplet itself can be held at the position of the magnet, but, as the flow is faster, the spikes on the droplet move downstream with the water flow as if they rotate around the droplet.
NONDIMENSIONAL ANALYSIS OF ANNULAR DUCT FLOW IN MAGNETORHEOLOGICAL/ELECTRORHEOLOGICAL DAMPERS
Authors: YOO JIN-HYEONG , WERELEY NORMAN M.
Published: June 2005

Approximate analytical expressions describing MR/ER damper performance for an axisymmetric annular duct under the assumption of uniform field are presented. The key performance metric is the damping coefficient, which is the ratio of the equivalent viscous damping constant, Ceq, to the Newtonian viscous damping constant, C. To develop these approximations, a quadratic equation was used to approximate the center of the plug location in the annular duct. This equation simplified the calculation of the annular duct solution without resorting to numerical methods to solve the boundary value problem. Approximations for the damping coefficient are developed on this basis.
NONDIMENSIONAL QUASISTEADY ANALYSIS OF A MAGNETORHEOLOGICAL DASHPOT DAMPER
Authors: CHOI YOUNG-TAI , WERELEY NORMAN M.
Published: June 2005

This paper addresses nondimensional analysis of a magnetorheological (MR) dashpot damper. An MR dashpot damper consists of a loosely fitting piston within a hydraulic cylinder or reservoir of MR fluids. The fluid flow within such a damper presents both Poiseuille (flow mode or pressurized flow through the duct) and Couette (shear mode or shear flow due to relative motion between piston and hydraulic cylinder wall) simultaneously. Thus, an MR dashpot damper, which mixes both shear and flow modes of behavior, is called a mixed mode damper. In this study, a quasi-steady analysis of MR dashpot dampers was revisited based on the utilization of the Bingham-plastic constitutive model to assess performance metrics such as damping capacity. For the mixed mode MR damper, key physical quantities are derived: fluid velocity profile, shear stress profile, and damping coefficient. In addition, the plug thickness equation to characterize the relationship between the Bingham number and the plug thickness is constructed. Through computer simulation, damping characteristics of the mixed mode MR dashpot damper are evaluated and compared to the flow mode case.
DEVELOPMENT OF A 3-D REHABILITATION SYSTEM FOR UPPER LIMBS USING ER ACTUATORS IN A NEDO PROJECT
Authors: FURUSHO JUNJI , KOYANAGI KEN'ICHI , NAKANISHI KAZUHIKO , RYU USHIO , TAKENAKA SHIGEKAZU , INOUE AKIO , DOMEN KAZUHISA , MIYAKOSHI KOICHI
Published: June 2005

New training methods and exercises for upper limbs rehabilitation are made possible by application of robotics and virtual reality technology. The technologies can also make quantitative evaluations and enhance the qualitative effect of training. We have joined a project managed by NEDO (New Energy and Industrial Technology Development Organization as a semi–governmental organization under the Ministry of Economy, Trade and Industry of Japan) 5-year Project, "Rehabilitation System for the Upper Limbs and Lower Limbs", and developed a 3–DOF exercise machine for upper limbs (EMUL) using ER actuators. In this paper, we also present the development of software for motion exercise trainings and some results of clinical evaluation. Moreover, it is discussed how ER actuators ensure the mechanical safety.
PRESSURE CHARACTERISTICS OF ER DAMPER WITH DIFFERENT PISTON VELOCITIES
Authors: YAMAGUCHI HIROSHI , INOUE DAISUKE , SHIMADA KUNIO , SHUCHI SHIGEMITSU , NISHIYAMA HIDEYA
Published: June 2005

A basic experiment for the gap flow in a closed piston - cylinder system of ER fluid was carried out with regard to engineering application to dampers. The purpose of this study is to gain system characteristics and to elucidate flow behaviors of ER fluid in the piston–cylinder system; the model damper. Pressure, which is the system characteristic, was examined in the present study. The test fluid was a smectite ER fluid in silicone oil base of the 3wt% particle dispersion concentration. In the apparatus the piston moves in the vertical direction at a given speed. Theoretical formula of pressure difference is considered by the one-dimensional analysis of the ER flow in the gap of cylinder. It was shown that the response of the pressure was retarded with strong electric field. In comparison with the theoretical estimation and experimental value, the theoretical pressure difference was in good agreement with experimental data. For a sake of giving an insight to flow phenomena, visualization was also achieved using model Newtonian fluid in the piston-cylinder system, and shown that vorticity generated at the rear corner of the piston plays an important role for the pressure characteristic.
PRE-PROTOTYPE DESIGN OF ER/MR DEVICES USING COMPUTATIONAL FLUID DYNAMICS: UNSTEADY FLOW
Authors: BULLOUGH W. A. , ELLAM D. J. , ATKIN R. J.
Published: June 2005

A feasibility investigation into modelling ER/MR devices in transient operation using CFD is summarised. This particular study is one part of a project which has previously included examining 1D and 2D steady state flow, heat transfer, and field distributions using CFD. Though developed piecewise, these various CFD approaches can be integrated to allow a full pre-prototype assessment programme for almost any device conceived, in any mode or sequence of operation. Solutions which include translating boundary motion and inertial boundaries are introduced. In order to verify the CFD results, some new experimental works were carried out on a hydrodynamic bearing and clutch apparatus.
DESIGN PROGRAM IN GRAPHIC USER INTERFACE ENVIRONMENT FOR AUTOMOBILE ER DEVICES
Authors: LIM S. C. , PARK J. S. , SOHN J. W. , CHOI S. B.
Published: June 2005

This work presents a design and analysis program for vehicle devices utilizing an electrorheological (ER) fluid. The program is operated in graphic user interface (GUI) environment and the initial window is consisted of four subprogram modules which are related to ER shock absorber, ER seat damper, ER engine mount, and ER anti-lock brake system (ABS), respectively. In order to execute each module, both material properties and design parameters are to be chosen by the user. Then, the output display window shows the field-dependent performance characteristics to be considered as design criteria. In addition, control performances of the vehicle system equipped with ER devices are displayed in time and frequency domain. In order to demonstrate the effectiveness of the proposed program, ER shock absorber and ER ABS are designed and manufactured and their performance characteristics are evaluated.
ELECTRORHEOLOGICAL METHOD OF FIXATION OF COMPLICATED PIECEWORKS UNDER MECHANICAL TREATMENT
Authors: KOROBKO E. V.
Published: June 2005

The data of previous researchers on the structure formation of electro sensitive suspensions under the action of an external electric field and on the resulting changes in the mechanical parameters of the fluid (viscosity, plasticity, elasticity) were used to develop a method of damping in a special clutches, which were used for fixing complicated shape construction (blade), that surfaces are to undergo fine turning. As demonstrated, the use of a fluid, the structure of which responds to an electric field as a clutching layer, improves the technological characteristics of the product and increase its reliability.
A NEW ER FLUID BASED HAPTIC ACTUATOR SYSTEM FOR VIRTUAL REALITY
Authors: BÖSE H. , BAUMANN M. , MONKMAN G. J. , EGERSDÖRFER S. , TUNAYAR A. , FREIMUTH H. , ERMERT H. , KHALED W.
Published: June 2005

The concept and some steps in the development of a new actuator system which enables the haptic perception of mechanically inhomogeneous virtual objects are introduced. The system consists of a two-dimensional planar array of actuator elements containing an electrorheological (ER) fluid. When a user presses his fingers onto the surface of the actuator array, he perceives locally variable resistance forces generated by vertical pistons which slide in the ER fluid through the gaps between electrode pairs. The voltage in each actuator element can be individually controlled by a novel sophisticated switching technology based on optoelectric gallium arsenide elements. The haptic information which is represented at the actuator array can be transferred from a corresponding sensor system based on ultrasonic elastography. The combined sensor-actuator system may serve as a technology platform for various applications in virtual reality, like telemedicine where the information on the consistency of tissue of a real patient is detected by the sensor part and recorded by the actuator part at a remote location.
RESEARCH ON THE INFLUENCE OF SPRING STIFFNESS IN AN ER ISOLATOR
Authors: WANG JUAN , ZHANG SHAOHUA
Published: June 2005

In this paper, the problem of Electrorheological(ER) technology's application in the vibration isolation system is empirically studied. Based on the particular characteristics of the Electrorheological Fluids (ERF) tunable damping, a metal-spring ER isolator was designed and its working principle is mainly discussed. By theoretical analysis of its simplified physical model, the dynamic response of an ER isolator is frequency- and amplitude- dependent and sensitive to structural parameters. The controllable parameters here can be the system equivalent spring stiffness K and damping coefficient C of ERF. With experiment, the exertion of ER effect was controlled through the change of K and C. Consequently, the system dynamic stiffness, which is used to describe the dynamic properties of system isolation performance, can be changed obviously. According to the dynamic performance tests, the result confirmed that applying different electric field strength could change the dynamic peculiarity of the metal-spring ER isolator. The configuration design of the ER equipment, such as stiffness ratio of two fluid chambers and the size of the electric field, which are important factors for the tunable range of ER isolator.
PROGRESS OF PASSIVE-TYPE FORCE DISPLAY SYSTEM WITH ER FLUID DEVICES
Authors: KOYANAGI KEN'ICHI , FURUSHO JUNJI
Published: June 2005

Passive type systems are essentially safe, and expected that the system generating large force can be developed easily. We had developed ER fluid brakes and a 2-DOF (degrees of freedom) passive type force display system using ER brakes, and had made a presentation on it at ERMR2001. In this paper, we introduced progress of our study from ERMR2001.
DEVELOPMENT OF A NEW LINEAR GUIDE SYSTEM WITH ELECTRICALLY CONTROLLABLE DAMPER USING LIQUID CRYSTALLINE POLYMER
Authors: ZHANG JIAN , FURUSHO JUNJI , UDA MASAKI , YAMAGUCHI TOSHIAKI
Published: June 2005

Rolling element linear guide systems are widely used in the industrial machines such as machine tools for the advantages of high-precision, high-rigidity and low-friction. However, the principal disadvantage of such systems is their inferior damping characteristics, which cause the degradation of working efficiency and quality in certain circumstances, especially where vibration is to be expected. To meet the demands of increasing speed together with higher precision, a rolling element linear guide system with electrically controllable additional damping element (ER damper) is developed in this study. Liquid crystalline polymer, a sort of homogeneous ER fluid, is used because this fluid is thought be suitable for industrial positioning systems for the characteristics of high out-put, nearly-linearity, no sedimentation and no particle-crushing. Some basic experiments were carried out and the good characteristics were ascertained.
ELECTRICALLY CONTROLLED EXTENSION EFFECTS IN SOFT SOLIDS
Authors: BULLOGH WILLIAM A. , SCARPA FABRIZIO
Published: June 2005

Some recent work has involved the incorporation of solids into soft matrices in order to acquire an improvement in their mechanical and damping performances [R. S. Lakes et al, Nature, Vol. 410, 565-567]. Other more general analytical works have dealt with the application of electrical and magnetic fields to susceptible materials, usually involving a relatively hard fluid filled sandwich. In the present note the effect of soaking soft porous solids in magneto or electro-rheological fluids (MRF or EFG respectively) on their stiffness is announced. In this case the pores or cells of the carrier soft solid hold polarisable solids. When the resulting composites are excited by a magnetic (MRF) or electric field (ERF) the stiffness of the sections thus produced are increased (in a passive sense) under loading. Unique results are obtained when auxetic MR soft soaked foams are excited – significant magnetostrictive effects are measured.