Types Of Magnetorheological Fluid Research Articles

Vibration response of small-scaled FG-CNTRC sandwich plates with MR fluid core supported by Kerr elastic substance

The current work is a continuation of the previous work by proposing the refined zigzag theory (RZT) for the vibration response of the micro sandwich plate. The face sheets of this structure are magnetostrictive and reinforced with single-walled carbon nanotubes (SWCNT) in four different patterns (FG-AV, FG-O, FG-X, and UD) following the rule of mixtures (ROM). The core material contains magnetorheological (MR) fluid which can work as a damper under a magnetic field. The micro sandwich plate is supported by an elastic substance utilizing the Kerr model. Additionally, the modified couple stress theory (MCST) is employed to predict size effects, and the magnetostrictive material (MsM) properties are considered viscoelastic based on the Kelvin–Voigt model. The Hamilton principle is applied to derive the size-dependent equations of motion. Then, an analytical solution is presented to evaluate the efficacies of various parameters including the volume fractions and the functional arrangement of carbon nanotubes, the geometrical aspect ratio of the system, the magnetic field intensity, the type of MR fluid, the small-scale parameter, damping coefficients of the system, and the elastic medium. Consequently, 29% increase in the dimensionless frequency for [Formula: see text] is indicated when the small scale changes from [Formula: see text] to [Formula: see text]. This research can be contributed to the design and optimization of systems that use micro sandwich plates, addressing practical and essential engineering considerations.

Research on vertical vibration characteristics of rolling mill based on magnetorheological fluid damper absorber

The study of rolling mill vibration theory has always been a scientific frontier in the field of rolling forming, which is very important to the quality of sheet metal and the stable operation of equipment. A magnetorheological fluid damper absorber is designed to control the nonlinear vertical vibration of rolling mill. Considering the fractional order and delay factors in the control effect of magnetorheological fluid, the fractional order delay nonlinear vertical vibration equation with magnetorheological damping damper is established. The amplitude-frequency characteristic equations of the main resonance and sub-resonance of the system are solved by multi-scale method. The effects of stiffness coefficient, damping coefficient, time delay, fractional order, and exciting force on the vibration characteristics of roller system are analyzed by comparing the amplitude-frequency curve, time-domain curve and phase diagram. The transition set of the steady-state response of the system and the corresponding bifurcation topology structure are analyzed by using the singularity theory. A magnetorheological fluid damper absorber platform of rolling mill is built based on modern test technology, and the influence laws of the control threshold, control current, type of magnetorheological fluid and reduction rate are analyzed. The correctness and feasibility of the design of the magnetorheological fluid damper absorber are verified, which provided theoretical guidance and technical support for the nonlinear dynamic analysis and stability control of the rolling mill.

Rheological modelling of carbonyl-iron particles (CIP) paraffin oil-based magneto-rheological fluids

New types of magneto-rheological fluids are increasingly being developed lately, but there is a dearth of information on the performance of commonly used rheological models for emerging MRFs such as carbonyl-iron particles (CIP) paraffin-oil-based MRF. This work aims to investigate the performance of some rheological models for application in predicting shear stress and yield strength in an emerging MRF suitable for flow-mode applications. CIP, low viscosity paraffin oil, and lithium grease were used as magnetic particles, carrier fluid, and additives, respectively, to prepare the MRF. Based on different mixing proportions determined with the Taguchi method of experimental design, sixteen samples were prepared following a standard procedure. For each sample, the values of viscosity and shear stress were determined using a viscometer and rheometer, respectively, with an incorporated self-developed magnetic device. By fitting the data and using the multi-objective nonlinear programming solver in Micro-soft Excel to determine optimum parameters for each model, the Bingham Model, Herschel–Buckley Model, Casson Model, Cross models, and Power-law were used to model the experimental data. Predicted shear stress values and yield strength were then analyzed using ANOVA at a 5% confidence level. The relative errors were determined using RMSE, Mean Square Error, and Mean Absolute Error. There was a significant variation in the predicted outcomes of all the models. Overall, all the models gave relatively acceptable results. However, the Herschel-Buckley model gave the best results, while the Casson model gave the worst results, judging by their values of errors. It is shown that the Herschel-Buckley model should be best used for predicting the rheological characteristics of CIP and paraffin oil-based MRF.

Study on the tribological and rheological properties of magnetorheological fluids based on different base oils

Abstract Base oil has great influence on the tribological and rheological properties of magnetorheological fluid. In this paper, four types of magnetorheological fluid are prepared respectively by silicone oil, mineral oil, synthetic oil (PAO) and castor oil, and their tribological and rheological properties are investigated. Firstly, the viscosity of the magnetorheological fluid is measured by a viscometer. Then the friction coefficient and wear scar diameter of the magnetorheological fluid is measured by a four ball friction testing machine. Next, the sedimentation rate of the magnetorheological fluids is calculated by the observation method. Finally, the shear yield stress of the magnetorheological fluid is measured by a rheometer. By analyzing the experimental data, it is concluded that the magnetorheological fluid prepared by white mineral oil and castor oil has excellent wear resistance. The magnetorheological fluid prepared by castor oil has better sedimentation stability and higher shear yield stress. Consequently, the magnetorheological fluid prepared by castor oil has better comprehensive properties.

New bell plate controlled multi-inertia channel magnetorheological fluid mount wide frequency vibration isolation control study

This paper introduces a novel type of magnetorheological fluid (MRF) mount designed to achieve wide-frequency vibration isolation for engines. While previous studies have explored vibration isolation using hydraulic mounts, there has been limited research on achieving wideband isolation with MRF mounts. Consequently, this paper presents an innovative MRF mount structure and investigates wideband vibration isolation control for engines. Initially, experiments with a multi-channel MRF damper validate the switchable operation of controllable channels. A novel controllable multi-inertia channel MRF mount system is proposed, aligning the working mode of controllable inertia channels with that of the MRF damper. The lumped parameter method is employed to derive the mathematical model of the MRF mount, and its high and low-frequency dynamic characteristics are thoroughly examined. Subsequently, a real-time multi-island genetic algorithm-optimized controller is developed to investigate wideband vibration isolation within the MRF mount system. The findings indicate that: (1) The MRF mount demonstrates adjustable low-frequency dynamic stiffness and loss angle within the frequency range of f = 0–50 Hz. In the frequency range of f = 50–100 Hz, the mount achieves its lowest dynamic stiffness value, effectively addressing the issue of high-frequency stiffening. (2) The real-time multi-island genetic optimized controller exhibits superior vibration isolation performance compared to traditional sky-hook control and hybrid sky-hook control methods, achieving optimal vibration isolation for the mount.

Development of Durability Test Device for Magnetorheological Fluids with Two Types of Rotors and Their Long-Term Torque Characteristics

Magnetorheological fluids (MRFs) are composites of micron-sized and/or nano-sized Fe particles and nonmagnetic oils, and their rheological properties change with changes in the magnetic field. To distinguish between material and mechanical deterioration, we developed a durability test system without the influence of mechanical sealing and bearing on the MRFs. We used a set of rotors and stators to create a V-shaped MRF layer. However, the test device produces a constant magnetic field with a permanent magnet instead of an electromagnetic coil to make a compact design and cannot be tested under various dynamic magnetic inputs. Therefore, we developed a durability test system with an electric magnet to create a variable magnetic input and two sets of rotors, and compared their magnetic properties and the results of the durability tests. From the findings, the measured torque for the parallel plate case was lower than the predicted value. In contrast, the V-shaped disk exhibits a higher torque than the estimated values. Durability tests for the two types of MRFs were conducted. The torque variation for the nano MRF is significantly smaller for both the parallel and V-shaped plates. In addition, the duration of both MRFs for the V-shaped plate was much shorter than that for the parallel plate.

Analysis on Flow and Temperature Field of High-Power Magnetorheological Fluid Transmission Device

Aiming to solve the problem of high-power magnetorheological fluid transmission heat dissipation, a new type of magnetorheological fluid drive disk is designed. The characteristics of the flow field and temperature field of high power MR fluid transmission devices are analyzed. Meanwhile, the influence of factors, such as rotating speed, inlet velocity, inlet position, diameter and number of magnetic columns, on the flow field are also investigated. Furthermore, the distribution characteristics of the ultimate slip power and the transient temperature field are obtained. The experimental platform of an MR fluid transmission device was established, and the torque transfer performance and heat dissipation performance were tested. The experimental results show that the device has good heat dissipation performance and can transfer high-power torque.

Molecular Dynamics Simulations and Experimental Studies of the Microstructure and Mechanical Properties of a Silicone Oil/Functionalized Ionic Liquid-Based Magnetorheological Fluid.

Magnetorheological (MR) fluids are smart materials that show enormous potential in vibration control, mechanical engineering, etc. However, the effects of the solid-liquid interface strength and the interaction strength between carrier liquid molecules on the mechanical properties and sedimentation stability of MR fluids have always been unresolved issues. This work presents a new type of MR fluid that has a novel carrier liquid, i.e., silicone oil (SO) mixed with a hydroxyl-functionalized ionic liquid (IL-OH). An all-atomic Fe/SO/IL-OH interface model for studying the relationship between mechanical properties and interface strength and intermolecular interactions is established. On the basis of simulation results and theoretical analyses, the mechanical properties and sedimentation stability of the SO/IL-OH-based MR fluids are thoroughly investigated by experiments. The results show that functional ionic liquids significantly improve the mechanical properties and sedimentation stability of MR fluids. These results are essentially attributed to the stronger solid-liquid interface strength, van der Waals forces, and hydrogen bonds between the silicone oil and the functional ionic liquid. The explicit results not only help elucidate the numerous phenomena involved in the research process for MR fluids at the atomic scale but also provide insightful information on the fabrication of high-performance MR fluids.

Visualizing rheological mechanism of magnetorheological fluids

In order to study the rheological properties of aqueous magnetorheological fluids (MRFs) from microscopic point of view, an experimental observation method based on fluorescence confocal laser scanning microscope is proposed to clearly shown the chain shape of magnetic particles. Firstly, the mathematical model of the magnetic particles is established in a magnetic field using the magnetic dipole theory, and the MRFs with different volume fraction and different magnetic fields are investigated. Furthermore, an aqueous MRFs experiment is prepared, in which the magnetic particles are combined with Alexa 488 fluorescent probe. On this basis, an observation method is innovatively developed using two-dimensional and three-dimensional image analysis by the fluorescence confocal microscope. The rheological mechanism of the aqueous MRFs is investigated using four different types of MRFs in an external magnetic field. The analysis results demonstrate that the simulation and experimental rheological properties of the MRFs are consistent with the magnetic dipole theory. Moreover, the proposed method is able to real-time observe the rheological process of the MRFs with a very high resolution, which ensures the correctness of the analysis result of the rheological mechanism.

High performance magnetorheological fluids: very high magnetization FeCo-Fe3O4 nanoclusters in a ferrofluid carrier.

High magnetization Fe3O4/OA-FeCo/Al2O3 nanocomposite magnetic clusters have been obtained using a modified oil-in-water miniemulsion method. These nanocomposite clusters dispersed in a ferrofluid carrier result in a magnetorheological fluid with improved characteristics. The magnetic clusters have a magnetic core consisting of a mixture of magnetite nanoparticles of about 6 nm average size, stabilized with oleic acid (Fe3O4/OA) and FeCo/Al2O3 particles of about 50 nm average size, compactly packed in the form of spherical clusters with a diameter distribution in the range 100-300 nm and a hydrophilic coating of sodium lauryl sulphate surfactant. The surface chemical composition of the Fe3O4/OA-FeCo/Al2O3 clusters investigated by XPS indicates the presence of the Co2+ and Co3+ oxidation states of cobalt and the components of Fe2+ and Fe3+ characteristic to both an enhanced oxidation state at the surface of the FeCo particles and to the presence of magnetic nanoparticles of spinel structure which are decorating the supporting FeCo. This specific decorating morphology is also indicated by TEM images. Advanced characterization of the Fe3O4/OA-FeCo/Al2O3 magnetic clusters has been performed using Mössbauer spectroscopy and magnetization measurements at various temperatures between 6 K and 200 K. The unexpected formation of Co ferrite decorating nanoparticles was supported by Mössbauer spectroscopy. The dispersion of magnetic clusters in the ferrofluid carrier highly influences the flow properties in the absence of the field (shear thinning for low and moderate shear rates) and especially in applied magnetic field, when significant magnetoviscous effect and shear thinning was observed for the whole range of shear rate values. Detailed analysis of the magnetorheological behavior of the nanocomposite magnetic clusters dispersed in a ferrofluid carrier evidence significantly higher normalized dynamic yield stress values in comparison with the magnetite nanocluster suspensions of the same mass concentration, a promising result for this new type of nanocomposite magnetorheological fluid.

Study on the rheological properties and polishing properties of SiO2@CI composite particle for sapphire wafer

To study the rheological properties and polishing performance of magnetorheological fluids (MRFs) prepared with SiO2@carbonyl iron (CI) core-shell particles, SiO2@CI core-shell particles with different shell thicknesses were synthesized by an improved Stöber method controlling the amount of tetraethyl orthosilicate (TEOS). Then, four types of MRFs which dispersed with core-shell particles with thin shells, core-shell particles with thick shells, SiO2 particles, or carbonyl iron were prepared for sapphire polishing. The results show that the rheological properties of MRF based on thicker shell SiO2@CI are enhanced compared to those of MRFs prepared by dispersing abrasive and CI. Comparing with other MRFs, sapphire can obtain better surface quality when using thicker shell SiO2@CI. The MRF fabricated by SiO2@CI core-shell particles can increase the contact area between the abrasive and the workpiece and enhance the contact stress, which improves the solid-phase reaction rate and mechanical removal efficiency of silica and sapphire, thereby improve the polishing efficiency.

Vibration analysis of magnetorheological fluid circular sandwich plates with magnetostrictive facesheets exposed to monotonic magnetic field located on visco-Pasternak substrate

Magnetorheological fluids are materials that react to the applied magnetic field and are converted to the quasi-solid phase from the liquid one. Their applications in control and suppression of vibration have interested scientists nowadays. The present study is focused on the vibrational behavior of magnetorheological fluid circular plates that are embedded with magnetostrictive face layers. Magnetostrictive materials are also playing an important role in vibration control and are used widely in smart devices such as sensors and actuators. The structure is exposed to the transverse monotonic magnetic field and is located on the visco-Pasternak elastic substrate. Using Hamilton’s principle and based on classical plate theory, the motion equations and boundary conditions are extracted, and the generalized differential quadrature method is selected to solve them. Three different types of magnetorheological fluids are considered, and their effect on the results is discussed. The outcomes of this study can be used to design more capable and precise dampers, smart structures, and devices.

Material Characterization of MR Fluid on Performance of MRF Based Brake

This study focuses on material characterizations of magneto-rheological fluid (MRF) on performance characteristics of MRF based brake (in short MRB). In this study, three different types of MRF (low viscosity, medium viscosity and high viscosity) are considered for several types of MRB. Firstly, the optimization solution of the MRB design is proposed based on Bingham plastic model of the MRFs and finite element analysis of MRB magnetic circuit. From optimal design of the MRBs with different MRFs, performance characteristics of the MRBs such as braking torque, off-state torque and power consumption are evaluated. In addition, the compact size of MRB using different MRFs is also studied. Finally, some observations and guidance on selection of MRFs in MRB design are summarized.

Influence of additives on the synthesis of carbonyl iron suspension on rheological and sedimentation properties of magnetorheological (MR) fluids

Magnetorheological (MR) fluid is one of the major constituent element in structural suspensions and damping characteristic in automobile applications. The major drawback is sedimentation in MR fluids, in the present study an attempt has been done to address the sedimentation issue. The synthesis and characterization of MR fluid in combination with clay and additives leads to improvement in sedimentation rate. The four different types of MR fluid were prepared in combination with clay, friction reducing agent and poly-alpha-olefin (PAO) oil naming as MRFp-1, 2, 3 and 4 as tabulated in table 1. The cost effective MRFp-3 shows better result compared to commercially available MR fluid with respect to off/on state shear stress, viscosity. It is also observed that in-house prepared MRFp-3 has better sedimentation than commercially available (LORD-132DG) up to 700 h.

Transient Magnetic Model of Magnetorheological Damper and Its Experimental Verification

The present paper deals with the transient magnetic model of the magnetorheological (MR) damper and its experimental verification. The response time of MR damper affects the quality of semi-active control of this damper. The lower the response time, the higher the system efficiency. The most important part of the response time of the MR damper is the response time of magnetic field of the MR damper which can be determined by transient magnetic model. The transient magnetic model was created by the software Ansys Electromagnetics 17.1 as 2D axisymmetric and verified by measurement of magnetic field in the gap of MR damper piston. The maximum difference between the model and the experiment was 28 %. The response time depends on the electric current in the coil of MR damper. The transient magnetic model was used for determination of influence of MR fluid type, material of cover and material of magnetic circuit on the response time of magnetic field of MR damper. The type of MR fluid has a significant influence on the response time. The lower the mass concentration of ferromagnetic particles, the lower the response time of magnetic field. A material selection of magnetic circuit is always a trade-off between the response time and the maximum magnetic flux density (dynamic force range) in the gap of the MR damper. According to the verified transient magnetic model, it is possible to find a suitable material of magnetic circuit for specific application (response time).

Response time of magnetorheological fluid–based haptic device

Haptics is a tactile feedback technology that recreates the sense of touch to the user by applying forces, vibrations, or motions. Haptic devices should have a high performance in their output characteristics, for example, low friction in off-state, constant force with constant input, and quick response with dynamic input, in order to generate a sufficient sense of touch to human skin. We have focused on rapid response of magnetorheological fluid and decided to use it as the working material of the haptic device. There are several types of magnetorheological fluids available, and the effects of the different types of magnetorheological fluids on the response time of the haptic device have not yet been reported. The objective of this study is to experimentally investigate the response time of a magnetorheological fluid–based haptic device with two different types of magnetorheological fluids. We originally developed a single-disc type magnetorheological fluid–based haptic device, and its response time was investigated with two types of magnetorheological fluids. We set three experimental conditions with regard to the fluid gap and rotational velocity. We modeled the haptic devices as a classic first-order lag system, and the time constant of this system was assumed to be representative of the response time of the haptic device. According to the results, the response times of a sample tend to be smaller with the narrow gap (0.1 mm), whereas those of the other tend to be smaller with the large gap (0.5 mm). In addition, the response time is non-dimensioned and investigated with Mason number.

Selection of Materials in Designing Magnetorheological Brake

The braking system is among the most significant active safety systems in a vehicle application for preventing injuries and property damage. Whether for light or heavy vehicles, brakes are no longer a small issue whereas it becomes a crucial problem to maintain the safety and to avoid the unpredictable cases especially on the road. Advanced technology in automotive industry has produced a new coming design of Magnetorheological (MR) brake which a field change is triggered off by changing the current in the coils exciting the magnetic field. MR fluid is one of the members of smart material which applicable usage to achieve the standard of rotary high speed similar as the existing brake disc in hydraulic system. A new MR brake disc was proposed using the squeeze mode rather than only conventional mode at the upper and lower rotating rotor. Parameters that have been considered are the types of MR fluid, selection of magnetic material, non-magnetic material and coil configurations. Then a finite elements analysis was performed to analyse the result of magnetic circuit and magnetic field strength within the MR brake configuration. MRF-140CG has been selected to represent the fluid to enhance the maximum magnetic flux density. The results showed that AISI 1020 and Stainless Steel 316 meet the requirement of material selection of magnetic and non-magnetic. Indirectly, yield stress has been significant increase when the magnetic field strength rises at certain value. Therefore, intention on design innovation of MR brake is useful to efficient control by upgrading function of those parameters which has been presented.

Optimal design of magnetorheological fluid-based dampers for front-loaded washing machines

In this research, a magnetorheological fluid-based damper to attenuate vibration due to unbalanced laundry mass from a front-loaded washing machine is proposed and optimally designed with experimental validation. First, rigid vibration mode of the washing machine due to an unbalanced mass is analyzed, and an optimal positioning of the suppression system for the washing machine is figured out. In order to attenuate vibration from the washing machine, several configurations of magnetorheological damper are proposed considering available space and the required damping force of the system. Based on the Bingham rheological model of magnetorheological fluid, damping force of the proposed magnetorheological dampers is then derived. An optimal design problem for the proposed magnetorheological damper is constructed considering its zero-field friction force and the maximum damping force. The optimization objective is to minimize the zero-field friction force of the magnetorheological damper while the maximum value of damping force is kept being greater than a required value. An optimization procedure based on finite element analysis integrated with an optimization tool is employed to obtain optimal geometric dimensions of the magnetorheological dampers featuring different types of magnetorheological fluid. Optimal solutions of the magnetorheological dampers are then presented and the optimized damper is figured out. In addition, performance characteristics of the optimized magnetorheological damper are presented and discussed.

재질과 자기장 세기가 자기유변유체의 마찰 특성에 미치는 영향

Magnetorheological (MR) fluid belongs to the group of smart materials. In MR fluid, iron particles in base oil form chains in the direction of the applied magnetic field, thus resulting in a variation in the stiffness and damping characteristics of the fluid. Research is being carried out on controlling the stiffness and damping characteristics as well as the tribological characteristics of the MR fluid. In this study, the friction characteristics of MR fluid have been evaluated using three types of materials and magnetic fields of different strengths. The coefficients of friction of the three types of MR fluid are measured, and the relationship between the coefficient of friction and the strength of the applied magnetic field is obtained.

Nanofinishing of freeform surfaces of prosthetic knee joint implant

The freeform complex surfaces have become an inevitable part of many components to perform specific functions. Many of these components require nanometer surface roughness to meet specific requirements in their application domain. Therefore, finishing operation as a final operation is necessary for such components. A magnetorheological fluid-based finishing tool is developed for finishing knee joint implant, which has complex freeform surfaces. Different types of magnetorheological fluids and various finishing steps are proposed to reduce finishing time. Surface characteristics of the knee joint implant are studied using a surface roughness measuring instrument and atomic force microscopy before and after finishing. A significant reduction in surface roughness (the best final surface roughness value obtained = 28 nm) is observed on the component after finishing. The surface roughness obtained on different surfaces is well within the values recommended in the ASTM standard for total knee joint prosthesis.