Showing papers on "Magnetorheological fluid published in 2022"
TL;DR: In this article , the influence of temperature on the rheological characteristics of the MR gel sample is systematically investigated and an oscillatory shear test is used to investigate the impact of temperature and magnetic field on the modulus of the sample.
Abstract: Magnetorheological (MR) gel is a new generation of MR material, which can overcome disadvantages attaching MR fluid such as sedimentation. MR gel is formed by the soft magnetic particle suspension in the gel‐like matrix and its rheological properties are mainly controlled by the following two factors, i.e., magnetic field and temperature. Herein, MR gel based on polyurethane gel with a 60% weight fraction of carbonyl iron is prepared. The influence of temperature on the rheological characteristics of the MR gel sample is systematically investigated. Oscillatory shear test is used to investigate the impact of temperature on the modulus of the sample. It is observed that temperature has a significant effect on the viscoelastic properties of MR gel. The hysteresis responses activated by harmonic strain signal with frequencies of 0.1, 5, and 15 Hz and amplitude of 10% and 50% under five temperature levels are measured and employed to analyze the viscous and elastic properties of MR gel and the viscoelastic–plastic model is employed to capture the nonlinear hysteresis characteristics. From the analysis results, the viscoelastic–plastic model can predict the hysteresis properties of MR gel accuracy under various temperatures.
59 citations
TL;DR: In this paper , a double cup-shaped gap magnetorheological (MR) clutch with three smart gels was designed by using a magneto/mechanical finite element method model, which was numerical calculated by COMSOL Multiphysics software.
Abstract: Abstract This work describes the magnetic analysis of an innovative double cup-shaped gap magnetorheological (MR) clutch featuring with three smart MR gels. Four kinds of Halbach array is used to excite the MR gel. The apparatus is designed by using a magneto/mechanical finite element method model, which is numerical calculated by COMSOL Multiphysics software. After describing the configuration, the transmittable torque in the designed MR clutch is derived based on the Bingham-Plastic field-dependent constitutive model of the MR gel. Considering the viscosity in the model building, such as the shear yield stress, which also various with change of magnetic flux density. The magnetic flux density distribution, the shear yield stress distribution, the dynamic viscosity distribution and the shear stress distribution inside the MR gel are obtained and carefully studied. Furthermore, the chain layer of internal cylindrical part, external cylindrical part, internal disc part and external disc part with lowest shear stress are found to calculate the transmission torque and slip torque. Then, the structure of the prototype is optimized based on multi-physics analysis. Finally, the optimal MR clutch is developed and the magneto-static torque is tested with detail analysis.
39 citations
TL;DR: In this paper , an endovascular catheterization robotic system (ECRS) was developed to improve collaborative operation and haptic force feedback, which generally depend on the flexible operability and the accurate force feedback of a robotic system.
Abstract: Robot-assisted technology is often used to perform endovascular catheterization surgeries, which generally depend on the flexible operability and the accurate force feedback of a robotic system. In this paper, an endovascular catheterization robotic system (ECRS) was developed to improve collaborative operation and haptic force feedback. A couple of operating handles were designed to maximize the use of the natural operations of surgeons on the master side, which is a flexible and ergonomic device. A magnetically controlled haptic force feedback structure is proposed based on hydrogel and solid magnetorheological (MR) fluid to offer a sense of haptic feedback to operators; this has potential influence on the field of force feedback. In addition, a unique tremor-reduction structure is introduced to enhance operating safety. Tracking performance experiments and in vitro experiments were conducted to evaluate the performance of the developed ECRS. According to these experimental results, the average translation-tracking error is 0.94 mm, and the average error of rotation is 0.89 degrees. Moreover, in vitro experiments demonstrated that haptic feedback has the advantage of reducing workload and shortening surgery completion time. The developed ECRS also has the benefits of inspiring other researchers to study collaborative robots and magnetically controlled feedback.
21 citations
TL;DR: In this paper , an integral magnetorheological damper (IMRD) is proposed to combine the elastic support and the squeeze film as a whole, where both magnitude and direction of oil film force are adjustable.
20 citations
01 Feb 2022
TL;DR: In this article , the magnetic polarities of microparticles in the resulting structure can be controlled via a permanent magnet structure which is designed and added into the printing system to effectively deliver the magnetic composites ink with a high viscosity, a rotating needle is utilized to induce the microscale Weissenberg effect and help ejecting the polymer solution.
Abstract: Soft magnetic composites have been orderly deposited using an advanced four-dimensional electrohydrodynamic printing process to build deformable actuators that have favorable attributes in fast response, untethered control, and harmless human-machine interactions under low-strength magnetic fields. To effectively deliver the magnetic composites ink with a high viscosity, a rotating needle is utilized to induce the microscale Weissenberg effect (MWE) and help ejecting the polymer solution. The magnetic polarities of microparticles in the resulting structure can be controlled via a permanent magnet structure which is designed and added into the printing system. The main process parameters have been investigated for obtaining optimal options of the motor rotational speed (2000 rpm), electrostatic field strength (2.0 kV), and the ratio (0.732) of the needle diameter to nozzle diameter. Prototype actuators with different magnetization orientations and profiles have been designed and tested, including magnetically powered electrical switches and bionic soft robots to emulate the operations of inchworms and dragonflies. As such, this printing process offers a facile and effective path to fabricate soft magnetic composites toward potential applications.
19 citations
TL;DR: In this paper , ultra-soft hybrid MREs (≈1-10 kPa stiffness) are conceptualized combining experimental and computational approaches, and the results reveal that the magneto-mechanical performance can be optimized by selecting an adequate mixing ratio between particles.
Abstract: Abstract Recent advances in magnetorheological elastomers (MREs) have posed the question on whether the combination of both soft- and hard-magnetic particles may open new routes to design versatile multifunctional actuators. Here, we conceptualise ultra-soft hybrid MREs (≈1–10 kPa stiffness) combining experimental and computational approaches. First, a comprehensive experimental characterisation is performed. The results unravel that the magneto-mechanical performance of hybrid MREs can be optimised by selecting an adequate mixing ratio between particles. Then, a multi-physics computational framework provides insights into the synergistic magneto-mechanical interactions at the microscale. Soft particles amplify the magnetisation and hard particles contribute to torsional actuation. Our numerical results suggest that the effective response of hybrid MREs emerges from these intricate interactions. Overall, we uncover exciting possibilities to push the frontiers of MRE solutions. These are demonstrated by simulating a bimorph beam that provides actuation flexibility either enhancing mechanical bending or material stiffening, depending on the magnetic stimulation.
19 citations
TL;DR: In this paper , a magneto-active solid-liquid state transformable millirobot (named MRF-Robot) made from a magnetorheological fluid (MRF) was proposed.
Abstract: Magnetically actuated soft millirobots (magneto-robot) capable of accomplishing on-demand tasks in a remote-control manner using noninvasive magnetic fields are of great interest in biomedical settings. However, the solid magneto-robots are usually restricted by the limited deformability due to the predesigned shape, while the liquid magneto-robots are capable of in situ shape reconfiguration but limited by the low stiffness and geometric instability due to the fluidity. Herein, we propose a magneto-active solid-liquid state transformable millirobot (named MRF-Robot) made from a magnetorheological fluid (MRF). The MRF-Robot can transform freely and rapidly between the Newtonian fluid in the liquid state upon a weak magnetic field (∼0 mT) and the Bingham plasticity in the solid state upon a strong magnetic field (∼100 mT). The MRF-Robot in the liquid state can realize diverse behaviors of large deformation, smooth navigation, in situ splitting, merging, and gradient pulling actuated by a weak magnetic field with a high gradient. The MRF-Robot in the solid state is distinguished for the controllable locomotion with reconfigured shapes and versatile object manipulations (including pull, push, and rotate the objects) driven by a strong magnetic field with a high gradient. Moreover, the MRF-Robot could continuously maneuver to accomplish diverse tasks in the comprehensive scenes and achieve liquid-drug delivery, thrombus clearance, and fluid-flow blockage in the phantom vascular model under magnetic actuation.
18 citations
TL;DR: In this article , a novel adaptive parameter identification method was proposed for a model consisting of an estimated model, a hysteresis observer, and adaptive algorithms, whose parameters captured the MR elastomer (MRE) characteristics well at different frequencies, amplitudes, and magnetic field strengths.
18 citations
TL;DR: In this paper, a novel adaptive parameter identification method is proposed for a model consisting of three components: an estimated model, a hysteresis observer, and adaptive algorithms, which is characterized by fast convergence and simple calculations that facilitate the design of vibration control systems with uncertain parameters and hysteretic state.
18 citations
TL;DR: In this article , a unified modeling framework for hard and soft magnetorheological elastomers is presented, including the response of the s-MREs as a limiting case when the dissipation is set to zero, where the model is dual in the sense of a partial Legendre-Fenchel transform of the magnetic part.
17 citations
TL;DR: In this article , a hybrid slot-entry journal bearing system (SEJBs) operating under misaligned journal conditions with bearing surface irregularities was investigated and the numerically simulated result revealed that due to journal misalignment conditions, the fluid film thickness is reduced, whereas, the value of fluid film damping coefficient and frictional torque gets increased.
TL;DR: In this article , the authors provide an overview of the constitutive models of magnetorheological fluids and the applications of these models in MR device modeling, including quasi-static modeling, dynamic modeling, and finite-element modeling, along with a brief coverage of the constituents and rheological properties.
TL;DR: In this article , an innovative seat suspension installed with variable stiffness and variable damping (VSVD) rotary magnetorheological (MR) dampers was designed and prototyped for the suspension, making the suspension's stiffness and damping controllable.
TL;DR: In this article , the trochoidal toolpaths for polishing the surface of a biomaterial: Duplex stainless steel (DSS) via the magnetorheological fluid assisted finishing (MFAF) process are presented.
TL;DR: In this paper, a novel compact rotary magneto-rheological (MR) damper with variable damping and stiffness has been proposed and analyzed, where the controllable storage modulus in pre-yield region of MR fluid is used to achieve magnetic field dependent stiffness.
TL;DR: A review of magnetorheological fluids can be found in this article , where the authors present a review of literature that introduces the properties and applications of magnetic fluids (MRFs).
Abstract: This paper presents a review of literature that introduces the properties and applications of Magnetorheological fluids(MRFs). first, magnetic particles (iron or cobalt), base fluids(oil (mineral-synthetic) or water), and how to prepare magnetorheological fluids are discussed. Then, in the continuation of this research, considering that magnetorheological fluids are smart and soft liquids, the methods of stability and properties (viscosity, hysteresis loop, Shear yield stress, etc) Of these magnetorheological fluids are discussed. Due to the different properties of Magnetorheological fluids, the behavior of these fluids in different states is discussed. These intelligent fluids change their properties when exposed to an external magnetic field. The most important and obvious feature of magnetorheological fluids is their reversibility from liquid to semi-solid state or vice versa in the Presence or the absence of a magnetic field in a fraction of a second. This change in state and properties is known as the magnetorheological effect. This effect depends on various factors, such as the concentration of magnetic particles, the distribution of magnetic particles, the strength of the magnetic field, additives, and so on. The low magnetic effect and instability of magnetorheological fluids are the most important problems against their widespread use in modern industries. According to research, carbonyl iron particles are the most promising particles for the dispersed phase in MRF. The choice of carbonyl iron particles contributes to their high saturation magnetism, relatively low cost, low coercion, and widespread availability. Finally, according to the different properties and behaviors of these fluids, different applications of magnetorheological fluids are discussed. MRF-based control systems are increasingly used in engineering applications such as rheological magnetic electrolytes in batteries, anti-lock braking systems, magnetic clutches, vibrating dampers, shock absorbers, control valves, and various types of vibrating dampers. One of the newest applications of magnetic fluids is the magneto-rheological electrolyte. The use of MRFs in batteries introduces a new class of magnetic field-sensitive electrolytes that has the potential to increase impact resistance, safety, thermal conductivity, and energy storage in electronic devices through reversible active switching electrolyte mechanical properties. • Introduces the properties and applications of magnetorheological fluids (MRFs) • Magnetorheological fluids are smart and soft liquids. • Viscoelastic properties of MRFs are changed when they are exposed to a magnetic field. • Different applications of magnetorheological fluids are discussed.
TL;DR: In this article , a metamaterial MRE isolator with controllable vibration bandgaps was designed and prototyped, and the mechanism of the formation of vibration bands was analyzed theoretically using the method of mass-spring model.
01 Mar 2022-Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology
TL;DR: In this article, a novel high-efficiency magnetorheological polishing process, which employs Halbach array as magnetic field excitation to improve the processing efficiency, is presented.
Abstract: Magnetorheological polishing is a potential process for the low-damage manufacture of optics, semiconductors, and related devices. However, due to magnetic materials’ size and magnetic field strength limitations, a high-efficiency material removal rate can hardly be achieved in practical application. This work presents a novel high-efficiency magnetorheological polishing process, which employs Halbach array as magnetic field excitation to improve the processing efficiency. The Halbach array provides a large-area, high-intensity magnetic field, which is verified by finite element simulation and experiments. The force analysis of carbonyl iron particles in the magnetic field revealed the distribution of polishing pressure and polishing marks. The polishing performance of the process as well as the distribution of polishing pressure and polishing marks were investigated by polishing experiments. The effects of process parameters on the removal rate and surface roughness have also been systematically investigated. The novel magnetorheological polishing process can achieve 3.8 times material removal rate compared with the previous process. In the polishing processes of fused silica, the surface roughness reduced from 1979.154 nm to 0.544 nm in 60 minutes. To sum up, Halbach array could significantly improve the efficiency of magnetorheological polishing while preserving polishing quality.
TL;DR: In this article , three different MFI values such as 0.34, 0.36, and 0.40 Tesla were chosen for finishing on Stainless Steel 316L (SS 316L).
Abstract: Abstract In Rotational Magnetorheological Abrasive Flow Finishing (R-MRAFF) process, Magnetic Field Intensity (MFI) is the primary factor for the formation of ferrous chains which is responsible for finishing. Changing the pole distance between magnets to achieve a difference in MFI values will alter the strength of the ferrous chains. In this study, three different MFI values such as 0.34, 0.36, and 0.40 Tesla were chosen for finishing on Stainless Steel 316L (SS 316L). Surface wettability, bio-corrosion, and hemocompatibility studies were conducted to investigate the in-vitro behavior of SS 316L. The wettability of the implants changed from hydrophobic (100.92°) to hydrophilic (83.452°) surface as the MFI value increased. Bio-corrosion studies revealed improved corrosion resistance for R-MRAFF process finished samples, with the corrosion rate reduced from 3.693 to 0.967 μ m year −1 . Hemocompatibility of SS 316L was improved with reduced platelet adhesion when compared to the pristine sample.
TL;DR: In this article , the authors presented an alternative solution based on hard-magnetic elastomers to provide stiffening responses that can be sustained along time without the need of keeping the external magnetic field on.
Abstract: Abstract Magnetorheological elastomers (MREs) mechanically respond to external magnetic stimuli by changing their mechanical properties and/or changing their shape. Recent studies have shown the great potential of MREs when manufactured with an extremely soft matrix and soft-magnetic particles. Under the application of an external magnetic field, such MREs present significant mechanical stiffening, and when the magnetic field is off, they show a softer response, being these alternative states fully reversible. Although soft-magnetic particles are suitable for their high magnetic susceptibility, they require the magnetic actuation to remain constant in order to achieve the magneto-mechanical stiffening. Here, we present an alternative solution based on hard-magnetic MREs to provide stiffening responses that can be sustained along time without the need of keeping the external magnetic field on. To this end, we manufacture novel extremely soft hard-magnetic MREs (stiffness in the order of 1 kPa) and characterise them under magneto-mechanical shear and confined magnetic expansion deformation modes, providing a comparison framework with the soft-magnetic counterparts. The extremely soft nature of the matrix allows for easily activating the magneto-mechanical couplings under external magnetic actuation. In this regard, we provide a novel approach by setting the magnetic actuation below the fully magnetic saturating field. In addition, free deformation tests provide hints on the microstructural transmission of torques from the hard-magnetic particles to the viscoelastic matrix, resulting in macroscopic geometrical effects and intricate shape-morphing phenomena.
01 Mar 2022-Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology
TL;DR: In this article , a novel high-efficiency magnetorheological polishing process, which employs Halbach array as magnetic field excitation to improve the processing efficiency, is presented.
Abstract: Magnetorheological polishing is a potential process for the low-damage manufacture of optics, semiconductors, and related devices. However, due to magnetic materials’ size and magnetic field strength limitations, a high-efficiency material removal rate can hardly be achieved in practical application. This work presents a novel high-efficiency magnetorheological polishing process, which employs Halbach array as magnetic field excitation to improve the processing efficiency. The Halbach array provides a large-area, high-intensity magnetic field, which is verified by finite element simulation and experiments. The force analysis of carbonyl iron particles in the magnetic field revealed the distribution of polishing pressure and polishing marks. The polishing performance of the process as well as the distribution of polishing pressure and polishing marks were investigated by polishing experiments. The effects of process parameters on the removal rate and surface roughness have also been systematically investigated. The novel magnetorheological polishing process can achieve 3.8 times material removal rate compared with the previous process. In the polishing processes of fused silica, the surface roughness reduced from 1979.154 nm to 0.544 nm in 60 min. To sum up, Halbach array could significantly improve the efficiency of magnetorheological polishing while preserving polishing quality. • A novel high efficiency magnetorheological polishing process excited by Halbach Array magnetic field is proposed. • The Halbach Array excites a high field strength and gradient magnetic field to form a large area polishing pad, which greatly improves the polishing efficiency. • Volume removal rate of this process is greatly improved, up to 3.8 times than previous study. • The proposed novel MRP can ensure surface quality together with polishing efficiency.
TL;DR: In this paper , a single-input programmable pseudo negative stiffness (PNS) scheme is proposed to control the vibration of the stay cable more practically and efficiently, and the simulation of dynamic response of stay cable shows the superiority of programmable control scheme.
TL;DR: In this article , an efficient non-Newtonian fluid polishing method for zirconia ceramics based on the weak magnetorheological strengthening thickening effect was proposed.
TL;DR: In this paper , a novel compact rotary magneto-rheological (MR) damper with variable damping and stiffness has been proposed and analyzed, where the controllable storage modulus in pre-yield region of MR fluid is used to achieve magnetic field dependent stiffness.
TL;DR: In this article , a 15-story shear building where the MR damper is attached to the tuned mass dampers (TMD) to generate active control force of TMD on the rooftop of the structure is investigated.
TL;DR: In this paper , the static and dynamic performances of sandwich plates with magnetorheological elastomer (MRE) core are investigated, in which the MRE core includes two copper wire layers, two inner metal layers, and one MRE layer.
Abstract: This paper investigates the static and dynamic performances of sandwich plates with magnetorheological elastomer (MRE) core, in which the MRE core includes two copper wire layers, two inner metal layers, and one MRE layer. First, based on the complex modulus method, the Jolly theory and the pre-defined magnetic coefficients, the dynamic moduli, and loss factors of MRE are assumed as a function of magnetic induction intensity. Furthermore, a theoretical model of the MRE sandwich plates (MRESPs) is proposed, which considers the internal magnetic field excitation and four types of panel materials, namely fiber-reinforced polymer (FRP), fiber-reinforced polymer with carbon nanotubes (CNT-FRP), metal and fiber-metal hybrid (FMH) panels. After the deformation and energy equations are derived to solve the static bearing stiffness, dynamic stiffness, and damping parameters, some literature results are employed to provide the initial validation of the model developed. Subsequently, four MRESP specimens with the FRP, CNT-FRP, metal, and FMH panels are fabricated and measured to further verify the model as well as to evaluate the mechanical performance. The influence of critical geometric and material parameters related to MRE on static and dynamic properties is also discussed to summarize some practical conclusions for engineering applications.
TL;DR: In this article , a rotary electrorheological (ER)-fluid brake is used to engage the highly backdrivable unit to the high force unit, and the end effector driven by a mini motor is connected to the brake rotor.
Abstract: Robots designed to interact physically with humans are typically characterized by low impedance and low output force, but in many circumstances, high force is needed. Integrated to a high-torque velocity source, antagonistic designs of electrorheological (ER)-fluid or magnetorheological (MR)-fluid clutches enabled a range of achievable impedances for rotational uses. This letter presents an alternative novel concept of linear actuator which uses a rotary ER-fluid brake to engage the highly backdrivable unit to the high force unit. The end effector driven by a mini motor is connected to the brake rotor. Since the brake rotation allows the relative translation between the endpoint and the high-force actuator, the mechanical impedance can be modulated by controlling the brake friction through the applied voltage. The ER-fluid brake using multiple concentric cylinders for high torque-to-inertia ratio was characterized experimentally. The macro-mini linear actuator with an intrinsic failsafe can be applied for active body weight support systems requiring antigravity high force.
TL;DR: In this paper , a hybrid magnetorheological material is prepared by DIW 3D printing technology, which is composed of magnetorsheological fluid and magnetorshield elastomer.
Abstract: A new hybrid magnetorheological material is prepared by DIW 3D printing technology, which is composed of magnetorheological fluid and magnetorheological elastomer. It does not only exhibit high magnetorheological effect of magnetorheological fluid, but also shows high mechanical stability of magnetorheological elastomer. The maxima absolute and relative magnetorheological effect of hybrid magnetorheological material are about 11.1 MPa and 7474%, which are simultaneously improved to be 2.9 times and 7.8 times comparing to single magnetorheological elastomer. Furthermore, the hybrid magnetorheological material is evaluated for application in soft robotic grippers. It shows larger clamping force (7.0 × 10−3 N) and faster response rate (ca.2.0s) comparing to other actuators. The work provides a new method to prepare hybrid magnetorheological material with high performance for various applications.
TL;DR: The MR damper is a sophisticated application of a semi-active device that reduces vibration efficiently in both on and off modes due to its control capabilities as discussed by the authors , which can create a high damping force while consuming very little power, responding quickly and flexibly, and being simple to build.
TL;DR: In this paper , progress of medical applications of magnetorheological fluid in the last two decades are systematically reviewed, mainly focused on six categories: lower limb prosthesis, exoskeleton, orthosis, rehabilitation device, haptic master, and tactile display.
Abstract: Abstract Magnetorheological (MR) fluid, whose rheological properties can be changed reversibly by applied magnetic field, offers superior capabilities and opportunities since its invention. The most crucial feature of MR fluid is its controllable and continuous yield stress. Taking this advantage, MR fluid is gaining popularity in various medical applications to meet their force/torque requirements. In this review article, progress of medical applications of MR fluid in the last two decades are systematically reviewed, mainly focused on six categories: lower limb prosthesis, exoskeleton, orthosis, rehabilitation device, haptic master, and tactile display. With MR fluid, natural and stable limb motions in lower limb prostheses, exoskeletons, and orthoses, flexible muscle trainings in rehabilitation devices, and high transparency and resolution haptic feedback can be realized. Relevant discussions and future perspectives are also provided.