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Magnetorheological fluid

About: Magnetorheological fluid is a research topic. Over the lifetime, 8538 publications have been published within this topic receiving 131502 citations. The topic is also known as: MRF & MR fluid.


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Journal ArticleDOI
TL;DR: In this article, semiactive controllers based on backstepping and quantitative feedback theory techniques are proposed and their performances are compared with each other on the problem of vibration control in a structure with an MR damper.
Abstract: Magnetorheological (MR) dampers have been widely studied and employed to solve the vibration problem in structures such as buildings and bridges. It is known that MR dampers can generate high damping forces with low-energy requirements and low-cost productions. However, the complex dynamics that characterize MR dampers make difficult the control design to achieve the vibration reduction goals in an efficient manner. In this paper, semiactive controllers based on the backstepping and quantitative feedback theory techniques are proposed and their performances are compared with each other on the problem of vibration control in a structure with an MR damper. They are applied to a large-scale three-story building with an MR damper at its first floor subject to seismic motions. The performance of the proposed controllers is experimentally evaluated by means of real-time hybrid testing scheme that accounts for time delays and actuator dynamics, allowing for the test of velocity-dependent devices. Copyright © 2009 John Wiley & Sons, Ltd.

90 citations

Journal ArticleDOI
TL;DR: In this article, the influence of ferromagnetic particle content and particle arrangement in relation to an external magnetic field was investigated, and it was found that the structure of a fabricated MRE depends on the viscosity of the matrix before curing and the flux density of the applied magnetic field.
Abstract: Smart composites based on carbonyl-iron particles in a polyurethane matrix, known as magnetorheological elastomers (MREs), were manufactured and studied. The influence of ferromagnetic particle content and particle arrangement in relation to an external magnetic field was investigated. Several different elastomers with different stiffnesses were used as matrices. It was found that the structure of a fabricated MRE depends on the viscosity of the matrix before curing and the flux density of the applied magnetic field. Two different magnetic field strengths were used: 0.1 and 0.3 T. The amount of carbonyl iron particles was varied from 1.5 to 33.0 vol%. Scanning electron microscopy technique was used to observe MRE microstructure. The particles’ orientation and their arrangement were also investigated by vibrating sample magnetometer. A correlation was found between MRE microstructure and magnetic properties. Compression tests on cylindrical samples in the presence and absence of a magnetic field showed that a magnetic field increased the stiffness of the material. Additionally the rheological properties of MREs were tested in a magnetic field. It was found that the amount of ferromagnetic particles and their arrangement have a significant influence on the rheological properties of MREs. The highest relative change of storage modulus under 200 mT magnetic field, equal to 282%, was recorded for samples with 11.5 vol% of particles.

89 citations

Journal ArticleDOI
TL;DR: In this paper, the interaction between two particles made of an isotropic linearly polarizable magnetic material and embedded in an elastomer matrix is studied, and an interpolation formula for the resistance of the elastic matrix to the field-induced particle displacements is proposed.
Abstract: The interaction between two particles made of an isotropic linearly polarizable magnetic material and embedded in an elastomer matrix is studied. In this case, when an external field is imposed, the magnetic attraction of the particles, contrary to point dipoles, is almost wraparound. The exact solution of the magnetic problem in the linear polarization case, although existing, is not practical; to circumvent its use, an interpolation formula is proposed. One more interpolation expression is developed for the resistance of the elastic matrix to the field-induced particle displacements. Minimization of the total energy of the pair reveals its configurational bistability in a certain field range. One of the possible equilibrium states corresponds to the particles dwelling at a distance, the other—to their collapse in a tight dimer. This mesoscopic bistability causes magnetomechanical hysteresis which has important implications for the macroscopic behavior of magnetorheological elastomers.

89 citations

Journal ArticleDOI
TL;DR: In this paper, the field-dependent dynamic flexural rigidity of a simply supported sandwich beam with a soft core composed of a magnetorheological elastomer (MRE) part and non-MRE parts is studied.
Abstract: The field-dependent dynamic flexural rigidity of a simply supported sandwich beam with a soft core composed of a magnetorheological elastomer (MRE) part and non-MRE parts is studied in this paper. The skins of the sandwich beam are nonconductive such that there are no magnetoelastic loads applied to the skins during vibration. The orientation of the chain-like structures inside the MRE part is perpendicular to the skins such that the MRE part operates in shear mode. Due to such a configuration, the dynamic flexural rigidity of the sandwich beam can be controlled by applied magnetic fields due to the field-dependent shear modulus of the MRE part. Based on the Hamilton principle, a dynamic model of the proposed sandwich beam is developed. A simply supported beam excited by a vertical force, distributed uniformly in a narrow region around the center of the beam is simulated. The anti-resonant frequencies are found to change with the shear modulus of the MRE part up to 40%, while the resonant frequencies change only slightly. Although MRE is an extremely soft material with a zero-field shear modulus about 0.4 MPa, the results from the current research indicate that the sandwich configuration can well utilize the controllable properties of MRE to realize applicable semi-active devices with controllable stiffness.

89 citations

Journal ArticleDOI
12 Mar 2007
TL;DR: A novel exoskeleton mechanical power transmission system was designed, utilizing rapid prototype parts, to transmit resistive forces to the user's fingertips, and a first iteration force feedback glove was developed and tested on human subjects for overall usability.
Abstract: Magnetorheological fluid (MRF) is a smart material that has the property of changing its viscosity when exposed to a magnetic field. By placing this fluid into a sealed cylinder with an electromagnet piston as a core, a controllable resistance motion dampener can be created. A novel exoskeleton mechanical power transmission system was designed, utilizing rapid prototype parts, to transmit these resistive forces to the user's fingertips. A first iteration force feedback glove was developed and tested on human subjects for overall usability. The eventual goal of the system is to provide an alternative force producing system for exercises and rehabilitation. The entire system is lightweight, low power, and easily portable

89 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
2023283
2022678
2021419
2020512
2019652