scispace - formally typeset
Search or ask a question
Topic

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.


Papers
More filters
Journal ArticleDOI
TL;DR: The ensemble of results suggests that "chaining" and "clustering" processes are also happening inside the gel and are responsible for the rheological behavior, provided they are happening on a smaller length scale (long chains and clusters are hindered).
Abstract: Swollen physical magnetorheological (MR) gels were obtained by self-assembling of triblock copolymers containing dispersed soft magnetic particles. The transient rheological responses of these systems were investigated experimentally. Upon sudden application of a homogeneous magnetic field step change, the storage modulus of MR gels continued to increase with time. Such increase trend of the storage modulus could be expressed by a double-exponential function with two distinct modes, a fast and a slow one. The result was compared with the transient rheological response of equivalent MR fluids (paraffin oil without copolymer) and a MR elastomer (PDMS) and interpreted as the consequence of strong rearrangement of the original particle network under magnetic field. Similar to the structure evolution of MR fluids, the ensemble of results suggests that "chaining" and "clustering" processes are also happening inside the gel and are responsible for the rheological behavior, provided they are happening on a smaller length scale (long chains and clusters are hindered). We show that response times of several minutes are typical for the slow response of MR gels. The characteristic time t(2) for the slow process is significantly dependent on the magnetic flux density, the matrix viscoelastic property, particle volume fraction, and sample's initial particle distribution. In order to validate our results, the role of dynamic strain history was clarified. We show that, in the linear viscoelastic region, the particle rearrangement of MR gels was not hindered or accelerated by the dynamic strain history.

64 citations

Journal ArticleDOI
TL;DR: In this article, a hybrid magnetorheological fluid elastomeric (MRFE) damper is investigated for adjustable or programmable lag mode damping in helicopters, so that damping requirements can be varied as a function of different flight conditions.
Abstract: A laboratory demonstration of a hybrid magnetorheological fluid?elastomeric (MRFE) damper is investigated for adjustable or programmable lag mode damping in helicopters, so that damping requirements can be varied as a function of different flight conditions. The laboratory demonstration of this hybrid MRFE lag damper consists of a double lap shear elastomeric damper in parallel with two magnetorheological (MR) flow mode dampers. This is compared to a damper where only elastomeric materials are implemented, i.e., a double lap shear specimen. The relationship between the output force and the quasi-steady harmonic displacement input to a flow mode MR damper is exploited, where the output force can be adjusted as a function of applied magnetic field. Equivalent viscous damping is used to compare the damping characteristics of the hybrid damper to a conventional elastomeric damper under steady-state sinusoidal displacement excitation. To demonstrate feasibility, a hybrid MRFE damper test setup is designed, and single frequency (lag frequency or rotor in-plane bending frequency) and dual frequency (lag frequency and rotor frequency) tests are conducted under different magnetic fields. The hybrid MRFE damper exhibits amplitude-dependent damping behavior. However, with application of a magnetic field, the damping level is controlled to a specific damping level objective as a function of displacement amplitude. Similarly, under dual frequency conditions, damping degradation at the lag frequency, because of lag motion at the rotor frequency, can also be recovered by increasing magnetic field. A time-domain analysis is developed to study the nonlinear dynamic behavior of the hybrid MRFE damper. Using rate-dependent elasto-slides, the amplitude-dependent behavior of the hybrid MRFE damper is accurately reconstructed using both constant and current-dependent (i.e.?controllable) parameters. The analysis is physically motivated and can be applied to the elastomer and MR fluid damper components separately.

64 citations

Book
08 Nov 2012
TL;DR: In this paper, the authors describe a suspension system for passenger vehicles and a brake system for tracked and railway vehicles, which is used for Vibration and impact control in heavy vehicles.
Abstract: Magnetorheological (MR) Fluid Physical Properties Potential Applications Control Strategies Semi-Active Control PID Control LQ Control Sliding Mode Control Hysteretic Behaviors of MR Fluid Preisach Hysteresis Model Identification Polynomial Hysteresis Model Identification Some Final Thoughts MR Suspension System for Passenger Vehicles Optimal Design Damping Force Control Full-Vehicle Test Some Final Thoughts MR Suspension System for Tracked and Railway Vehicles Tracked Vehicles Railway Vehicles Some Final Thoughts MR Applications for Vibration and Impact Control MR Engine Mount MR Impact Damper Some Final Thoughts MR Brake System Bidirectional MR Brake Torsional MR Brake Some Final Thoughts MR Applications for Heavy Vehicles MR Fan Clutch MR Seat Damper Some Final Thoughts Haptic Applications for Vehicles Multifunctional MR Control Knob MR Haptic Cue Accelerator Some Final Thoughts Index References appear at the end of each chapter.

63 citations

Journal ArticleDOI
TL;DR: Spot polishing tests were performed on a variety of optical glasses and ceramics over a period of nearly three weeks with no signs of MR fluid degradation or corrosion, and stable material removal rates and smooth surfaces inside spots were obtained.
Abstract: We report on magnetorheological finishing (MRF) spotting experiments performed on glasses and ceramics using a zirconia-coated carbonyl-iron (CI)-particle-based magnetorheological (MR) fluid. The zirconia-coated magnetic CI particles were prepared via sol-gel synthesis in kilogram quantities. The coating layer was ~50-100 nm thick, faceted in surface structure, and well adhered. Coated particles showed long-term stability against aqueous corrosion. “Free” nanocrystalline zirconia polishing abrasives were cogenerated in the coating process, resulting in an abrasive-charged powder for MRF. A viable MR fluid was prepared simply by adding water. Spot polishing tests were performed on a variety of optical glasses and ceramics over a period of nearly three weeks with no signs of MR fluid degradation or corrosion. Stable material removal rates and smooth surfaces inside spots were obtained.

63 citations


Network Information
Related Topics (5)
Finite element method
178.6K papers, 3M citations
82% related
Control theory
299.6K papers, 3.1M citations
78% related
Ultimate tensile strength
129.2K papers, 2.1M citations
78% related
Nonlinear system
208.1K papers, 4M citations
77% related
Fracture mechanics
58.3K papers, 1.3M citations
77% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
2023283
2022678
2021419
2020512
2019652