Magneto Mechanical Properties of Iron Based MR Fluids

Premalatha, S. Elizabeth; Chokkalingam, Ramesh Babu; Mahendran, M.

doi:10.5923/j.ajps.20120204.01

Cited by 74 publications

(20 citation statements)

References 24 publications

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“…Here, we present an athermal, magnetically addressable shape‐memory polymer composite, produced by dispersing droplets of a commercial magneto‐rheological fluid in a crosslinked poly(dimethylsiloxane) (PDMS) matrix, shown schematically in Figure a. Magneto‐rheological fluids are able to undergo a substantial change at the millisecond timescale when subjected to a magnetic field, with mechanical properties such as viscosity, shear modulus, and yield stress increasing by up to six orders of magnitude . By encasing the magneto‐rheological fluid in an elastomeric matrix, we are able to manufacture a soft elastic composite with exceptional magneto‐mechanical properties.…”

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confidence: 99%

Magnetically Addressable Shape‐Memory and Stiffening in a Composite Elastomer

et al. 2019

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With a specific stimulus, shape‐memory materials can assume a temporary shape and subsequently recover their original shape, a functionality that renders them relevant for applications in fields such as biomedicine, aerospace, and wearable electronics. Shape‐memory in polymers and composites is usually achieved by exploiting a thermal transition to program a temporary shape and subsequently recover the original shape. This may be problematic for heat‐sensitive environments, and when rapid and uniform heating is required. In this work, a soft magnetic shape‐memory composite is produced by encasing liquid droplets of magneto‐rheological fluid into a poly(dimethylsiloxane) matrix. Under the influence of a magnetic field, this material undergoes an exceptional stiffening transition, with an almost 30‐fold increase in shear modulus. Exploiting this transition, fast and fully reversible magnetic shape‐memory is demonstrated in three ways, by embossing, by simple shear, and by unconstrained 3D deformation. Using advanced synchrotron X‐ray tomography techniques, the internal structure of the material is revealed, which can be correlated with the composite stiffening and shape‐memory mechanism. This material concept, based on a simple emulsion process, can be extended to different fluids and elastomers, and can be manufactured with a wide range of methods.

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confidence: 99%

Magnetically Addressable Shape‐Memory and Stiffening in a Composite Elastomer

et al. 2019

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“…This is essential as high-density particles tend to settle, which can render the device ineffective if left untreated [138]. Additives such as oils, thixotropic agents [140], and Span ® 80 and TWEEN ® 80 emulsifiers are often used to improve the sedimentation stability [141], while organic acid and stearic acid are often used to increase the density of the carrier liquid [135] and stabilize the sedimentation [138].…”

Section: Magnetorheological Fluidsmentioning

confidence: 99%

Review of Magnetorheological Damping Systems on a Seismic Building

et al. 2021

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Building structures are vulnerable to the shocks caused by earthquakes. Buildings that have been destroyed by an earthquake are very detrimental in terms of material loss and mental trauma. However, technological developments now enable us to anticipate shocks from earthquakes and minimize losses. One of the technologies that has been used, and is currently being further developed, is a damping device that is fitted to the building structure. There are various types of damping devices, each with different characteristics and systems. Multiple studies on damping devices have resulted in the development of various types, such as friction dampers (FDs), tuned mass dampers (TMDs), and viscous dampers (VDs). However, studies on attenuation devices are mostly based on the type of system and can be divided into three categories, namely passive, active, and semi-active. As such, each type and system have their own advantages and disadvantages. This study investigated the efficacy of a magnetorheological (MR) damper, a viscous-type damping device with a semi-active system, in a simulation that applied the damper to the side of a building structure. Although MR dampers have been extensively used and developed as inter-story damping devices, very few studies have analyzed their models and controls even though both are equally important in controlled dampers for semi-active systems. Of the various types of models, the Bingham model is the most popular as indicated by the large number of publications available on the subject. Most models adapt the Bingham model because it is the most straightforward of all the models. Fuzzy controls are often used for MR dampers in both simulations and experiments. This review provides benefits for further investigation of building damping devices, especially semi-active damping devices that use magnetorheological fluids as working fluids. In particular, this paper provides fundamental material on modeling and control systems used in magnetorheological dampers for buildings. In fact, magnetorheological dampers are no less attractive than other damping devices, such as tuned mass dampers and other viscous dampers. Their reliability is related to the damping control, which could be turned into an interesting discussion for further investigation.

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“…As the shear rate reaches an extreme value, the structure of the chain breaks, causing the fluid flows again. The stress that MRF retains at this extreme shear rate is called as fluids apparent yield stress [102]. The highest stress attained prior to the MRF continuous flow is known as yield stress, which correlated to the viscoelasticity behaviour enhancement [27].…”

Section: Magnetorheological Fluid (Mrf)mentioning

confidence: 99%

“…Oils are by far the most commonly used carrier fluids for MRF, as shown in Table 1 [33,73,102,106]. Low viscosity advantages of oils make them the dominant candidate in the selection of MRF carrier fluid.…”

Section: The Carrier Fluidmentioning

confidence: 99%

“…The most important function of all is preventing the occurrence of sedimentation [70]. Thixotropic agents and emulsifiers are added to enrich sedimentation stability [102,147]. Thixotropic agents such as grease have the capability of forming a weak network between particles at low shear stress, which is a necessity in lessen, if not stopping the sedimentation problem.…”

Section: The Additivesmentioning

confidence: 99%

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A Brief Review of Preparation Method and Challenges of Magnetorheological Fluids

Unuh¹,

Muhamad²

2020

ARMS

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In recent years, there has been an increased interest in the application of smart material technologies. The primary features of smart materials are the ability to provide multifunctional behaviour. Among smart materials technologies, magnetorheological fluids (MRFs) have been efficiently utilised in a variety of applications, especially in mechanical vibration engineering. In this paper, a brief review of past studies on the preparation methods, MRFs contents that contribute to the performance of MRFs as a smart material is conducted. The effect of particle size, shapes and also volume concentration is also discussed. This papers concludes with discussion on some current challenges and future prospect of MRFs.

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Magneto Mechanical Properties of Iron Based MR Fluids

Cited by 74 publications

References 24 publications

Magnetically Addressable Shape‐Memory and Stiffening in a Composite Elastomer

Magnetically Addressable Shape‐Memory and Stiffening in a Composite Elastomer

Review of Magnetorheological Damping Systems on a Seismic Building

A Brief Review of Preparation Method and Challenges of Magnetorheological Fluids

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