Viscosity and dispersion state of magnetic suspensions

Jeon, Jonggu; Koo, Sangkyun

doi:10.1016/j.jmmm.2011.08.025

Cited by 22 publications

(10 citation statements)

References 18 publications

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“…In the present work, attention is paid to the problem of limiting stresses. The main factors that affect the ability to achieve a suitable value of this parameter are the magnetic field strength acting on the fluid and the composition of the MR fluid, especially the quantity, size and magnetic parameters of the ferromagnetic particles used to prepare the suspension [5,[22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Experiments and Analysis of the Limit Stresses of a Magnetorheological Fluid

Horak

Stępień

Sapiński

2022

Acta Mechanica Et Automatica

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This paper presents the results of a rheological test of a commercial magnetorheological (MR) fluid (MRF-132DG). The research includes the problem of measuring and interpreting limit stresses under conditions close to the magnetic saturation of the fluid. Four different limit stresses were determined, two related to the yield point and two related to the flow point. Methods for determining limit stresses, especially due to excitation conditions, were also analysed. The aim of this study is to determine the effect of selected parameters on the values of limit stresses of the selected MR fluid. An additional objective is to highlight the problems of defining and interpreting individual limit stresses in MR fluids, particularly in the context of selecting the values of these stresses for the purpose of modeling systems with MR fluids.

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Section: Introductionmentioning

confidence: 99%

Experiments and Analysis of the Limit Stresses of a Magnetorheological Fluid

Horak

Stępień

Sapiński

2022

Acta Mechanica Et Automatica

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“…The MREAs are similar to passive hydraulic EAs in which the fluid in the hydraulic cylinder is pushed through an orifice. However, instead of using a passive hydraulic fluid, an adaptable magnetorheological (MR) fluid that consists of micrometer-scale iron particles suspended in a carrier fluid (Jeon and Koo, 2012) is used for the MREAs. An electromagnetic coil is integrated into the MREAs so as to generate magnetic field in response to an electric current.…”

Section: Introductionmentioning

confidence: 99%

Optimal control of drop-induced shock mitigation using magnetorheological energy absorbers considering quadratic damping

Wang

Chen

Yan

et al. 2021

Journal of Intelligent Material Systems and Structures

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The optimal control of a magnetorheological energy absorber (MREA) shock mitigation system is investigated considering quadratic damping in the MREA. To this end, the equation of motion of a single-degree-of-freedom (SDOF) shock suspension system using an MREA with quadratic damping is analyzed. To achieve a soft landing and to maintain stroking load below a maximum allowable value, it is required that the payload comes to rest after fully utilizing the available stroke. For low sink rates, a generalized Bingham number (quadratic) or GBN-Q control algorithm is developed that achieves a soft landing by selecting an initial magnetorheological (MR) force level or generalized Bingham number (GBN) for the quadratic damping at the initial sink rate. To cope with the cases above a critical sink rate, where the deceleration exceeds a maximum allowable threshold when using the GBN-Q control only, a minimum duration deceleration exposure-quadratic (MDDE-Q) controller is developed. This controller seeks to maintain the stroking load at its maximum allowable threshold until the payload slows such that the GBN-Q controller can be used to achieve the soft landing condition. The switching methodology between the GBN-Q controller and the MDDE-Q controller is discussed. Each control method relies on an optimal GBN that is computed to ensure a soft landing. Results show that the MDDE-Q controller can successfully minimize the exposure of the payload to the maximum allowable stroking load.

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“…It is made up of magnetic polarizable particles and non-reactive and non-magnetic carrier fluid along with coating [2]. MRFs behave almost like Newtonian fluids whose off-state viscosity are determined by the carrier fluid and the number of polarizable particles [3,4]. When the external magnetic field is applied on the MR fluid, the polarizable particles aligned along the magnetic field forming chain like structures thereby behaving like a quasisolid instantaneously [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Magnetorheological fluids should not be confused with similar smart materials such as ferrofluids which have Nano sized particles making it nearly 1000 times smaller than the particles used in MRF. The ferrofluids have similar composition, but due to Nano sized particles in dispersion, they do not show profound viscoplastic effects like MR fluids [3,8]. The ER fluids have similar working principle except for electrically controlled rheological properties instead of the magnetic field [9].…”

Section: Introductionmentioning

confidence: 99%

Study on Sedimentation Stability of Mahua and Simarouba Oil Based Magnetorheological Fluids

Vannarth¹,

Babu²,

Jebraj³

2019

Acta mech. Malays.

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Magnetorheological fluids (MRFs) are peculiar of smart fluids whose rheological properties can be efficiently controlled by varying applied magnetic field. Owing to this peculiar property, it can be utilized in industrial applications in semi-active devices such as dampers, actuators, etc. In this work, an effort has been attempted to produce MRFs using natural oils as carrier fluids and tested for potential replacement of conventional carrier fluids such as silicone oil. The MR fluids are prepared using silicone oil and two natural oil namely Mahua oil and Simarouba oil. Carbonyl iron (CI) and Electrolytic iron (EI) are used as suspended particles with lithium grease as an additive. The MRF using two natural based oil are known as Green magneto rheological fluids (GMRF). The characterization of suspended particles and carrier liquids was performed, followed by tests on sedimentation stability of prepared samples. To compare the sedimentation stability, the graphs of sedimentation ratio versus time are plotted for all MR fluids samples. It is found that the sedimentation stability of natural oils based MRFs are relatively better than silicone oil based MRFs for the same concentration of magnetic particles. There is potential of these natural oils based MRFs to replace the conventional MRFs However, other rheological properties like yield strength, flow characteristics etc. needs further investigation.

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Viscosity and dispersion state of magnetic suspensions

Cited by 22 publications

References 18 publications

Experiments and Analysis of the Limit Stresses of a Magnetorheological Fluid

Experiments and Analysis of the Limit Stresses of a Magnetorheological Fluid

Optimal control of drop-induced shock mitigation using magnetorheological energy absorbers considering quadratic damping

Study on Sedimentation Stability of Mahua and Simarouba Oil Based Magnetorheological Fluids

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