Magnetic carbonyl iron nanoparticle based magnetorheological suspension and its characteristics

Park, Bong Jun; Song, Kilhong; Choi, Hyoung Jin

doi:10.1016/j.matlet.2009.03.013

Cited by 89 publications

(29 citation statements)

References 16 publications

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“…A MRF is desired that essentially does not settle, but instead provides the full MR effect the first time it is used even in the absence of remixing. Methods have been proposed to reduce settling, such as chemical modification of CI particles [6], [7], or substitution of micro-scale magnetic particles for nano-scale particles [8]- [10]. Although substitution of nonmagnetic particles for magnetic CI particles in MRF has been investigated for shear mode magneto-rheometers [11], [12], such a study is lacking in the context of MR dampers or flow mode devices.…”

Section: Introductionmentioning

confidence: 99%

Magnetorheological Fluids Employing Substitution of Nonmagnetic for Magnetic Particles to Increase Yield Stress

2012

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Magnetorheological fluids (MRFs) were synthesized to investigate potential enhancements in magnetorheology when replacing magnetic particles with nonmagnetic micro-scale glass beads, that is, to increase yield stress, while reducing density and particle settling rate. Two MRF samples having 40 volume percent (vol%) of particles were synthesized: MRF-40 and MRF-37. MRF-40 had 40 vol% of carbonyl iron (CI) particles, and MRF-37 contained 35.7 vol% of CI particles and 4.3 vol% of glass beads. A comparative study of MRF characteristics was conducted to determine the impact of the nonmagnetic glass beads on yield stress, as well as viscosity, and settling rate. Both MRFs were characterized as follows: 1) magnetorheology as a function of magnetic field, 2) sedimentation rate in a fluid column measured using an inductance-based sensor, and 3) cycling of a small-scale damper undergoing sinusoidal excitations at frequencies of 1 Hz for characterization and 4 Hz for endurance tests. Optical micrographs of the glass beads were taken before and after damper cycling to assess durability. The MRF with glass beads initially doubled the damper yield force (relative to the MRF with no glass beads) at high field strengths in damper tests. This increase in yield force did not persist as the damper was cycled in an endurance test and the glass beads eroded. Fe particle sedimentation rate was reduced by about 4% in the MRF with glass beads.Index Terms-Magnetorheological fluids, nonmagnetic glass beads, yield stress.

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Section: Introductionmentioning

confidence: 99%

Magnetorheological Fluids Employing Substitution of Nonmagnetic for Magnetic Particles to Increase Yield Stress

2012

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“…The calculation of hydrodynamic forces in oil-film requires solving the average Reynolds equation. The average Reynolds equation, originally developed by Patir and Cheng, is employed in the present work to include the effect of surface texture on hydrodynamic lubrication (Park et al, 2009;Patir and Cheng, 1978):…”

Section: Basic Equationmentioning

confidence: 99%

Effects of using smart fluid in lubrication on skirt‐liner friction

Mahdavi

Mansouri

Kimiaeifar

2012

Industrial Lubrication and Tribology

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Purpose -The purpose of this paper is to present, for the first time, a mathematical model for a piston skirt in mixed lubrication with respect to applying a smart fluid in lubrication. In this way, the smart fluid, as a lubricant with controlled variable viscosity, is proposed and applied to minimize the power loss in the interaction between liner and skirt. Design/methodology/approach -Based on signal processing, the relationships between viscosity of lubricant and the friction loss, the hydrodynamic and contact friction force consequently are found, as part of an effective approach to acquire the function of variable viscosity. Findings -It is shown that hydrodynamics and contact friction forces can be controlled and minimized by using the variable viscosity signal with the optimized viscosity signal technique. Originality/value -In this paper, a mathematical model for a piston skirt in mixed lubrication with respect to applying a smart fluid in lubrication is presented for the first time.Nomenclature a ¼ vertical distance from the top of the skirt to the wrist pin (m) b ¼ vertical distance from the top of the skirt to the piston center of gravity (m) C ¼ clearance (m) c g ¼ horizontal distance between piston center of mass and wrist pin (m) c p ¼ wrist-pin offset (m) e b , e t ¼ distance between the center at the bottom and top of the skirt and the cylinder axis, respectively, (m) e c ¼ eccentricity of center of piston skirt (m) e r ¼ angle of piston rotation (rad) F ¼ connecting rod force (N) F f ¼ total friction acting on the skirt (N) F G ¼ combustion gas force acting on the top of piston (N) F IC ¼ lateral inertia force due to piston skirt mass (N) F IC ¼ axial inertia force due to piston skirt mass (N) F IP ¼ lateral inertia force due to wrist pin mass (N) F IP ¼ axial inertia force due to wrist pin mass (N) hðu; y; tÞ ¼ mean oil-film thickness (m) I pis ¼ piston momentum of inertia (kg · m 2 ) L ¼ piston skirt length (m)M ¼ total moment about wrist-pin due to all the normal forces (N · m) M c ¼ moment about wrist-pin due to solid-tosolid contact pressure (N · m) M f ¼ moment about wrist-pin due to all the friction forces (N · m) M fc ¼ moment about wrist-pin due to contact friction (N · m) M fh ¼ moment about wrist-pin due to hydrodynamic friction (N · m) M h ¼ moment about wrist-pin due to hydrodynamic pressure (N · m) M IC ¼ inertia moment of piston (N · m) U ¼ piston sliding velocity (m/s) m pin ¼ wrist-pin mass (kg) m pis ¼ piston mass (kg)¼ hydrodynamic shear stress (Pa) F x , F y ¼ pressure flow factors F s ¼ shear stress flow factor F f , F fp , F fs ¼ shear stress flow factors f ¼ angle of connecting road (rad) c ¼ crank angle (rad) v ¼ crankshaft rotational speed (rad/s)The current issue and full text archive of this journal is available at

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“…In order to get magnetic CI nanoparticle additive, we synthesized in a rather simple process [16]. Decomposition of penta carbonyl iron was shown in Fig.…”

Section: B Synthesis Of Magnetic CI Nanoparticlesmentioning

confidence: 99%

“…Particles for MR fluids should be magnetized under an external magnetic field, indicating that ferromagnetic materials can be used as a disperse phase of MR fluid [14]. However, it is well known that the soft magnetic materials, which are easy to magnetize and demagnetize, are superior to hard magnetic materials due to the ability to control the rheological properties of MR fluids by tuning the external field [6], [15], [16]. Carbonyl iron (CI) is widely used as magnetizable particles for the MR fluids due to its high magnetic permeability, soft magnetic characteristics and common availability.…”

mentioning

confidence: 99%

Effect of Magnetic Nanoparticle Additive on Characteristics of Magnetorheological Fluid

2009

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Magnetorheological (MR) fluids, suspension of magnetic pure carbonyl iron (CI) in non magnetic carrier, were prepared with and without magnetic CI nanoparticle additive in this study. Initially, the magnetic CI nanoparticle additive was synthesized in a rather simple process of decomposition of penta carbonyl iron (Fe(CO) 5 ) using oleyl amine and kerosene. Magnetic property and morphology of the synthesized magnetic CI nanoparticles were confirmed via vibration sample magnetometer (VSM) and transmission electron microscopy (TEM), respectively. MR fluids, prepared as a mixture of pure CI and CI nanoparticle additive of different weight ratio in carrier fluid, was investigated under different external magnetic field strengths via a rotational rheometer. Sedimentation of the MR fluid was characterized by an optical analyzer, Turbiscan. Their flow behaviors at a steady shear mode were examined with and without magnetic CI nanoparticle additive under magnetic field strength. The MR fluids with magnetic CI nanoparticles added demonstrated slightly higher yield behaviors, suggesting that pure CI and CI nanoparticle additive were being oriented in the magnetic field direction under an applied magnetic field and with much strengthened structure.Index Terms-Additive, carbonyl iron, magnetorheological fluid, nanoparticle.

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Magnetic carbonyl iron nanoparticle based magnetorheological suspension and its characteristics

Cited by 89 publications

References 16 publications

Magnetorheological Fluids Employing Substitution of Nonmagnetic for Magnetic Particles to Increase Yield Stress

Magnetorheological Fluids Employing Substitution of Nonmagnetic for Magnetic Particles to Increase Yield Stress

Effects of using smart fluid in lubrication on skirt‐liner friction

Effect of Magnetic Nanoparticle Additive on Characteristics of Magnetorheological Fluid

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