scholarly journals Effects of Silicone Oil Viscosity and Carbonyl Iron Particle Weight Fraction and Size on Yield Stress for Magnetorheological Grease Based on a New Preparation Technique

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1778 ◽  
Author(s):  
Kejie Wang ◽  
Xiaomin Dong ◽  
Junli Li ◽  
Kaiyuan Shi ◽  
Keju Li
Keyword(s):  
Yield Stress ◽  
Carbonyl Iron ◽  
Silicone Oil ◽  
Weight Fraction ◽  
Iron Particle ◽  
Preparation Technique ◽  
Oil Viscosity ◽  
Dynamic Yield Stress ◽  
Carbonyl Iron Particle ◽  
Dynamic Yield

This paper investigated the effects of silicone oil viscosity (SOV) and carbonyl iron particle (CIP) weight fraction and size on dynamic yield stress for magnetorheological (MR) grease. The MR grease samples were prepared using orthogonal array L9 on the basis of a new preparation technology. The shear rheological tests were undertaken using a rotational shear rheometer and yield stress was obtained based on the Bingham fluid model. It was found that CIP fractions ranging from 65 wt% to 75 wt% and SOV varying from 50 m2·s−1 to 1000 m2·s−1 significantly affect the magnetic field-dependent yield stress of MR grease, but the CIPs with sizes of 3.2–3.9 μm hardly had any influence based on the analysis of variance (ANOVA). In addition, the yield stress of MR grease mainly depended on the CIP fraction and SOV by comparing their percent contribution (PC). It was further confirmed that there were positive effects of CIP fraction and SOV on yield stress through response surface analysis (RSA). The results showed a high dynamic yield stress. It indicated that MR grease is an intelligent material candidate which can be applied to many different areas requiring high field-induced rheological capabilities without flow for suspension. Moreover, based upon the multivariate regression equation, a constitutive model was developed to express the function of the yield stress as the SOV and fraction of CIPs under the application of magnetic fields.

Rheological properties of dimorphic magnetorheological gels mixed dendritic carbonyl iron powder

2017 ◽  
Vol 29 (1) ◽  
pp. 12-23 ◽  
Author(s):  
Pingan Yang ◽  
Miao Yu ◽  
Jie Fu ◽  
Hongping Luo
Keyword(s):  
Yield Stress ◽  
Storage Modulus ◽  
Carbonyl Iron ◽  
Magnetic Particles ◽  
Engineering Application ◽  
Iron Particle ◽  
Iron Particles ◽  
Shear Yield Stress ◽  
Carbonyl Iron Particle ◽  
Shear Yield

Magnetorheological gels typically are colloids of spherical micrometer magnetic particles dispersed in a high-viscosity polymer matrix. However, some major parameters of this kind of mono-disperse magnetorheological gel, such as the shear storage modulus and yield stress, cannot meet the needs of practical engineering application. In this study, a systematic experiment was investigated on the use of dendritic carbonyl iron particles to enhance the comprehensive performance in conventional (microsphere-based) magnetorheological gels formulated in polyurethane matrix. Two kinds of carbonyl iron particles that have very similar magnetic properties but very different morphologies (one is spherical and the other is dendritic) are employed. The dimorphic magnetorheological gels were prepared by adding dendritic carbonyl iron particles into the conventional spherical carbonyl iron particle–based magnetorheological gel and a series of dimorphic magnetorheological gel samples were prepared. The magnetorheological properties of those samples, both under oscillatory and rotational shear rheometry, were systematically tested. It was found that the dendritic carbonyl iron particle additives can significantly improve the shear storage modulus and response time of the dimorphic magnetorheological gels compared with conventional magnetorheological gels. Meanwhile, when the mass ratio of dendritic particles to carbonyl iron particles is 25% and 50%, the shear stress, static shear yield stress, and dynamic shear yield stress of dimorphic magnetorheological gels can also be greatly enhanced.

scholarly journals The field-dependent viscoelastic and transient responses of plate-like carbonyl iron particle based magnetorheological greases

2019 ◽  
Vol 30 (5) ◽  
pp. 788-797 ◽  
Author(s):  
Norzilawati Mohamad ◽  
Saiful Amri Mazlan ◽  
Ubaidillah ◽  
Seung-Bok Choi ◽  
Fitrian Imaduddin ◽  
...  
Keyword(s):  
Carbonyl Iron ◽  
Weight Fraction ◽  
Iron Particle ◽  
Milling Process ◽  
Iron Particles ◽  
Carbonyl Iron Particle ◽  
Dynamic Rheological Properties ◽  
Field Dependent ◽  
Surface Diameter ◽  
Surface Microstructures

The field-dependent viscoelastic and transient behaviours of plate-like-carbonyl-iron-particle-based magnetorheological greases are experimentally investigated in this study. The plate-like carbonyl-iron particles are made from spherical carbonyl-iron particles through a milling process using a rotary ball mill. Several samples of magnetorheological greases consisting of different weight percentages of plate-like carbonyl-iron particles are prepared. The surface microstructures and distributions of the plate-like carbonyl-iron particles in the grease are observed using various types of microscopic investigations. Subsequently, the viscoelastic and transient (dynamic) rheological properties of the plate-like carbonyl-iron particles are investigated using a commercial rheometer. The spherical carbonyl-iron particles are transformed into the flattened plate-like carbonyl-iron particles with a larger surface diameter. It is shown that the viscoelastic properties such as storage modulus and response time of the plate-like carbonyl-iron particles significantly depend on the shape and particle weight fraction. The findings reveal that the shape of the carbonyl-iron particles has a significant effect on the field-dependent behaviours. Thus, the results presented in this work provide very useful scientific contributions for devising appropriate applications utilizing the plate-like-carbonyl-iron-particle-based magnetorheological greases.

scholarly journals Влияние гигантской магнитострикции на динамический предел текучести в условиях высокоскоростной деформации

2021 ◽  
Vol 63 (12) ◽  
pp. 2070
Author(s):  
В.В. Малашенко
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Yield Stress ◽  
High Strain ◽  
Dynamic Yield Stress ◽  
High Strain Rate Deformation ◽  
Dynamic Yield ◽  
Giant Magnetostriction

The high-strain rate deformation of crystals with giant magnetostriction is theoretically analyzed. It is shown that giant magnetostriction has a significant effect on the dynamic yield stress of crystals.

INFLUENCE OF SURFACTANTS ON PROPERTIES OF ELECTRORHEOLOGICAL FLUIDS CONTAINING POLYANILINE

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2461-2467 ◽  
Author(s):  
MAŁGORZATA BOCIŃSKA ◽  
HENRYK WYCIŚLIK ◽  
MARCIN OSUCHOWSKI ◽  
JANUSZ PŁOCHARSKI
Keyword(s):  
Yield Stress ◽  
Current Density ◽  
Silicone Oil ◽  
Flow Curves ◽  
Different Types ◽  
Order Of Magnitude ◽  
Dynamic Yield ◽  
Rate Of Sedimentation ◽  
Er Fluids

Sedimentation which is a natural process in most of ER fluids can be reduced by addition of surfactants that influence also other properties of the fluids. To study both the ER effect and the rate of sedimentation was the aim of the investigations. The ER fluids comprised powdered polyaniline and silicone oil to which surfactants of different polarity were added. The rate of sedimentation was measured by a sedimentation balance. The flow curves were recorded under electric field up to 2.5 kV/mm. Current density was also measured as a function of shear rate. It was found that the activity of a surfactant depends strongly on its polarity. The lipophylic surfactants stabilized the suspension very well but about 30% decrease of the dynamic yield stress was observed. The current density was reduced as well by almost one order of magnitude. The hydrophylic surfactants hardly stabilized the suspension but increase of yield stress was observed that was not followed by increase of current density. The role of different types of non-ionic surfactants was discussed.

Zirconia-coated carbonyl-iron-particle-based magnetorheological fluid for polishing optical glasses and ceramics

2009 ◽  
Vol 48 (35) ◽  
pp. 6797 ◽  
Author(s):  
Shai N. Shafrir ◽  
Henry J. Romanofsky ◽  
Michael Skarlinski ◽  
Mimi Wang ◽  
Chunlin Miao ◽  
...  
Keyword(s):  
Carbonyl Iron ◽  
Iron Particle ◽  
Magnetorheological Fluid ◽  
Optical Glasses ◽  
Carbonyl Iron Particle
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