scholarly journals Static yield stress of a magnetorheological fluid containing pickering emulsion polymerized Fe3O4/polystyrene composite particles

2019 ◽  
Author(s):  
Sangsok Han ◽  
Junsok Choi ◽  
Hoyun Kim ◽  
Sehyun Kim ◽  
Yongsok Seo
Keyword(s):  
Yield Stress ◽  
Magnetorheological Fluid ◽  
Pickering Emulsion ◽  
Composite Particles ◽  
Static Yield ◽  
Static Yield Stress

STATIC YIELD STRESS IN MAGNETORHEOLOGICAL FLUID

2001 ◽  
Vol 15 (06n07) ◽  
pp. 1078-1084 ◽  
Author(s):  
W. KORDONSKI ◽  
S. GORODKIN ◽  
N. ZHURAVSKI
Keyword(s):  
Experimental Data ◽  
Yield Stress ◽  
Magnetorheological Fluid ◽  
Dynamic Yield Stress ◽  
Mr Fluids ◽  
Static Yield ◽  
Dynamic Yield ◽  
Static Yield Stress

A method and a device for measuring a true static yield stress in magnetorheological (MR) fluids are proposed. The data obtained by means of this device are compared with the measured values of the dynamic yield stress for similar compositions as well as with the quantities calculated by the reported models. It is shown that the dynamic yield stress exceeds the static one. The experimental data better agree with Rosensweig's model.

LANTHANUM TITANATE NANOPARTICLES ER FLUIDS WITH HIGH PERFORMANCE

2012 ◽  
Vol 26 (13) ◽  
pp. 1250079 ◽  
Author(s):  
DE WANG ◽  
RONG SHEN ◽  
SHIQIANG WEI ◽  
KUNQUAN LU
Keyword(s):  
Yield Stress ◽  
Silicone Oil ◽  
Heating Temperature ◽  
Hydroxyl Group ◽  
Lanthanum Titanate ◽  
Different Temperatures ◽  
Static Yield ◽  
Er Fluids ◽  
Er Fluid ◽  
Static Yield Stress

A new type of electrorheological (ER) fluid consisting of lanthanum titanate (LTO) nanoparticles is developed. The ER fluids were prepared by suspending LTO powder in silicone oil and the particles were fabricated by wet chemical method. This ER fluid shows excellent ER properties: The static yield stress reaches over 150 kPa under 5 kV/mm with linear dependence on the applied DC electric field, and the current density is below 10 μA/cm2. In order to investigate the affect factor on the ER behavior, the LTO powder were heated under different temperatures. The ER performances of two particles treated under different temperatures were compared and the composition changes for those particles were analyzed with TG-FTIR technique. It was found that the static yield stress of the suspensions fell from over 150 kPa to about 40 kPa and the current densities decreased prominently as the rise of the heating temperature. TG-FTIR analysis indicated that polar groups remained in the particles such as alkyl group, hydroxyl group and carbonyl group etc., contribute to the ER effect significantly. The experimental results are helpful to understand the mechanism of the high ER effect and to synthesize better ER materials.

scholarly journals A study of the static yield stress in a binary Lennard-Jones glass

2004 ◽  
Vol 120 (6) ◽  
pp. 2788-2801 ◽  
Author(s):  
F. Varnik ◽  
L. Bocquet ◽  
J.-L. Barrat
Keyword(s):  
Yield Stress ◽  
Lennard Jones ◽  
Static Yield ◽  
Static Yield Stress

Static yield stress of ER fluids and the role of electric current

1997 ◽  
Vol 40-41 ◽  
pp. 699-704
Author(s):  
T. Sakai ◽  
K. Kobayashi ◽  
M. Sato
Keyword(s):  
Electric Current ◽  
Yield Stress ◽  
Static Yield ◽  
Er Fluids ◽  
Static Yield Stress

scholarly journals The determination of static and dynamic yield stresses using a steel ball

1949 ◽  
Vol 197 (1050) ◽  
pp. 416-432 ◽  
Keyword(s):  
Mild Steel ◽  
Yield Stress ◽  
Plane Surface ◽  
Steel Ball ◽  
Polished Surface ◽  
Normal Velocity ◽  
Chrome Steel ◽  
Static Yield ◽  
Von Mises ◽  
Static Yield Stress

The static and dynamical yield stress of the material of a thick steel plate may be estimated by pressing and by dropping a hard steel ball on a plane surface of the plate which has been ground and then polished. Under these conditions, the first appearance of an indentation on the polished surface can be detected with good accuracy, either by an optical interference method, or by an optical reflexion method. The statical experiment consists in finding the least force which must be applied to the steel ball to produce a permanent indentation, whilst the dynamical experiment consists in finding the least normal velocity of impact which gives similarly a permanent indentation. Using either the Guest-Mohr principal-stress difference or the von Mises shear strain energy hypotheses as criteria of failure, combined with an analysis of the stresses in the plate, it is shown how the appropriate yield stress can be calculated from the experimental data. Tests were made on a specimen of mild steel, two specimens of homogeneous armour plate and a very hard nickel-chrome steel of the type used for ball and roller bearings. The ratio of the dynamic value of the yield stress to the static value was found to increase as the hardness number decreases; the ratio was practically unity for the nickel-chrome steel, about 1⋅1 for the armour plate and about 2 for the mild steel. The values of the static yield stress found by the ball method and by an ordinary tensile or compression test are different; this is probably due partly to the inaccuracy of the criteria of plastic flow, partly to the difference in work-hardening in the two experiments, and partly to changes in the structure of the surface due to polishing. This discrepancy is without effect on the ratio of the dynamic to static yield stress as determined by the ball method, since the stress distributions in the static and dynamic ball experiments are identical.

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