Novel ring-type measurement system of shear yield stress for magnetorheological fluid under high temperature

Magnetorheological fluid is a kind of new intelligent materials, because of its good controllable and mechanical properties; therefore it can be widely used in aerospace, mechanical engineering and automotive engineering, precision processing engineering, control engineering and engineering field. This paper introduces magnetorheological fluid mechanics model of MRF, temperature static shear yield stress, and the influence of MRF static shear yield stress test, introduces magnetorheological fluid in the application of variable hardness collar. The application tendency of the magnetic fluid flow is pointed out

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The shear and compressive yield stress of fibrillated acacia pulp fiber suspensions

Nordic Pulp & Paper Research Journal ◽

10.1515/npprj-2019-0065 ◽

2020 ◽

Vol 35 (2) ◽

pp. 243-250

Author(s):

Jiulong Sha ◽

Yueyue Yang ◽

Can Wang ◽

Wei Li ◽

Peng Lu ◽

...

Keyword(s):

Yield Stress ◽

Paper Industry ◽

Pulp Fiber ◽

Fiber Suspensions ◽

Fiber Morphology ◽

Shear Yield Stress ◽

Geometrical Properties ◽

Compressive Yield Stress ◽

Shear Yield ◽

Fiber Cell Wall

AbstractThe degree of interactions between fibers and the tendency of fibers to form flocs play an important role in effective unit operation in pulp and paper industry. Mechanical treatments may damage the structure of the fiber cell wall and geometrical properties, and ultimately change the fiber-fiber interactions. In this study, the gel crowding number, compressive and shear yield stress of fibrillated acacia pulps were investigated, and the results showed that the gel crowding number of the refined pulp samples ranged from 8.7 to 10.7, which were much lower than that of un-refined pulps. As the concentration increased, both the compressive yield stress {P_{y}} and shear yield stress {\tau _{y}} of all suspensions increased accordingly, and the yield stress was found to depend on a power law of the crowding number. Moreover, the values of {\tau _{y}}/{P_{y}} were also examined and the variation of {\tau _{y}}/{P_{y}} became largely dependent on the fiber morphology and mass concentration.

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Shear yield stress of partially flocculated colloidal suspensions

AIChE Journal ◽

10.1002/aic.690440305 ◽

1998 ◽

Vol 44 (3) ◽

pp. 538-544 ◽

Cited By ~ 137

Author(s):

Peter J. Scales ◽

Stephen B. Johnson ◽

Thomas W. Healy ◽

Prakash C. Kapur

Keyword(s):

Yield Stress ◽

Colloidal Suspensions ◽

Shear Yield Stress ◽

Shear Yield

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Demonstration of Combined Shear and Squeeze Strengthening Modes in a Searle-Type Magnetorheometer

Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation and Control of Adaptive Systems; Integrated System Design and Implementation ◽

10.1115/smasis2013-3244 ◽

2013 ◽

Cited By ~ 6

Author(s):

Andrew C. Becnel ◽

Norman M. Wereley

Keyword(s):

Yield Stress ◽

Energy Absorption ◽

Shear Yield Stress ◽

Particle Chain ◽

Solids Loading ◽

Mr Fluids ◽

Shear Yield ◽

Microstructure Model ◽

Novel Method ◽

A Chain

This research details a novel method of increasing the shear yield stress of magnetorheological (MR) fluids by combining shear and squeeze modes of operation to manipulate particle chain structures, to achieve so-called compression-assisted aggregation. The contribution of both active gap separation and particle concentration are experimentally measured using a custom-built Searle cell magnetorheometer, which is a model device emulating a rotary Magnetorheological Energy Absorber (MREA). Characterization data from large (1 mm) and small (250 μm) gap geometries are compared to investigate the effect of the gap on yield stress by compression enhancement. Two MR fluids having different particle concentrations (32 vol% and 40 vol%) are also characterized to demonstrate the effect of solids loading on compression-assisted chain aggregation. Details of the experimental setup and method are presented, and a chain microstructure model is used to explain experimental trends. The torque resisted by practical rotary MREAs is directly related to the strength of the MR fluid used, as measured by the shear yield stress. This study demonstrates that it is feasible, utilizing the compression-enhanced shear yield stress, to either (1) design a rotary MREA of a given volume to achieve higher energy absorption density (energy absorbed normalize by device volume), or (2) reduce the volume of a given rotary MREA to achieve the same energy absorption density.

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