Shear Stress Dependence of Force Networks in 3D Dense Suspensions

Soft Matter ◽  
2021 ◽  
Author(s):  
Lance Edens ◽  
Enrique Alvarado ◽  
Abhinendra Singh ◽  
Jeffrey Morris ◽  
Gregory Schenter ◽  
...  
Keyword(s):  
Shear Stress ◽  
Shear Thinning ◽  
Stress Dependence ◽  
Dense Suspensions ◽  
Force Networks

The geometric organization and force networks of 3D dense suspensions that exhibit both shear thinning and thickening have been examined as a function of varying strength of interparticle attractive interactions...

Investigation on the Rheological Behavior of Polyamide6/Montmorillonite Nanocomposites by Reactive Extrusion

2011 ◽  
Vol 233-235 ◽  
pp. 1998-2001 ◽  
Author(s):  
Ming Zhao ◽  
Xiao Zhong Lu ◽  
Kai Gu ◽  
Xiao Min Sun ◽  
Chang Qing Ji
Keyword(s):  
Activation Energy ◽  
Shear Stress ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Reactive Extrusion ◽  
Shear Thinning ◽  
Experimental Results ◽  
Montmorillonite Nanocomposites

The rheological behavior of PA6/montmorillonite(MMT) by reactive extrusion was investigated using cone-and-plate rheometer. The experimental results indicated that PA6/MMT exhibited shear-thinning behavior. The shear stress of both neat PA6 and PA6/MMT increased with the increase in the shear rate. The reduction of the viscous activation energy with the increase of shear stress reflected PA6/MMT can be processed over a wider temperature.

Determination of Shear Stress at a Solder Paste/Stencil Interface

1993 ◽  
Vol 323 ◽  
Author(s):  
Linda M. Head ◽  
Vincent Rogers ◽  
Chitteranjan Sahay ◽  
James Constable
Keyword(s):  
Shear Stress ◽  
Mechanical Test ◽  
Test Procedure ◽  
Shear Thinning ◽  
Solder Paste ◽  
Parallel Plates ◽  
Release Process ◽  
Stencil Printing ◽  
Plate Separation ◽  
Lift Off

AbstractTo create a model for the release process of solder paste during stencil printing for surface mount applications it is necessary to determine the shear stress developed at the interface between the solder paste and stencil sidewall. An experiment has been developed to determine the value of the shear stress for solder paste samples. For the purpose of this experiment a Micro-mechanical tester has been adapted and programmed to provide both a shear thinning cycle and a pull-off cycle that simulate aperture fill and stencil lift-off. The shear stress developed at the solder/stencil-sidewall interface is estimated from the data obtained during the pull-off portion of the Micro-mechanical test procedure. The micro-mechanical tester is fitted with a set of parallel plates that can be adjusted for plate separation and surface roughness.The experiment consists of two parts: (1) the shear thinning cycle and (2) the horizontal pull-off. After application of the solder paste and adjustment of plate separation, a back and forth movement of the upper plate provides shear thinning of the paste. This step is necessary to simulate the shear thinning that occurs from the application of squeege pressure during aperture fill. The horizontal pull-off then simulates the lift-off step of the stencil printing procedure. During the horizontal pull-off data is. taken which allows calculation of the force developed as the upper plate is pulled away from the lower. Results from this experiment show the values of shear stress that develop during pull-off with a variation of surface treatments and plate separations.This paper will present the experimental set-up, a description of the relationship between this experiment and the actual stencil lift-off process, and shear stress data that has been acquired for a variety of solder pastes and plate separations.

scholarly journals Surface shear stress dependence of gas transfer velocity parameterizations using DNS

2016 ◽  
Vol 121 (10) ◽  
pp. 7369-7389 ◽  
Author(s):  
S. T. Fredriksson ◽  
L. Arneborg ◽  
H. Nilsson ◽  
R. A. Handler
Keyword(s):  
Shear Stress ◽  
Gas Transfer ◽  
Surface Shear Stress ◽  
Stress Dependence ◽  
Transfer Velocity ◽  
Surface Shear ◽  
Gas Transfer Velocity

scholarly journals Determination of loading capacity depending on bevel angle of the wooden bonded scarf joint

2010 ◽  
Vol 56 (No. 4) ◽  
pp. 159-165 ◽  
Author(s):  
O. Dajbych ◽  
D. Herák ◽  
A. Sedláček ◽  
G. Gűrdil
Keyword(s):  
Shear Stress ◽  
Normal Stress ◽  
Theoretical Method ◽  
Loading Capacity ◽  
Stress Dependence ◽  
Method Of Determination ◽  
Scarf Joint ◽  
Formula Derivation ◽  
Mohr’S Circle

The paper is focused on comparison of experimental and simple theoretical method of determination of loading capacity depending on bevel angle of wooden bonded scarf joint. The Mohr's circle principle, thus shear stress dependence on normal stress, is used for loading capacity formula derivation. It has been established that for random bevel angle under approximately 70 degrees the future loading capacity can be calculated from knowledge of ultimate force for bevel angle 0 and 90 degrees.

The Impact of Hemorheology on Wall Shear Stress in a Separated and Reattached Flow Region

2013 ◽  
Author(s):  
Khaled J. Hammad
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Yield Stress ◽  
Flow Region ◽  
Shear Thinning ◽  
Progression Rate ◽  
Vortex Center ◽  
Wall Shear ◽  
Separated And Reattached Flow ◽  
The Impact

Wall-bounded separating and reattaching flows are encountered in biological applications dealing with blood flows through arteries and prosthetic devices. Separated and reattached flow regions have been associated in the past with the most common arterial disease, atherosclerosis. Previous studies suggest that local wall shear stress (WSS) patterns affect the location and progression rate of atherosclerotic lesions. A parametric study is performed to investigate the influence of hemorheology on the wall shear stress distribution in a separated and reattached flow region. Recent hemorheological studies quantified and emphasized the yield stress and shear-thinning non-Newtonian characteristics of unadulterated human blood. Numerical solutions to the governing equations that account for yield stress and shear-thinning rheological effects are obtained. A low WSS region is observed around the flow reattachment point while a peak WSS always exists close to the vortex center. The yield shear-thinning hemorheological model always results in the highest observed peak WSS. The yield stress impact on WSS distribution is most pronounced in the case of severe restrictions to the flow.

scholarly journals Shear Stress Dependence of Melt Viscosity for Polypropylene

1965 ◽  
Vol 22 (244) ◽  
pp. 513-519
Author(s):  
Nobuo Yamada ◽  
Naoyuki Kishi ◽  
Hiroyuki Iizuka
Keyword(s):  
Shear Stress ◽  
Stress Dependence ◽  
Melt Viscosity

Cold start analysis of an engine coolant-MWCNT nanofluid: Synthesis and viscosity behavior under shear stress

2021 ◽  
pp. 095440702110192
Author(s):  
Luiz U R Sica ◽  
Edwin M C Contreras ◽  
Enio P Bandarra Filho ◽  
José A R Parise
Keyword(s):  
Thermal Conductivity ◽  
Shear Stress ◽  
Shear Rate ◽  
Internal Combustion Engines ◽  
Shear Thickening ◽  
Cold Start ◽  
Shear Thinning ◽  
Pollutant Emissions ◽  
Flow Index ◽  
Engine Coolant

During cold start of internal combustion engines, coolant temperature, and thermal conductivity are key parameters in the heat transfer processes that ultimately affect pollutant emissions and engine performance. Hereupon the use of coolants with suspended nanoparticles, to enhance thermal conductivity, emerged as a promising technology. However, for Newtonian materials, viscosity also increases with nanoparticle concentration. To overcome increased pumping power, the use of non-Newtonian nanofluids makes such application potentially feasible, specifically for shear-thinning materials, in which a higher shear rate leads to reducing shear viscosity due to higher shear stress. Accordingly, a nanofluid, suitable for engine cooling (0.2 wt.% MWCNT-engine coolant/distilled water 30/70 v/v%), was here fabricated and mapped. Shear rate and temperature were varied, with focus on cold start investigation. Shear thinning and shear thickening regions were mapped according to the shear rate levels, for each temperature considered. The nanofluid behaved as shear-thinning material for the entire range of temperatures (−10°C–25°C). Above shear rates of 500 s−1 and flow curves with temperatures below −5°C, a prominent shear thickening behavior was observed. Additionally, the relative apparent viscosity data were compared with four classical models. Regarding the curve fitting parameters of a modified Herschel-Bulkley equation, above 0°C, the apparent yield stress, [Formula: see text], was invariant with temperature. Besides, for the temperature range from 0°C to 20°C, the flow index remained approximately constant. For temperatures above −5°C, infinite-shear-rate viscosity and consistency index presented a linear decrease and a third-degree polynomial-like behavior, respectively.

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