Effect of Alumina Addition on the Rheological Behavior of Shear Thickening Fluids

Shear thickening fluids (STF) have attracted much attention in many applications including body armor. In this study, suspensions of silica colloidal particles and polyethylene glycol fluid were prepared at varying volume fractions φ = 0.3 to 0.52 and their rheological behavior was investigated. It was found that the suspensions exhibited a Newtonian behavior for φ < 0.4, whilst a shear thinning followed by a thickening behavior could clearly be observed for φ > 0.4. Furthermore, the critical shear rates for the onset of shear thickening was found to decrease with increasing silica volume fraction but the corresponding critical shear stresses were independent of the volume fraction. To improve the ballistic protective performance, small amount of hard material particles, such as alumina, were added into the silica suspension of φ = 0.5. It was shown that the critical shear rates of the reinforced-STFs decreased with increasing volume fraction and decreasing alumina particle size. However, higher thickening ratio was observed for the alumina additive with agglomerated structure and this ratio increased with increasing alumina volume fraction.

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A phenomenological theory-based viscosity model for shear thickening fluids

Materials Research Express ◽

10.1088/2053-1591/ac46e4 ◽

2021 ◽

Author(s):

Kun Lin ◽

Jiapeng Qi ◽

Hongjun Liu ◽

Minghai Wei ◽

Hua Yi Peng

Keyword(s):

Experimental Data ◽

Impact Resistance ◽

Shear Thickening ◽

Phenomenological Theory ◽

Logistic Function ◽

Viscosity Model ◽

Model Parameters ◽

Shear Rates ◽

Marquardt Algorithm ◽

Shear Thickening Fluids

Abstract A viscosity model for shear thickening fluids (STFs) based on phenomenological theory is proposed. The model considers three characteristic regions of the typical material properties of STFs: a shear thinning region at low shear rates, followed by a sharp increase in viscosity above the critical shear rate, and subsequently a significant failure region at high shear rates. The typical S-shaped characteristic of the STF viscosity curve is represented using the logistic function, and suitable constraints are applied to satisfy the continuity of the viscosity model. Then, the Levenberg–Marquardt algorithm is introduced to fit the constitutive model parameters based on experimental data. Verification against experimental data shows that the model can predict the viscosity behavior of STF systems composed of different materials with different mass concentrations and temperatures. The proposed viscosity model provides a calculation basis for the engineering applications of STFs (e.g., in increasing impact resistance and reducing vibration).

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Composition – Property Relations in Shear Thickening Fluids

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.87.91 ◽

2014 ◽

Vol 87 ◽

pp. 91-97

Author(s):

Łukasz Wierzbicki ◽

Marcin Leonowicz

Keyword(s):

High Strain ◽

Volume Fraction ◽

Solid Phase ◽

Loss Modulus ◽

Shear Thickening ◽

Complex Viscosity ◽

High Viscosity ◽

Polypropylene Glycol ◽

Shear Thickening Fluids ◽

Composition Property

It was shown that fumed silica particles (FS), dispersed in polypropylene glycol (PPG), form shear thickening fluids (STF). PPGs with different molar mass were tested. The best combination of the properties (high viscosity, obtained at high shear rate) present the fluids composed of 7 nm FS and PPG 425. The highest volume fraction of FS, which was possible to disperse in PPG 425, was 25%. This fluid exhibited the highest viscosity. The highest magnitude of shear thickening effect was obtained, however, for 17.5 vol.% of the solid phase. Dynamic oscillatory shear experiments were conducted at either a constant amplitude or frequency. The constant strain amplitude tests showed, that for the frequency sweep, the systems showed viscous properties, except that of 25 vol.% of FS in PPG 425, which exhibited elastic properties in almost entire range of the frequency investigated. For the constant strain sweep, for low strains, the elastic modulus and loss modulus were hardly dependent on the strain, but for relatively high strain, this dependency was increasing. Also the complex viscosity was also growing for high strain values.

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Flow of Dispersions Near Close Packing

MRS Proceedings ◽

10.1557/proc-155-65 ◽

1989 ◽

Vol 155 ◽

Cited By ~ 1

Author(s):

L. Marshall ◽

C. F. Zukoski

Keyword(s):

Hard Sphere ◽

Creep Compliance ◽

Volume Fraction ◽

Shear Thickening ◽

Time Spectrum ◽

Close Packing ◽

Shear Rates ◽

Volume Fractions ◽

Exponential Relaxation ◽

Hard Sphere Liquids

ABSTRACTThe flow of hard sphere-like suspensions near close packing is explored. The change in viscosity with stress and volume fraction shows that at volume fractions above 0.5 shear thickening occurs and that the characteristic shear rates for shear thinning and shear thickening decrease rapidly above this volume fraction. The creep compliance is well characterized by a stretched exponential relaxation time spectrum above volume fractions of 0.52. These results suggest that the limiting volume fraction where the zero shear rate viscosity diverges is determined by a liquid/glass phase transition very similar to that predicted for hard sphere liquids.

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CONCENTRATED SUSPENSIONS UNDER FLOW: SHEAR-THICKENING AND JAMMING

Modern Physics Letters B ◽

10.1142/s0217984905008608 ◽

2005 ◽

Vol 19 (13n14) ◽

pp. 613-624 ◽

Cited By ~ 11

Author(s):

PASCAL HÉBRAUD ◽

DIDIER LOOTENS

Keyword(s):

Shear Rate ◽

Experimental Evidence ◽

Colloidal Particles ◽

Shear Thickening ◽

Concentrated Suspensions ◽

Flow Shear ◽

Concentrated Suspension ◽

Shear Rates

When a concentrated suspension of colloidal particles is sheared at high enough shear rates, its viscosity increases with the shear rate. Depending on the details of the interactions between particles, this increase may be continuous and the suspension is said to shear-thicken, or may be discontinuous, leading to an arrest of flow: the suspension jams. We review recent experimental evidence that both behaviors are the consequence of the formation of dynamical aggregates under flow.

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Impact of the Carbon Nanofillers Addition on Rheology and Absorption Ability of Composite Shear Thickening Fluids

Materials ◽

10.3390/ma13173870 ◽

2020 ◽

Vol 13 (17) ◽

pp. 3870

Author(s):

Paulina Nakonieczna-Dąbrowska ◽

Rafał Wróblewski ◽

Magdalena Płocińska ◽

Marcin Leonowicz

Keyword(s):

Carbon Nanotubes ◽

Graphene Oxide ◽

Rheological Behavior ◽

Shear Thickening ◽

High Energy ◽

Polypropylene Glycol ◽

Shear Thickening Fluids ◽

Carbon Nanofillers ◽

Energy Absorbing ◽

Composite Shear

Synthesis and characterization of composite shear thickening fluids (STFs) containing carbon nanofillers are presented. Shear thickening fluids have attracted particular scientific and technological interest due to their unique ability to abruptly increase viscosity in the case of a sudden impact. The fluids have been developed as a potential component of products with high energy absorbing efficiency. This study reports on the rheological behavior, stability, and microstructure of the STFs modified with the following carbon nanofillers: multi-walled carbon nanotubes, reduced graphene oxide, graphene oxide, and carbon black. In the current experiment, the basic STF was made as a suspension of silica particles with a diameter of 500 nm in polypropylene glycol and with a molar mass of 2000 g/mol. The STF was modified with carbon nanofillers in the following proportions: 0.05, 0.15, and 0.25 vol.%. The addition of the carbon nanofillers modified the rheological behavior and impact absorption ability; for the STF containing 0.25 vol.% of carbon nanotubes, an increase of force absorption up to 12% was observed.

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Body armor for stab and spike protection, Part 1: Scientific literature review

Textile Research Journal ◽

10.1177/0040517517690623 ◽

2017 ◽

Vol 88 (7) ◽

pp. 812-832 ◽

Cited By ~ 19

Author(s):

Rajkishore Nayak ◽

Ian Crouch ◽

Sinnappoo Kanesalingam ◽

Jie Ding ◽

Ping Tan ◽

...

Keyword(s):

Military Personnel ◽

Scientific Literature ◽

Shear Thickening ◽

Body Armor ◽

Nano Materials ◽

Soft Body ◽

Small Arms ◽

The Past ◽

Shear Thickening Fluids ◽

Aramid Fabrics

Since the invention of small arms ammunition, the human torso has required protection from hand-gun bullets, and today’s civil and military personnel are regularly clad in soft body armor systems to cope with these threats. However, increasingly, the threat spectrum has widened to include a plethora of both edged and pointed weapons. Over the past two decades in particular, this has required development of either specific soft armors to defeat that particular threat, or the development of multi-threat vests that can resist both hand-gun bullets and knife and spike attacks. In this review, we provide more details about the various material combinations that are used to defeat a knife or spike, since these armor materials are a lot different from the conventional aramid fabrics, and numerous, widely-different solutions are being pursued. The penetration mechanisms associated with the various forms of attack—stabbing and slashing—are discussed, as well as the use of new fibers, shear thickening fluids, and nano-materials in developing these body armor systems.

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Novel Approach to The Design of Sound Insulating Composites by Means of a Non-linearly Extrapolated Master Curve

The Open Materials Science Journal ◽

10.2174/1874088x01812010014 ◽

2018 ◽

Vol 12 (1) ◽

pp. 14-28

Author(s):

Cecchini Federico ◽

Cherubini Valeria ◽

Francesco Fabbrocino ◽

Francesca Nanni

Keyword(s):

Smart Materials ◽

Composite Structures ◽

Transmission Loss ◽

Weight Ratio ◽

Shear Thickening ◽

Sound Insulation ◽

Commercial Vehicles ◽

Shear Rates ◽

Novel Approach ◽

Shear Thickening Fluids

Background:The increasing use of composite structures with a high stiffness-to-weight ratio in commercial vehicles has brought about a reduction in fuel consumption but, on the other hand, has significantly increased noise transmission particularly in case of thin and lightweight structures. Noise is a primary issue for commercial vehicles, such as airplanes, helicopters and cars. The present research deals with the use of smart materials, as Shear-Thickening Fluids (STF, or dilatants) in view of manufacturing elements with increased sound insulation properties.Methods:The response of a sandwich material with the STF core was investigated both experimentally and numerically, by choosing the Sound Transmission Loss (STL) of the composite structure as the figure of merit.The experimental investigation was focused on the manufacturing of a sandwich structure made of metallic skins and a STF core that was successively characterized by sound insertion loss measurement.The numerical investigation was carried out by using a Generalized Transfer Matrix Method (GTMM) and a Statistical Energy Analysis (SEA) in view of selecting the fluid capable of granting the highest acoustic transmission loss.Results:Finally, the test results were compared to the numerical results, showing a noticeable agreement. The used STF showed increasing viscosity at increasing shear rates.

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