Dissertations / Theses on the topic 'Shear thickening'
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Shah, Ashish, and ashishshah7@yahoo co in. "Rheology of Shear Thickening Mineral Slurries." RMIT University. Civil, Environmental and Chemical Engineering, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080725.133946.
Full textMadraki, Fatemeh. "Shear Thickening in Non-Brownian Suspensions." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1584354185678102.
Full textSadrizadeh, Sasan. "Instabilities in Pulsating Pipe Flow of Shear-Thinning and Shear-Thickening Fluids." Thesis, Linköpings universitet, Mekanisk värmeteori och strömningslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-82037.
Full textAndrew, Chryss, and andrew chryss@rmit edu au. "Pipeline Transport of Coarse Mineral Suspensions Displaying Shear Thickening." RMIT University. Civil, Environmental and Chemical Engineering, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20081127.112225.
Full textPetel, Oren. "Response of shear thickening materials to uniaxial shock compression." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104531.
Full textCette etude est une etude experimentale et numerique de la propagation des ondes de choc dans les suspensions polyphasiques. Des suspensions de particules sont utilisees comme un moyen d'obtenir un systeme dans lequel le contact initial entre les particules est limite et il y a un grand degre de variabilite parametrique. Les suspensions ont ete preparees dans l'ethylene glycol `a plusieurs fractions de volume (41%, 48% et 54%) de particules de carbure de silicium, des m´elanges qui se sont reveles etre rheoepaississantes dans les etudes rheologiques. La reponse dynamique des fluides rheoepaississents est etudiee dans une gamme des deformations pertinentes aux impacts balistiques.Une serie d'experiments d'impact de plaque ont ete menees pour obtenir les Hugoniots des chocs des differentes suspensions de particules a des vitesses dans l'ordre de 200-900 m/s. Les resultats experimentaux montrent une transition dans le comportement de propagation des ondes d'un regime de propagation domine par la compressibilite de la phase liquide de la suspension a un regime ou la reponse du melange devient dominee par les reseaux de contacts inter-particules. La transition dans le Hugoniots des choc des suspensions indique un choc induit par le raidissement de la suspension. Des mesures des contraintes longitudinales et laterales in situ sont en suspension dans la fraction volumique intermediaires a deux vitesses d'impact differentes demontrant une composante contrainte deviatorique a l'etat de stress au sein de la suspension.Des modeles analytiques et numeriques sont utilises pour demontrer la cause probable de la transition dans le comportement des suspensions, resultant de la variation de la fraction volumique de phase solide de la suspension avec des ondes de choc croissantes. Les resultats sont discutes en termes de developpement de contacts entre les particules etendu dans un mecanisme de compression induites par cisaillement classique analogue a un epaississement de suspensions denses.
Zhu, Weijie Kelvin. "Numerical analysis of shear thickening fluids for blast mitigation applications." Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/10717.
Full textTabassum, Maisha. "Mechanical and Energy-Absorbing Properties of Shear-Thickening Fluids (STFs)." Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/16856.
Full textSwarna. "Rheology of shear thickening fluids and their effect on energy dissipation of impregnated fabrics." Thesis, IIT, Delhi, 2019. http://eprint.iitd.ac.in:80//handle/2074/8071.
Full textBettin, Giorgia. "Energy absorption of reticulated foams filled with shear-thickening silica suspensions." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33904.
Full textIncludes bibliographical references (p. 92-98).
The need for smarter and adaptive, energy absorption materials especially for human protection applications has fueled the interest in new and alternative energy absorbing composites. In this thesis a 'novel' energy absorbing fluid-composite that utilized a shear thickening fluid is developed. Shear-thickening fluids are a class of field responsive fluids that have the ability to transition from low viscosity to high viscosity under an imposed deformation field. Two different types of silica particles are used to create shear thickening fluids. The first are polydisperse and non spherical, with a median diameter of 1.7 ± 1.4 micrometer, while the second are monodisperse spherical particles of 0.3 ± 0.03 micrometer diameter. The particles are dispersed in ethylene glycol at volume fractions of up to [phi]=47% for the polydisperse sample and up to [phi]=60% for the monodisperse spheres. The behavior of the silica suspensions is studied under steady shear, small and large amplitude oscillatory shear flow and also in transient extensional flow. The viscosity of the polydisperse suspension is found to be much greater than the monodisperse one due to the difference in particles shape. Oscillatory experiments indicate that both the onset and magnitude of the shear thickening depends on the frequency and strain applied and show that rapid time-varying deformations result in maximum energy dissipation.
(cont.) Two different regimes are found through extensional flow measurement: at low extension rates the suspensions respond as a viscous rate-thinning fluid, whereas beyond a critical extension rate, the suspension strain-hardens and ultimately fractures in a solid-like fashion. Polyurethane open cell or 'reticulated' foam with relative density of 0.03 and average cell size of 360 micrometer is chosen to envelop the concentrated silica suspensions. The behavior of this nonlinear fluid-solid composite is studied over a range of filling fractions under quasi-static deformation rates (strain rates between 10⁻² - s⁻¹ ), under dynamic impact loading (with energy densities of e = 10⁵ - 10⁶ J/m³) and under high strain-rate deformations (strain rates up to 800 s⁻¹). Results show that, if the foam is filled with a shear thickening suspension, the composite stiffens even at strain rates of 10⁻² s⁻¹ as the impregnated fluid shear-thickens due to the high local strain rates that develop on cellular length scales. High impact load experiments show two different mechanisms for energy absorption: at lower impact energies viscous dissipation is dominant; whereas, after a critical impact energy is reached, the fluid undergoes a transition from liquid-like to solid-like. High-speed digital video-imaging shows that cracks form and propagate through the sample and the impact energy is absorbed by viscoplastic deformation.
(cont.) The addition of these shear-thickening fluids in polyurethane foam is shown to increase the composite energy absorption capability by 35-fold.
by Giorgia Bettin.
S.M.
Hasib, Mohammad Tarik. "Vibration Control of Sandwich Beams by Integration of Shear Thickening Fluid." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/13520.
Full textHodgson, Daniel James Matthew. "Particulate granulation and rheology : towards a unifying perspective." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/23651.
Full textXu, Yue. "Stabbing resistance of soft ballistic body armour impregnated with shear thickening fluid." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/stabbing-resistance-of-soft-ballistic-body-armour-impregnated-with-shear-thickening-fluid(c5e8d517-6d46-4049-960c-383b10245800).html.
Full textCui, Xiaoyu. "Drop-weight Impact Behaviour of a Shear Thickening Fluid in a Finite Volume." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/25941.
Full textRamirez, Jose G. (Jose Guadalupe) 1980. "Characterization of shear-thickening fluid-filled foam systems for use in energy absorption devices." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32777.
Full textIncludes bibliographical references (leaf 44).
The absorption of energy during impacts is ubiquitous in society. From our car seats to body armor, the ability to divert or dissipate unwanted energy is an aspect that has many engineering challenges. One approach to this issue is the use of fluid-filled elastomeric foams. In the present thesis, the fluid within these foams is a non-Newtonian shear-thickening fluid composed of 300 nm silica particles suspended in a solvent, ethylene glycol, at high concentrations, 45-55 %. The field of energy absorption using elastomeric foams has been extensively researched in industry. In addition, the effects and mechanism driving shear-thickening fluids (STF's) has also been well studied in industries involving particle suspensions, such as paints and medical applications. This research intends to combine the analysis of these two systems in an effort to characterize advanced energy absorption mechanism. It was found that the primary factors dominating fluid filled foams containing this STF are the volume fractions and compressional strain rate. In addition, the energy absorption capability of these foams has been compared to that of 'dry' foams and Newtonian-fluid filled foams, and has demonstrated an increase in energy absorption capabilities.
by Jose G. Ramirez.
S.B.
Cheng, Jialun. "Striker Shape Effect on Low-velocity Impact Energy Absorption of a Shear Thickening Fluid." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/22694.
Full textLaha, Animesh. "Development and impact performance analysis of shear thickening fluid treated 2D and 3D fabric structures." Thesis, IIT Delhi, 2017. http://localhost:8080/xmlui/handle/12345678/7250.
Full textGuy, Ben Michael. "The physics of the flow of concentrated suspensions." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/29572.
Full textEgres, Ronald G. Jr. "The effects of particle anisotropy on the rheology and microstructure of concentrated colloidal suspensions through the shear thickening transition." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 12.78 Mb., 263 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3200542.
Full textSuzuki, Shinya. "Rheological Properties of Telechelic Associative Polymer in Aqueous Solution." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/200500.
Full textNess, Christopher John. "Suspension rheology and extrusion : a discrete element method study." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20392.
Full textHammack, Bishop I. "Rheological Investigations of Latex-Surfactant-Associative Thickener Aqueous Systems." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2063.
Full textAnderson, Brian. "Development of a non-Newtonian latching device." Thesis, Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/3855.
Full textAzzouzi, Houssain. "Propriétés rhéophysiques d'un système micellaire viscoélastique : rhéoépaississement apparent et oscillations des contraintes." Metz, 2005. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2005/Azzouzi.Houssain.SMZ0521.pdf.
Full textWe have studied rheological and optical properties of viscoelastic micellar solutions. We focus on a specific solution of CTAB/NaSal (50/100 mM), which shows, apparent shear-thickening in a narrow range of shear rates after a perfect plateau of shear stress characteristic of shear-banding. In this regime, in phase oscillations of the shear stress and of the first normal stress difference are recorded in a shearing device operating under controlled strain. The main goal of this work consists in finding correlations between rheological reponses, optical observations and ultrasonic velocimetry measurements in order to bring information on the mechanism which leads to the formation of these time periodic variations of shear stress. The direct observation of the annular gap of a Couette cell in a direction perpendicular to a plane containing the vorticity shows that the turbidity of the whole sample also undergoes time dependent variations with the same period as the shear stress; these variations are related to a periodic variations of the concentration of shear induced structures (SIS). However local velocity measurements reveal clearly the presence of slip at the walls of the Couette cell. In the shear-thickening regime, velocities present periodic fluctuations which probably induce shear stress oscillations
Liard, Maxime. "Suspension concentrées : systèmes non newtoniens et thixotropie sous écoulement." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE039/document.
Full textThis thesis has been done in collaboration with the company SIKA, one of the leader if the construction industry. This thesis report is organized in three chapters where each of them tries to answer a problem coming from industrial processes. In the first chapter, we studied the impact of particles concentration on the flowing properties of complex fluids such as shear-thinning and shear-thickening fluids. We demonstrated the importance of local contacts between particles to explain the evolution of the viscosity with the volume fraction. In the second chapter, we studied the aggregation of colloidal attractive suspensions under small perturbations and proved the existence of a maximum of elastic modulus during the rebuilding of the structure. Finally, the third chapter is a study of a phase diagram of a concentrated suspension jets. In the diluted and semi-diluted regimes, we found results in agreement with the bibliography, meanwhile at very high concentration, we studied a new regime where the jet, unstable, is oscillating. We showed those oscillations can be explained by the shear-thickening behaviour of the suspensions at those high concentrations
Wone, Michel. "Rhéologie des suspensions non Browniennes concentrées : une étude numérique." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1070/document.
Full textSuspensions of rigid grains in a fluid constitute a class of complex fluids that present a rich rheology. Even simpler cases of non-Brownian, non-colloidal spherical grains suspended in a Newtonian fluid feature macroscopic behaviours that are still not completely understood, especially when the concentration of particles is high. In these materials, the complexity of the dynamic is the result of the subtle balance that occurs between hydrodynamic interactions mediated by the interstitial fluid, and contact forces between grains. In this work, we tackle those questions from the point of view of discrete numerical simulations, in the context of the simple shear of 2D concentrated suspensions. Hydrodynamic interactions are modelled by pair lubrication, coupled with a possibly frictional contact law. Grains inertia is not neglected. We have access to the whole stress tensor, allowing the measure of pressure, shear stress, and normal stress difference, as well as their associated viscosities. The study of constant volume simple shear shows the existence of a shear-thickening transition between a viscous regime at low shear rate (stress proportional to the shear rate) and an inertial regime at high shear rate (stress proportional to the shear rate squared), depending on whether the stress is dominated by lubrication interactions or grains inertia. The position of the measured transition shear rate is consistent with a scaling argument for the stress that takes its divergence with concentration into account. Constant pressure simple shear simulations then let us explore the behaviour of very concentrated suspensions (up to 1% to the theoretical jamming fraction) in their viscous flow domain. We show that the rheology of the mix can then be described by a flow law that is only function of the viscous number, constructed as the ratio of a typical time for the local rearrangement of grains subjected to viscous forces, and a convection time consistent with the imposed flow. This allows a precise characterization of the divergence of stress with particles concentration. At last, we measure the stationary microstructure that develops within the flow. We show an important anisotropy of contacts, and discuss the evolution of this distribution with the concentration of the suspension
Chatté, Guillaume. "Propriétés d'écoulement de suspensions concentrées de particules de PVC et leur lien avec la physico-chimie du système." Electronic Thesis or Diss., Paris Sciences et Lettres (ComUE), 2017. https://pastel.hal.science/tel-03934778.
Full textHighly concentrated and non-colloidal suspensions consisting of micrometric PVC particles dispersed in a liquid phase, were studied. These suspensions, called plastisol, are mostly used in vinyl flooring manufacture.A key feature of these suspensions is shear-thickening, since viscosity greatly increases as a function of the applied shear rate. This phenomenon is explained as being related to frictional forces between particles. Indeed, using an Atomic Force Microscope, we were able, for the first time, to link the macroscopic stress, at which shear-thickening appears, with the microscopic stress needed to enter a frictional regime.We then characterize the suspension viscosity up to 100 000 s-1. We observed that shear thickening is lowered with a more polydisperse powder. Large normal stress differences N1 and N2 were also measured, along with shear thickening. In addition, using both X-ray radiography and ultrasound, no particle migration in the sheared suspension could be detected.We also found that geometry plays a major role in the features of the flow of concentrated suspensions. For a smaller gap, the viscosity is lower and shear-thickening is pushed to higher shear rates. A non-local approach accounts for our experimental results.Replacing a number of PVC particles with CaCO3 particles changes both the viscosity and the maximum packing fraction quite dramatically. For both of these, we developed simple models that matched quite well with the experimental data. Moreover, we elucidate the rheological changes resulting from adding surfactant at the surface of each particle type.Finally, we investigated some instabilities observed while coating at high speed. At a moderate speed, a ribbing phenomenon appears. At a higher speed, a deposit is formed on the knife (downstream). The appearance of these instabilities correlates with normal stress differences
Machado, Anaïs Coline. "Contribution à la rhéologie des suspensions : migration, rhéoépaississement." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0161/document.
Full textFlows of non-Brownian suspensions are present in different fields, and exhibitdifferent behavior in function of concentration. Flows of semi-dilute suspensions aremainly governed by the spatial repartition of the particles. At low Reynolds numbers,it is indeed generally non-uniform due to cross-stream migration towards low shearedregions of the flow. In this work we aim at testing the idea that interactions betweenparticles could also be involved in the shear induced migration phenomenon. In orderto quantify the strength of shear induced migration, we take advantage of horizontalflow of buoyant particles in slits, where viscous resuspension is in competitionwith buoyancy.Using advanced particle imaging velocimetrie techniques and confocalmicroscopy, we measure systematically both volume fraction and velocity profiles.We compare two systems with and without interaction and any different was found.Concentrated suspensions exhibit a wide range of non linear rheological phenomena.This work characterizes the local rheology of a continuous shear thickening. We areused ultrasonic rheology and tomography RX in Couette cell for measured the volumefraction profile and velocity profile. We report that the rheological properties dependstrongly of the confinement and roughness, and sometimes we observed instabilitiesdue to the interface
Chatté, Guillaume. "Propriétés d'écoulement de suspensions concentrées de particules de PVC et leur lien avec la physico-chimie du système." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET005.
Full textHighly concentrated and non-colloidal suspensions consisting of micrometric PVC particles dispersed in a liquid phase, were studied. These suspensions, called plastisol, are mostly used in vinyl flooring manufacture.A key feature of these suspensions is shear-thickening, since viscosity greatly increases as a function of the applied shear rate. This phenomenon is explained as being related to frictional forces between particles. Indeed, using an Atomic Force Microscope, we were able, for the first time, to link the macroscopic stress, at which shear-thickening appears, with the microscopic stress needed to enter a frictional regime.We then characterize the suspension viscosity up to 100 000 s-1. We observed that shear thickening is lowered with a more polydisperse powder. Large normal stress differences N1 and N2 were also measured, along with shear thickening. In addition, using both X-ray radiography and ultrasound, no particle migration in the sheared suspension could be detected.We also found that geometry plays a major role in the features of the flow of concentrated suspensions. For a smaller gap, the viscosity is lower and shear-thickening is pushed to higher shear rates. A non-local approach accounts for our experimental results.Replacing a number of PVC particles with CaCO3 particles changes both the viscosity and the maximum packing fraction quite dramatically. For both of these, we developed simple models that matched quite well with the experimental data. Moreover, we elucidate the rheological changes resulting from adding surfactant at the surface of each particle type.Finally, we investigated some instabilities observed while coating at high speed. At a moderate speed, a ribbing phenomenon appears. At a higher speed, a deposit is formed on the knife (downstream). The appearance of these instabilities correlates with normal stress differences
Landazuri, Gomez Gabriel. "Les études de la dynamique du système micellaire P103/Eau et système de rhéoépaississement CTA-n-Fluorobenzoato." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00955891.
Full textMandal, Anirban. "Computational Modeling of Non-Newtonian Fluid Flow in Simplex Atomizer." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1202997834.
Full textLiu, Wen-Hong, and 劉玟泓. "Shear thickening and properties of polyionomer solutions." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/44254633678148511720.
Full text元智大學
化學工程與材料科學學系
95
Using dynamic light scattering (DLS) and capillary dynamic viscoelasticity (DVE) analyzer, we investigated: (1) dilute (0.5 mg/ml) poly(diallyl dimethyl ammonium chloride) (PDADMAC) aqueous solutions properties for three different molecular weights PDADMACs mixed with various concentrations of NaCl; and (2) physical properties of 5 wt% poly(N-isopropyl acryl amide) (poly(NIPAM)) (Mv=3.22x105) semi-dilute solutions in H2O, D2O, and THF (tetrahydrofuran) solvents. PDADMAC is a cationic polyelectrolyte. In the first part of this thesis, the influences of polymer molecular weight and NaCl concentration on the PDADMAC conformations in dilute aqueous solutions were studied. By analyzing dynamic shear viscosity, viscoelastic relaxation times tr, and shear rate at tube wall ŕa of PDADMAC aqueous solutions in oscillatory flows, we proposed polymers chains conformations varied with increasing shear frequency via the following steps: intra-polymer associations, dissociation of intra-polymer associations, stretching of polymer chains, inter-polymer aggregations, and dissociations of inter-polymer aggregations. The intra-polymer associations lowered the n’ exponent of storage modulus G’with n’< 2, and the polymer chains stretching and inter-polymer aggregations caused shear thickening of PDADMAC aqueous solutions. The behaviors of the lowering of n’ exponent with n’< 2 and the shear thickening were favored by increasing ionic strength of solutions. By comparing data with DLS hydrodynamic radii (Rh) data, we also confirmed the possibility of inter-polymer aggregations in dilute solutions when polymers chains were stretched in oscillatory flows. Poly(NIPAM) is a polymer consists of hydrophilic –NHC=O groups and hydrophobic –CH(CH3)2 groups and hydrophobic –CH2-CH- backbone. In the second part of this thesis, the influences of H-bonding (D-bonding) of H2O and D2O with –NHC=O group and hydrophobic property of polY(NIPAM) in H2O, D2O, and THF solvents were investigated. The DLS data showed that there were poly(NIPAM) slow mode inter-polymer chains associations in H2O and D2O solvents. However, no DLS slow mode was observed in poly(NIPAM)/THF solutions. The DSV data showed that there are shear thickening behavior in these three poly(NIPAM) solutions, resulting in a maximum shear viscosity in the viscosity versus shear frequency curve. The slow mode hydrodynamic radius
Li, Wan Cheng, and 李萬成. "Developing the Protective Materials Containing Shear-Thickening Nanocomposites." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/90616560681974146110.
Full text國防大學理工學院
化學工程碩士班
103
The shear thickening behaviors of concentrated dispersions of micro-silica and nano-silica particles in the ethylene glycol (EG)/poly ethylene glycol (PEG) mixtures are studied by a rheometer. The results show that all SiO2/PEG/EG suspensions possess the reversible shear thickening behaviors. The effects of nano-silica content and EG content on the maximum viscosity and critical shear rate are observed. On the other hand, the ballistic performance and stab resistance of the shear thickening fluids with different compositions are investigated by a drop weight tester and a low velocity ballistic impact test (muzzle velocity of 200 ± 50 m/s) conducted using a gas gun and then finally ballistic impact test (muzzle velocity of 350 ± 50 m/s) conducted tested by practical shooting with 90mm bullet to assess the best conditions for obtaining the best bulletproof and anti-puncture capability.
Asija, Neelanchali. "Synthesis and characterization of shear thickening fluids for high strain rate applications." Thesis, 2017. http://localhost:8080/iit/handle/2074/7324.
Full textLin, Jhih-Jhang, and 林志璋. "Study of Impact Resistance of Composites Containing Shear Thickening Fluid." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/3vfnxc.
Full text國立臺北科技大學
化學工程研究所
101
In this study, shear thickening fluid was prepared by two methods. Polyethylene glycol was used as the fluid and silicon dioxide nanoparticles of two different sizes were used as the colloid. From the results, we observed that the mixtures of high loading level of silica nanoparticles with polyethylene glycol demonstrated significant shear thickening behavior. For the PEG fluid containing 40 wt% 15 nm silicon dioxide nanoparticles, the viscosity of fluid instantly increased 29 to 30 times when shear rate increased from 5/s to 28.9/s. Also, for the PEG fluid containing 72.93 wt%, 450 nm silicon dioxide nanoparticles, the viscosity of fluid instantly increased 7 to 9 times when shear rate increased from 61.1/s to 217/s. One of the applications of STF is protection. Impregnating Kevlar fabrics with shear thickening fluid into Kevlar fabric may significantly reduce the layers of Kevlar fabric needed for ballistic impact resistance and improve the flexibility of the composite. In this study, ballistic testing samples were prepared from neat Kevlar fabrics and STF-impregnated ones using Kevlar fabrics with various amount of shear thickening fluid. The result shows that samples reinforced with STF showed a significant improvement in bullet energy absorption.
Yan, Rui-Liang, and 顏瑞良. "Shear thickening fluids applied to the study of liquid armor." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/80836172599145133408.
Full text國防大學中正理工學院
應用化學碩士班
99
Shear thickening fluid (STF) has found its applications in protective materials recently. Generally, the STF consists of colloidal silica particles, their average size being about 450nm, being dispersed in a liquid solvent. However, the particle size of the particles has tremendous influence on the rheological behavior of the suspension. Therefore, in this study, shear thickening behaviors of nano silica , submicron silica and carbon nanotubes dispersions in ethylene glycerol (EG) and polyethylene glycol (PEG) have been studied with rheometer. The dispersion stabilities, thermal characteristics and rheological behaviors of silica suspensions were studied to elucidate the effects of particle size and solid content. This paper also presents an experimental research regarding the ballistic performance of STF-containing Kevlar fabrics and UHDPE. STF shows its potential in many possible civilian applications, such as protective equipment, motorcycle clothing and damping material. The study, shear thickening behaviour and dispersions in room temperature vulcanized (RTV) and Shear thickening fluid have been studied with foam. The dispersion stabilities, thermal characteristics and rheological behaviors of silica suspensions were studied to elucidate the effects of particle size and solid content. This paper also presents an experimental research regarding the impact test performance of STF-RTV composite materials. STF-RTV composite materials shows its potential in many possible civilian applications, such as protective equipment, motorcycle clothing and damping material.
Chen, Poyun, and 陳柏元. "Investigation Of The Fibrous Protection Material Using Shear Thickening Liquid." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/77b2dd.
Full text國防大學理工學院
化學工程碩士班
100
The stab resistance performance of newly developed fabric composites composed of hexagonal paper honeycombs, filled with shear thickening fluid (STF), and woven Kevlar® fabric or Spectra was investigated in this study. The STF was prepared by dispersing submicron SiO2 particles into polyethylene glycol (PEG). Our results indicate that the STF-Kevlar composite possessed lower penetration depth than that of neat Kevlar. In other words, the STF-Kevlar composite can attain the same energy level in stab-resistance test with fewer layers of Kevlar fabrics than that of the neat Kevlar fabrics. It also indicates that STF can be used for the fabrication of flexible body armors and can provide improved protection against stab threats. We found that the stab resistance of the STF-Kevlar composite increases with the increase of SiO2 concentration in STF. Moreover, the silica particles functionalized with silane coupling agent can further improve the stab resistance. In ballistic impact tests, five layers neat Kevlar fabric can expense 16.22% of the ballistic rate. Use STF-Kevlar composite in the same ballistic tests can expense 20.22% of the ballistic rate. Shows that if STF is increased viscosity and critical shear rate will increase the identity of resisting bullet.
Joshi, Anil Kumar. "Wall shear stress and intimal thickening in the right coronary artery." 2004. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=80993&T=F.
Full textChen, Yao-Chun, and 陳堯鈞. "Preparation and Properties of multi-layer Kevlar / Shear Thickening Fluid Composites." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/n9543p.
Full text國立臺灣科技大學
材料科學與工程系
104
This study reports a “scale up process” of shear thickening fluid (STF). The 40 wt% STF / Kevlar composite was manufactured by two different process. One is impregnating Kevlar fabrics with STF. The other method uses “mangle machine” padding the STF into Kevlar fabrics. The air gun impact test result of the impregnating method showed that STF impregnating with 2 layers Kevlar K129 can significantly increase EDP by 31%. The air gun impact test results of the “mangle machine” method prepared composite is similar with the sample prepared by the impregnating method. However, stab test results showed that sample prepared by the mangle method showed a better resistance than the sample prepared by the impregnating method. The ballistic impact, drop tower, and flexibility tests were conducted. To determine the performance of 30 layers Kevlar without coating STF and the 20 layers STF/Kevlar coated with STF and made by the “mangle machine” method. The result of ballistic impact tests showed both 20 layers STF/Kevlar and 30 layers Kevlar were of the same protection level. They both meet the requirement of NIJ 0101.04-II protection standard. The thickness of 20 layers STF/Kevlar composites were 70% of 30 layers Kevlar. The flexibility tests showed that 20 layers STF/Kevlar composites possesses better flexibility than 30 layers Kevlar. The drop tower test indicated that the 20 layers STF/Kevlar showed similar protective effect as 30 layers Kevlar. The ballistic impact test also showed similar results. Adding STF made the composites lighter and more flexible than conventional Kevlar.
Shen, Ching, and 沈情. "Synthesis of Core-Shell Nanoparticles and Its Application as Shear Thickening Fluid." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/fz42aa.
Full text國立臺北科技大學
化學工程研究所
102
Shear thickening fluid, a type of non-Newtonian fluid, changes viscosity based on shear rate. It has low viscosity at low shear rates, and high viscosity at high shear rates. Thus, this fluid stays mobile under normal conditions, but swiftly hardens upon high-speed impact, resulting in a material useful in liquid armor. So far, most studies have focused on silica-based material as the primary particles in shear thickening fluids, but they often show limited resistance to puncturing. Herein, an approach to synthesize core-shell (alumina/silica) nanoparticles, which can be used as the dispersed phase in the liquid armor materials. Notably, the combination of alumina and silica materials shows significant advantage for enhancing the protective properties of the liquid armor. The core-shell nanoparticles in this study were synthesized using a sol-gel process wherein the silica shell was grown on alumina nanoparticles via a condensation reaction with TEOS. Subsequently, characterization was performed through dynamic light scattering, TEM, and zeta potential measurements. Rheometer measurements were also made using the as-synthesized nanoparticles (treated via sonication) dispersed in a polyethylene glycol medium with varying volume fractions. Thus, the rheological properties of the core-shell system could be investigated and the shear thickening phenomenon observed at high shear rates. Finally, the application of alumina/silica core-shell nanoparticles in liquid armor and the optimization of their comprehensive feasibility and rheological properties are discussed.
CHEN, YING-JU, and 陳盈儒. "Research of the Protective Materials Containing Shear- thickening-fluid with Graphene Composites." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/95389444518702825488.
Full text國防大學理工學院
化學工程碩士班
104
Shear thickening fluid (STF) is a colloidal suspension of solid particles suspended in fluid and exhibits the shear thickening phenomenon resulting in large, sometimes discontinuous increase in viscosity above a critical shear rate. This particular rheological property of STFs can be utilized to improve their impact resistance and can be used in many protective applications. However, the impact resistance and threats including puncture, stab and 9 mm bullet impacts (muzzle velocity of 350 ± 10 m/s) varies from the low velocity range to high velocity range. Therefore, the effect of the magnitude of critical shear rate on impact performance is investigated in this research. The critical shear rate of STF is adjusted by varying the size and content of silica particles as well as the solvent composition. In addition, the graphene is also added into STFs to change their rheological property which in turn changing their protective properties. The results of this research can aid in the development of a broad range of protective materials for both consumer and military applications.
Majumdar, Sayantan. "Flow Induced Instabilities, Shear-Thickening And Fluctuation Relations In Sheared Soft Matter." Thesis, 2012. https://etd.iisc.ac.in/handle/2005/2560.
Full textMajumdar, Sayantan. "Flow Induced Instabilities, Shear-Thickening And Fluctuation Relations In Sheared Soft Matter." Thesis, 2012. http://hdl.handle.net/2005/2560.
Full textHsieh, Wei-Ting, and 謝瑋庭. "Studies on impact resistance and energy dissipation properties of shear thickening polymer mixtures." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/zwp2v3.
Full text國立臺灣科技大學
材料科學與工程系
104
The main aim of this present dissertation is to prepare effective condition and formulation of the shear thickening fluid of the SiO2 blended with polyethylene glycol (200) was performed through the rheometer by measured shear thickening phenomenon with various concentrations. The shear thickening effect was optimized to find out the best conditions for usage as the protective equipment. Upon increase the volume fraction of SiO2, the viscosity was increased continuously (CST) to discontinuously (DST). The slope of viscosity curve in shear thickening part was found as increased with increased volume fraction (Φ) and diverged at critical volume fraction(Φ_c). Such a diverging viscosity is mainly related to jamming phenomenon. Also, we have found the normal force emerges while rheological measurement, which is attributed to the formation of particle’s anisotropic microstructure (hydrocluster). In addition, influence of external temperature was studied to understand shear thickening behaviors upon the increase the temperature. The reduction of the shear thickening effect was observed while increased temperature of SiO2 blend. Thus, we have used the viscosity of PEG200 to normalize the temperature effect, and found that the main reason for shear thickening effect reduction due to the continuous phase of PEG200, which was influenced by temperature. In order to understand further shear thickening phenomenon, we have used large amplitude oscillatory shear (LAOS) to investigate the nonlinear viscoelastic behavior of shear thickening phenomenon. The obtained results indicated the elastic nonlinearity and viscous nonlinearity were donated by strain-rate. However while increased the angular frequency, viscous nonlinearity have been converted to strain dominated. Finally, we have obtained the dissipated energy by integrating the area of Lissajous-Bowditch curve, which shows an obvious increase in energy dissipation in the shear thickening region. The dissipated energy of DST is more efficient than dissipated energy of CST, and an increase of angular frequency tends to enhance the dissipated energy. These results imply that obtained shear thickening fluid composite can raise viscosity (hardness) and energy dissipation as shear thickening occurs. The above comparison results revealed that presented optimized condition may possible to produce fluid analogue to usage as the protective equipment.
Chien, Shih-Shun, and 簡士勛. "Synthesis of Alumina and Core-Shell Nanoparticles and Their Application as Shear Thickening Fluid." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/08424170518396013973.
Full text國立臺灣大學
化學工程學研究所
101
Abstract Shear thickening fluid, so called STF, which has a special rheological behavior of the fluid. When suddenly exposed to external shocks, it rapidly presented like a solid which has hardness of properties in a short time (about a few milliseconds). Army Research Laboratory (ARL) first developed shear thickening fluid for military. They researched based on the Kevlar fibers, which was immersed the shear thickening fluid which consists silica nanoparticles and polyethylene glycol mixing, and they called it liquid armor. This shear thickening fluid can greatly enhance the application of Kevlar fiber strength and impact resistance. So far, study of shear thickening fluid based on nano silica particles is now quite mature, the tests on STF-Kevlar fiber containing the liquid armor by spikes, razor, needle, and low-speed bullet attack presented in much effective impact on defense capabilities in general Kevlar fiber. This result makes shear thickening fluid earn greatly in the military''s attention. There are many capable STF research direction currently, so our major research is core-shell (polystyrene / silica) and alumina, which can replace silica nanoparticles as a new dispersed phase and then disperse in polyethylene glycol alcohol. Finally, we use rheometer to test their rheological behavior, exploring the future of this shear thickening fluid.
Srivastava, Ankita. "Studies on impact resistance behavior of woven textile structures treated with shear thickening fluids." Thesis, 2013. http://localhost:8080/xmlui/handle/12345678/6586.
Full textRabb, Robert James 1966. "A mesomechanical particle-element model of impact dynamics in neat and shear thickening fluid kevlar." Thesis, 2007. http://hdl.handle.net/2152/3268.
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ZHENG, MING ZHE, and 鄭明哲. "The Study on Anti-stab Property of Fabric with Kevlar/Shear Thickening Fluid/ Graphene Oxide." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/222q6m.
Full text逢甲大學
纖維與複合材料學系
105
In order to reduce the number of layers of Kevlar fabric effectively and to improve the mobility of personnel, we used colloidal silica dispersed in polyethylene glycol to prepare shear thickening fluid that was used in protective armor with effective protective properties. The addition of graphene oxide was discussed in this paper to investigate its impact on the effect of shear fluid properties. In this study, we investigated the puncture test, falling weight impact test, rheological test and torsion test of colloidal silica in different molecular weight of polyethylene glycol (PEG) impregnated Kevlar KK10 fabric. The falling weight impact test was carried out by using blunt-nosed bullet (9 mm) and pointed bullet (7.62 mm), and hope the test results can be applied to the anti-bullet protection. The experimental results showed that the fabric impregnated with PEG molecular weight of 200 and 60 wt% of colloidal silica had better puncture resistance than that of non-impregnated fabric by 414%. In the falling weight impact test with blunt-nosed bullet, the absorption energy of the impregnated fabric was increased by 66.87%; whereas the absorption energy of the impregnated fabric with pointed bullet was increased by 126.11%. The addition of graphene oxide impacted on the shear thickening phenomenon, and enhanced the anti-puncture property of PEG with molecule weight of 600; however, it decreased that of PEG with molecule weight of 200.
Rabb, Robert James. "A mesomechanical particle-element model of impact dynamics in neat and shear thickening fluid kevlar /." 2007. http://www.lib.utexas.edu/etd/d/2007/rabbr70962/rabbr70962.pdf#page=3.
Full textTse-WeiWu and 吳則葳. "A Study of Viscoelastic Behavior for Shear Thickening Material and its Application to Structural Vibration Suppression." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/77957769918291424745.
Full text國立成功大學
航空太空工程學系碩博士班
101
The thesis proposed how to design a vibration absorber under dynamic loadings with different frequency by using Finite Element code – ABAQUS. When a satellite launched, it is tolerated with complicated dynamic loadings. In order to protect electrical equipments in satellite, how to design a specific vibration absorber to improve the dynamic response seems important. Frequency-dependent viscoelastic materials are applied to absorbers in order to further dissipate energy. In addition, these kinds of viscoelastic materials will affect absorber’s performance obviously. Thus, in order to understand these dynamic behaviors of viscoelastic materials, 14 nm fumed silica particles and polypropylene glycol (PPG) are used to fabricate the shear thickening fluid (STF). Based on test results, when the shear loading is increased, the corresponding viscosity is increased for STF. Upon examining rheometrical tests, it reveals that STF possesses frequency-dependent characteristic in the current work. The relationship between material properties and structural response can be analyzed by vibrating beam testing (VBT). Finally, ABAQUS is used to analyze and design the proposed absorber. All of discussions and influences about absorbers’ performance caused by frequency-dependent material properties under complicated dynamic loading are presented.
Nilsson, Michael Andrew. "Multiphase Flows with Digital and Traditional Microfluidics." 2013. https://scholarworks.umass.edu/open_access_dissertations/735.
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