Application of shear thickening nonnewtonian fluid to minimize head and neck injury work in progress jose herrera student at vaughn college of aeronautics and technology, flushing, ny, usa, email protected mamunur anik student at vaughn college of aeronautics and technology, flushing, ny, usa, email protected advisors. They saturate the kevlar with the diluted fluid and place it in an oven to evaporate the ethanol. A first type of technology based on shear thickening fluids was invented in 1999 by the british engineer richard palmer palmer and green, 2001 and is commercialized by the d3o company. Shear thickening fluids in protective applications. The nanosio2polyethylene glycol peg dispersion system was prepared by centrifugal mixing, and its rheological properties were investigated. Dynamic properties of sandwich structures with integrated shearthickening fluids c fischer, s a braun, pe bourban et al. Hydrodynamics the dynamics of colloidal dispersions is inherently a manybody, multiphase fluidmechanics problem. The shear thickening fluids comprise 1 a water swellable granular clay present in sufficient quantity so that, upon interaction with an aqueous phase, a stiff paste rapidly forms having a strength of at least 2000 lbs100 ft 2, 2 a nonaqueous phase comprising. Typically a shear thickening fluid consists of a colloidal dispersion of nonaggregating particles in a polar organic solvent. Impact studies of shear thickening fluids incorporated withi. At low re, viscoelasticity decreases the drag on a cylinder. Pdf incorporation of shear thickening fluid effects into.
They are considered possible candidate materials for liquid body armour and sporting protective clothing and other applications because of their unique. Experimental and modeling study of viscoelastic behaviors of magnetorheological shear thickening fluids koreaaustralia rheology j. Synthesis and rheological behavior of shear thickening fluids stfs for liquid armor applications shear thickening is a phenomenon which is generally observed in concentrated colloidal dispersions and defined as the increase in viscosity with increasing shear stress or shear rate. Shear thickening fluid impregnated ballistic fabric. The shearthickening characteristics in some nonfluids are being exploited to provide substantial nonlinear damping to sudden.
Dynamic properties of sandwich structures with integrated shear thickening fluids c fischer, s a braun, pe bourban et al. One approach to this issue is the use of fluidfilled elastomeric foams. Apr, 2010 those authors referred to the process as fluid fracture, 39,52 a sharp decrease in viscosity after shear thickening called fluid fracture in their paper was observed, similar to what we report here. Shear thickening fluids stfs are novel fieldresponsive materials that can be engineered to be useful nanocomposites for enhanced ballistic and impact protection, puncture resistant medical gloves, energy absorbing materials for mitigating impacts and concussions, as well as in systems for. Liquid armor using shear thickening fluid stf is being developed at the u. In this project, the application of shear thickening nonnewtonian fluid is proposed to dampen sudden acceleration and deceleration to minimizing neck trauma also known as whiplash. In the present thesis, the fluid within these foams is a nonnewtonian shear thickening fluid composed of 300 nm silica particles suspended in a solvent, ethylene glycol, at high concentrations, 4555 %. Posts about shear thickening fluid written by nbkaye.
By varying the rheological properties of the shear. This phenomena is called shear thickening, in which the fluid viscosity increases with increasing applied force. Your speechlanguage therapist slt will recommend which consistency you should use. The stf referred to in this article is made up of hard silica particles suspended in polyethylene glycol, a nontoxic fluid. Shear thickening fluids liquid intelligence business. This shear thickening phenomenon can be used to improve the ballistic protection of body armor.
Shear thickening fluids stfs based on additives with different concentrations and molecular chain lengths were investigated. Shear thickening fluid an overview sciencedirect topics. In the present thesis, the fluid within these foams is a nonnewtonian shearthickening fluid composed of 300 nm silica particles suspended in a solvent, ethylene glycol, at high concentrations, 4555 %. Suitable for people with feeding or swallowing problems and makes swallowing safer. Accurate measurement of fluid flow properties is a complex task. The shearthickening properties allow for more effective cuttings transport and more effective hole cleaning. However, the mechanism of defeating a projectile using a shear thickening fluid impregnated multilayered fabric is not fully understood and can be considered as a gap in the research done on. Shear thickening dilatancy in concentrated dispersions a new criterion is introduced for the onset of shear thickening in a concentrated dispersion.
Shear thinning is a behavior of drilling fluids in which the viscosity of a certain drilling fluid decreases under shear strain. In this work, a novel prototype shear thickening fluid damper was fabricated and its dynamic characteristics were experimentally investigated. Pigford chaired professor in the university of delaware s department of chemical and biomolecular engineering, will deliver an american chemical society webinar, future protective materials for first responders, football players, and astronauts. Shear thickening fluids or dilatant fluids are a type of non newtonian fluids that exhibit increase in their dynamic viscosity with increase in the rate of shear deformation or shear rates. The thickness of fluid that you require depends on your specific. On the other hand, this liquid can be as stiff as solid if you try to stir it vigorously or smash it with a hammer. In comparison with available data for suspensions in newtonian media, shear thickening occurs at much lower volume fractions. To make liquid body armor using shear thickening fluid, researchers first dilute the fluid in ethanol. Review on shear thickening fluids and applications abstract recently, research in the area of shear thickening fluids stfs has increased due to the potential for commercial application. Mar 22, 2007 this video shows some of the properties of a dilatant compound shear thickening fluid including its ability to stretch, flow, and tear. With a few simple ingredients you too can make shear thickening fluid bullet resistant kevlar panels that are more protective and resilient than anything on the market today.
It includes a foam elastomeric polyurethane matrix in which a borated silicone shear thickening fluid is distributed. Energy absorption in a shearthickening fluid springerlink. A force balance at small interparticle distances is used to. The combination of the fluid and the fabric allowed the fabric to resist penetration by hypervelocity particles in space. They treat soft body armor with shearthickening fluid and end up with something that can stop a. A wellcontrol shear thickening composite comprising 1 water swellable clay granules capable of rapidly forming a high strength paste when brought into contact with water, 2 a hydrophobic phase comprising oil and a surfactant and 3 an aqueous phase comprising water and a water soluble polymer wherein the clay granules, present in sufficient quantity so as to form a. Shear thickening fluids stf are usually composed of hard particles of metal oxides involving silica, corundum, kaolin etc.
The rheology of shear thickening fluid stf and the dynamic. May leave a film of residue in the cup after being poured. Shearthickening response of fumed silica suspensions. An analysis of the model reveals that the shear thickening fluid shows an instability in a shear flow for some regime and exhibits the. Shearthickening response of fumed silica suspensions under steady and oscillatory shear srinivasa r. This video shows some of the properties of a dilatant compound shear thickening fluid including its ability to stretch, flow, and tear. This study investigates energy absorption in a shearthickening fluid stf containing nanosize fumed silica as a suspending material. Shear thickening fluid stf is a nonnewtonian fluid. Shear thickening is studied in suspensions consisting of micrometer sized polystyrene spheres dispersed in boger fluids. The properties of shear thickening fluid stf, based on polypropylene glycol and amorphous silica, modified by the addition of multiwalled carbon nanotubes mwcnts, were studied. Poland developing liquid body armor popular science. Shear thickening fluid, body armour, aramid, ballistics, damping. People can find that drinking thickened fluids is not as pleasant as.
Sep 27, 2016 in order to observe shear thickening behaviour in a suspension, there are three important factors to consider. Research and applications of shear thickening fluids. In colloid systems, phase separation during flow leads to shear thinning. For example, the velocity required to penetrate a single layer of kevlar is about 100 ms, but kevlar formulated with a colloidal silica shear thickening fluid can stop projectiles up to 250 ms. Characterization of shearthickening fluidfilled foam. Stfs draw continued attention as they are considered possible candidate materials for liquid body armour and sporting protective clothing because of their unique properties.
The role of shearthickening fluids stfs in ballistic. May 10, 2012 shearthickening fluids stfs are a special nonnewtonian fluid that act like a solid when they experience a force. Although shear thickening fluids are significantly less common in industry than shear thinning fluids, they. Khan1 department of chemical engineering, north carolina state university, raleigh, north carolina 276957905 received march 14, 1996. The next generation of protective equipment is looking a lot less bulky and a lot more fluid. In order to develop a design method of stf damper for engineering application, it is important to build the database of stf fluid as figure 7 shows and use the. This means that the viscosity of fluid decreases whenever the rate of shear increases. You can see this effect in the slow motion videos below. Shearthickening fluid duncan price physics department, the college of wooster, wooster, ohio 44691, usa dated.
Shear thinning and shear thickening non newtonian confined fluid flow over rotating cylinder. Icme overview of shear thickening fluids in body armor evocd. Design and manufacturing of a novel shear thickening fluid. Mildly thickened fluids pour quickly from a cup but more slowly than regular, unmodified fluids. One approach to this issue is the use of fluid filled elastomeric foams.
The criterion follows from the assumption that shear thickening occurs when the shear forces overrule the interparti cle forces. Shear thickening fluid duncan price physics department, the college of wooster, wooster, ohio 44691, usa dated. Future protective materials for first responders, football. You will need a tub of thickening agent such as nutilis, thick and easy or resource thicken up clear. Stf is a kind of nonnewtonian fluid, where the shear stress is not linearly related with the shear rate. Recently, research in the area of shear thickening fluids stfs has increased due to the potential for commercial application. Increasing the concentration of particles within the fluid will lead to an enhancement of the thickening effect, therefore the weight fraction has to be evaluated according to the system viscosity requirement. The rheology of shear thickening fluid stf and the. Such a shear thickening fluid, also known by the initialism stf, is an example of a nonnewtonian fluid. Thickening behavior is observed in dense colloidal suspensionswhich are composed of solid particles silica, calcium. Shear thickening fluid exhibits a tremendous ability to dissipate energy under an unexpected attack by presenting an abrupt increase in viscosity. Our standard formulation sg offers a great way to explore the potential benefits of shear thickening fluids for a variety of products, including motion control, impact protection, and puncture resistance applications.
Pigford chaired professor in the university of delawares department of chemical and biomolecular engineering, will deliver an american chemical society webinar, future protective materials for first responders, football players, and astronauts. Hydrodynamics the dynamics of colloidal dispersions is inherently a manybody, multiphase fluid mechanics problem. Remove any lumps or grit by pouring the fluid through a sieve. Recent advancements in shear thickening fluid applications a. On the other hand, the other patent 33 studied the rheology of a colloidal pegbased shear thickening fluid emulsified with silicone oil. This study investigates energy absorption in a shear thickening fluid stf containing nanosize fumed silica as a suspending material. Shear thinning and shear thickening characteristics in. Characterisation of shear thickening fluids convention rheometer tells you whether a fluid discontinuously shear thickens and critical shear rate no indication of the energy absorbed by the fluid upon impact fluid impact tests rounded plunger head cup containing fluid load cell attached to base of cup used to measure stress generated upon. This behaviour is usually not observed in pure materials, but can occur in suspensions. Many modern drilling fluid systems are nonnewtonian.
A normalized method that considers the effects of electric. Though the exact cause of shear thinning is not fully understood, it is widely regarded to be the effect of small structural changes within the fluid, such that microscale geometries within the fluid rearrange to facilitate shearing. The stf then permeates the kevlar, and the kevlar strands hold the particlefilled fluid in place. They are considered possible candidate materials for liquid body armour and sporting protective clothing and other.
To date, both research and existing national terminologies, have studied or recommended the classification of drinks based on viscosity. The shearthickening characteristics in some nonfluids are being exploited to provide substantial nonlinear damping to. Mechanism of shear thickening in reversibly crosslinked. Stf kevlar is also stab proof whereas no other light weight 3 protection is. Shear thickening fluid is a rather prosaic blend of plastics producing another promising type of new armor, according to scientists at rice university in houston. Shear thickening fluid exxon production research co. Introduction to shear thickening fluids stf shear thickening fluids or dilatant fluids are a type of non newtonian fluids that exhibit increase in their dynamic viscosity with increase in the rate of shear deformation or shear rates. Impact response of shear thickening fluid stf treated high. Shear thickening fluids stfs have been studied extensively, and an enormous number of patents have been generated due to their potential for commercial applications. However, viscosity measurement is not accessible to most clinicians or caregivers. Suspensions in normal nonlinear viscoelastic media typically do not display shear thickening at all. When the revolution speed of the centrifugal mixer was fixed at a high speed of 1200rpm, the. In nonnewtonian fluids, viscosity can change when under force to either more liquid or more solid. Those authors referred to the process as fluid fracture, 39,52 a sharp decrease in viscosity after shear thickening called fluid fracture in their paper was observed, similar to what we report here.
Recent advancements in shear thickening fluid applications. Jaeger james franck institute, the university of chicago, chicago, il 60637 dated. Examples of thin fluids that need to be thickened and mixed consistency foods to avoid are provided. The viscosity of fluid increases as shear rate or applied stress increases on the medium 2631. In 2010, british arms giant bae announced a body armor made with kevlar and shear thickening fluid. If the fluid is too thin then add a little more thickener and repeat the steps. Design of a bulletproof vest using shear thickening fluid. The fluid has low viscosity at shear rates lower than a critical value and high viscosity when the shear rate. Here are a couple of videos from the nonnewtonian silly putty demonstration.
Pdf design of a bulletproof vest using shear thickening fluid. Higgins 1mcgill university, department of mechanical engineering, montr. A comprehensive literature exists on the viscoelastic fluids flow over a stationary circular cylinder 21. Pdf bulletproof vests are used to protect the user from bullets fired at them. Army research laboratory at aberdeen proving grounds. It is often termed as a dilatant fluid and is characterized by significant, and sometimes discontinuous, increase in viscosity when the applied shear rate reaches a critical value. Our standard formulation sg offers a great way to explore the potential benefits of shear thickening fluids for a variety of products, including motion control, impact. The results showed the revolution and rotation speed during the centrifugal mixing have a significant effect on the rheological properties of sio2peg system. Gong, the rheology of shear thickening fluid stf and the dynamic performance of an. There are some lighter carbon nanotube panels and lighter uhmwpe panels but they are not as robust and will fail with fewer impacts. A nonnewtonian fluid is a fluid that does not follow newtons law of viscosity, i. The role of shearthickening fluids stfs in ballistic and stabresistance improvement of flexible armor.
May 10, 2012 shear thickening fluids stfs are a special nonnewtonian fluid that act like a solid when they experience a force. Stf samples were prepared with silica and additive dispersed in. Application of shear thickening non newtonian fluid to. Application of shear thickening nonnewtonian fluid to. The instant invention is directed to shear thickening fluids to prevent unwanted flow in wells penetrating subterranean formations. Both traditional, clay viscosified and newer polymer viscosified systems exhibit. Shear thickening dilatancy in concentrated dispersions. To make liquid body armor using shearthickening fluid, researchers first dilute the fluid in ethanol. One of the most dramatic properties of shear thickening fluids is their strong response to impact. Understanding of this phenomena may allow us to take advantage of the unique and impressive impact resisting properties of shear thickening fluids. Pdf shear thickening fluids based on additives with. Its a type of clear polyurethane that not only stops bullets, but also seems to absorb them. Stf technologies is now offering our shear thickening fluids for sale.
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