Kevlar

Aerospace engineer and composites expert Greg Mark founded MarkForged to explore the possibilities of automating the fabrication of advanced composites. Recently the company announced the production of its Mark One printer, the world's first 3D printer of continuous carbon fiber. The Mark One enables users to create physical objects with extreme strength-to-weight ratios-higher than 6061-T6 Aluminum. The carbon fiber prints are also twenty times stiffer and five times stronger than ABS plastic. According to MarkForged, what distinguishes the Mark One technology is the use of long, continuous strands of carbon fiber-instead of the weaker polymers with short carbon fiber inclusions used to make some carbon-reinforced composites. The Mark One also prints in a range of other materials including fiberglass, nylon, and biodegradable PLA. This material versatility not only makes the printer desirable for a variety of projects, but also as a prototyping machine-giving users the opportunity to print test models in inexpensive polymers before making final versions in carbon fiber or Kevlar. MarkForged claims that the Mark One printhead operation and curing process are superior to conventional 3D printers, since its chemical-free materials harden immediately. Without a lengthy post-curing process or vacuum bagging requirement, the Mark One seems ideal from an indoor environmental quality perspective, and a desirable desktop appliance in a design office. The Mark One may be pre-ordered for $4,999, and is due out later this year. The full developer kit-complete with Kevlar filament-is available for a hefty $8,799.

Key words In this research study Hardness (shore D), Water absorption, Flexural, Impact Test, and Fracture Toughness of polymer nano composites. The polymer nano composites based on unsaturated polyester resin reinforced with Kevlar fibers (K.F). The samples are attended by hand lay – up method according to (Rule mixture) for various volume fractions of unsaturated polyester resin, fiber and carbon nanotube. The polyester resin was matrix strengthened with 3% volume fraction from Kevlar fiber and (0.5%, 1%, 1.5%, 2%) volume fractions of carbon nanotube. The water absorption, hardness (shore D), flexural test, impact test and toughness fracture properties were studied. Results showed that the water absorption increase with volume fraction increase of fiber with Carbon Nanotube, the sample (polyester+3%K.F+0.5% CNTs) has lower water absorption than other samples. The hardness (shore D), flexural test, impact test and toughness fracture for the sample (polyester+3%C.F+0.5% CNTs) has higher value for Nano-composites.

Dynamic behaviour of automotive dry clutches depends on the frictional characteristics of the contact between the friction lining material, the flywheel and the pressure plate during the clutch engagement process. During engagement due to high interfacial slip and relatively high contact pressures, generated friction gives rise to contact heat, which affects the material behaviour and the associated frictional characteristics. In practice excess interfacial slipping and generated heat during torque transmission can result in wear of the lining, thermal distortion of the friction disc and reduced useful life of the clutch.
This paper provides measurement of friction lining characteristics for dry clutches for new and worn state under representative operating conditions pertaining to interfacial slipping during clutch engagement, applied contact pressures and generated temperatures. An analytical thermal partitioning network model of the clutch assembly, incorporating the flywheel, friction lining and the pressure plate is presented, based upon the principle of conservation of energy. The results of the analysis show a higher coefficient of friction for the new lining material which reduces the extent of interfacial slipping during clutch engagement, thus reducing the frictional power loss and generated interfacial heating. The
generated heat is removed less efficiently from worn lining. This might be affected by different factors observed such as the reduced lining thickness and the reduction of density of the material but mainly due to poorer thermal conductivity due to the depletion of copper particles in its microstructure as the result of wear.
The study integrates frictional characteristics, microstructural composition, mechanisms of heat generation, effect of lining wear and heat transfer in a fundamental manner, an approach not hitherto reported in literature.

Współczesne pole walki wymaga nowoczesnych rozwiązań technologicznych, głównie w obszarze wyposażenia  żołnierza oraz  środków rażenia. Zastosowanie nowoczesnych materiałów, takich jak włókna polimerowe czy materiały kompozytowe, pozwala na ochronę ciała  żołnierza przy jednoczesnym zmniejszeniu ciężaru jego oporządzenia. Zastosowanie
nowoczesnych technologii umożliwia wyposażenie  żołnierza w lżejszą broń palną oraz amunicję. Prowadzone sąrównieżbadania nad umundurowaniem umożliwiającym rejestrowanie uszkodzenia ludzkiego ciała i przesyłanie informacji do centrum dowodzenia.

Contemporary battlefield requires new technology, to be applied mainly in the production of a soldier’s outfit and warfare means. The use ofmodern materials such as polymer fibres or composite material enables to protect soldiers and  reduce the weight of their outfit and equipment (lighter firearms and ammunition). The research is also conducted as regards new uniforms with capability to trace injuries of humanbody and send this information to the command center.

Resumen— En este documento se presenta el estudio para el desarrollo de una rutina de termocurado para la manufactura de un laminado multicapa con fibras de Kevlar (ref. 7451A1) unidas en un material compuesto por una resina termoplástica. Para estudiar los modos de falla y las propiedades mecánicas del material compuesto, se realizaron una serie de experimentos diseñados a partir de los modelos matemáticos de diseño robusto de experimentos de Taguchi. Los parámetros utilizados para la caracterización mecánica del material fueron: resistencia del adhesivo (ASTM D3164), resistencia a impacto bajo tensión (ASTM 1822) y resistencia al punzonamiento (ASTM D4833). Finalmente propone una rutina de termocurado para el material: Temperatura: 200ºC, Tiempo a 200ºC: 15 min, Curva de calentamiento: Progresivo (haciendo una pausa en la curva de calentamiento manteniendo el panel a 130ºC por 15 minutos, después continuar con el calentamiento normal), Curva de enfriamiento: 0,02ºC/s, Orientación de Fibras: 45º, Presión de compactación alta.

Everything around us is equipped with technologies and we are desperately trying to run these with clean energy. But the thought of making bullet proof jackets smart never occurs to mind. Soldiers who protect our country must not only be given a simple kevlar vest but an E-Uniform which runs on clean energy. In this research paper, such uniform is proposed. The uniform gives soldier better protection as well as resistance towards heat and cold in extreme weather conditions. It is equipped with a solar panel that charges the battery. The peltier plate installed gives the cooling and heating effect required. The uniform also has GPS for accurate location of soldier and GSM for contacting the soldier. It also has metal detector for detecting land mines.

This work focuses on the preparation of polymer matrix composite specimens by (Hand Lay-Up) method to make bulletproof armor from the unsaturated polyester resin (UP) as a matrix reinforced by Kevlar fibers at different volume fractions with and without (3%) of Al2O3 powder. The tensile test was performed for these composite specimens which include: (modulus of elasticity, tensile strength and elongation percentage), in addition of ballistic test were studied.
The results of this work show that the values of tensile test increase with increasing the volume fraction of fibers. And the values of tensile test of a composite reinforced by kevlar fibers and addition (3%) of Al2O3 powder was less than those composite without addition of Al2O3 powder.
The numerical method based on FEM was used to analysis of the bullet proof armor ballistic test of the composite specimens by finding the values of stresses, strains and deformations.
The numerical results that obtained from the program (ANSYS 14.5) represent the maximum value of stress happened to the composite specimens when reinforced by eight layers of the kevlar, and vice versa to the deformations and strain also the numerical results shown a good agreement with results that were obtained experimentally.
Results of ballistic test of composite specimens show the volume fraction of fibers has an effect on the deformations of the front face and back face of these composite specimens. And the values of the ballistic test for the composite reinforced by kevlar at eight layers give the best values from other each of composite specimens.

Natural fibres are gaining more and more interest as reinforcing materials for polymer composite due to their environmental and economical benefits.  Bast fibers is a prominent reinforcement for use in polymeric materials because of its low specific weight and cost, eco-friendly and abundantly available in nature. Several authors manifest the cellulosic fibers based polymeric composites as advantageously used in automobile industries and structural applications, but certain problems have been associated during usage of such fiber such as high water/mosture-uptake and low strength than inorganic fibers. These problems have been reduced to a major extent with enhancements in mechanical properties by the researchers through hybridization of these natural fiber based composites with synthetic fiber (glass/Kevlar). In the present article, we reviewed the effect of hybridization of glass/Kevlar synthetic fibers on mechanical properties of bast fiber (jute, hemp, kenaf, flax) reinforced po...

In this study robotic hands and fingers' materials are investigated from past to present and a sponge robotic hand is designed for biomedical applications. Emergence and necessity of soft robotic technology are explained and description of soft robot is made. Because of the importance of hand in a person's body, researchers have dealt with robotic hand prostheses for many centuries and developed many hand types. To mimic the best for the human limbs, softness of the hand is one of the important features. Recent studies are summarized in a table. In the table you can see materials that are used in robotic hand and fingers; they are classified as soft and rigid with their years. In literature sponge was found as the most suitable material for the fingers, but there is no study about a sponge hand. This study aims to fill this gap in literature. In this paper manufacturing of a Sponge Robotic Hand's production parameters and stages are explained clearly. Finally advantages of sponge robotic hand and future studies about sponge robotic hand are mentioned.

In this paper Laser Raman Spectroscopy (LRS) was used to estimate interfacial strength of single Kevlar 29/ Epoxy composite system under tension. The debonding was due to local stress concentration and matrix yielding giving rise to exponential increase of the transfer length. At 1.5% matrix strain the fibre is debonded from the matrix.

Representing and Policing the Body in Western Culture International Conference
08-09 Oct 2018
School of Arts and Humanities · FLUL, Lisbon.

The Body Shelter is an empirical project combining artistic and ethnographic work, where visitors are invited to undergo a creative experience by means of a total isolation of their bodies.
Arising from our concern with the political and socio-economic situation in the northeast of Italy, this project aims at breaking down the retinal relationship with reality, providing a time and a place for complete isolation and sensorial recovery of the body. At the core of the project there is a non-patriarchal techno-sculpture, designed to encapsulate the body. The Body Shelter challenges dominant representations of the body by subtracting it from the diktat of the vision and returning it to the use of the neglected senses.

Kevlar is the most commonly used material as armour for protection against bullets used in hand guns because of its impact resistance, high strength and low weight. These properties make Kevlar an ideal material to be used in bullet-proof vests as compared to other materials. In the present study, different numbers of layers of Kevlar with different weights are tested to determine the weights and the number of layers needed to design a safe bullet-proof vest. For this purpose, several ballistic tests were performed on combinations of ballistic gel and Kevlar layers of different weights. Ballistic impacts are generated by 9 mm Parabellum ammunition. The objective is to assess the characteristics of high-speed ballistic penetration into a combination of a gel and Kevlar and determine the number of layers needed to safely stop the 9 mm bullet and thereby contribute to the design of safe bullet-proof vests. The tests provide information on the distances the bullets can travel in a gel/Kevlar medium before they are stopped and to identify the resistance capabilities of Kevlar of different grams per square meter (GSM). The tests were conducted with the use of a chronograph in a controlled test environment. Specifically, results identify the number of layers of Kevlar required to stop a 9 mm Parabellum projectile, and the effectiveness of using different number of layers of GSM Kevlar material.

The objectivity of the engineering is to perform the task in an optimal way and this could be done by selection of prominent material to use in that engineering. When we say material, this means we are going to deal property like physical and mechanical properties under the desirable parameter like cost, availability and also environment. But environment is very important in the process to explore the environment. So finding eco-friendly, renewable kind of material which is fewer hazards and minimizing the use of conventional kind of material is big challenge for us when we do not compromise the quality and cost of it. For this purpose the composite material can be one answer in which natural fiber with less quantity with conventional kind of material are used. Modern testing methods are required to be in use and especially for the composite the test procedure should be strictly follow with eliminating the uncertainty of procedure. As a solution hybrid composite material can be use as it gives improved mechanical, physical and thermal properties and also allow using natural material as per our objective. Scope of this paper is to understand the material characteristics in the sense of future requirement.

Bullet proof vests, made of Kevlar are used for preventing projectiles from injuring humans. Soft armours are capable of protecting humans from low energy projectiles while hard-plate reinforced armours use metal plates, which weigh over 14+ kg for protection against high energy projectiles. NonNewtonian fluids which have time dependent properties (particularly viscosity) are prepared and tested for energy absorbing properties.

It was proved that when Kevlar was used with Oobleck sample, the deformation produced in test plate was reduced considerably as compared to that of only Kevlar sample.

Given the importance of hybrid materials and their uses in many field of life in all the world such as since of medicine used in the manufacture of orthoses and in the automobile industry, aircraft and ships and in the areas of sport in tennis rackets and bicycle tires and other...
so in this paper we have been making and testing five group of samples of the hybrid materials that have specific volume fraction of glass fibers and Kevlar fibers in malty layers and then a tensile mechanical testing them by means of a special machine of composite materials at the Institute Specialist For Engineering Industries according to the standard. It should be noted that each of number of layers and type of reinforced materials under investigation resulted a typical effect on FRP composite properties being produced. It showed that each of these parameters influences the properties of the resulted composites in different ways. The research was to investigate the influence of processing parameters on the mechanical properties (tensile) of the composites and determine an optimum processing route. A considerable positive hybrid effect was noticed for tensile strength and tensile modulus, particularly for the samples consisting of more than one layer and reinforced with two kinds of fibers.

Composite laminates are considered one of the most popular damage-resistant materials when exposed to impact force in civil and military applications. In this study, a comparison of composites 12 and 20 layers of fabrics Kevlar and ultrahigh-molecular-weight poly ethylene (UHMWPE)-reinforced epoxy under low-velocity impacts represented by drop-weight impact and Izod pendulum impact has been done. During the Izod test, Kevlar-based composite showed damage at the composite center and fiber breakages. Whereas delamination was observed for UHMWPE reinforced epoxy (PE). The maximum impact strength was for Kevlar-reinforced epoxy (KE) and increases with the number of laminates. Drop-weight impact test showed the highest absorbed energy for (KE) composites. The results revealed that different behavior during the impact test for composites belongs to the impact mechanism in each test.

Tekst dotyczy wynalazku kevlaru - tworzywa sztucznego o ogromnej odporności, które jest wykorzystywane głównie na kamizelki kuloodporne, hełmy żołnierskie, ale także na skafandry astronautów. Wynalazku tego dokonał zespół firmy DuPont, kierowany przez Stefanię Kwolek, Amerykankę, której rodzice byli Polakami. Oryginalny tytuł felietonu brzmiał: "330. Co pewna Polka dała bohaterskim stróżom prawa, walecznym żołnierzom, kosmonautom… i gangsterom", ale został zmieniony przez redakcję.

Recently, the sustainable issue is critical to function which encourages researchers to look for naturally sourced, sustainable materials in any application besides lower costs and improved performance. The effect of durian skin fibre loading on the mechanical properties of Kevlar/ durian skin/ phenolic hybrid composites was investigated. DSF is cellulose-based fibres extracted from durian skin. The fibre content in the composites in this study was 0 and 30 vol % of fibre loading. Increasing Durian skin fiber (DSF) content in the Kevlar Durian skin phenolic hybrid composites (KDSPHC) has reduced the tensile and flexural strength of the composites meanwhile the impact resistance increased up to about 40 % compared to 0 vol % DSF loading. A morphological study observed by Scanning Electron Microscope and optical microscope showed that the interaction between DSF and Kevlar fibre was decent which contributed to the variation in the composite properties.

The investigation of mechanical properties of materials at high strain rates has become increasingly important in recent years. To establish the dynamic behavior of materials the acquisition of full-scale deformation field plays a key role. Traditional strain measuring techniques rely on the use of extensometers and strain gauges. But there are certain limitations of traditional measuring techniques, such as frequency response, rate of loading, and range of strain in which situation non-contacting measuring technique is ...

The objectivity of the engineering is to perform the task in an optimal way and this could be done by selection of prominent material to use in that engineering. When we say material, this means we are going to deal property like physical and mechanical properties under the desirable parameter like cost, availability and also environment. But environment is very important in the process to explore the environment. So finding eco-friendly, renewable kind of material which is fewer hazards and minimizing the use of conventional kind of material is big challenge for us when we do not compromise the quality and cost of it. For this purpose the composite material can be one answer in which natural fiber with less quantity with conventional kind of material are used. Modern testing methods are required to be in use and especially for the composite the test procedure should be strictly follow with eliminating the uncertainty of procedure. As a solution hybrid composite material can be use as it gives improved mechanical, physical and thermal properties and also allow using natural material as per our objective. Scope of this paper is to understand the material characteristics in the sense of future requirement

In this study two groups of hybrid composite materials were experimentally studied in static uniaxial compression test. The first group consisted of Kevlar/glass fiber and the second group consisted of carbon/glass fiber reinforced epoxy resin. Each group contained four subsets (A, B, C and D) of hybrid composite materials. Compression test was carried out according to ASTM D695 and each test was replicated five times. It was observed that for the same type of hybrid composites, placing carbon or Kevlar fiber layers at the top and bottom; and glass fiber layers in the middle did not give significant effects than placing glass fiber layers at the top and bottom and carbon or Kevlar fiber layers in the middle of the specimens under compressive test. Furthermore, the results showed that hybrid composite laminates for the same number of layers with carbon/glass fiber provided the highest amount of the compressive stress value up to 40% compared to the results of the group which was reinforced with Kevlar/glass fiber.