Soft Body Armor for Law Enforcement Applications

2013 ◽  
Vol 8 (2) ◽  
pp. 155892501300800 ◽  
Author(s):  
Arvind Purushothaman ◽  
Gopal Coimbatore ◽  
Seshadri S. Ramkumar
Keyword(s):  
Law Enforcement ◽  
High Performance ◽  
High Strength ◽  
Woven Fabrics ◽  
Body Armor ◽  
Soft Body ◽  
Ballistic Protection ◽  
Structural Coherence ◽  
Cut Resistance ◽  
The Impact

This paper focuses on the development of a novel ballistic protection composite which can provide both cut resistance and impact protection. The ballistic shield is made by sandwiching high strength, impact resistant, multi-layered woven fabrics between a leather strike face layer and a needlepunched fabric layer that offers protection upto Level IIIA and cut resistance. The needlepunched fabric when punched into the ballistic layer(s) pushes the fibers in the Z direction providing enhanced structural coherence and strength. Three different high performance fibers (Kevlar®, Spectra® and Twaron®) were used to make the composite. Ballistic tests were performed using V50 ballistic requirement based on NIJ standard. The availability of leather layer reduces the velocity of the impact and aides with the blunting of the bullet. A new phenomenon, “mushrooming” of the bullet has been observed. Results on the ballistic protection capabilities of different strike and impact resistant composite chest shields are presented in this paper.

scholarly journals Analytical investigation of high-velocity impact on hybrid unidirectional/woven composite panels

2016 ◽  
Vol 30 (4) ◽  
pp. 545-563 ◽  
Author(s):  
H Shanazari ◽  
GH Liaghat ◽  
H Hadavinia ◽  
A Aboutorabi
Keyword(s):  
Cross Sections ◽  
Shear Failure ◽  
Failure Criteria ◽  
Analytical Investigation ◽  
Woven Fabrics ◽  
Body Armor ◽  
Ballistic Performance ◽  
Nonwoven Fabrics ◽  
Ballistic Protection ◽  
Maximum Tensile Strain

In addition to fiber properties, the fabric structure plays an important role in determining ballistic performance of composite body armor textile. Textile structures used in ballistic protection are woven fabrics, unidirectional (UD) fabric structures, and nonwoven fabrics. In this article, an analytical model based on wave propagation and energy balance between the projectile and the target is developed to analyze hybrid fabric panels for ballistic protection. The hybrid panel consists of two types of structure: woven fabrics as the front layers and UD material as the rear layers. The model considers different cross sections of surface of the target in the woven and UD fabric of the hybrid panel. Also the model takes into account possible shear failure by using shear strength together with maximum tensile strain as the failure criteria. Reflections of deformation waves at interface between the layers and also the crimp of the yarn are modeled in the woven part of the hybrid panel. The results show greater efficiency of woven fibers in front layers (more shear resistance) and UD yarns in the rear layers (more tensile resistance), leading to better ballistic performance. Also modeling the yarn crimp results in more trauma at the backface of the panel producing data closer to the experimental results. It was found that there is an optimum ratio of woven to UD materials in the hybrid ballistic panel.

Interplay of fabric structure and shear thickening fluid impregnation in moderating the impact response of high-performance woven fabrics

2020 ◽  
Vol 54 (28) ◽  
pp. 4387-4395
Author(s):  
Sanchi Arora ◽  
Abhijit Majumdar ◽  
Bhupendra Singh Butola
Keyword(s):  
Beneficial Effect ◽  
Energy Absorption ◽  
Impact Energy ◽  
High Performance ◽  
Research Work ◽  
Impact Resistance ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Fabric Structure ◽  
The Impact

The beneficial effect of STF impregnation in enhancing the impact resistance of high-performance fabrics has been extensively reported in the literature. However, this research work reports that fabric structure has a decisive role in moderating the effectiveness of STF impregnation in terms of impact energy absorption. Plain woven fabrics having sett varying from 25 × 25 inch−1 to 55 × 55 inch−1 were impregnated with STF at two different padding pressures to obtain different add-ons. The impact energy absorption by STF impregnated loosely woven fabrics was found to be higher than that of their neat counterparts for both levels of add-on, while opposite trend was observed in case of tightly woven fabrics. Further, comparison of tightly woven plain, 2/2 twill, 3/1 twill and 2 × 2 matt fabrics revealed beneficial effect of STF impregnation, except for the plain woven fabric, establishing that there exists a fabric structure-STF impregnation interplay that tunes the impact resistance of woven fabrics.

scholarly journals Experimental Tests and Reliability Analysis of the Cracking Impact Resistance of UHPFRC

Fibers ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 74
Author(s):  
Hussain A. Jabir ◽  
Sallal R. Abid ◽  
Gunasekaran Murali ◽  
Sajjad H. Ali ◽  
Sergey Klyuev ◽  
...  
Keyword(s):  
High Performance ◽  
Steel Fiber ◽  
Impact Resistance ◽  
High Strength ◽  
Experimental Tests ◽  
Fiber Reinforced Concrete ◽  
Fiber Types ◽  
Impact Performance ◽  
High Performance Fiber ◽  
The Impact

Ultra-high performance (UHP) concrete is a special type of fibrous cementitious composite that is characterized by high strength and superior ductility, toughness, and durability. This research aimed to investigate the resistance of ultra-high performance fiber-reinforced concrete (UHPFRC) against repeated impacts. An adjusted repeated drop mass impact test was adopted to evaluate the impact performance of 72 UHPFRC disc specimens. The specimens were divided into six mixtures each of 12 discs. The only difference between the mixtures was the types of fibers used, while all other mixture components were the same. Three types of fibers were used: 6 mm micro-steel, 15 mm micro-steel, and polypropylene. All mixtures included 2.5% volumetric content of fibers, however with different combinations of the three fiber types. The test results showed that the mixtures with the 15 mm micro-steel fiber absorbed a higher number of impact blows until cracking compared to other mixtures. The mixture with pure 2.5% of 15 mm micro-steel fiber exhibited the highest impact resistance, with percentage increases over the other mixtures ranging from 25 to 140%. In addition, the Weibull distribution was used to investigate the cracking impact resistance of UHP at different levels of reliability.

Nanoadditives - Future of High Performance Concrete

2017 ◽  
Vol 908 ◽  
pp. 83-87
Author(s):  
Martin Labaj ◽  
Jaroslav Válek ◽  
Tomáš Jarolím ◽  
Lucia Osuská
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Concrete Surface ◽  
Cement Stone ◽  
Hardened Cement ◽  
Concrete Technology ◽  
High Quality ◽  
Long Time ◽  
The Impact

These days it is almost impossible to imagine the technology of high performance concrete without the use of any kind of additive. Whether it is a material capable of achieving high strength, excellent mobility of the fresh mix without losing cohesion or producing high quality architectural concrete surface, microadditives have their certain place for a long time now. Although the research in this field still has something to offer, it does not hurt to try to consider the future and imagine the path that will be taken in the production of high performance concrete of next generation. The article deals with the possibility of using nanoparticles in concrete technology. These materials can actively participate in the creation of very high-quality cement stone. In addition, due to the extreme reactivity of nanoparticles, these reactions can take place almost immediately after the onset of hydration and during its first hours. The experimental part of the paper assesses the impact of nanoparticles on selected properties of fresh cement paste and hardened cement mortar. In all cases, there was a positive effect and it has been demonstrated that nanoparticles may eventually create a new category of high performance concrete additives.

scholarly journals Preparation and Impact Resistance Properties of Hybrid Silicone-Ceramics Composites

2020 ◽  
Vol 10 (24) ◽  
pp. 9098
Author(s):  
Katarzyna Kośla ◽  
Paweł Kubiak ◽  
Marzena Fejdyś ◽  
Karolina Olszewska ◽  
Marcin Łandwijt ◽  
...  
Keyword(s):  
Impact Resistance ◽  
Young Modulus ◽  
Drop Tower ◽  
Body Armor ◽  
Soft Body ◽  
Ballistic Performance ◽  
Composite Armor ◽  
New Type ◽  
The Impact ◽  
Soft Body Armor

This article presents the method of preparation a new type of ballistic armor based on hybrid silicone-ceramic (HSC) composites with considerable flexibility. An experimental study on the ballistic behavior of HSC composites connected with soft body armor is presented against FSP.22 fragments. The effect of Al2O3 ceramics on the ballistic performance of HSC composite was investigated, and the fragmentation resistance process of the composite armor combining the HSC composite and soft aramid insert is clarified. Furthermore, impact resistance tests made with a drop tower which allows for a gravity drop of a mass along vertical guides onto a sample placed with an energy of 5 J were performed. The results presented in this paper show that the HSC composites can be successfully used as a hard body armor. However, they do not exhibit the properties of absorbing the impact energy generated during the drop tower tests. The test results show that the ballistic performance of composite armors is influenced by the hardness and Young modulus of ceramics and soft body armor panel. Additionally, in the article, the results of mechanical properties of silicones used for preparation of composites were presented and compiled to determine their role in the performance of impact protection.

Nanotehnologija the use of Aluminium-containing Raw Materials in the Petrochemical Industry to Produce High -performance Brick

2020 ◽  
pp. 55-66
Author(s):  
V. Z. Abdrakhimov ◽  
E. S. Abdrakhimova
Keyword(s):  
High Performance ◽  
Raw Materials ◽  
High Strength ◽  
High Alumina ◽  
Anthropogenic Factors ◽  
Petrochemical Plant ◽  
Ceramic Brick ◽  
Spent Catalyst ◽  
Traditional Natural ◽  
The Impact

The reduction in the reserves of traditional natural raw materials makes us look for new ways to replace it with different types of waste. At the same time, the costs of exploration, construction and operation of quarries are excluded, and significant land plots are exempt from the impact of negative anthropogenic factors. The experience of advanced foreign countries has shown the technical feasibility of this direction and its application as a tool for protecting the natural environment from pollution. On the basis of inter-shale clay and high-alumina nanotehnologija raw materials petrochemical spent catalyst IM-2201 NovoKuibyshev petrochemical plant derived ceramic brick with high physical-mechanical properties without the use of traditional natural materials. Using nanotechnogenic petrochemicals - spent catalyst IM-2201, containing more than 70% A12O3, a ceramic brick was obtained that corresponds to the M200 brand. It is possible to build load-bearing walls of the lower floors of high-rise buildings (15 floors or more) from M200 ceramic bricks. Innovative proposals for the use of industrial waste: interslant clay and spent catalyst in the production of high-strength ceramic earthquake-resistant bricks with high strength and frost resistance have been developed. The absolute advantage of using multi-tonnage waste of the spent IM-2201 catalyst and inter-shale clay for the waste of oil shale is the unloading of the environmental situation.

scholarly journals Hyperelastic modelling of yarn structures for dynamic applications

2018 ◽  
Vol 183 ◽  
pp. 01031
Author(s):  
Pietro del Sorbo ◽  
Jeremie Girardot ◽  
Frederic Dau ◽  
Ivan Iordanoff
Keyword(s):  
High Performance ◽  
Three Dimensional ◽  
Weight Ratio ◽  
High Strength ◽  
Material Model ◽  
Linear Elastic ◽  
Mesoscopic Models ◽  
First Results ◽  
Hyperelastic Model ◽  
The Impact

Dry fabrics comprised of high performance polymeric fibers have been widely used as protection layers in structures submitted to high velocity impacts (HVI). Their outstanding impact energy dissipation ability combined with an high strength-to-weight ratio make them a preferable choice in different applications such as bullet vests or blade containment systems over standard materials. Among the different approaches adopted to study these structures numerical methods assume a central role. Thanks to their reduced costs and the related possibility of evaluating the effects of single phenomena, they are often used to predict the structure ballistic limits or to study the physical events which occur during the penetration. Among the different strategies adopted to model a fabric, mesoscopic models have been largely adopted by different authors. These models assume the yarns as a continuum body while the fabric geometry is explicitly described. Nowadays yarn material models are universally assumed to be linear elastic and orthotropic. This modelling approach mostly focuses on the longitudinal behaviour of the yarn, however fiber-scale analyses and experimental results shows the importance of three-dimensional stress state on the ballistic limit. In order to obtain a three-dimensional description of the yarn strain state during the impact, a novel hyperelastic model for yarn structures here is developed. In a first step, fiber-level preliminary analyses have been performed to obtain the effective behaviour of these structure under the projectile collision. In the second step, the hyperelastic model has been implemented and identified thanks to microscopic elementary tests. Finally, a continuum model of the yarn have been performed. First results show the relevance of the hyperelastic model compared to the fiber-level observation and enhance the limit of the classical linear elastic material model.

scholarly journals Mechanical and Static Stab Resistant Properties of Hybrid-Fabric Fibrous Planks: Manufacturing Process of Nonwoven Fabrics Made of Recycled Fibers

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1140 ◽  
Author(s):  
Yu-Chun Chuang ◽  
Limin Bao ◽  
Mei-Chen Lin ◽  
Ching-Wen Lou ◽  
TingAn Lin
Keyword(s):  
High Performance ◽  
High Strength ◽  
Woven Fabrics ◽  
Test Results ◽  
High Modulus ◽  
New Materials ◽  
Nonwoven Fabrics ◽  
Pet Fibers ◽  
Recycled Fibers ◽  
Hybrid Fabric

With the development of technology, fibers and textiles are no longer exclusive for the use of clothing and decoration. Protective products made of high-strength and high-modulus fibers have been commonly used in different fields. When exceeding the service life, the protective products also need to be replaced. This study proposes a highly efficient recycling and manufacturing design to create more added values for the waste materials. With a premise of minimized damage to fibers, the recycled selvage made of high strength PET fibers are reclaimed to yield high performance staple fibers at a low production cost. A large amount of recycled fibers are made into matrices with an attempt to decrease the consumption of new materials, while the combination of diverse plain woven fabrics reinforces hybrid-fabric fibrous planks. First, with the aid of machines, recycled high strength PET fibers are processed into staple fibers. Using a nonwoven process, low melting point polyester (LMPET) fibers and PET staple fibers are made into PET matrices. Next, the matrices and different woven fabrics are combined in order to form hybrid-fabric fibrous planks. The test results indicate that both of the PET matrices and fibrous planks have good mechanical properties. In particular, the fibrous planks yield diverse stab resistances from nonwoven and woven fabrics, and thus have greater stab performance.

scholarly journals Mechanical and Crash Behaviour of Sheet Moulding Compound Materials

2005 ◽  
Vol 14 (1) ◽  
pp. 096369350501400
Author(s):  
Qiang Yuan ◽  
Stuart Bateman ◽  
Lin Ye
Keyword(s):  
Energy Absorption ◽  
High Performance ◽  
Adhesive Bonding ◽  
High Strength ◽  
Mechanical Fastening ◽  
Mechanically Fastened ◽  
Sheet Moulding Compound ◽  
Increasing Temperature ◽  
Crash Behaviour ◽  
The Impact

The mechanical and crush behaviour of high-performance sheet moulding compounds (SMCs) was studied. SMC laminates and half tubes were consolidated using a hot press. SMC tubes were made using two half tubes joined together with adhesive bonding and/or mechanical fastening. Both high-toughness SMC (SMC-T) and high-strength SMC (SMC-S) showed excellent tensile and flexural properties under static loading. The fracture toughness of SMC-S was somewhat higher than that of SMC-T, but at room temperature the energy absorption of SMC-T was higher than that of SMC-S. However, the impact strength of SMC-T decreased rapidly with increasing temperature, while that of SMC-S dropped only slightly up to 100°C. Dynamic mechanical thermal analysis (DMTA) results showed that SMC-S maintained its mechanical properties up to 150°C, while the storage modulus of SMC-T reduced rapidly with increasing temperature. SMC tubes were crushed at a speed of 500 mm/min. The specific energy absorption of both SMC-S and SMC-T tubes could reach 50 kJ/kg. The crush strength of the mechanically fastened SMC tubes was much higher than that of adhesively bonded ones.

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