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In this study, laminate composite materials are numerically modeled and simulated for application as ballistic protection. Using Abaqus Explicit FEA software for the numerical study, Mild Steel, Bulk Metallic Glass, and Dyneema were used as the target laminate materials and tested against 7.62mm API bullets. The maximum Von Mises stress was 9.003E8N/m2 at a velocity of 275 m/s and a plate thickness of 10 mm, with an average deflection of 0.0008 m. The greatest Von Mises stress at 264m/s was 8.689E8 N/m2, and the deflection was 0.00078 m. At 249 m/s, the Von Mises stress and deflection was 8.538E8N/m2 and 0.00074m respectively. At 215m/s, the Von Mises stress was 8.510E8N/m2, and the average deflection was 0.00068m. Thicker targets of the same material and configuration deflect bullet kinetic energy more effectively than thin targets. The weight on the wearer increases with the thickness of the material used. The simulation demonstrated that a material with a 13mm thickness could withstand the impact of a 7.62API projectile traveling at a speed of up to 850m/s. According to NIJ Standard-0101.06, this ballistic limit satisfies the standards for Level IV armour because Level IV armour is intended to stop armour-piercing rifle rounds up to and including 30 caliber M2 AP ammunition, which has a comparable velocity range. Because level IV armour plates can only weigh a maximum of 3.6kg, a thickness of 14mm is suggested for the design, giving it a ballistic limit more than 850m/s. The thicker the material, the higher its ballistic limit.

Failure of composite not only includes tensile or compression failure of fiber matrix, but also the delamination between plies. The current study investigates a methodology for the Ply-Delamination of Dyneema material due Ballistics impact using LSDYNA. A new methodology was implemented in order to effectively capture the ply delamination and the damage caused due to the impact for different velocities. Numerical results obtained were correlated with previous existing simulation results. [ABSTRACT FROM AUTHOR]

Off-road racing vehicles require protection on the underside of their chassis in order to protect vital components from impact damage. The use of composites in thin laminate form to achieve this protection is widespread, although failure due to impact from foreign objects still occurs. The use of UHMWPE (Ultra High-Molecular Weight Polyethylene) fibres, which have superior mechanical properties to aramid fibres in vehicle belly guards, is not prevalent and, hence, could prove useful in this application. A comprehensive Finite Element Analysis (FEA) is performed in order to determine suitable laminate panel layups that can be tested, analysed, and compared to the original laminate layup, which comprises six layers of aramid and two layers of carbon fibre fabrics. This provides initial insight into the comparison of the new proposed laminates and reveals if improvements have been made. The laminates found using FEA are manufactured into panels that represent the fixture and loading cases seen in racing vehicles. Experimental testing is carried out on the various panels, and the results are compared to those of the mathematical modelling. Substituting the currently used carbon fibres with more aramid fibres increases the impact resistance of the panel. Using UHMWPE fibres greatly increases the impact resistance of the panel; however, fibre delamination becomes more prevalent. This is due to the poor fibre wettability of UHMWPE fibres and the large strain before failure of the fibres. The modelled results show good agreement with the experimental results in terms of the locations at which damage occurred. [ABSTRACT FROM AUTHOR]

This study investigates the ballistic performance of a ceramic composite target plate consisting of Alumina with the Dyneema fiber. The objective is to achieve a lightweight structure. Different thickness combinations of alumina/Dyneema targets were studied based on the areal density of the targets. Energy absorption criteria were used to determine the ballistic performance of the target. The ANSYS/LS-DYNA® code was used to conduct the finite-element numerical simulations. 12.7 mm projectile core and 7.62 mm projectile core was used to normally impact the target plate. The projectile impact velocities were in the range–500–887 m/s. First, the model is verified by comparing it with existing experimental studies. Subsequently, various thickness combinations of alumina with different numbers of layers of Dyneema were studied numerically to determine the effective thickness combination of the entire target. The initial kinetic energy of the target dissipated into the ceramic fracture, and the remaining energy in the deformation of the composite plate. Projectile erosion and the target's energy absorption are the determining factors of the study. [ABSTRACT FROM AUTHOR]

Textile auxetic materials with negative Poisson’s ratio (NPR) have potential applications in protective textile, filtration, and energy absorbance. However, cotton core-spun based auxetic textile is rarely investigated. In this study, cotton core-spun (Lycra)-based helical auxetic yarn (HAY) was developed, and the effects of core filament linear density on the auxetic behavior were studied. Core-spun cotton yarns of 8/1 Nec containing core filament (180, 260, and 420 D) were developed. Then, these core-spun yarns were wrapped with 50 D Dyneema filament at 393 twist/m to make the HAY. The diameter, NPR, and tensile strength of HAY were increased with increasing linear density of Lycra filament. Image analysis of HAY containing 420 D Lycra showed 57% diameter increase with the change in axial strain from 0 to 15 mm. The maximum auxetic behavior with NPR of −3.97 and tensile strength of 26.71 cN/tex was observed in 420 D Lycra-based HAY. This study proved that the cotton core spun-based HAY can be produced with significant auxetic properties for practically potential use in wearable protective textiles.

Textile auxetic materials with negative Poisson's ratio (NPR) have potential applications in protective textile, filtration, and energy absorbance. However, cotton core-spun based auxetic textile is rarely investigated. In this study, cotton core-spun (Lycra)-based helical auxetic yarn (HAY) was developed, and the effects of core filament linear density on the auxetic behavior were studied. Core-spun cotton yarns of 8/1 Nec containing core filament (180, 260, and 420 D) were developed. Then, these core-spun yarns were wrapped with 50 D Dyneema filament at 393 twist/m to make the HAY. The diameter, NPR, and tensile strength of HAY were increased with increasing linear density of Lycra filament. Image analysis of HAY containing 420 D Lycra showed 57% diameter increase with the change in axial strain from 0 to 15 mm. The maximum auxetic behavior with NPR of -3.97 and tensile strength of 26.71 cN/tex was observed in 420 D Lycra-based HAY. This study proved that the cotton core spun-based HAY can be produced with significant auxetic properties for practically potential use in wearable protective textiles. [ABSTRACT FROM AUTHOR]

Single high-performance fibers (Kevlar® K129, Twaron® 2040, Technora® T200, Dyneema® SK76, Zylon® AS, Vectran® HT, and S-glass) are subject to lateral cutting action by an industrial blade. Due to the inherent variability of such testing, 40–60 replicate experiments were performed for each fiber type, at each of three different loading orientations, and the data were fit with a generalized extreme value distribution to summarize likelihood of failure under each condition. The results show that when organic fibers are cut at an angle that introduces shear loads, cut resistance drops by 60–90% compared to normal-incidence cut loading. This trend is driven by the highly oriented and fibrillar nature of organic fibers, in contrast to the isotropic S-glass fibers which show comparatively little change in cut resistance with blade orientation. Overall, the Vectran fibers provide the best resistance to normal loading, while the S-glass fibers are most resistant to non-normal loading. Micrographs show that, for organic fibers, shear loads lead to more localized failure compared to normally loaded fibers. [ABSTRACT FROM AUTHOR]

Lightweight fibre-reinforced polymer composites are currently being applied extensively in the design of transport structures to replace conventional metallic solutions, and also in structures that are exposed to the risk of foreign object impact. Therefore, an experimental study was undertaken to assess and compare the low- and high-velocity impact behaviour of S-2 glass®, HTA carbon and ultra-high-molecular-weight polyethylene (Dyneema®) composites. Three different impact test methods were applied: Charpy pendulum impact tests, drop-weight impact tests and ballistic impact tests with a gas gun. The results with the focus on penetration energy are compared in terms of correlation between the three test methods and in terms of weight-specific material performance. While the S-2 glass® fibre showed the best performance of the epoxy-based composites, the PUR-based Dyneema® HB26 panels proved the best penetration resistance in this study. [ABSTRACT FROM AUTHOR]

The main aim of the present research is to investigate the quasi-static penetration process of cylindrical indenters with different nose shapes into multilayered composite panels made of Dyneema and Glass woven fibers, and aluminum face sheets. For better understanding of the perforation mechanism of the composite panels, effects of indenter geometry, stacking sequences, and boundary conditions are studied and their effects on energy absorption, specific absorbed energy, maximum deformation, peak load, and failure modes are evaluated and discussed. Samples with different layering configurations loaded under quasi-static punch and indentation with loading rate of 5 mm/min using universal testing machine and cylindrical rigid indenters with different nose shapes geometries consist of blunt, hemispherical, conical, and ogival. Regarding the boundary condition effects, two different rigid fixtures are designed and manufactured with the same external square perimeter (250 × 250 mm) and two different internal perimeters of circular and square shapes respectively, with diameter of 15 mm and edge side of 100 mm. Results show that the hybrid composite panels composed of Dyneema sheets, exhibits significantly better load carrying capacity and specific absorbed energy under both loading conditions. Indenter nose shape significantly affects elastic load, peak load, and energy absorption and maximum deformation. Furthermore, from visual observations based on digital microscopic images, fiber breakage, fiber pull out, intralaminar delamination, and debonding between the composite layers within the damage zone were inspected and recognized as the main damage mechanisms of panels. Output data obtained from all the experimental investigation were reported, discussed, and commented upon. [ABSTRACT FROM AUTHOR]

U radu su realizovana istraživanja materijala neophodnog za održavanje zaštitnih balističkih prsluka. Predloženo je novo konstrukciono rešenje sa savremenim materijalom za izradu balističkih uložaka. U radu su prikazani rezultati laboratorijskih balističkih ispitivanja uložaka sa novim materijalom. Na osnovu rezultata ispitivanja zaključuje se da predloženo konstrukciono rešenje za izradu balističkih uložaka u potpunosti ispunjava zahteve aktuelnog standarda. / The work presents research of the materials necessary for the maintenance of protective ballistic vests. In this paper is proposed a new construction design with modern materials for ballistic inserts producing. This paper also presents the results of laboratory tests of ballistic cartridges with new materials. Based on the test results, it can be concluded, the proposed technical solution for making ballistic inserts adequately meets current standards.

The commercial hydrocode ANSYS AUTODYN ® was used to create a thermally dependent model of an Ultra-High Molecular Weight Polyethylene (UHMW-PE) composite under high and hypervelocity impact. In particular this model was validated against high-velocity fragment-simulating projectile (FSP) impacts and hypervelocity polycarbonate cylinder impacts at 2,100 m/s and 3,500 m/s. It appeared that despite the same material model being used for thick unidirectional Dyneema ® laminates and thin woven Spectra ® laminates, the model showed reasonable correlation in all cases. This suggests that modelling results from these types of studies are not sensitive to the exact parameters used in the material model. [ABSTRACT FROM AUTHOR]

The ballistic performance of Dyneema® HB26 and Spectra® 3124 subjected to high velocity impact of steel and copper Fragment Simulating Projectiles was evaluated. A 3D High Speed Digital Image Correlation was used for measurement of the panels front face deformation and the back face deformation. The information obtained from the measurements, along with the post-mortem observation of the panels, allowed to draw conclusions with respect to the importance of various energy dissipation mechanisms that occurred in the tested materials. It was observed that, although Dyneema® HB26 and Spectra® 3124 deform very differently during the impact event, they had a similar ballistic performance. [ABSTRACT FROM AUTHOR]

The method for determining the transverse mechanical response of Kevlar® KM2 and Dyneema® SK76 fibers was improved upon from previous versions of single fiber compression tests. Two fibers were laid parallel and compressed between two tool steel platens. The new experimental setup ensures that the individual fibers are being compressed evenly along the length and that the platens are parallel during compression. Nominal stress–strain curves were obtained for quasi-static loading of both types of fibers. To evaluate the rate effects on the transverse behavior, high-rate transverse compression experiments were also performed using a miniature Kolsky bar loading on single-fiber specimens to obtain the corresponding stress–strain response of these high performance fibers at high rates of deformation. [ABSTRACT FROM AUTHOR]

Predictive computational modeling of the response of armor systems to dynamic threats such as blast and impact requires understanding and quantification of the behavior of the armor materials. This paper describes the mechanical characterization of Dyneema HB26. The in-plane tensile, compressive, and shear stress-strain behavior and strength of the laminate at low rates has been determined experimentally. The tensile behavior of the Dyneema SK76 fibers, which comprise 83% of the laminate has been determined, including the effect of temperature and rate. [ABSTRACT FROM AUTHOR]

Objective. Development of structure and knitting technology of hyper strength weft knitted fabrics for manufacture of personal body armor for combatants, soldiers, volunteers, journalists and security structures employees. Methodology. Methods of analysis and synthesis of scientific-technical and patent literature in the field of hyper strength textile materials, theory of weft double-layer knitwear structure formation were applied. Findings. The knitting structure was developed and initial knitting process data were suggested for hyper strength knitted fabric production. It belongs to the group of fabrics of special purpose, namely ballistic textile materials with an increased level of strength. The knitting parameters were determined, which provide normal course of knitting process on double circular rib machine. The proposed structure is a double-layer knitting fabric with a press connection of layers by main yarns. For the knitted fabric production were used ultrahigh molecular weight polyethylene yarn trademark Dyneema®. Originality. The developed double-layer knitwear structure of hyper strength is capable of withstanding more than 800N spot-kick. The parameters of knitting mode are determined, that provide normal loop forming action by processing on knitting equipment of the new non-traditional raw material - ultra-high molecular weight polyethylene yarn DyneemaTM. Practical Value. Establishing of domestic production of knitted fabrics for armored vests of hidden type and body armor protective layer elements manufacture, using which helps minimize the impact of a bullet ricochet and its fragments, and due to construction lightweight allows the soldier to move freely and carry out combat tasks. [ABSTRACT FROM AUTHOR]

Ball-bearing impact tests are performed on Ultra High Molecular Weight Polyethylene (UHMWPE) laminates over a range of areal densities. A critical transition areal density is identified, below which plates will either: survive with no fibre failure, or fail through the full thickness (binary regime); and above which partial fibre failure in the front portion of the plate is possible (progressive regime). In the progressive regime, where fibre fracture occurs, the plate exhibits two distinct regions of deformation, termed proximal and distal. The authors elucidate the relevance of the critical transition areal density to plates with areal densities above this threshold. It is demonstrated that if the plate survives, the survived fraction (distal region) is greater than or equal to the critical transition areal density. A simple model is used to fit the experimental data to estimate the dissipated energy per areal density in both the proximal and distal regions. The distal region is seen to be 6.5 times more effective than the proximal region at dissipating the kinetic energy of the projectile. A further set of experiments was performed incorporating a 'pre-delamination' along the mid-plane of the plates. Addition of an interface promotes an earlier transition from deformation in the proximal region to deformation in the distal region, than would otherwise have occurred in a monolithic plate of the same areal density. This results in an increase in the ballistic limit (up to 10%). [ABSTRACT FROM AUTHOR]

The work presents research of the materials necessary for the maintenance of protective ballistic vests. In this paper is proposed a new construction design with modern materials for ballistic inserts producing. This paper also presents the results of laboratory tests of ballistic cartridges with new materials. Based on the test results, it can be concluded, the proposed technical solution for making ballistic inserts adequately meets current standards. [ABSTRACT FROM AUTHOR]

Auxetic materials have negative Poisson ratio which has a multiple ranges of functional applications. The helical auxetic yarn was successfully developed through direct twist system by using core and wrap yarn or filament, which shows Auxeticity when the HAY is stretched in longitudinal direction in response it expand in transverse direction, Helical Auxetic Yarns were developed using various parameters of the core and warp filament, these parameters are wrapping angle (Twist per meter), diameter ratio, and modulus ratio. The strength of Helical yarn was characterized using single yarn strength and Image J software was used for the calculation of poisson's ratio. According to test results, it is concluded that the core filament of helical auxetic yarn increased its thickness in transverse direction under stress, and a considerable negative poisson's ratio was calculated. The values of negative poisson's ratio described that the auxeticity had a direct relation with core filament thickness or diameter and inversely proportional to the linear density of wrap filament, in case of the wrap angle the auxeticity of HAY yarn had an inverse effect with wrap angle. Kevlar/polypropylene combination sample showed maximum auxeticity at a 15-degree angle while Kevlar/nylon combination sample showed minimum auxeticity at a 25-degree wrap angle. [ABSTRACT FROM AUTHOR]

Light and medium protection for small naval vessels guarantees their high performance and safety during the guard duties. In this study, a protective shield fabricated from Dyneema HB25 fibers has been utilized as an add-on layer on the coast guard boat hull. Finite element analyses have been conducted using Chocron's model. Two standards of gun-fire were employed and various thicknesses of the composite layers were examined by ballistic impacts. Afterward, numerical simulations results compared with experiments and revealed a good consistency. Finally, some graphs have been presented to help designers for choosing more convenient shield based on protection and weight characteristics after judgment of vessel requirements. [ABSTRACT FROM AUTHOR]

We experimentally study thermal stability of conduction cooled superconducting coils from a viewpoint of structural materials of the coils. The materials are Dyneema fiber reinforced plastics (DFRPs). The DFRP has properties of high thermal conduction and negative thermal expansion. We evaluated the stability of the conduction cooled coils having DFRP bobbins with changing the DFRP's thermal expansion. According to the experimental results, when the expansion became large, the stability also became better. It is expected that the DFRP is the effective heat sink bobbin material. [ABSTRACT FROM PUBLISHER]

Abstract: Utilizing shock compression physics considerations and explicit numerical techniques a methodology has been developed to design composite personnel armor by optimizing the role each layer plays during projectile defeat. The initial design consists of a very hard 1st layer to deform and fracture the projectile, an orthotropic 2nd layer to slow down the shock wave propagation in the through thickness direction, whilst allowing rapid propagation in the transverse directions, a 3rd porous layer to absorb the shock wave energy through PV-work, and a 4th layer to provide confinement for the porous medium. Based on the above armor protection concept, composite plates comprising of alumina (Al2O3) Ceramic, Dyneema® HB25 and porous polyurethane (PU) foam were constructed to test against baseline armor AISI 4140 steel plate. A hypothetical orthotropic material model closely resembling that of Dyneema HB25 was derived based on fundamental materials relations as well as limited available literature information. Material models for the other materials used in this research were based on existing sources. An integral experiment was conducted to validate this composite armor against numerical simulations. Through this study, the composite armor has been shown experimentally to be more effective in resisting penetration than a steel plate of equivalent (and slightly greater) areal density, and that the material layering sequence is fundamentally correct, while the numerical modeling has provided a general guidance to the behavior of the system. This research was done to explore this kind of approach to armor design to evaluate its merit. We make no claim that this design is ready for field use. [Copyright &y& Elsevier]

We have studied the vibration of superconducting windings during AC excitation of coils. Our previous study revealed that mechanical loss due to the vibration of a coil that had an expansion bobbin during cool-down was smaller than that of a coil having a contraction bobbin. However, critical currents of the coil with the expansion bobbin decreased as the number of thermal cycles increased between room and cryogenic temperatures. Hence, excessive expansion of the bobbins causes degradation of coil performance. In this study, we fabricated superconducting coils whose bobbins expanded a little, and measured the mechanical losses of those coils. We present here the expansion properties of the bobbins, test results of the critical currents and mechanical losses, and the dependence of the thermal cycles on those results. [ABSTRACT FROM AUTHOR]

This chapter covers recent developments in the production of well established high performance fibers such as Kevlar, PBO, Spectra and Dyneema fibers and depicts a new super strong M5. The latter fibers have the modulus of 330GPa and tenacity of 5GPa. DuPont de Nemours is currently developing commercial M5 fibers and yarns. A very interesting monomer namely, 2,5-dihydroxyterephthalic is used for making poly{2,6-diimidazo[4,5-b:4',5'-e]pyridinylene-1,4-(2,5-dihydroxy)phenylene} (PIPD). The unique feature of the polymer is that the two hydroxyl groups (on terephthalic acid) can form intermolecular hydrogen bonds and therefore fibrillation, that is often a problem for aramid fibers, is practically eliminated. As a result, M5 fibers have the highest compressive strength among synthetic fibers. Exploratory evaluation of the UV stability of M5 indicated excellent performance in that field. The mechanical properties of the new fiber make it competitive with carbon fiber in most applications - in light, slender, load bearing stiff advanced composite components and structures. [ABSTRACT FROM AUTHOR]

We fabricated small superconducting coils whose bobbins were made of a Dyneema fiber reinforced plastic (DFRP), a Dyneema and glass fiber reinforced plastic (DGFRP), and a glass fiber reinforced plastic (GFRP). Because Dyneema fibers in the FRP expand, we are able to control thermal expansion/contraction property in a circumferential direction of the DFRP and the DGFRP pipes during a cooling process from room temperature to low temperature. We fabricated two kinds of the DFRP and the DGFRP coils whose properties were expansion and contraction. The GFRP has always a characteristic of contraction during cool-down. We measured a mechanical loss that occurred in the coil during AC excitation of those coils. The mechanical losses decreased with increasing winding tension of the conductor in the coils according to the experimental data. And the mechanical loss of the coils whose bobbins had characteristic of expansion was considerably smaller than that of contraction. It was experimentally shown that the bobbins with expansion property during the cooling down were effective to decrease the mechanical loss of the AC coils. [ABSTRACT FROM AUTHOR]

The article describes the use of biodegradable sutures and suture anchors with increasing frequency for various procedures in sports medicine. The need for more appropriate surgical implants in arthroscopic surgery that could take advantage of the minimally invasive techniques are necessary. Biodegradable materials play a significant role in arthroscopic fixation. Furthermore, biodegradable nature of the implant permits suture anchor to do its job. The surgeon selecting a biodegradable implant should be aware of its material properties, rate of strength loss, and degradation profile.

Combination of proper design, structure and specific property mix of the particular textile assemblies are of immense importance to the parachute designer. This is applicable to braided cordages also. These cordages in wide range of materials and constructions are being used in parachutes as rigging line, weak tie, lashing cord, stowing and whipping cords. In general, the paper covers the requirement of cordages for parachute applications, various constructions of cordages, research studies carried out on constructional variables and their effect on end properties of cordages. The paper widely covers development of various Para-aramid, Dyneema, Spectra and Vectran Cordages at ADRDE and also comparative studies of these cordages to evaluate their performance for parachute application. [ABSTRACT FROM AUTHOR]

This study aims to assess whether ultra-high-molecular-weight polyethylene (UHMWPE) fibers can be successfully embedded in a polylactic acid (PLA) matrix in a material extrusion 3D printing (ME3DP) process, despite the apparent thermal incompatibility between the two materials. The work started with assessing the maximum PLA extrusion temperatures at which UHMWPE fibers withstand the 3D printing process without melting or severe degradation. After testing various fiber orientations and extrusion temperatures, it has been found that the maximum extrusion temperature depends on fiber orientation relative to extrusion pathing and varies between 175 °C and 185 °C at an ambient temperature of 25 °C. Multiple specimens with embedded strands of UHMWPE fibers have been 3D printed and following tensile strength tests on the fabricated specimens, it has been found that adding even a small number of fiber strands laid in the same direction as the load increased tensile strength by 12% to 23% depending on the raster angle, even when taking into account the decrease in tensile strength due to reduced performance of the PLA substrate caused by lower extrusion temperatures. [ABSTRACT FROM AUTHOR]