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Researches for the development of materials with less environmental impact have been more common. Pectin is a natural polysaccharide, presenting in plants and the peel of some fruits. It is atoxic, biocompatible, not expensive and is available as a byproduct of fruit juice industry. In the literature, pectin is commonly found mixed with other polymers. The objective of this work was to study the thermoplasticization with glycerol of high methoxylation pectin by extrusion/thermo-compression for films with industrial application compared to casting films. Properties of water vapor permeablility (1.27–2.47 g mm/KPa h m2), tensile strength (3.44–8.74 MPa), and puncture resistance (43.01–230.75 N/mm) of extrusion/thermo-compression films were evaluated. Color parameters exhibited possibility of samples application in packages that require the consumer to view the product. The results obtained for extruded/thermo-compressed films are similar or superior to those obtained in extruded thermoplasticized starch works. Results showed efficient production of plasticized pectin films with the possibility of industrial application for extrusion/thermo-compression process.

The area of forests continues decreasing while the water/soil loss becomes worse. In these complicated environments, mechanical properties, stability, high modulus and low elongation of geotextiles are required. On a premise of the acquisition of good mechanical properties and the improvement in the deformation and puncture resistance of nonwoven fabric, woven/nonwoven hybrid geotextiles are designed and made with needle punch processing technology in this study. The test results indicate that the mechanical properties of hybrid geotextiles are improved significantly when the areal density of nylon fabrics is increased. In particular, with the areal density of 400 g/m2, hybrid geotextiles exhibit the maximal mechanical properties and puncture resistance. Moreover, the pore fraction of hybrid geotextiles decreases as a result of a rise in the areal density of nylon top/bottom layers. The use of a 3 D mesh fabric as the interlayer provides the needle punched composite geotextiles with the highest tensile resistance, puncture resistance. The composite geotextiles are treated with acid and alkali to simulate the corrosion under natural conditions of stabilized soil. The resultant geotextile has good mechanical properties and acid/alkali degradation resistance. This allows the hybrid geotextiles to stabilize water and soil conservation in complicated conditions.

Silkworm cocoons display outstanding properties in many aspects, such as thermal protection, biocompatibility and mechanical resistance and so on. In this paper, we focus on the puncture properties without detailed exploration of four types of cocoons (three domesticated cocoon and Eri silkworm). Different sections, end and middle, as well as different directions, puncturing from inner and outer surface, of four types of aforementioned cocoons were systematically analyzed and compared. The results of present research show that the middle section exhibits a relatively greater needle-puncture resistance compare with end section for three B. mori silkworm cocoons. With regard to different puncture directions, from external and internal surface, puncturing from internal surface exhibits a relatively higher needle-puncture load as well as fracture displacement tendencies compared with needle-puncture performance from external surface no matter in middle or end sections. Combining physical parameter assessment, statistical analysis and needle-puncture performance, this research inspires a clear-cut frame to design a composite with high puncture resistance.

This study explores the influences of needle punching and a shear-thickening fluid (STF) on the stab resistance sandwich-structured composites made of nylon nonwoven and aramid fabrics. Needle punching and different treatments of aramid fabric are conducted to obtain the composites. The effects of needle punching and different treatments of aramid fabrics on the sandwich-structured composites were examined using quasi-static puncture resistance, quasi-static stab resistance, dynamic puncture resistance, and bursting property tests. Results show that needle punching and incorporation of STF positively influence the stab resistance of the composites. This study provides an innovative method to reduce the number of lamination layers and decrease the weight.

The very thin and lightweight silkworm cocoon has outstanding mechanical properties attributed to its specific composite microstructure. However, the microstructures of the cocoons have not been studied quantitatively, and their anti-puncture performance has not been examined as well. In this study, both domesticated ( Bombyx mori) and wild silkworm cocoons ( Antheraea pernyi, Antheraea mylitta and Samia canningi) were investigated for their microstructures using fractal theory, and their quasi-static puncture resistance was tested and compared. In addition, the effects of cocoon layers and hot-press treatments on the puncture resistance of two cocoon types ( B. mori and A. pernyi) were investigated. The three wild cocoons demonstrated significantly higher fractal dimensions, higher fiber intersectional densities and low porosities, indicating their structures are more optimized. They also displayed better puncture resistance than B. mori. Increased layer numbers could significantly increase the puncture resistance of both cocoon types and A. pernyi showed more remarkable increases. Moreover, the two cocoon types showed optimum puncture resistance after heat treatment with hot-press temperature of 135℃ and pressure of 25 MPa, and A. pernyi showed better puncture resistance after such treatment. Finally, both the maximum puncture force and puncture energy of cocoons displayed a linear increase with the increasing fractal dimensions. The new insights can guide the development of novel protective fiber composites with desirable and predictable anti-puncture performance.

The shape of the needle tip that is currently used in the medical field is a “lancet point,” which is a diagonally cut cylindrical pipe, further cut on both sides. The shape of the needle shank is typically cylindrical. In this paper, tip and shank shapes that differ from the standard shape are experimentally investigated for the purpose of reducing puncture resistance. Microneedles of various cross-sectional shapes, such as polygonal and star-like, were fabricated using stereo laser lithography. Before the needle penetrates the skin, sharp edges at the needle tip may be effective to generate a stress concentration on the skin, inducing a skin fracture. After the needle penetrates the skin, corners in the cross section of the needle shank may effectively reduce the frictional resistance because the contact area between the skin and needle is limited at the corners. A needle insertion experiment was conducted against an artificial skin made of polydimethylsiloxane. The puncture resistance decreased respectively for the circular needle, polygonal needle, and star-shaped needle. For the star-shaped needles, the maximum resistance decreased as the number of corners (N) decreased. For the polygonal needle, the maximum resistance increased as N increased from 3 to 5; however, there was no observable difference for N from 6 to 8. The experimental results show that a triangular star-shaped microneedle is the most effective in reducing the puncture resistance.

In the present work, an attempt has been made to study the effect of structural changes on the sustainable properties of needle punch nonwoven geotextile. There are two important process parameters, which influence the structure significantly. The parameters are punch density and depth of penetration of the needle. This research work is designed by considering the two parameters. Whereas, three-levels of each parameter taken and nine samples prepared by using two-factor three-level full factorial design. The structural analysis was carried out by an image analysis technique. All measured physical and mechanical properties of nonwovens have a strong correlation with the structural parameter. The significant effect noticed on fabric thickness, tensile strength, pore diameter, puncture resistance and impact resistance with the varying considered parameters; punch density and needle depth penetration.

A facile route for fabrication of polypropylene separators for lithium-ion batteries with high elongation and strong puncture resistance has been proposed in this work. Polypropylene separators imm...

This study investigates the mechanical properties and damage behavior of flexible laminated composites. Needle punching is performed to combine woven Kevlar fabric and two nonwoven low-melting point polyester (LMPET) fabrics into a fabric interlayer. A sheet-extrusion machine is used to bond two thermoplastic polyurethane (TPU) sheets on each side of a fabric interlayer. The tensile strength, peel load, and static puncture resistance of the flexible laminated composites are evaluated, and the influences of needle-punching rates and depths are examined. Test results show that a high needle-punching rate or depth positively affects tensile strength by promoting fiber entanglement. The tensile strength of the 300-15 group reaches 24.70 MPa. Moreover, when the needle-punching depth does not exceed 11 mm, melted LMPET fibers help bond two-phase materials and thus increase the peel loads of the final composites. The 200-11 group has an optimal puncture resistance of 5.86 N. The combination of TPU sheets and woven Kevlar fabrics yields flexible laminated composites with good static puncture resistance. The results of this study can be applied to improve the performance of flexible laminated composites.

In order to deeply explore the fiber characteristics influencing on stab resistance of shear thickening fluid (STF)- impregnated fabrics, two different weaving fabrics, ultra-high molecular weight polyethylene (UHMWPE) fabric and Kevlar fabrics are saturate the various concentrations and particle size of STFs. Result shows that, SiO2/PEG-200 blends demonstrate quick shear-thickening property, and the critical shear rate lowers to 1.2-45 s-1 with higher concentration of 75 nm SiO2. STF concentration and particle size significantly affect spike puncture resistance property, but the knife stab resistance mainly depends on fiber characteristics. Comparatively, STF-UHMWPE composite fabrics exhibit better knife stab resistance but weaker spike puncture resistance than STF-Kevlar fabrics. This study can provide an optimization for structure design of stab resistance armors in the future.

Protective textiles require massive consumption of fibers and fabrics, which is responsible for diverse highstrength fabric waste. Wrongly arranged disposal of textile waste is equivalent to the waste valuable resource while causing environmental pollutions. Aramid selvages are worthwhile recycling and used in this study. They are scattered into Aramid staple fibers and mixed with low melting point polyester (LMPET) fibers to form the Aramid matrices employing the nonwoven process. The matrices are added to different combinations to form Aramid composite matrices and hybrid-fiberreinforced composite boards. The process of shearing, crowding, and friction helps improve the mechanical properties of the composite boards according to the evaluations of conducted tests. With the premise of minimum damage to the fibers, this study uses recycled Aramid waste to produce composite boards that have features of high performance and low production cost. As a test result, the hybrid-fiber-reinforced composite boards with 90 wt% of recycled Aramid fibers have the optimal mechanical property and static puncture resistance.

Understanding the internal microstructure of silkworm cocoons is beneficial for developing biomaterials. In this study, both domesticated (Bombyx mori) and wild silkworm cocoons (Antheraea pernyi and Antheraea mylitta) were studied using the X-ray micro computed tomography (XCT), and their microstructural characteristics were analyzed quantitatively. It is discovered that fiber widths of the cocoons significantly increased from the inner to the outer layer. It is also detected that for the three cocoons in the core regions, unaffected by the surface condition, from the inner to the outer layer, fiber percentages show significant decrease initially, and then no obvious change, and the fibers in different layers are more aligned towards the short diameter of the cocoon, and Antheraea mylitta fibers display the highest fiber orientation. Fractal dimension of the domestic cocoon was significantly reduced, whereas those of the wild cocoons display no obvious change. The two wild cocoons show significantly higher maximum strength, initial modulus and breaking energy than the domesticated cocoons, and Antheraea pernyi performs better maximum strength and breaking energy than Antheraea mylitta. The tensile property is closely related to fiber percentage, fiber intersectional density and fractal dimension.

In this study, unlike the previous studies focusing merely on high-performance fabrics (i.e, aramid based Twaron, Kevlar) low velocity impact behaviour of neat and shear thickening fluid (STF) impregnated kevlar, hybrid (Kevlar/Carbon) and carbon fabrics was investigated. In the first stage, STFs with the silica concentrations of 5 wt%, 10 wt%, 15 wt% and 20 wt% were produced separately and the rheological measurement of each individual fluid concentration were carried out. In the second stage of the study, kevlar, hybrid and carbon fabrics were impregnated by STF having a silica content of 20 wt%. Yarn pull-out tests, dynamic puncture tests and quasi-static (QS) puncture tests were carried out on both the neat and impregnated fabrics. The rheological measurements showed that, the resulting silica/PEG400 suspensions exhibit good shear thickening behaviours, however it is not the case for those under a critical silica concentration. The yarn pull out tests revealed that, STF enhances the inter-yarn frictions of all three types of fabric. Correspondingly, STF positively affected the dynamic puncture resistance of kevlar and hybrid fabrics, while it had an adverse effect on carbon fabric. Besides, STF caused increases on the QS puncture resistances of all three fabric types.

The effects of heat treatment and the addition of tarragon essential oil on physical and mechanical properties of films prepared with 5% whey protein isolate (WPI) and 5% glycerol were investigated in this study. Heat treatment of the film-forming solution caused increases in thickness, moisture content, swelling degree, water vapor permeability (WVP), b*-value, &Delta, E*-value, transmittance values in the 200&ndash, 300-nm region, transparency, and puncture resistance of the film, but decreases in water solubility, L*-value, a*-value, transmittance values in the 350&ndash, 800-nm region, and puncture deformation. When incorporated with tarragon essential oil, heat-treated films have the potential to be used as antimicrobial food packaging. The addition of tarragon essential oil in film-forming solution caused increases in moisture content, solubility in water, WVP, a*-value, b*-value, &Delta, E*-value, and transparency of the film, decreases in transmittance values in the range of 600&ndash, 800 nm, and variations in swelling degree, L*-value, transmittance values in the range of 300&ndash, 550 nm, puncture resistance, and puncture deformation. Nevertheless, different tendencies were noticed in UNT (untreated) and HT (heat-treated) films with regards to transparency, light transmittance, puncture resistance, and puncture deformation. Based on these findings, HT films show improved physical and mechanical properties and, therefore, are more suitable for food-packaging applications.

Ensuring material performance reliability and lifetime is crucial for practical operations. Small cracks on the material surface are often detrimental to its safe operation. This study describes the development of a hydrogen bond-rich puncture-resistant polyurethane elastomer with supertoughness. The as-prepared polyurethane transparent films feature high tensile break strength (57.4 MPa) and great toughness (228 MJ m-3). Additionally, a facile, low-cost, crack self-diagnostic approach through photoluminescence using a small luminous pen is reported. The materials efficiently achieved self-healing at 90 °C after the crack formation. The change of fluorescence intensity on the crack can be used to track the self-healing process. Therefore, this work provides a guideline for the material design of supertough, puncture-resistant, transparent, and healable elastomers and a crack self-diagnosis and healing approach.

Auxetic materials expand in at least one dimension, when stretched longitudinally i.e. they have negative Poisson’s ratio. Development of 2D woven auxetic fabrics (AF) is a new approach to develop mechanically stable auxetic textile structures. However, the mechanical response of such emerging structure is still not studied in detail yet, therefore different mechanical properties of 2D woven AF are compared with conventional non-auxetic fabric (NAF). AF was developed by orienting yarns in auxetic honey-comb (AHC) geometry and auxeticity is induced due to such orientation of yarns. AF was developed using conventional (non-auxetic) materials; cotton yarn and elastane cotton yarn in warp and weft dimension respectively, using air jet loom. Structure and auxeticity of AF were analyzed using a digital microscope and its different mechanical properties (tensile strength, tear strength, bursting strength, cut resistance, and puncture resistance) were studied. AF showed superior mechanical properties with a lower initial modulus, which is beneficial for different protective textiles applications like cut resistance gloves, blast resistant curtains, and puncture tolerant elastomeric composites.

This paper focuses on the semi-blunt puncture behavior of woven fabrics via finite element analysis (FEA) approaches. In these finite element (FE) models, main structure parameters, such as weave structure, warp density as well as friction coefficient, are systematically considered and calculated via FEA. These microstructure geometrical models are builtup with full consideration of interaction between warp and weft yarns. The theoretical results show that plain woven fabric has better puncture resistance compared with 2/1 twill and 5-harness satin fabrics. With the increase of warp density and friction coefficient, the puncture property of woven fabric will be dramatically improved. Finally, an energy consumption method is adopted to analyze the puncture damage process of woven fabric. The simulation results will benefit for the optimum design of woven fabric with excellent puncture performance.

The dilatancy (Shear-thickening) is a time-independent rheological behaviour exhibited by some non-Newtonian fluids. These fluids manifest a surge in the apparent viscosity with an increase in the shear rate. If these fluids are encapsulated, they can be used to manufacture high-end stab resistance inserts (Cecchini et al., 2018) [1]. In the first part of this work, a comparison between the rheological performance of different shear-thickening fluids (STFs) based on nanosilica dispersed in glycols is presented. This analysis attempts to investigate the combinations of fillers and carriers with the highest energy-absorbing capabilities, among the various glycol-based colloidal STFs. In the second part, the influence of the composition of the STF on its rheological properties is analyzed statistically. The statistical analysis is performed by evaluating the interaction between the main design variables of the fluids (filler dimension, weight-to-weight ratio and molecular weight of the carrier). Finally, the puncture resistance of a composite system obtained by encapsulating the previously manufactured shear-thickening fluids in a polymeric shell is analyzed by means of a high-speed puncture test. This test is performed on the mockup of a tyre tread containing the best performing STF. The results showed that the use of the STF core increased the resistance to puncture by 20% as compared to the same volume of tyre tread material. Furthermore, the STF hermetically sealed the pierced sample, even when the tyre mockup was inflated at high internal pressures.

Natural rubber (NR) latex gloves are widely used as a very important barrier for healthcare workers. However, they can still be perforated easily by sharp devices and instruments. The aim of this study was to investigate the effect of the addition of graphene oxide (GO) to low-ammonia NR latex on its puncture resistance, mechanical properties and thermal stability. GO was synthesized using modified Hummers’ reaction. The produced GO was mixed into the NR latex solution at various doses (0.01-1.0 wt. %), followed by a coagulant dipping process using ceramic plates to produce film samples. Puncture resistance was enhanced by 12% with 1.0 wt. % GO/NR. Also, the incorporation of GO improved the stress at 300% and 500%, the modulus at 300% and 500% and the tear strength of low-ammonia NR latex films.

Stab and puncture resistant body armor is widely used by the law enforcement personnel, security and military in many countries. The primary requirement for the armor is to provide protection against various weapons used in an attack. Comfort properties are given increased importance in many countries and considered the second most important requirement. In this research Kevlar was blended with wool and wool–nylon. The resultant fabrics were coated with silica and their stab and puncture resistance in quasistatic conditions was examined using the universal tensile tester. It was hypothesized that the application of coating will generate higher friction to restrict the lateral movement of yarns, and thus present a higher number of yarns for direct resistance to impact during the attack and dissipating the impact energy, whereas the use of wool and nylon will provide the required ergonomics of wearability and stretch. It was observed that the application of the silica coating helped in improving the resistance to the stab and punctures using weapons such as knife (P1, as specified in NIJ 0115.00), ball and pointed impactors. In the quasistatic tests, the highest value of the maximum resistant force was recorded when the ball was used and the lowest was observed for the knife. Furthermore, the application of coating helped in absorbing impact energy. However, the fabric stiffness increased due to the coating, which will negatively impact the ergonomics and wearability.

In this research, eight different 3D weft-knitted fabrics were developed and evaluated. 3D fabrics have been knitted on circular weft-knitting machines with two different gauges: 20E gauge and 28E gauge. Three different raw materials were used for the fabric’s production: high molecular mass polyethylene (HPPE) yarn and 0.05 mm diameter steel wire in the outer layers (for the front and reverse) and polyamide yarn in the binding layer. The experiments were conducted on the developed 3D knitted fabrics to determine the fabric’s resistance to mechanical risks such as circular blade cut, puncture, abrasion, and also to evaluate the comfort parameter, such as air permeability. It was defined that 3D weft-knitted fabrics best results on tests: circular blade cut, puncture and abrasion resistant were achieved using HPPE yarn twisted with steel wire, higher mass per unit area with more significant amount of steel wire. According to the standard EN 388:2003, three samples of developed 3D weft-knitted fabrics had the highest 5th blade cut and the highest (4th) abrasion resistance level. All of them had the highest (4th) level of puncture resistance. 3D fabrics knitted on a circular weft-knitting machine of gauge 28E ensured 1.3–2.1 times greater blade cut and 4.9–12.1 times greater abrasion resistance result, than fabrics knitted on gauge 20E, due to a higher stitch density, higher mass per unit area, density and fabric’s thickness. But on the other hand, these parameters lowered air permeability by 20.2–43.0%.

High-modulus PET filaments and thermal bonding are used to reinforce the puncture resistance stability of the insole composite. This study aims to discuss the influences of the amount of low-melting-point polyester fibers (LMPET) and needle densities (ND) on tensile, bursting, and quasi-static puncture resistance properties. Besides, significance of LMPET amount and ND on puncture resistance against flat-head (A), spherical-head (B), and pointed-head (C) probes are in particular investigated to simulate the diversified application environments for insoles. Research result shows that, LMPET amount significantly affects the static puncture resistance against three probes; ND only significantly influences the puncture resistance against Probe A and C. Thermal bonding significantly improves the puncture strength against Probe B with various LMPET amounts of insoles, but evidently increases the puncture resistance against Probe A and C when being punched at various ND. The amount of LMPET fibers has a positive influence on the puncture strength of insoles, and 70 wt% of LMPET provide the average static puncture resistance up to 342.6 N. The high-modulus resultant insoles have advantages of flexibility, ease of process, and bendability with a higher and more stabilized puncture resistances.

Nonwoven fabrics were used as reinforcement to laminated composites to improve the mechanical properties and damage behaviors. The needle-punched Kevlar/LMPET nonwoven interlayer and two TPU covers were combined via thermal bonding to form the laminated composites. Tensile strength, peel load, and static puncture resistance of the laminated composites were evaluated in terms of needle punching rate and depth of the nonwoven interlayer. Results showed that tensile strength and static puncture resistance depended on the needle punching depth, primarily on the tangled fiber points. The peel load was dependent on the needle punching rate, especially on the resulting melted LMPET fibers. The laminated composites exhibited desirable tensile properties, peel load, and static puncture resistance.

Puncture resistance has become one of the most requested safety features, not only for protective garments such as stab vests, but also for safety shoes and gloves. Currently, this characteristic is highly demanded in the tyre industry. Conventional protective solutions, such as metallic plates and composite inserts prove to be either bulky or ineffective. The main objective of this work is the design and validation of a novel insert resistant to puncture. This composite insert consisted of a sandwich material with shear-thickening fluid interposed as the core. The dilatancy (shear-thickening) is time-independent rheological behaviour exhibited by some non-Newtonian fluids. These fluids manifest a surge in the apparent viscosity with an increase in the shear rate. In the first part of this work, a comparison between the rheological performance of different shear-thickening fluids (STFs) based on nanosilica dispersed in glycols is presented. This analysis attempts to investigate the combinations of fillers and carriers with the highest energy-absorbing capabilities among various glycol-based colloidal STFs. In the second part, the influence of the composition of the STF on its rheological properties is analyzed statistically. Finally, the puncture resistance of a composite system obtained by encapsulating the previously manufactured shear-thickening fluids in a polymeric shell is analyzed by means of a high-speed puncture test. This test was performed on the mockup of a tyre tread containing the best performing STF. The results showed that the use of the STF core increased the resistance to puncture by 20% as compared to the same volume of tyre tread material. Furthermore, the STF hermetically sealed the pierced sample, even when the tyre mockup was inflated at high internal pressure.

In this study, the dynamic puncture behavior of nonwoven needle-punched polyester geotextiles has been studied using video processing technique. Twenty-seven needle-punched geotextile samples were produced by changing areal weight, needle penetration depth and punch density as independent variables. Cone drop test was carried out on the samples. In addition to measuring the hole diameter (HD), the video processing technique with a high frame rate camera was employed to calculate the energy absorbed by geotextile fabric up to puncture point (Ep) and the hole expansion energy (Ee). Multiple linear regression method was used to develop the predicting relationships between independent and reply variables. The models showed that an increase in areal weight results in an increase in Ep, whereas it causes a decrease in Ee and HD. Moreover, increasing punch density and needle penetration depth, leads to less Ep, and more Ee and HD. In addition, it was also found that significant relationships exist for Ep-HD and Ee-HD.

Composite materials offer a number of distinct advantages in a wide range of low and high technology engineering applications. Considering the fact, in this study, a facile fabrication method of highly cut resistant composite fabrics using Kevlar and polyethylene is reported. 100% Kevlar, 100% Polyethylene and 50% Kevlar/50% Polyethylene composite fabrics are fabricated by weaving and knitting techniques. These fabrics were tested for cut index, abrasion, and puncture resistance for comparative exploration. Owing to higher mechanical strength and greater number of interlacements; the woven fabrics demonstrated twice cut resistance in contrast to knitted fabrics. The surface morphology of deformed samples investigated by Scanning Electron Microscopy (SEM) also proved that the woven fabrics of all types offered much resistance towards cutting than the knitted fabrics. Moreover, it is found that greater thickness of fabrics leads to intensification of the cut resistance. Furthermore, the effect of fiber type on cut resistant property of the fabrics was also measured and it was found that the composite fabric exhibited double cut resistance than 100% Kevlar and 100% Polyethylene fabrics. The 50% Kevlar/50% Polyethylene composite woven fabric resisted up to 35 consecutive strokes of sharp steel cutter whereas the knitted fabric completely torn apart at 20 strokes only. Thus, the as synthesized 50% Kevlar/50% Polyethylene composite woven fabric exhibiting superior cut resistance property offer a judicious choice for the preparation of efficient cut resistant fabric for industrial and domestic applications.

Bombyx mori cocoon, a natural nonwoven material has excellent puncture resistance and unique structure. Based on the structure of cocoon, this paper designed a biomimicry composite, aiming to improve the static puncture resistance through polyurethane impregnated treatment. In this article, four different types of polyurethane (TPU 85 A, TPU 90 A, PEUR 855 A, PEUR 991 A) are selected and five concentration gradients (5, 7, 9, 11, 13 wt%) are set. The tensile and static puncture resistance of the impregnated composites and damaged morphology after puncture are systematically studied. The results show that the static puncture resistance of nonwovens impregnated by polyurethane is improved obviously. This study provides a new way to design better static puncture resistant materials.

The polyester (PET) fibers and Kevlar® staple fibers, which are recycled from discarded selvages of PET and Kevlar® woven fabrics, are made into nonwoven fabrics using a needle-bonded process. The PET/Kevlar® nonwoven matrices are used as the surface layers, while a glass fiber woven fabric is used as the interlayer. The sandwich-structured composites are saturated with waterborne PU resin and then hot pressed, forming puncture resistant PU-reinforced PET/Kevlar® sandwiches. The sandwiches are evaluated in terms of the tensile property test, the bursting property test, the constant-rate puncture test, the dynamic puncture test, and the drop-weight impact test. The test results indicate that increasing the pick-up rate of PU resin can significantly improve all mechanical properties, suggesting that PU-reinforced PET/Kevlar® sandwiches have protective functions and make good candidate for insoles.

Needle-punched nonwoven fabrics are the most common textile structures used as geotextiles. In most applications, geotextile layers are subjected to compressive forces perpendicular to their plane. These forces will lead to the deformation of the layers and eventually cause puncture. In this study, the puncture behavior of nonwoven fabrics was simulated based on hyperelastic model, using finite element method (FEM) and considering geotextile layer as a continuous surface. For this purpose, three needle-punched fabrics with different weights of 460, 715, and 970 gr/m2 were selected and two tests of CBR (ASTM D6241) and Pin (ASTM D4833) were considered to evaluate the puncture process. Thus, puncture behavior of fabrics based on both of these tests were simulated using the ABAQUS software. Considering the puncture behavior in terms of stress-strain diagrams, results obtained from experiments and finite element analysis (FEA), showed good agreement. It was also shown that non-woven fabrics with higher weight exhibited higher puncture stress in both CBR and Pin tests. The mechanism of puncture at macroscopic scale obtained by finite element method was also qualitatively compared to that of experimental results.

Uncovering energy absorption and surface effects of various penetrating velocities on laminar structures is essential for designing protective structures. In this study, both quasi-static and dynamic penetration tests were systematical conducted on the front surfaces of metal sheets coated with a graphene oxide (GO) solution and other media. The addition of a GO fluid film to the front impact surface aided in increasing the penetration strength, improving the failure extension and dissipating additional energy under a wide-range of indentation velocity, from 3.33 × 10−5 m/s to 4.42 m/s. The coated -surfaces improved the specific energy dissipation by approximately 15~40% relative to the dry-contact configuration for both single-layer and double-layer configurations, and specific energy dissipations of double-layer configurations were 20~30% higher than those of the single-layer configurations. This treatment provides a facile strategy in changing the contact state for improving the failure load and dissipate additional energy.

Flexible natural armors from fish, alligators or armadillo are attracting an increasing amount of attention for their unique combinations of hardness, flexibility and light weight. The extreme contrast of stiffness between hard scales and surrounding soft tissues gives rise to unusual and attractive mechanisms, which now serve as models for the design of bio-inspired armors. Despite this growing interest, there is little guideline for the choice of materials, optimum thickness, size, shape and arrangement for the protective scales. In this work, we explore how the geometry and arrangement of hard scales can be tailored to promote scale-scale interactions. We use 3D printing to fabricate arrays of scales with increasingly complex geometries and arrangements, from simple squares with no overlap to complex ganoid-scales with overlaps and interlocking features. We performed puncture tests and flexural tests on each of the 3D printed materials, and we report the puncture resistance – compliance characteristics of each design on an Ashby chart. The interactions between the scales can significantly increase the resistance to puncture, and these interactions can be maximized by tuning the geometry and arrangement of the scales. Interestingly, the designs that offer the best combinations of puncture resistance and flexural compliance are similar to the geometry and arrangement of natural teleost and ganoid scales, which suggests that natural evolution has shaped these systems to maximize flexible protection. This study yields new insights into the mechanisms of natural dermal armor, and also suggests new designs for personal protective systems. Statement of Significance Flexible natural armors from fishes, alligators or armadillos are attracting an increasing amount of attention for their unique and attractive combinations of hardness, flexibility and low weight. Despite a growing interest in bio-inspired flexible protection, there is still little guideline for the choice of materials, optimum thickness, size, shape and arrangement of the protective scales. In this work, we explore how the geometry and arrangement of hard scales affect puncture resistance and flexural compliance, using 3D printing and mechanical testing. Our main finding is that the performance of the scaled skin in terms of puncture resistance can be significantly improved by slight changes in their geometry and arrangement. Our results also suggest that natural evolution has shaped scaled skins to maximize flexible protection. This study yields new insights into the mechanics of natural dermal armors, and also suggests new designs for personal protective systems.

This work is conducted to investigate the hierarchical structure, mechanical behavior and fracture resistance of grass carp scales with different water contents (hydrated and dehydrated) and load conditions (uniaxial, biaxial and punch tests). The whole cross-section of scales is investigated, and it is found that the bony layer displays discontinuity and partly embeds in collagen layer. Four different locations are considered under both tensile and punch tests. The results of the uniaxial tensile test show a correlation between the failure mode and the distribution of surface morphology on scales. The biaxial test results show that there are minor differences in the tensile strength and the Young’ modulus compared with those of the uniaxial tests, but the ultimate strain is about 20% – 50%. Puncture tests are also conducted with different size of needles and different hardness silicon rubbers as substrate. The results show that the puncture force and deformation are dependent on the size of needle and the hardness of substrate. The failure pattern of scales is related to the water content. Radial cracks occur in the bony layer of hydrated scale, and the collagen fibers twist around the puncture site. However, the shear failure occurs in the bony layer of dehydrated scale.

Beetles are by far one of the most successful groups of insects, with large diversity in terms of number of species. A part of this success is attributed to their elytra, which provide various functions such as protection to their bodies from mechanical forces. In this study, stag beetle (Lucanus cervus) elytra were first examined for their overall flexural properties and were observed to have a localized shape-retaining snap-through mechanism, which may play a possible role in partly absorbing impact energy, e.g., during battles and falls from heights. The snap-through mechanism was validated using theoretical calculations and also finite element simulations. Elytra were also characterized to examine their puncture and wear resistance. Our results show that elytra have a puncture resistance that is much higher than that of mandible bites. The measured values of modulus and hardness of elytra exocuticle were 10.3 ± 0.8 GPa and 0.7 ± 0.1 GPa, respectively. Using the hardness-to-modulus ratio as an indicator of wear resistance, the estimated value was observed to be in the range of wear-resistant biological material such as blood worms (Glyrcera dibranchiata). Thus, our study demonstrates different mechanical properties of the stag beetle elytra, which can be explored to design shape-retaining bio-inspired composites with enhanced puncture and wear resistance.

This study proposes fabric composites with improved static and dynamic puncture via increasing a friction force to restrain the slide of filaments as well as the compression and abrasion between the fibers and the puncture probe. The the bi-layered shell layers of composite fabrics are composed of aramid staple fibers and nylon staple fibers and a layer of low-melting-point polyester (LPET). The nonwoven layer consisting of recycled aramid and nylon staple fibers provides a shear effect to dissipate part of the puncture energy. Reinforcing interlayers include a woven fabric and PET filaments that are circularly aggregated between the surface layers, providing isotropic filament reinforcement and strengthening the resistance against the tip of the puncture probe. The reinforcing filaments may slide after the employment of needle punching, and to compensate for this disadvantage, the LPET layers are used to thermal bond the composite fabrics and the total thickness is controlled at 2 mm. The thermally bonded fabric composites are evaluated in terms of puncture resistance, thereby examining the effects of fabric structure and thermal bonding. According to the test results, the optimal composite structure is the sample N/L/W/F/L/N, which was reinforced by the LPET adhesive layer and irregularly aligned filaments. The sample which used the LPET adhesive layer had a positive influence on static puncture resistance and dynamic puncture resistance, preventing the slide of filaments, but the poor interfacial combination only contributed to limited reinforcement.

Reinforced polyester composites are widely used in many applications where puncture resistance is important. This research is aimed at understanding whether exposure to different temperatures, high and very low, affects the puncture resistance of a glass cloth reinforced polyester composite and the unreinforced polyester matrix. The temperature range investigated was +80 °C to −80 °C. A hemispherical drop-weight impactor was used for the puncture tests in an environmentally controlled chamber. The reinforced composite specimens are more puncture-resistant compared with the unreinforced polyester at all temperatures. The damage created by the impact reduces with decreasing temperatures, while the energy absorbed remains constant with temperature.

In order to solve the recycling of the puncture-resistant soft composites, this study constructs a multiscale self-healing gel-fabric soft composite synergistically toughened by Pluronic/PMEA hydrogel, hydroxyapatite nanoparticles (HAP NPs) and aramid fabric. Results show that the gel matrix has a self-healing efficiency of 85% after puncture damage, and the stab resistances are highly positively associated with the toughness of the hydrogel matrix. When toughened by 4% HAP NPs, the spike and knife resistances of soft composites are improved by 132% and 130%, respectively. After being laminated, the composite exhibits a self-repairing efficiency of 52% and still has excellent performance after multiple punctures. At lamination angle of 45° and the gel volume fraction of 45%, the composite has the best puncture resistance properties, and the 37 layers can resist against the E1 stab resistance energy. The synergistic toughened mechanism is due to the interfacial shear strength between the fiber and the gel matrix. Overall, this research provides a novel structural design for the recycling of high-performance puncture-resistant composites.

Recycling of puncture-resistant soft composites is challenging. In this paper, we report a new strategy of designing puncture-resistant composites with self-healing and synergistic toughening efficacy for secondary utilization after puncture damage. Puncture-resistant soft composites are prepared with Pluronic/PMEA hydrogel and aramid fabrics. The composites exhibit extremely high toughness and puncture resistance that are superior to those of their neat components. This result proves that the tough hydrogel and aramid fabrics have a synergistic effect, which provides the composites with a maximal spike-resistant peak force of 155 N and a maximal knife- resistant peak force of 182 N. The peak force of the composites is about 12 times that of neat fabric. In addition, the Pluronic/PMEA hydrogel matrix attains 85% self-healing efficiency at 100℃ in 3 h. The proposed soft composites with effective puncture- resistant performance can serve as an important guidance for future design of recyclable puncture-resistant composites after damage.

This study investigates the performance level of different protective gloves produced from woven fabrics, and optimizing their performance using grey relational analysis (GRA). The fabric areal density and poly vinyl chloride (PVC) dotting were the variables used to produce nine different glove samples. The performance of developed gloves was evaluated in terms of abrasion resistance, blade cut resistance, puncture resistance and tear strength. It was concluded that cut and puncture resistance are not affected by dotting type or increase in areal density (GSM). Tear resistance is improved by increasing GSM of the fabric, while abrasion resistance increases with increase in the diameter of dot. The grey relational analysis was performed to optimize the performance of gloves. It was found that the glove produced with 559 GSM fabric and 35 dots/inch2 offered best performance against all responses.

This study focuses on the puncture resistance performance of woven high modulus polypropylene (HMPP) fabric impregnated with shear-thickening fluids (STFs) composed of fumed silica nanoparticles suspended in polyethylene glycol (PEG). The puncture resistance performance of STF-treated HMPP fabrics were evaluated by the quasi-static puncture test. The results showed that the STF-treated fabric exhibited significant enhancement in puncture resistance performance as compared to neat fabric. The possible improving mechanisms responsible for puncture resistance performance of STF-treated fabric were also discussed.

Geotextiles are commonly used in pavements, earth retaining structures, and landfills, as well as in other geotechnical applications. The puncture strength test evaluates the ability of geotextiles to withstand stresses and loads during construction, which are among the severe conditions that geotextiles can experience. ASTM has recently replaced the standard pin puncture strength test, D4833, with the California bearing ratio (CBR) puncture strength test, D6241. However, many state departments of transportation and the FHWA still refer to ASTM D4833. Other state departments of transportation refer to ASTM D4833 and to D6241 or provide a list of alternative test methods to be considered in place of either of these tests. The objective of this research was to correlate the CBR and pin puncture strengths for various categories of geotextiles, regardless of weave type and mass per unit area. Five types of polypropylene geotextiles, three nonwoven and two woven, were subjected to testing in accordance with ASTM D4833 and D6241 standard procedures. Ten and 15 samples of each geotextile type were tested with CBR and pin puncture strength tests, respectively. All five types of geotextiles exhibited puncture strength values, whether pin or CBR, which were consistent within each group. Similarly, distinct load-displacement curves were exhibited within each material group. Statistical analyses were conducted to establish a correlation between the CBR and pin puncture strength values. The correlations were successfully used to estimate the CBR puncture strength values from the pin test with reasonable accuracy ( R2 = .78).

Polyurethane foam has been develocped for years. In the past, the most study is focused on one function of Polyurethane foam including noise absorption, thermal protection, and mechanical impact as well as cushioning properties, and thus interdisciplinary functions of these foam boards become an innovation research. Therefore, the objective of study is to develop the multifunctional protective composite boards which are suitable for diversified environments. In this study, the carbon fibers (CF) and glass fibers (GF) are used as reinforcements for PU composite boards which are denoted as CFR-PU and GFR-PU respectively. The composite boards are made with different thickness and different contents of reinforcing fibers. The drop-weight impact test adopts a circular drop weight that falls from a certain height in order to observe the deformation mechanism of the boards. Different fracture modes that are caused by the bursting, compression, drop-weight impact, and puncture resistance tests are then examined. The test results indicate that the CFR-PU and GFR-PU fiberreinforced composite boards have a satisfactory impact load of 90 % and a favorable absorption coefficient at a certain frequency, and also have improved mechanical properties.

The sclera provides the structural support of the eye and protects the intraocular contents. Since it covers a large portion of the eye surface and has relatively high permeability for most drugs, the sclera has been used as a major pathway for drug administration. Recently, microneedle (MN) technology has shown the possibility of highly local and minimally-invasive drug delivery to the eye by MN insertion through the sclera or the suprachoroidal space. Although ocular MN needs to be inserted through the sclera, there has been no systematic study to understand the mechanical properties of the sclera, which are important to design ocular MNs. In this study, we investigated a MN-based method to measure the puncture resistance and fracture toughness of the sclera. To reflect the conditions of MN insertion into the sclera, force-displacement curves obtained from MN-insertion tests were used to estimate the puncture resistance and fracture toughness of sclera tissue. To understand the effect of the insertion conditions, dependency of the mechanical properties on insertion speeds, pre-strain of the sclera, and MN sizes were analyzed and discussed. Statement of Significance Measurement of mechanical property of soft biological tissue is challenging due to variations between tissue samples or lack of well-defined measurement techniques. Although non-invasive measurement techniques such as nano/micro indentation were employed to locally measure the elastic modulus of soft biological materials, mechanical properties such as puncture resistance or fracture toughness, which requires “invasive” measurement and is important for the application of “microneedles or hypodermic needles”, has not been well studied. In this work, we report minimally-invasive measurement of puncture resistance and fracture toughness of sclera using a double MN insertion method. Parametric studies showed that use of MN proved to be advantageous because of minimally-invasive insertion into tissue as well as higher sensitivity to sub-tissue architecture during the measurement.

This study focuses on the puncture resistance performance of woven high modulus polypropylene (HMPP) fabric impregnated with shear-thickening fluids (STFs) composed of fumed silica nanoparticles suspended in polyethylene glycol (PEG) and those containing carbon nanotubes (CNTs). The shear-thickening characteristics and rheological features of suspensions were determined at steady and oscillatory shear stress using a stress controlled rheometer. The puncture resistance performance of STF-treated HMPP fabrics were evaluated by the quasi-static puncture test. To gain a better understanding of the effect of these two suspensions on puncture resistance mechanism of fabric, yarn pull-out test was conducted to examine internal shear strength and inter yarn frictional behavior of fabric. The results showed that both the STF-treated fabrics exhibited significant enhancement in puncture resistance performance as compared to neat fabric. However, the fabric impregnated with the suspension containing CNTs showed lower enhancement, due to its lower degree of shear-thickening as confirmed by rheological measurement. The possible improving mechanisms responsible for puncture resistance performance of STF-treated fabrics were also discussed.

The low-earth orbit environment contains small micrometeoroid and orbital debris (MMOD) particles traveling at characteristic velocities of several kilometers per second. In addition to being a direct threat to astronauts and spacecraft, upon impact with the exterior surface of a space vehicle, these highly energetic MMOD particles can create cut and puncture hazards for astronauts performing extra-vehicular activities (EVA). In this work, we demonstrate that replacing the standard neoprene-coated nylon absorber layers with woven aramid textiles intercalated with colloidal shear thickening fluids, i.e., STF-Armor™, can provide a meaningful enhancement to the cut and puncture resistance of the thermal micrometeoroid garment (TMG). Quasi-static puncture testing is performed using hypodermic needles of varying gauge to simulate the cutting and puncture hazards at deformation rates characteristic of human motion. At equal areal densities, we find that a TMG lay-up containing STF-Armor™ greatly improves puncture protection with a reduction in weight and comparable flexibility.

A new approach for intra-/inter-laminar reinforcement using needle-punching and thermal bonding was proposed for improvement of puncture resistance of multilayer compound fabrics that were composed of different kinds of nonwovens and woven fabrics. Effects of woven fabric orientation and thermal bonding on static and dynamic puncture properties were explored. Multilayer compound fabrics with different compositions of nonwoven and sequence of woven fabrics were comparatively discussed to confirm fabric and nonwoven influencing on static and dynamic puncture resistances. Puncture resistance mechanism of plied orientation and thermal bonding was analyzed for multilayer compound fabrics. The research result shows that woven fabric orientation affected static and dynamic puncture resistances more significantly when multilayer compound fabrics were comprised of high-modulus nonwovens and woven fabrics. Plied orientation correlated with the yarn density of woven fabric that was contained in compound fabrics. Contact length between woven fabric and nonwoven, as well as specific fiber toughness from nonwoven, was respectively responsible for static and dynamic puncture resistances of multilayer compound fabrics.

This paper addresses the response of glass fiber-reinforced shear thickening fluid (STF) under low-velocity impact. Experimental tests were performed according to ASTM: D5628 for initial impact energy 6.89 J and for samples with STF+ nanoclay (30% silica and 3% clay nanoparticles), STF+ nanoclay (30% silica and 1% clay nanoparticles), STF (30% silica nanoparticles), and STF (20% silica nanoparticles).The effect of impregnating glass fabrics with STFs on their quasi-static puncture resistance performance has been investigated. A STF was prepared successfully, and rheological behavior was investigated. The results of rheological tests indicate that the increase in the fraction weight of nanosilica and nanoclay leads to the increase in suspension viscosity and reduction in the critical shear rate. One of the disadvantages of STF is high concentration. Glass fabrics were soaked in STF/ethanol solution to prepare STF–glass fabric composite and STF–nanoclay–glass composite. For better immersion of fibers, at fi...

This paper presents a computational framework that analyzes the effect of fluid–structure interaction (FSI) on the impact dynamics and puncture failure of pressurized commodity tank cars carrying hazardous materials. Shell (side) impact tests have been conducted on full scale tank cars resulting in deformed or punctured tank cars. A finite element (FE) modeling method is applied that explicitly simulates the three distinct phases in a tank car loaded with a liquefied substance: pressurized gas, pressurized liquid and solid structure. Furthermore, an equivalent plastic strain based fracture initiation criterion expressed as a function of stress triaxiality is adopted to depict the fracture behavior of the tank car steel material. The fracture initiation is implemented for ductile, shear and mixed fracture modes and followed by further material deterioration governed by a strain softening law. The force, displacement and impact energy results obtained from the FE analysis show good agreement with the corresponding shell impact test data. The simulations demonstrate that FSI plays a critical role in predicting the correct dynamics of tank car impact. The puncture resistance of a tank car, characterized as limit impact conditions in terms of puncture energy or puncture velocity, is further analyzed in shell impact scenarios. The puncture energy is shown to increase as the initial fluid pressure decreases, the tank car thickness increases or the effective impactor size increases. Quantitative correlations between puncture energy/velocity and each of these factors are obtained using the FE analysis method developed in this paper.

Resistance to permeation of noxious chemical substances should be accompanied by resistance to mechanical factors because the glove material may be torn, cut or punctured in the workplace. This study reports on glove materials, protecting against mineral oils and mechanical hazards, made of carboxylated acrylonitrile–butadiene rubber (XNBR) latex. The obtained materials were characterized by a very high resistance of the produced materials to oil permeation (breakthrough time > 480 min). The mechanical properties, and especially tear resistance, of the studied materials were improved after the addition of modified bentonite (nanofiller) to the XNBR latex mixture. The nanocomposite meets the requirements in terms of parameters characterizing tear, abrasion, cut and puncture resistance. Therefore, the developed material may be used for the production of multifunctional protective gloves.

In this article, the new model of dynamic puncture behaviors of intra-/inter- reinforced compound fabrics which are fabricated by nonwovens and reinforced fabrics using needle-punching and thermal bonding technique is constructed by the maximum deformation and stress-wave transmission theory. Moreover, the number of layers for E1 puncture protection is optimized based on numerical analysis of penetration depth. Dynamic puncture model shows that the dynamic puncture resistance depends on elastic modulus of reinforced fabrics, deformation radius and thickness of compound fabrics. The maximum puncture resistance and penetration depth both have parabola relations to number of layers. This study provides the accurate prediction model of puncture force and safety layers for designing puncture-resisting body armor in the future.

Stab performance is one of the most important mechanical characters for textile structure, especially for geo-textiles. This paper gives an energy approach to studying the effect of friction on the stab property of woven fabrics. Both results show that the stab performance enhances when the friction between warp and weft yarns increases. This paper concludes that nanofiber membrane is the best candidate for stab-proof application.