Dynamic Puncture Resistance Research Articles

Thermoplastic Laminated Composites Applied to Impact Resistant Protective Gear: Structural Design and Development

Laminated composites have been commonly applied to all fields. When made into laminated composites, Kevlar woven fabrics are able to provide the required functions. In this study, two types of TPU are incorporated to improve the intralayer features of Kevlar/TPU laminated composites. Hence, the Kevlar/TPU laminated composites consist of firmly bonded laminates while retaining flexibility of the fabrics. Being the interlayer of the laminated composites, the TPU layer provides adhesion while strengthening the tensile property, dynamic puncture resistance, and buffer strength of Kevlar/TPU laminated composites. The test results indicate that with a blending ratio of two types of TRU being 85/15 wt%, the Kevlar/TPU laminated composites exhibit a tensile strength of 18.08 MPa. When the stacking thickness is 1 mm, the tensile strength is improved to 357.73 N with the buffering strength reaching 4224.40 N. Notably, with a thickness being 1.2 mm, the laminated composites demonstrate a dynamic resistance being 672.15 N. In the meanwhile, functional Kevlar fabrics are allowed to keep the fiber morphology owing to the protection of TPU composite films. Considering the composition of protective gear, Kevlar/TPU laminated composites possess a powerful potential and are worthwhile exploring.

Puncture resistance of STF impregnated MWCNTs-grafted carbon fabrics

In this study, STF with the silica concentration of 20 wt% was fabricated. Functionalized multi-walled carbon nanotubes (MWCNTs) were chemically bonded onto the carbon fibers by using grafting technique. In grafting technique, DMF/PAN fiber/MWCNTs suspension sprayed onto each surface of carbon fabric and MWCNTs were grafted by a thermal treatment at 250 °C. Neat and MWCNTs-Grafted carbon fabrics were impregnated with STF with the silica loading of 20 wt%. Then, dynamic and quasi-static puncture resistance of neat, STF impregnated, MWCNTs-Grafted and MWCNTs-Grafted-STF impregnated carbon fabrics were examined. STF impregnation was detected to lead to a decrease in dynamic puncture resistance and an increase in quasi-static puncture resistance. Dynamic puncture resistance of MWCNTs-Grafted carbon fabric was found to be less than neat fabrics due to larger gaps between yarns occurred after thermal stabilization. Also, due to the greater gap between yarns, complete perforation occurred at lower penetration depth in MWCNTs-Grafted carbon fabrics than neat carbon fabrics in quasi-static puncture tests.

Dynamic puncture behavior of the calendered geotextile compound fabrics: optimization using the Taguchi design of experiment

For improving dynamic puncture resistance (cone drop test) of the needle-punched nonwoven geotextile fabrics, employing a calendered compound tri-layer sandwich-structure of nonwoven/woven/nonwoven was aimed by reinforcement of the nonwoven fabric with incorporating a high strength low extensible woven fabric. For this purpose, five main variables including woven fabric structural characteristics, compound punch density and fundamental adjustments of the calendering treatment, individually in three levels were statistically investigated using Taguchi design of experiment. In addition to conventional measuring diameter of the hole created by the dropping cone, a high-speed video processing technique was also used to calculate the expansion energy of the formed hole using MATLAB-designed software. A comprehensive review of the results showed while the studied reinforcement leads to an increase in the puncture resistance, the calendering parameters have the highest effect on the hole diameter and the expansion energy is also more affected by the woven fabric variables.

Synergistic Effects of Needle Punching and Shear-Thickening Fluid on Sandwich-Structured Composites Made of Nonwoven and Woven Fabrics

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.

Fabric Composites Reinforced with Thermally Bonded and Irregularly Aligned Filaments: Preparation and Puncture Resistant Performance.

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.

Optimizing the processing parameters of mechanical and hydraulic conductivity of geotextile liner

ABSTRACTGlass geotextile reinforcement and needle-punch bonding are applied to compensate for the low mechanical strength of a geotextile clay liner (GCL) and reduce damage under complicated service conditions. Moreover, the effects of glass fibers embedded in the bentonite on hydraulic conductivity are investigated. A hybrid-structure glass geogrid-reinforced GCL (GGCL) is constructed by needle punching the bentonite laminated by a glass geogrid layer and separated by a 0.3 mm thick meltblown nonwoven layer. The central composite design (CCD) is proposed to discuss the effects of needle punch density (ND) and depth of punch (DP) on the tensile properties, quasi-static and dynamic puncture resistances, and hydraulic conductivity of the GGCL, and an empirical regression model of these properties is established. Results show that ND and DP significantly affect tensile the properties and puncture resistances while DP insignificantly affects the hydraulic conductivity of the GGCL. Glass fibers embedded into the bentonite improve the hydraulic conductivity of the material. At the 95% confidence interval, the process parameters can be optimized by the empirical regression model. The proposed regression model is consistent with experimental results and can thus be used to predict the mechanical properties and hydraulic conductivity of GGCL.

Using unwrapped filament tows to strengthen sandwich composites: Puncture and bursting resistance

The combination of appropriate materials and structural design can compensate for flaw of a single pattern, providing the products with better functionalities. In this study, the custom-made nonwoven fabric machine can unwrap the filament tows before needle punching stage. Sandwich composites are proposed, consisting of two nonwoven fabrics as surface layers and laminated loops of filaments as the core. The puncture resistance of the sandwich composites are examined in terms of weight of filament loops and needle-punching depth, examining their influences. The employment of filaments has a remarkable influence on the mechanical performance of the composites. GF4G has static puncture resistance, dynamic puncture resistance, and bursting strength that are 89%, 30%, 88% higher than those of GF1G; 332%, 127%, and 500% higher than those of 2G; and 671%, 400%, and 1260% higher than those of G. Using filaments to reinforce nonwoven fabrics only requires simple equipment and easy operation. Furthermore, based on the requirements of different final products, diverse filaments and multiple parameters can be combined, thereby providing the composites with efficient production, solid reinforcement, and broad applications.

An Investigation into Dynamic Puncture Resistance of the Polyester Needled Nonwoven Geotextiles using Video Processing Technique

Abstract 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.

Numerical simulation of dynamic puncture behaviors of woven fabrics based on the Finite Element Method

Research on the simulation and modeling of dynamic puncture penetration is more complex problem due to full consideration of the tightness of the fabric and the sharp profile of the puncture. This study presents numerical simulation of complicated dynamic puncture behaviors on the basis of the roles of extension and stress-wave transmission on the deformation. The unit cell model was used to simulate the yarn crimp and extension during the uniaxial dynamic puncture process. In addition, the puncture deformation and stress distribution of woven fabrics with different elastic modulus and friction distance were simulated followed with dynamic puncture penetration. The result shows that dynamic puncture damage critically depends on the elastic modulus of yarns and the distance between yarns; the inter-yarn distance affects dynamic puncture resistance more significantly. Dynamic puncture stress nonlinearly increases with the elastic modulus, and linearly decreases with yarn distance. The research result indicates that weaving density can be increased to improve dynamic puncture resistance more obviously.

Static and dynamic puncture properties of intra-/inter-laminar reinforced multilayer compound fabrics by needle-punching and thermal bonding

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.

Modeling and optimization of dynamic puncture behaviors for flexible inter-/intra- reinforced compound fabrics

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.

Quasi-static and dynamic mechanical responses of hybrid laminated composites based on high-density flexible polyurethane foam

Hybrid laminated composites were fabricated based on high-density flexible polyurethane foam and reinforced with inter/intra-ply hybrid laminates. Transient responses of hybrid composites under quasi-static and dynamic loadings with various thicknesses and expansion factors were comparatively investigated. Experimental results revealed that foam cell collapse and hybrid laminates rupture were dominant mechanisms of energy absorption. Interlaminar stress and composite tensile strength determined the compressive potential energy and double-peak behavior. Quasi-static bursting and puncture resistances exhibited totally different relationships to various constructions and expansion factors. Energy dissipation capacity is influenced more significantly by the constant rate of transverse (CRT) puncture than dynamic puncture process. CRT puncture resistance is superior to the corresponding dynamic puncture resistance for all constructions. The hybrid laminated composites contributes to eliminate more than 95% of the incident force in the drop weight impact test. Compared with non-laminated panel, the hybrid laminated composites exhibited higher resistance to static and dynamic loadings.

Puncture-resisting, sound-absorbing and thermal-insulating properties of polypropylene-selvages reinforced composite nonwovens

In order to realize recycling of polypropylene selvages, polypropylene nonwoven selvages with different plied orientation were inserted between Kevlar/Nylon/low-melting polyester nonwoven fabrics forming composite nonwoven. Low-melting polyester content of nonwoven fabric and hot-pressing temperature of composite nonwoven were both optimized after static and dynamic puncture resistances. Moreover, effects of hot-pressing and plied orientation on static and dynamic puncture resistances, sound absorbing and thermal insulating properties of composite nonwoven were discussed respectively. Result shows that, optimal low-melting polyester fiber content was 30%, and best hot-pressing temperature for composite nonwoven was 180°C. Polypropylene nonwoven selvages improved static puncture resistance, sound absorbing and thermal insulating properties. Hot-pressing slightly increased puncture resistance and obviously improved thermal insulation, but decreased sound absorption coefficient significantly. Plied orientation affected static and dynamic puncture resistance insignificantly, but influenced on sound-absorbing and thermal-insulating properties significantly. When composite nonwoven was plied with 90°/90° polypropylene selvages and hot-pressed at 180°C, the static and dynamic puncture resistances reached 120 N and 80 N, respectively, and thermal conductivity was 0.047 W/mK. Five layers of composite nonwoven before hot-pressing had sound absorption coefficient of above 0.94 at frequency of higher than 1890 Hz.

Low-velocity impact and static behaviors of high-resilience thermal-bonding inter/intra-ply hybrid composites

This study prepared inter/intra-ply hybrid composites reinforced with sandwich-structure recycled Kevlar nonwoven/glass woven compound fabric. Negative-depth needle punching and thermal bonding were applied to strengthen the structure with two compound cover plies and a fluffy cushioning center ply. The effects of center ply areal density, needle punching depth, and fiber blending ratio on the static and dynamic impact resistance behaviors of the composites were investigated. The results indicated that areal density significantly influenced the static and dynamic impact behaviors, which were both enhanced by the promotion of thermal-bonding points. As the needle punching deepened, the static and dynamic puncture resistances represented opposite tendencies because of different failure mechanisms. Static friction was the dominant factor for static puncture resistance, whereas kinetic friction was the dominant factor for dynamic puncture resistance. A similar phenomenon was observed when fiber blending ratio was varied. In terms of the non-penetrating dynamic cushioning test, areal density was the most distinct influence factor on cushioning behavior and the hybrid composites sample with an areal density of 700g/m2 could eliminate up to 66.5% of the incident force. Therefore, the inter/intra-ply hybrid composites showed high impact resistance and excellent dynamic cushioning property.

Static and dynamic puncture failure behaviors of 3D needle-punched compound fabric based on Weibull distribution

Through-thickness reinforcement structure of compound fabric was formed through a two-sided needle-punching and thermal-bonding processes. This study presents static and dynamic puncture resistances of compound fabric comprised of Kevlar®/PA6/low-melting PET nonwoven, low-melting PET/PET nonwoven and woven fabric. The effect of the staple fibers fraction on puncture resistance was investigated to assess optimal fiber content in the nonwoven layer. Static and dynamic puncture failure models of non-thermal-bonded and thermal-bonded compound fabrics were constructed using a Weibull probability distribution to predict puncture failure reliability. Result indicates that puncture forces increased and then decreased with low-melting PET fibers, but steadily improved with recycled Kevlar® fibers. Puncture failure probability models show that thermal-bonding largely improved failure reliability of the static puncture property, but slightly decreased dynamic puncture performance. Puncture failure mechanisms were respectively exposed according to SEM observations.

Manufacturing Technique and Stab-Resistance Evaluation of Three-Dimensional Nylon 6/LPET Compound Nonwoven Fabrics

This study aims to examine the influence of the temperatures of heat treatment on the puncture-resistance of Nylon6/LPET compound nonwoven fabrics. Polyamide 6 (Nylon 6) fibers and low-melting-point polyester (LPET) fibers are combined and undergo a heat treatment to make three-dimensional (3-D) Nylon 6/LPET compound nonwoven fabrics through a nonwoven process. The nonwoven fabrics are tested for their dynamic puncture resistance, constant rate puncture resistance, and impact strength. The experiment results show that when thermally treated at a high temperature, the compound nonwoven fabrics are rendered with a lower dynamic puncture resistance and a lower constant rate puncture resistance, but a greater impact strength.

Manufacturing Technique and Property Evaluations of Sandwich-Structured Nonwoven Composites

This study aims to examine the thickness of a sandwich structure and the lamination number of the Kevlar nonwoven fabrics o n the punch resistance strength and impact resistance strength of the nonwoven composites. Kevlar nonwoven fabrics and Nylon/low-melting-point polyethylene terephthalate (LPET) nonwoven fabrics are laminated with various combinations to form sandwich-structured nonwoven composites. The experiment results show that an increasing number of Kevlar nonwoven fabrics results in low dynamic and constant rate puncture resistance but high impact strength; and conversely, an increasing thickness of sandwich-structured nonwoven composites causes high dynamic and constant rate puncture resistances but low impact strength.

Effects of needle-punching and thermo-bonding on mechanical and EMI shielding properties of puncture-resisting composites reinforced with fabrics

Effects of needle-punching and thermo-bonding on tensile property, air permeability, puncture resistances and EMI shielding effectiveness were discussed for carbon-reinforced composite and glass-reinforced composite. The result shows that, needle-punching significantly improves static and dynamic puncture resistances. As increase of needle-punched density, static and dynamic puncture resistances show firstly increasing and then decreasing trend. Thermo-bonding almost has no influence on static puncture resistance, but effectively decreases dynamic puncture resistance. Comparatively, carbon-reinforced composite shows higher static and dynamic puncture resistances than glass-reinforced composites when being needle-punched at 200 needles/cm2. Meanwhile, carbon-reinforced composite has superior EMI shielding effectiveness to 40–60 dB at frequency of above 1 GHz, reaching 99.99 % shielding efficacy.

Static and dynamic puncture behaviors of compound fabrics with recycled high-performance Kevlar fibers

An economical and flexible compound fabric was prepared using Kevlar fabric and glass fabrics as well as recycled Kevlar/Nylon/low-Tm polyester nonwovens via needle-punching and thermal-bonding processes. Effects of Kevlar staple fibers fraction, number of layers and inter-laminar bonding on the static and dynamic puncture resistances were comparatively studied. Findings indicate that increase of Kevlar staple fibers fraction improved static puncture resistance more significantly, but inter-laminar shear effect influenced on dynamic puncture resistance more evidently. With 20wt% recycled Kevlar fibers, static puncture resistance had linear relation to number of layers, but dynamic puncture resistance showed a parabolic relationship. The contacting pressure and friction strength of compound fabric to probe was to resist against static puncture resistance, but mechanism for dynamic puncture resistance was due to fiber elongation of fabric interlayer and compactness of compound fabric. Yarn brittle-breakage was the main dynamic puncture resistance mechanism for G-CF, but pushing fiber apart was for K-CF, besides of contact pressure of probe to compound fabrics. The improved both of static and dynamic puncture resistances were attributed to cut resistance of Kevlar fibers and compactness of fiber assembles. Comparatively, cut resistance property of Kevlar fibers related to dynamic puncture behavior more significantly, but fiber compactness affected static puncture resistance obviously.

Manufacturing Technique and Property Evaluations of Protective Textiles

Global warming increases each day and causes people to pay more attention to the reduction of carbon dioxide emission in order to mitigate the increase in temperature. Reducing, reusing, and recycling can effectively reduce the emission of carbon dioxide, to attain goals of energy conservation and carbon reduction. This study aims to explore the difference in the punch resistance and impact strength between the polyethylene terephthalate (PET) nonwoven fabrics and PET/TPU honeycomb grid/PET (P/T/P) composites. Recycle PET, high strength PET, and low melting PET are made into PET nonwoven fabrics, two layers of which are laminated with a TPU honeycomb grid, the interlayer, to form P/T/P composites. The constant rate puncture resistance, dynamic puncture resistance, and impact strength of PET nonwoven fabrics and P/T/P composites are evaluated. The experiment results show that both the constant rate and dynamic puncture resistances of P/T/P composites are lower than those of PET nonwoven fabrics.