Kevlar Composites Research Articles

Mixed Mode‐I/II interlaminar fracture toughness Characterization of woven Carbon–Kevlar interyarn hybrid textile composites

AbstractIn actual service conditions, the composite structures are subjected to the combined effect of Mode‐I and Mode‐II loadings. It has great significance in the aerospace, defense, military, automobile, and marine sectors. This study aims to determine the Mixed Mode‐I/II interlaminar fracture toughness (ILFT) of plain and twill woven carbon, Kevlar monolithic, and interyarn hybrid textile composites under several hybridization schemes. The tailored properties are obtained using the interyarn hybridization of high stiff carbon yarn and high tough Kevlar yarn. The effect of individual yarn in the length direction in different hybrid composite laminates is carefully investigated. The Mixed Mode‐I/II ILFT characterization is experimentally performed using a mixed mode bending (MMB) test specimen on the Instron 8862 system under 45%, 55%, and 65% Mixed Mode ratios (MMRs). The increase in mode mixture percentage decreases the lever length, increases the load‐bearing capacity, and increases the Mixed Mode‐I/II ILFT of the MMB test specimen. Plain woven composites exhibited a higher ILFT than twill woven textile composites. The plain woven carbon–Kevlar hybrid composite laminate with carbon yarn‐in‐length direction shows the highest Mixed Mode‐I/II ILFT after CP laminates. Hybridization significantly increases the Mixed Mode‐I/II ILFT compared to monolithic Kevlar fabric‐reinforced composites. Moreover, the failure mechanisms are investigated using scanning electron microscopy.Highlights Mixed Mode‐I/II ILFT of carbon–Kevlar interyarn hybrid textile composites. ILFT at nonlinearity (NL), VIS, and 5%/Max load points for 45%, 55%, and 65% MMR. Advantage of placing carbon yarn‐in‐length direction in hybrid configurations. Effect of carbon–Kevlar interyarn hybridization on Mixed Mode‐I/II ILFT. Fractography of tested specimens to investigate several failure mechanisms.

Review on Tribological and Machining Characteristics of Kevlar Composites

Review on Tribological and Machining Characteristics of Kevlar Composites

Laser Machining of Kevlar Polypropylene Composites: Effect of Continuous versus Modulated Wave Operational Mode

Laser Machining of Kevlar Polypropylene Composites: Effect of Continuous versus Modulated Wave Operational Mode

Experimental investigation on the tensile, flexural, and thermal rigidity of ALON-reinforced Kevlar fabric-impregnated epoxy composites

Experimental investigation on the tensile, flexural, and thermal rigidity of ALON-reinforced Kevlar fabric-impregnated epoxy composites

Performance evaluation of kevlar fiber reinforced epoxy composite by depositing graphene/SiC/Al2O3 nanoparticles

The synergistic effect of adding Silicon Carbide (SiC), Aluminum Oxide (Al2O3), and Graphene (GR) nanoparticles into Kevlar fiber-reinforced epoxy composites is investigated in this study. Within the epoxy matrix and Kevlar fibre reinforcement, these nanoparticles come in a variety of compositions. The mechanical and flammability features of the composite are revealed by experimental evaluation. Of the nanoparticles, graphene performs the best; the composite reinforced with graphene shows 324 MPa of tensile strength, 8 J/mm of impact strength, and 75.2 HRC of hardness. The composite layers' interior structure is investigated using scanning electron microscopy examination. To evaluate thermal stability of the composition the thermogravimetric (TG) and the differential thermal analysis (DTA) investigations were performed. Thermal stability is achieved by the graphene-reinforced composite at 775 °C. Additionally, corrosion tests and water absorption tests were conducted to assess the material's moisture sensitivity. The overall goal of the research is to ascertain whether adding various nanoparticles to Kevlar produces the best outcomes; graphene has demonstrated promising results in terms of improving mechanical and thermal stability.

Surface engineering of textile structural composites with ZnO nanorods and graphene nanofillers for aircrew helmet applications

AbstractThis research aimed to augment the properties of interfibre interfaces through surface treatment with ZnO nanorods while simultaneously modifying the matrix with graphene nanoplatelets. The strategic approach of this research focused on synergizing these interventions to enhance the mesomechanical, and macromechanical properties, which are specifically targeted at improving the performance of aircrew helmets. This study investigated the effectiveness of these enhancements in improving the mechanical performance of aircrew helmets. The synergy of integrating ZnO nanorods and doped GNPs into Kevlar fabric resulted in a 29% increase in impact energy absorption compared to that of the standard Kevlar composite. Furthermore, the composite samples underwent thorough analysis through techniques such as thermogravimetric analysis (TGA), Raman spectroscopy, Fourier‐transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM) imaging. The findings indicate that incorporating 1% graphene nanofillers into Kevlar during the fourth seed cycle of ZnO treatment yields favorable mechanical performance characteristics. SEM at 50 KX magnification provided detailed visualization of the ZnO nanorods grafted onto the fabric substrates, with subsequent evaluation of the morphological damage and fractography of the impacted composites. The findings of this research hold significance for advancing the understanding of composite material behavior under impact loads and contribute to ongoing efforts to enhance the durability and performance of structural composites in diverse applications.Highlights Synergistic treatment with ZnO nanorods and graphene nanoplatelets boosted Kevlar composite properties for aircrew helmets. Adding 1% graphene during ZnO treatment increased impact energy absorption by 29%. Comprehensive analysis validated treatment efficacy, showing substantial mechanical improvements. The research advances composite understanding, paving the way for durable, high‐performance materials for applications like aircrew helmets.

Investigation on Mechanical Properties of Kevlar Fiber and Al2O3 – SiC used Nano-polymer Composite

Kevlar is a synthetic fiber that has become well-known all over the globe because of its many industrial uses. It functions well as a composite material and is mostly used in conjunction with other materials. This study discusses the fabrication of epoxy composites with different proportions of Al2O3 and SiC nanoparticles with Kevlar fiber. In this process, SiC, and Al2O3 nanoparticles were added to Kevlar fiber and fabricated the composite by a compressed moulding machine for shear, tensile and impact tests. From these test results, incorporating Al2O3 and SiC nanoparticles with Kevlar fiber under various compositions (1% to 4%) influences the composite mechanical behaviour such as strength. KBS 2 has the highest tensile strength of the four sample composites, measuring 5628 N/cm2, among the Kevlar fiber reinforced polymer composites containing epoxy resin. This is the highest value among the composite samples. Additionally, it is worth seeing that the shear strength of the Kevlar fiber-reinforced polymer composite featuring the KAS 2 value of 7735 N/cm2 has the highest value from the other composite including the KAS 1, KAS 3 and KAS 4. Moreover, the Kevlar fiber-reinforced polymer composite with KAS 2 (4.76 J) exhibits a larger impact strength than the composite with KAS 3 (3.42 J), KAS 1 (4.26 J, and KAS 4 (4.54 J). The findings indicate that Kevlar fiber reinforced with 3% Al2O3 and 2% SiC nanoparticles (KAS 2) exhibits superior strength and rigidity compared to the other nanoparticle combinations utilised in Kevlar fiber composites.

The mechanical properties of Kevlar three-dimensional angle-interlock fabrics and composites

In this article, in order to investigate the difference of mechanical properties between three-dimensional angle-interlock (3DAI) structure and two-dimensional (2D) structure. Kevlar filaments were used as raw material to prepare 3DAI fabrics. The tensile properties of Kevlar 3DAI fabrics were investigated and the influence of warp damage and crimp wave height on the tensile properties was analyzed too. The bending properties and low-velocity impact properties of the 3DAI Kevlar/EP composites and the 2D composites were compared. The results revealed that the warp degradation and crimp percentage in 3DAI fabrics increase with the increase of weft density. The maximum warp degradation rate is 15% and the maximum crimp percentage is 5.4%, which has a negative effect on the mechanical properties of the 3DAI fabrics and the developed Kevlar/EP composites. Compared with the 2D plain composites, the 3DAI composites have superior impact resistance and anti-stratification performance. Moreover, which also has a superior ability to withstand multiple impacts.

Structural Health Monitoring of Fiber Reinforced Composites Using Integrated a Linear Capacitance Based Sensor.

The demand for fiber-reinforced polymers (FRPs) has significantly increased in various industries due to their attributes, including low weight, high strength, corrosion resistance, and cost-efficiency. Nevertheless, FRPs, such as glass and Kevlar fiber composites, exhibit anisotropic properties and relatively low interlaminar strength, rendering them susceptible to undetected damage. The integration of real-time damage detection processes can effectively mitigate this issue. This paper introduces a novel method for fabricating embedded capacitive sensors within FRPs using a coating technique. The study encompasses two types of fibers, namely glass and Kevlar fiber/epoxy composites. The physical vapor deposition (PVD) technique is employed to coat bundle fibers with conductive material, thus creating embedded electrodes. The results demonstrate the uniform distribution of nanoparticles of gold (Au) along the fibers using PVD, resulting in a favorable resistance of approximately ≈100 Ω. Two sensor configurations are explored: axial and lateral embedding of the coated yarn (electrodes) to investigate the influence of load direction on the coating yarn. Axial-sensor configuration specimens undergo tensile testing, showcasing a linear response to axial loads with average sensitivities of 1 for glass and 1.5 for Kevlar fiber/epoxy composites. Additionally, onset damage is detected in both types of fiber composites, occurring before final fracture, with average stress at the turning point measuring 208 MPa for glass and 144 MPa for Kevlar. The lateral-sensor configuration for glass fiber-reinforced polymer (GFRP) exhibits good linearity towards strain until failure, with average gauge factors of 0.25 and -2.44 in the x and y axes, respectively.

Cytotoxicity of novel hybrid composite materials for making bone fracture plates

Bone fracture plates are usually made from steel or titanium, which are much stiffer than cortical bone. This may cause bone ‘stress shielding’ (i.e. bone resorption leading to plate loosening) and delayed fracture healing (i.e. fracture motion is less than needed to stimulate callus formation at the fracture). Thus, the authors previously designed, fabricated, and mechanically tested novel ‘hybrid’ composites made from inorganic and organic materials as potential bone fracture plates that are more flexible to reduce these negative effects. This is the first study to measure the cytotoxicity of these composites via the survival of rat cells. Cubes of carbon fiber/flax fiber/epoxy and glass fiber/flax fiber/epoxy had better cell survival vs. Kevlar fiber/flax fiber/epoxy (57% and 58% vs. 50%). Layers and powders made of carbon fiber/epoxy and glass fiber/epoxy had higher cell survival than Kevlar fiber/epoxy (96%–100% and 100% vs. 39%–90%). The presence of flax fibers usually decreased cell survival. Thus, carbon and glass fiber composites (with or without flax fibers), but not Kevlar fiber composites (with or without flax fibers), may potentially be used for bone fracture plates.

Mechanical, wear, thermal conductivity and hydrophobicity behavior of Kevlar fiber-epoxy structural composites reinforced with onion peel carbon quantum dot and commercial carbon nanotubes: a comparative study

Mechanical, wear, thermal conductivity and hydrophobicity behavior of Kevlar fiber-epoxy structural composites reinforced with onion peel carbon quantum dot and commercial carbon nanotubes: a comparative study

Driving into the Future: Nano Graphene and Silicon Dioxide Enriched Kevlar Composites for Automotive Applications

Driving into the Future: Nano Graphene and Silicon Dioxide Enriched Kevlar Composites for Automotive Applications

Modelling and optimization of hybrid Kevlar/glass fabric reinforced polymer composites for low-velocity impact resistant applications

Kevlar and glass-based fabric-reinforced polymer composites possess excellent impact resistance, corrosion and high specific strength properties which makes them suitable candidature for the fabrication of industrial helmets, riot shields, automobile parts etc. The polymer composite components are prone to impact failure, which restricts their wide commercial usage. In this work, to enhance the impact damage resistance of polymer composite laminates, a hybridized material model consisting of glass and Kevlar fabric was employed. The hybridization of Kevlar ‘K’ with glass ‘G’ fabric [K/K/G/G/K] results in a cost reduction of 32 % without any significant variation in performance when compared to non-hybrid Kevlar fabric-based composite laminate [K/K/K/K/K]. In comparison to plain glass fabric laminates [G/G/G/G/G], the [K/K/G/G/K] configuration exhibits a significant 16.68 % improvement in energy absorption. This improvement is rooted in a parametric study and optimization process employing the Preference Selection Index (PSI) technique to determine the optimum stacking sequence of fabrics within the composite laminate. In addition, it evaluates the projectile limit velocity necessary to prevent failure and assesses the total deformation for an optimized stacked [K/K/G/G/K] composite, taking into account various projectile shapes conforming to low-velocity impact applications. The results of this study provide valuable insights into the properties and capabilities of the hybrid composite laminate and may pave the way for the development of more effective materials for impact protection in various applications.

Development and characterization of kevlar and glass fibers reinforced epoxy/vinyl ester hybrid resin composites

AbstractThis research investigates the influence of kevlar and glass fiber reinforcements on the mechanical and thermal properties of epoxy/vinyl ester (hybrid resin) composite. The hybrid resin was synthesized by achieving an interpenetrating network between epoxy and vinyl ester. The composites were characterized using tensile, flexural, impact, and thermo‐gravimetric analysis (TGA). Scanning electron microscopy was employed to analyze surface morphology whereas Fourier‐Transformation Infrared Spectroscopy (FT‐IR) was used to investigate the possible interaction between the constituents of the composites. The findings have shown a notable improvement in the mechanical properties after the hybridization of the resin. For reference, the tensile strength of glass/hybrid resin and kevlar/hybrid resin composites were observed to increase by 8.33% and 23.65%, as compared to glass/epoxy and kevlar epoxy composites respectively, whereas, the bending strength of these composites was improved by 8.36% and 30.61%, respectively. TGA also showed an enhanced thermal stability of the hybrid resin‐based composites. Such improvements are noticed due to multi‐resin incorporation (the oxirane group of epoxy reacts with the hydroxyl group of vinyl ester), confirmed by the FTIR, TGA, and morphological analysis. This study signifies that the proposed hybrid composites are better in terms of strength and modulus relative to conventional metallic materials.Highlights The paper presents the development of novel hybrid resin, reinforced with synthetic fibers. Hybrid resin is imparted positively and is highly favorable in improving the mechanical properties of composites. The tensile strength of novel composites is increased by 8.33% and 23.65% relative to their base specimens, and a similar trend is observed in flexural and impact analysis. Fractured analysis showed that composite laminates deteriorated more intensely due to cohesive matrix fracture; adhesion failure was not observed at all, as evidenced by the emergence of micro‐cracks in resin. Developed novel composites exhibited maximum thermal stability; residual char in glass/epoxy/vinyl‐ester composite attained 17.81% higher, whereas kevlar/epoxy/vinyl‐ester achieved 3.56% relative to glass/epoxy and kevlar/epoxy base samples.

Experimental Investigation of Influence of Fibre Orientation on the Dynamic Properties of Carbon Fibre and Intra-Ply Woven Carbon-Kevlar/Epoxy Hybrid Composite

Composite materials are popular substitutes for conventional materials owing to their high strength-to-weight ratio. Reinforcements in the form of woven fabric clothes are common due to their ease of availability and preparation. The use of hybrid intra-ply as reinforcements synergises the advantages of more than one type of fibre. The current work focuses on the preparation of woven carbon fibre (CF) and carbon–Kevlar (CF-K) intra-ply hybrid fibre-based composites. Epoxy resin was used as the matrix and balsa sheet was used as the sandwich material. The angle of orientation of the woven fibre cloth was varied from 0° to 45° along the direction of loading. The dynamic properties of prepared samples were experimentally investigated using an impact hammer test. The natural frequency and damping ratio were influenced by the angle of orientation and the fibre reinforcement. The CF-K hybrid composite showed better dynamic properties when compared with the CF composite. The natural frequency was highest for the 0° sample, it reduced with the angle of orientation, and a reverse trend was observed for damping ratio. Both CF- and CF-K-based composites showed similar trends. The storage modulus variation also showed a similar trend as that of the natural frequency for both types of samples with orientation, but a reverse trend was observed for loss modulus, i.e., the loss modulus increased with the change in the angle of orientation, indicating the improvement in energy storage ability of the composite.

Evaluation and prediction of tensile properties of 3D‐printed continuous carbon/Kevlar fiber‐filled composites by coaxial hybrid process

AbstractContinuous hybrid fiber‐reinforced composites (CHFRCs) have excellent mechanical properties, and strong designability, and are widely used in aerospace and other fields. The development of 3D printing technology offers novel directions in the design and manufacture of complicated CHFRC components in aerospace. For this purpose, this study focused on the design and characterization of hybrid continuous fiber‐reinforced composites prepared by 3D printing. The rapid mold‐free integrated manufacturing of hybrid continuous Kevlar/carbon fiber‐reinforced composites was realized by coaxial hybrid 3D printing technology. The regulation and mechanism of tensile properties of 3D‐printed CHFRCs were elucidated. The tensile strengths of 3D‐printed CHFRCs were enhanced by up to 15.3% and 92.4%, respectively, compared to single continuous carbon and Kevlar fiber composites produced by the same process parameter. A new tensile modulus predicting method for 3D‐printed CHFRCs was proposed. It mitigated the influence of complex interfacial characteristics on mechanical property prediction and achieved precise estimation of the tensile modulus of 3D‐printed CHFRCs. This will provide the theoretical support for the application and development of 3D‐printed CHFRCs.Highlights Mouldless rapid manufacturing of coaxial hybrid fiber composites achieved. The tensile strength and modulus of the fiber composites are greatly improved. A new prediction method for the tensile modulus of 3D‐printed composites is proposed.

Comparative study of the mechanical properties of glass and Kevlar fiber-reinforced honeycomb composite

Honeycomb sandwich structures have wide range of applications in the aircraft, automobile, and satellite sectors due to their superior properties such as high specific strength, stiffness, energy absorption, and high impact strength. In this study, mechanical characteristics such as compression, three-point bending, and in-plane impact properties of 3D woven honeycomb composites produced from Kevlar and glass fiber were investigated. The focus of this research is to compare the mechanical performance of woven honeycomb composites developed from these two fibers with similar cell structures. The results revealed that Kevlar fiber honeycomb composite shows higher peak load and energy absorption for flatwise and edgewise compression while in three-point bending and in-plane impact, glass fiber honeycomb composite shows higher peak load, and impact energy absorption. The deformations shown in all the mechanical properties give the ductile behavior for Kevlar fiber and brittle behavior for glass fiber composite. The findings of the study suggest that the failure modes are mostly determined by the nature of the material itself.

DEVELOPMENT AND QUALIFICATION OF CNT-CFRP COMPOSITE COMPONENTS FOR SPACE APPLICATIONS

Space payloads are required to be compact, to withstand harsh climatic conditions, and perform well over the duration of a mission. Advanced lightweight materials with low density, high strength, and high specific stiffness, such as carbon fiber reinforce polymers (CFRP), controlled expansion alloy (CE7), and kevlar composites are better suited for space hardware. Despite of having superior mechanical qualities, CFRP composites have limited range of applications due to their worse electrical and thermal conductivities. By adding nano-fillers to improve conductivity, CFRP can be used extensively. The most often employed conductive nano-fillers in CFRP composites are graphene and carbon nanotubes (CNTs). By creating CFRP composites with superior conductivities, the use of CFRP composites can be extended over large applications for space missions. Materials such as aluminum, kovar, invar, and other composites (non-conductive in nature) may be replaced by CFRP-CNT composites. It can be used for fabricating broad variety of satellite hard wares, including satellite panels, reflectors, feed horns, wave guides, carrier plates, electronic package boxes, and covers. Based on tests with different configurations, it was discovered that 0.5% SWCNT offered better mechanical and electrical properties. CNT-CFRP composites are used in the development of carrier plates and reflectors. This article primarily focuses on development of qualification test strategy and how it differs from traditional systems test plan. Results from test coupons and the product level tests were compared and analyzed. The results are acceptable and found better in comparison to their conventional counterparts.

Experimental investigation on low-velocity impact behavior of glass, Kevlar, and hybrid composites with an elastomeric polyurethane matrix

Low-velocity impacts represent a critical dynamic condition for engineering structures. Combining two reinforcing fibers in a single matrix, i.e., hybridization, is considered a feasible way to improve composite performance. In this context, this paper presents an experimental work on composites with Kevlar and glass fabrics and a novel thermoset polyurethane matrix. The coupons are manufactured by vacuum infusion technique and low-velocity impact tests are carried out. First, the impact behavior of Kevlar and glass laminates of different thicknesses is assessed, and then impact tests are performed on different configurations of hybrid laminates, both symmetric and non-symmetric. For the non-symmetric specimens, impact tests were conducted on both sides of the stack. Load vs displacement curves are reported along with absorbed energy. To investigate the damage mechanism, the front, back, and cross-section views of the specimens are analyzed, and features related to the stacking sequences are discussed. Thermographic analyses are carried out on the impacted specimens to further analyze damage. The failure mechanisms are different from traditional epoxy composites and a hybridization effect is reported. The results evidence that the hybrid coupons are viable for structural applications, being capable of absorbing high-impact energies, in particular, non-symmetric hybrid laminates outperformed the Kevlar, glass, and symmetric ones, absorbing roughly 15% less energy for the highest energy impact.

Enhancing mechanical performance of TiO2 filler with Kevlar/epoxy-based hybrid composites in a cryogenic environment: a statistical optimization study using RSM and ANN methods

This research aims to investigate the mechanical performance of the different weight proportions of nano-TiO2 combined with Kevlar fiber-based hybrid composites under cryogenic conditions. The following parameters were thus considered: (i) Kevlar fiber mat type (100 and 200 gsm); (ii) weight proportions of TiO2 nanofiller (2 and 6 wt%); and (iii) cryogenic processing time (10–30 min at −196°C). The composites were fabricated through compression molding techniques. After fabrication, the mechanical characteristics of the prepared nanocomposites—such as tensile, bending, and impact properties—were evaluated. The optimal mechanical strength of nanofiller-based composites was analyzed using response surface methodology (RSM) and artificial neural networks (ANNs). Compositions, such as four weight percentages of nano-TiO2 filler, 200 gsm of the Kevlar fiber mat, and 20 min of cryogenic treatment, were shown to produce the maximum mechanical strength (65.47 MPa of tensile, 97.34 MPa of flexural, and 52.82 J/m2 of impact). This is because residual strains are produced at low temperatures (cryogenic treatment) due to unstable matrices and fiber contraction. This interfacial stress helps maintain a relationship between the reinforcement and resin and improves adhesion, leading to improved results. Based on statistical evaluation, the ratio of correlation (R2), mean square deviation, and average error function of the experimental and validation data sets of the experimental models were analyzed. The ANN displays 0.9864 values for impact, 0.9842 for flexural, and 0.9764 for tensile. ANN and RSM models were used to forecast the mechanical efficiency of the suggested nanocomposites with up to 95% reliability.