Fabric Layers Research Articles

Hybrid Soft Ballistic Panel Packages with Integrated Graphene-Modified Para-Aramid Fabric Layers in Combinations with the Different Ballistic Kevlar Textiles.

The purpose of the research discussed in this article is to explore the possibility of creating hybrid soft ballistic panel (BP) package variants by integrating into their composition layers of graphene-modified para-aramid fabrics in combinations with the different ballistic Kevlar textiles to improve the durability of the first layers of the soft ballistic panel. To address this goal, the liquid-phase exfoliation (LPE) method was used for integrating dispersions into composites to solve a number of topical problems in the stages of the technological sequence development of processing methods and optimizing processing parameters in accordance with the processing specifics of aramid textiles to achieve the desired properties of modified ballistic fabric, including the provision of coating adhesion to the surface to be modified. To test the results, ballistic experiments were performed and the back-face signature (BFS) of bullet impact on a backing material was analysed according to standards. Bullet impacts on the first ballistic protective fabric layers were also studied.

Carbon black and polyetherimide modified ES nonwovens for low-cost and continuous seawater desalination

Solar-powered desalination is considered a promising and sustainable method for producing clean water to alleviate freshwater shortages. However, most solar evaporators have drawbacks such as high costs, complicated processes and lack of durability. Here, we present solar evaporators modified with polyethyleneimine and gallic acid, decorated with carbon black nonwovens, for desalination to produce clean water. The carbon black photothermal nonwovens were produced by treating ES hot air nonwovens with a spray of carbon black solution. Utilizing the light-absorbing heat generation of carbon black and the skin-core structural characteristics of ES(PE/PET) nonwoven, the carbon black is firmly embedded in the PE skin layer of the nonwoven fabric. Subsequently, mussel chemistry inspired the formation of polyethyleneimine and gallic acid coatings on the surface of the carbon black-loaded nonwoven. By combining carbon black with mussel coatings, the photothermal nonwovens demonstrated improved hydrophilicity, excellent photothermal water evaporation performance, and enhanced light conversion efficiency. The modified interfacial evaporator exhibited a high evaporation rate of 1.22 kg m−2·h−1 and had high cost-effectiveness of 332.4 g·h−1·$−1. In addition, reusing, desalination, and outdoor experiments were conducted to showcase the potential of the evaporator for practical desalination. This work demonstrates the significant potential of photothermal ES nonwovens for efficient solar-driven clean water production to tackle global freshwater shortages.

Cobalt ferrite-embedded polyvinylidene fluoride electrospun nanocomposites as flexible triboelectric sensors for healthcare and polysomnographic monitoring applications

Human respiration is a vital physiological function of the body and a key metric for assessing overall health, particularly in conditions related to sleep deprivation. However, developing a real-time system for detecting sleeping position, heartbeat, and respiration is challenging yet crucial. Such a system should be easy to fabricate, comfortable to wear, and highly sensitive. In this study, we fabricated a flexible electrospun cobalt ferrite (CoFe2O4, CF) embedded polyvinylidene fluoride (PVDF) nanocomposite (NC) using an electrospinning technique. Additionally, we investigated the influence of varying CF content (0, 1, 3, and 5 wt%) on the crystalline β-phase in PVDF. The triboelectric nanogenerator (TENG) device was fabricated using PVDF-CF (P-CF) NC as the tribo-negative layer and non-woven fabric of thermoplastic polyurethane (TPU) as the tribo-positive layer. Among the four sample combinations used in this study, P-CF-3 (3 wt% CF in PVDF)/TPU TENG exhibited a significantly higher triboelectric open circuit voltage (Voc) of 5.8 V, nearly three times higher as compared to P-CF-0/TPU TENG (1.7 V). This work demonstrates an efficient method for enhancing the output efficacy of flexible TENG devices by varying the nanofiller concentration. Moreover, the fabricated TENG device was efficiently tested for real-time healthcare monitoring (HCM) and polysomnographic (PSG) related studies. This study aspires to provide a novel and pragmatic way of identifying real-time sleeping disorders and respiratory monitoring.

Multilayer polyester tire cord fabrics reinforced gamma irradiated SBR/devulcanized waste rubber: impact of fabric layers and devulcanization methods

Multilayer polyester tire cord fabrics reinforced gamma irradiated SBR/devulcanized waste rubber: impact of fabric layers and devulcanization methods

The influence of high temperature exposure on the tensile and cracking behavior of crimped-textile reinforced mortar composites (TRMs)

The use of textile reinforced mortar/concrete composites (TRM) in strengthening applications and new constructions necessitates understanding its behavior after exposure to high temperatures. Therefore, in this study, the residual tensile and cracking behavior of carbon based TRMs was studied. A total of 96 TRM samples were tested in the temperature range of 25–450 °C. The main parameters studied were the textile crimp, textile orientation, textile coating, multiple textile layers and hybrid reinforcement. The hybrid TRM was formed with a combination of uncoated and styrene butadiene (SBR) coated textile layers. This study served as one of the first experimental campaigns to use digital image correlation (DIC) for understanding the residual crack opening behavior of TRMs. The results demonstrated that the properties of the TRMs were noticeably influenced by temperature exposure of 450 °C. Unlike the uncoated or hybrid textile TRMs, the SBR coated textile TRMs demonstrated curvature and cracking after 450 °C exposure. The study showed that the load aligned crimped yarn TRMs were always associated with larger deformation irrespective of the exposure temperature. The crack openings also increased significantly after exposure to 450 °C. Whereas the presence of heat formed cracks caused higher initial rate of crack openings. The evolution in the crack spacing with increasing temperature fluctuated due to the possible relative degradation of cracking strength vs interfacial mortar textile bonding. Finally, the proposed empirical equation showed a good fit to the residual average crack opening vs. stress relations.

Experimental investigation on shear behavior of cracked reinforced concrete beams strengthened with carbon textile reinforced concrete

This study examines the strengthening effects of carbon textile-reinforced concrete (CTRC) on the shear behavior of pre-cracked reinforced concrete beams. Six reinforced concrete beams, each with an aspect ratio of 1.6, underwent three-point bending tests, comprising two control specimens and four strengthened specimens. Prior to the application of U-wrapped carbon textile reinforcement, all beams were subjected to pre-loading to induce shear cracking. The strengthening process involved utilizing either two or three layers of carbon textile. The findings reveal a significant enhancement in the shear capacity of the CTRC-strengthened beams compared to the control beams. Notably, the shear strength of the specimens reinforced with two layers of carbon textile increased by 34.7%, whereas those reinforced with three layers increased by 50.9% compared to the control specimens. Thus, carbon TRC effectively restored and elevated the shear capacity of damaged specimens to levels akin to those of control beams.

Experimental investigation on shear behavior of cracked reinforced concrete beams strengthened with carbon textile reinforced concrete

This study examines the strengthening effects of carbon textile-reinforced concrete (CTRC) on the shear behavior of pre-cracked reinforced concrete beams. Six reinforced concrete beams, each with an aspect ratio of 1.6, underwent three-point bending tests, comprising two control specimens and four strengthened specimens. Prior to the application of U-wrapped carbon textile reinforcement, all beams were subjected to pre-loading to induce shear cracking. The strengthening process involved utilizing either two or three layers of carbon textile. The findings reveal a significant enhancement in the shear capacity of the CTRC-strengthened beams compared to the control beams. Notably, the shear strength of the specimens reinforced with two layers of carbon textile increased by 34.7%, whereas those reinforced with three layers increased by 50.9% compared to the control specimens. Thus, carbon TRC effectively restored and elevated the shear capacity of damaged specimens to levels akin to those of control beams.

Developing novel multifunctional protective clothes for disabled individuals using bio-based electrospun nanofibrous membranes

A novel kind of protective apparel for handicapped persons has been created with bio-based electrospun nanofibrous (NFs) membranes. Hydrophobic membranes with fine polylactic acid (PLA) NFs had a smooth, bead-less structure with an average diameter of 950 nm. The hydrophilic layer has a similar pattern but a smaller fiber diameter dispersion and an average diameter of 750 nm. The silica nanoparticle-modified super-hydrophobic top layer (contact angle, ~153°) repels water and keeps the user dry. Super-hydrophilic silver nanoparticles in the fabric's bottom layer react with perspiration to kill microorganisms. The fabric's porosity (avg. 1.2–1.5 μm) allows for breathability, while silica nanoparticles boost infrared radiation reflection, keeping users cool on hot days. The dual-layer textile has 4.9 MPa ultimate tensile strength and 68 % elongation compared to the membrane's super-hydrophobic and super-hydrophilic layers. Wearing protective clothes reduced hand temperature by 25 % in direct sunlight and 13 % in a sun simulator with 1 Sun. This fabric will work well for adult diapers, outdoor clothing, and disability accessories. Overall, the protective textiles may improve the quality of life for disabled and elderly people by providing usable textile items adapted to their needs.

Experimental investigation of pseudo-ductility in plain weft-knitted epoxy composite laminates under tension

The inherent brittleness of unidirectional fiber-reinforced composites represents a major complication in their broad practical applications. However, exploiting different reinforcement architectures can offer an opportunity for highly desirable ductile fracture nature. This article is aimed at investigating experimentally the tensile behavior of an epoxy laminate reinforced by different layers of plain weft-knitted fabrics. The fabricated laminates were subjected to uniaxial tension in different loading directions, and the corresponding tensile responses were recorded. Basic mechanical properties were characterized and digital image correlation (DIC) was employed to capture surface deformations. Tensile test results demonstrated strong nonlinearity and pseudo-ductility as well as loading-direction dependence in this type of composite laminates. Fracture tests were conducted showing high fracture toughness ranging from 10 to 20 MPa·m1/2. Typical damage modes were characterized using microscopy, which were coupled to a few distinct tensile deformation stages. This work demonstrates that weft-knitted composites are promising in permitting great amounts of pseudo-ductility with clear warning before complete failure. It is also expected to contribute to the understanding of the specific role of weft knit fabrics in composite laminates.

Mechanical properties of web kapok/fiberglass-epoxy hybrid composites for marine structures

Abstract This study investigates the mechanical properties of hybrid composites composed of web kapok fibers and fiberglass reinforced with epoxy for potential application in the marine industry. The web kapok fibers were carefully processed using a carding technique to ensure better alignment and consistency. Various composite configurations were produced, and extensive mechanical testing was conducted, including flexural, tensile, and impact tests. The results revealed that the presence of two web kapok fiber layers within the composite significantly increased flexural strength and flexural modulus compared to pure fiberglass laminates. However, a single layer of web kapok fabrics exhibited the highest tensile strength, although it decreased with additional layers. The impact strength of these hybrid composites also showed promising results, especially when compared to raw fiberglass composites. Moreover, these composites exhibited improved resistance to water absorption and corrosion, making them potentially suitable for marine applications. This research highlights the potential of web kapok/fiberglass hybrid composites as an eco-friendly alternative for marine engineering, with implications for reduced environmental impact and sustainable technology in the industry.

High‐Performance Double‐Layer Textile‐Based Triboelectric Nanogenerator

This article aims to investigate the electrical output performance of the proposed textile‐based triboelectric nanogenerator (T‐TENG) under the operating principle of contact–separation mode. Herein, the T‐TENG structure is developed by electrospinning and weaving technologies. Therein, core–shell yarns are initially fabricated by applying nanocomposite zinc oxide /polyamide‐66 (ZnO–PAn) fibers on carbon (C) yarns. Then, yarns are directly woven as weft with polyamide‐66 yarns as warp to assemble the T‐TENG structure with the help of the polytetrafluoroethylene (PTFE) layer. The results show that increasing the microscopic factor (i.e., the surface roughness) of the PTFE layer about twice can, respectively, enhance the open‐circuit voltage and short‐circuit current of the T‐TENG up to 27% and 21.7% on average; besides that the thickness of the PTFE layer plays an important role in the electrical output quality of T‐TENG. Equally important, improving the rough surface of the active layer (i.e., woven fabric layer) through nanocomposite fibers (ZnO/PAn) can endow the T‐TENG structure to generate excellent electrical potentials under different tapping frequencies. Interestingly, the best electrical output performance obtained in this article can reach maximum values (≈14 μA and 200 V) at 10 Hz with a structure (C–ZnO5%PAn/PAf@PTFE2m) and achieve a 2.7 mW power density on a 27 MΩ external resistance.

Flexural strengthening of LWRC beams using RSHCC reinforced with glass fiber textile mesh

This study aims to explore the flexural behavior of crushed clay brick (CCB) lightweight concrete (LWC) beams strengthened with rubberized strain-hardening cementitious composite reinforced with glass fiber textile mesh layers (GFTM-RSHCC) at the tension side. For this purpose, an experimental investigation consisting of seven simply supported beams, including one un-strengthened specimen, was produced and tested using a monotonic 4-point loading scheme. All specimens had a 120 × 250 mm cross-section, a total length of 2400 mm, and a loaded span of 2200 mm. The studied parameters were the number of GFTM inside the RSHCC (1, 2, or 3) and the thickness of GFTM-RSHCC layer (30 or 40 mm). All the following aspects were tracked: crack pattern, ultimate load, mid-span defection, and ductility. The results show that increasing the number of layers of GFTM and the thickness of RSHCC generally leads to an increase in the ultimate loads and ductility, up to 68% and 83%, respectively, compared to the control beam. Finally, a proposed equation considering the contribution of the GFTM-RSHCC layer was developed to predict the flexural capacity of the strengthened beams. The proposed equation showed good agreement with the experimental results.

Improving shear performance of regular web openings concrete beams using steel mesh reinforced strain hardening cementitious composites: An experimental and numerical study

The majority of studies focused on shear strengthening methods for single or double transversely opened reinforced concrete (RC) beams; however, no studies examined beams with multiple openings. This study looked at the shear response of 10 RC beams with multiple openings that were strengthened with externally strain-hardening cementitious composites (SHCC) and supplied with various layers of steel mesh fabric (SMF). The square or circular shape of the openings, the use of internal stirrups, and the use of one, two, or three layers of SMFs to support the SHCC layer are investigated. Analysis was done on the beams' stiffness, ductility, ultimate load and corresponding deflection, load-displacement response and failure pattern. In the experimental program, the shear span-to-depth (a/d) ratio was 2.4 for each of the ten beams. To further examine the impact of the same key parameters on the shear response of the beams at an a/d of 1.2, a non-linear finite element model was built. The experimental results showed that dense stirrups beam, one layer SMF-beam, two layers SMF-beam, and three layers SMF-beam achieved improvements in the ultimate load of 21.3 %, 34.6 %, 38.6 %, and 47.3 %, as well as increases in the rigidity of 6.4 %, 9.4 %, 51.7 %, and 53.6 %, and gains in the ductility of 78.4 %, 28.5 %, 547 %, and 357 % when compared to comparable control beam with circular openings. The numerical results indicate that strengthening SHCC layers outperforms better for RC beams with a smaller a/d rate and that follow the arch action in the critical shear zone.

Effect of cellulose nanocrystals on the mechanical and free vibration behavior of hybrid glass/kenaf fiber reinforced polyurethane core-based sandwich structures

ABSTRACT Engineering applications widely use foam-core-based sandwich structures. The study incorporated cellulose nanocrystals (CNC) into a hybrid glass/kenaf fiber-based polymeric sandwich structure with a 65 kg/m3 polyurethane foam core. Four unique face sheets (S1, S2, S3, and S4) were made using glass, kenaf, and CNC. Three-point bending, Charpy impact testing, and free vibration testing were used to characterize sandwich structures. The inclusion of CNC in the matrix of face sheets improved the hybrid composite’s bending strength and impact resistance. One layer of Kenaf fabric and two layers of glass make up the hybrid composite, which is stronger in both flexural strength and impact resistance, with 14.56 MPa and 8.1 J, respectively. These improvements are 44.84% and 57.49% compared to the pure glass/epoxy composite face plate. Nevertheless, the incorporation of Computer Numerical Control (CNC) failed to result in a substantial enhancement in vibration characteristics. Both matrix modification and natural fiber (kenaf) can effectively substitute glass fabric in sandwich structures.

Static and fatigue performance of graphene nanoplatelets coated bi‐directional carbon fiber‐epoxy composites under bending loads

AbstractThe addition of graphene nanoplatelets as a nanofiller on the surface of pristine and oxidized carbon fiber for making reinforced polymer composites has shown improvement in monotonic flexural properties. However, the fatigue response of these laminates under bending loads has not been investigated so far. The current study aims to examine the monotonic and fatigue behavior of the graphene nanoplatelets (GNPs) coated bi‐directional pristine and oxidized carbon fiber epoxy composites under bending loads. Eight layers of fabrics were used to manufacture the laminates through vacuum‐assisted resin transfer molding technique (VARTM). An optimum amount of GNP addition on oxidized fiber leads to ~830‐fold enhanced fatigue life at higher stresses as compared to pristine laminates. However, excessive GNP addition on pristine as well as oxidized fiber leads to a deterioration in fatigue life. In‐situ optical microscopic examination was done to observe the crack initiation and propagation of all the specimens with respect to the number of cycles coupled with post‐mortem SEM images of the fracture surfaces.

PVA Hydrogels Supplemented with PLA Mesh for Tissue Regeneration Scaffold.

This study examined the tensile strength and biocompatibility properties of polyvinyl alcohol (PVA) hydrogel tissue regeneration scaffolds with polylactic acid (PLA) mesh fabric added as reinforcement, with a focus on the impact of heat treatment temperature and the number of layers of the PLA mesh fabric. The hydrogel scaffolds were prepared using a freeze-thaw method to create PVA hydrogel, with the PLA mesh fabric placed inside the hydrogel. The swelling ratio of the PVA/PLA hydrogel scaffolds decreased with increasing layer number and heat treatment temperature of the PLA mesh. The gel strength was highest when five layers of PLA mesh fabric were added, heat-treated at 120 °C, and confirmed to be properly placed inside the hydrogel by SEM images. The MTT assay and DAPI staining using HaCaT cells demonstrated that the cell proliferation was uninterrupted throughout the experimental period, confirming the biocompatibility of the scaffold. Therefore, we confirmed the possibility of using PLA mesh fabric as a reinforcement for PVA hydrogel to improve the strength of scaffolds for tissue regeneration, and we confirmed the potential of PLA mesh fabric as a reinforcement for various biomaterials.

Confinement mechanism and modeling of basalt TRM confined concrete: Effect of mortar matrix grade

Textile reinforced mortar (TRM) confinement significantly enhances the compressive strength and ultimate axial strain of concrete. This study mainly investigated the influence of mortar strength on the stress-strain behavior of TRM-confined concrete to advance understanding of its confinement mechanism. We conducted 48 compression tests on concrete columns, comparing those without jackets to those confined in basalt TRM (BTRM). Variables included the number of textile layers (0 to 4) and mortar matrix strengths (from low-grade ‘M1′ to high-grade ‘M3′). Results indicated that a critical confinement stiffness ratio of 0.024 is essential for strain hardening behavior with marked strain capacity enhancement. Low-grade mortar diminished the effective confinement stiffness of BTRM jackets, manifesting as either a steeper descending plateau in the strain-softening stress-strain curve or a more gradual ascending plateau in the strain-hardening curve. High-strength mortar significantly reduced both the hoop rupture strain of BTRM jackets and the ultimate axial strain of the confined concrete. This study integrated the identified BTRM confinement mechanism into an existing stress-strain model for FRP-confined concrete, enhancing its predictive accuracy for BTRM-confined concrete. Specially, a coefficient, termed km, was introduced to quantify the mortar grade's impact on confinement stiffness in the confining pressure equation. Predictive results closely matched experimental data, especially in replicating plateau characteristics of the stress-strain curve.

Low-velocity impact behavior of woven fabric-reinforced natural rubber composites

The progressive damage behaviors of woven fabric-reinforced natural rubber panels under low-velocity impact were studied by the drop-weight tests. The woven fabrics considered include nylon, Kevlar, and carbon. The impact force, impact energy, and delamination area were analyzed, and the damaged samples were observed using an optical microscopy and an X-ray scanner to investigate the damage mechanisms. The results show that the peak force of impact increases while the absorbed energy decreases as the fiber strength/stiffness and fiber content increase. Based on the peak force and the delamination area results, the natural rubber/Carbon/2 specimen, which consists of two carbon fabric layers inside the natural rubber, displays the best impact performance among the composites considered in this study.

A reflective textile metasurface for indoor signal coverage enhancement

The design of a reflective metasurface solely based on flexible textile material is presented for indoor signal coverage enhancement in a specific scenario – reflecting and reallocating radio frequency energy that would have leaked through a large window area. The proposed reflective metasurface design, reflective metasurface is composed of layers of square conductive textile patches and dielectric textile substrates. For the unit cell design, a reflective phase difference of up to 90° can be achieved via varying the size of the conductive patches. Meanwhile, a phase difference of up to 180° can be achieved by the alignment of conductive patches on different textile substrate layers, which is an ideal design philosophy for textile material. The proposed metasurface, consisting of 12 × 12 unit cells, can achieve a main reflected beam pointing in the direction of ±35° and a secondary reflected beam at ±63°. Simulated results show that the reflected beams remain relatively stable under the crumpling conditions often seen for curtains. A prototype of the design was fabricated and tested in a real-world scenario. A maximum signal strength enhancement of 15 dB and an average enhancement of 5.97 dB in a wide range of directions can be achieved with the reflective metasurface applied.

Effect of anchorages on C-FRCM/concrete interfacial shear performance

In this study, single-lap shear tests were performed on 42 concrete specimens that were reinforced with Carbon Fabric Reinforced Cementitious Matrix (C-FRCM). The interfacial properties were enhanced through the use of fabric end-bending anchorage, a U-shaped hoop, and multiple U-shaped hoops. The bond performance of the C-FRCM/concrete interface was analyzed by examining the failure mode, ultimate stress, and interface slip of the specimens, considering four parameters: bond length of C-FRCM, number of fabric layers, fabric end-bending anchorage, and U-shaped hoop anchorage, as well as their respective mechanisms. The bond-slip constitutive parameters were calculated based on the trilinear cohesive material law and load-displacement simulation curves were obtained for each specimen through numerical simulation, which were in agreement with the test results, verifying the law's validity. Finally, the positive effect of anchorages on the constitutive parameters was analyzed.