Weft Direction Research Articles

Influence of tetrahedral architectures on fluid transmission and heat retention behaviors of auxetic weaves

Recently auxetic textiles have captured the attention of researchers. Yet no work is reported on the development and characterization of novel tetrahedral woven auxetic structures. In this study, six two-dimensional (2D) woven auxetic structures including diamond-based vertical pointed twill (S1), vertical inverse pointed twill (S2), vertical broken pointed twill (S3), vertical pointed twill (S4), open tetrahedral (S5), and closed tetrahedral (S6) were developed. For performance analysis, thermal comfort properties including fluid transmission characteristics (air permeability, water vapor permeability index, overall moisture management capability (OMMC)), and heat retention attributes were characterized. These fabrics were also characterized by their mechanical behavior including negative Poisson’s ratio (NPR), tensile and tear strength, pilling, abrasion resistance, and stretch and growth %. S5 has longer floats, hence it became more flexible and open which resulted in higher dry fluid transmission. All specimens showed more than 85% wet fluid transmission tendencies. S6 showed the highest and S5 showed the least OMMC values. Furthermore, S2 has a higher thermal resistance because of low air permeability. The developed fabric structures showed NPR up to −0.64. A significant effect of float length has been found on the auxeticity of fabrics along the warp direction. S5 showed a higher tensile strength and stretch % in warp and weft directions. All the developed woven auxetic fabrics remained unteared in both the warp and weft directions along with viable pilling (4–5 grade) and showed improved abrasion resistance.

Failure analysis of high-performance woven fabrics during quasistatic stabbing

In recent years, stab protection is getting increasing attention from the researchers and practitioners. Most of the stab protective vests are made of high-performance fibre based woven fabrics. However, unlike ballistic protection, the roles of fibre material, fabric structure, and test parameters on the failure mechanism during stabbing are still not well-understood. This study systematically examines the effects of fibre type, weave architecture and stabbing direction on the quasistatic stab resistance of woven fabrics. P-aramid (Kevlar®), aromatic polyester (Vectran®), and ultra-high molecular weight polyethylene (Spectra®) fibres were used to weave plain, 3/1 twill, and 2/2 twill fabrics of same areal density. All the fabrics were tested in warp, weft and bias directions using a P1 knife (NIJ 0115.0 standard). Among the fibres, Spectra® demonstrated the highest stab resistance followed by Vectran®. Plain woven fabric showed higher stab resistance than the other two weaves in bias direction. For all weaves, stab resistance was also found to be higher in bias direction followed by weft and warp. Statistical analysis (three-way ANOVA) revealed that fibre type, weave architecture and stabbing direction have significant roles (p < 0.05) in determining the stab resistance of woven fabrics. The outcome of this research will be useful for designing stab resistant vest using high-performance woven fabrics.

Flame-Retardance Functionalization of Jute and Jute-Cotton Fabrics.

Jute is a ligno-cellulosic natural fiber that ranks second in terms of the volume of cellulosic fibers and is extensively utilized for technical textile applications. The goal of this study is to determine the flame-retardance (FR) properties of pure Jute and Jute-Cotton fabrics treated with Pyrovatex CP New at concentrations of 90% (owf), M:L: 1:7. Both fabrics exhibited a substantial improvement in flame-retardancy. After the ignition period, the recorded flame spread time in both FR treated fabrics was zero seconds; whereas for untreated Jute and Jute-Cotton fabrics, the flame spread time was measured 21 s and 28 s, respectively, to burn their entire length (15 cm). Within these flame-spread times, the length of the char was 2.1 cm and 2.57 cm in the Jute and Jute-Cotton fabrics, respectively. After FR finishing, on both fabrics in the warp and weft directions, the physico-mechanical properties significantly decreased. The deposition of flame-retardant finishes on the fabric surface was determined by Scanning Electron Microscope (SEM) images. According to Fourier Transform Infra-Red Spectroscopy (FTIR) analysis, the flame-retardant chemical had no effect on the inherent properties of the fibers. Thermogravimetric analysis (TGA) analysis revealed that FR treated fabrics had early degradation, resulting in the formation of more char than in the untreated samples. After FR treatment, both fabrics showed a significant improvement in residual mass (more than 50%). Although the formaldehyde content observed in the FR treated samples was significantly greater, it was still within the permitted limit formaldehyde content in textiles intended for outerwear and not worn next to the skin. The results of this investigation demonstrate the potential use of Pyrovatex CP New in jute-based materials.

Enhancing the interfacial adhesion of PET and silicone rubber by plasma-assisted coupling agent treatment

The poor interfacial adhesion between silicone rubber and polyethylene glycol terephthalate (PET) affects the safety and durability of fabric-rubber products in service. In this study, a low-cost and simple atmospheric plasma surface treatment device is used to treat the surface of polyester fabric continuously, followed by coating KH570 onto the fabric surface. The adhesion strength of fabric-rubber interface is successfully enhanced by this method. The peel strength of the specimens treated with this bonding process reaches 3.92 N/mm and 5.73 N/mm in the warp and weft directions, respectively, which are 5.16 and 7.44 times of untreated fabric samples, superior to commercially-available silicone rubber adhesive. In addition, the bonding mechanism of the interface is characterized by Fourier transform infrared spectra (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and water contact angle test. This study provides a practical and environmentally friendly method for fabricating fabric silicone rubber materials with high interfacial performances.

Experimental evaluation of the ballistic resistance of aramid fabrics under near simultaneous multiple fragment impacts

The ballistic resistance of protective equipment against fragment impacts, such as those typically generated from explosions, has been a major concern the past 50years. The simplifications required to investigate the material response to multiple fragment impacts were set based on the technological limitations of the past. Still, current standardised ballistic testing methodologies consider the interactions between multiple impacting fragments negligible, simulating the multiple impulsive loads with single impact tests. This paper challenges this assumption, introducing the parameters of spacing, formation and timing between multiple impacts in a laboratory test method.An in house pyrotechnical triple launcher is designed and implemented which can shoot three 1.102 g Fragment Simulating Projectiles (FSP) with each shot. An add-on dispersion unit allows for adjusting the distances between the impact points. The control over the projectile velocities and the dispersion of the three impact points enables the simulation of a dense fragment cluster impact with specific characteristics. The setup is used to test Aramid dry fabrics against fragmentation. In total 53 specimens of 15 layers of Kevlar 29 plain weave fabrics are tested against single and triple impacts with two different levels of projectile dispersion. The results show a drop in the target's ballistic limit of up to 13% against triple impacts compared to single impact tests. The fabric's ballistic performance seems to improve with increasing the distances between the impact points. For every triple impact test, the parameters: impacting velocity, distances between impact points, alignment of impact points with the warp and weft directions and time intervals between impacting projectiles is documented.

Evaluation of multi-directional compression behaviors and failure of three-dimensional orthogonal woven composites via liquid nitrogen temperature

Three-dimensional orthogonal woven composites (3DOWCs) are extensively employed in structural engineering applications for their lightweight, high designability, and excellent interlayer performances. This work constructed two 3DOWCs with different fiber volume contents, and their multi-directional compression properties and damage mechanisms at room and liquid nitrogen temperatures (RT and LNT) were thoroughly investigated and evaluated. Temperatures, fiber volume contents, and loading directions all had a significant influence on behaviors. The stress-strain curves presented ductility at RT and gradually decreased after reaching the maximum load, whereas they were brittle and rapidly decreased at LNT. Compared to the compression properties at RT, the compression strength of 3DOWC40-LNT and 3DOWC50-LNT increased by 22.6% and 9.3% in the warp direction, 11.8% and 29.0% in the weft direction, as well as 32.9% and 24.6% in the Z direction. Additionally, edge yarn stripping and shear cracking were the primary fracture patterns for 3DOWCs under RT, while they exhibited interface layering, yarn fracture, shear cracking, and interfacial debonding at LNT, especially the deformation along the warp direction was more pronounced under Z direction compression.

Manufacturing of window shutters from cotton waste fabrics for sustainable textiles

Purpose This study aims to manufacture alternative window shutters using waste cotton fabrics by stiffening using polyvinyl acetate (PVA) with vinyl acrylic binder solutions. Design/methodology/approach The manufactured fabrics were evaluated for their tensile strength, drapeability, bending length by weight and color fastness to light. And finally, an analysis of variance was done for each parameter. Findings As the percent of PVA with a vinyl acrylic solution and the number of layers increased, the tensile strength, drape coefficient (percent), bending length (cm), and color fastness to light increased in both directions. The percent of PVA with a vinyl acrylic solution and the number of layers are statistically significant for each response such as tensile strength, drape coefficient (percent), bending length (cm), color fastness to light and water repellency at a 95% confidence interval. Tensile strength, drape coefficient (%) and bending length (cm) are always greater in the warp direction than in the weft direction. The tensile strength, drape coefficient (percent), bending length (cm) and color fastness to light of treated fabrics samples are greater than those of the untreated fabrics. Originality/value The factory waste fabrics can be recycled into window shutters which will provide the cheaper raw material for window shutter manufacturers.

Combining acoustic emission and digital image correlation analysis for dynamic damage response of woven spacer structure reinforced sandwich composites

This study reveals the dynamic damage process and the bending response of woven spacer structure reinforced sandwich composites (WSRS) by combining the acoustic emission (AE) technique and the digital image correlation (DIC) method. The typical load–displacement curve of six WSRSs was divided into elastic deformation, damage developing, and rapid damage stages. According to AE, the primary failure modes of WSRS were foam failure, interface delamination and core-pile separation, and surface matrix cracking. The failure behavior of the specimens was identified. It revealed that when subjected to bending stress, the load-bearing capacity of WSRS in the weft direction was higher than in the warp direction. While the failure areas were extended, indicating that the core-pile structure played a dominant role. The stress was mainly concentrated in the core layer, increasing the failure degree and damage rate, while the strain nephogram showed superior integrity. Consequently, the weft direction of WSRS exhibited better integrity and load-bearing capacity.

Non-Covalent Bonding of Green Synthesized Copper Nanoparticles to Enhance Physicochemical Behavior of Sulfur-Dyed Cotton Fabric

Cotton fabric samples were treated with copper acetate mordant, in addition to green synthesized copper nanoparticles extracted from the Conocarpus erectus leaves, with two different concentrations of 10% and 20%, respectively. Two dyeing techniques, continuous dyeing and exhaust dyeing, were employed. X-ray diffraction confirmed the synthesis of copper nanoparticles with an approximate size of 30 nm. Scanning electron microscopy showed copper nanocrystals with a size range of 30–70 nm. The tensile strength showed an approximately 60% rise in the warp direction and an approximately 20% rise in the weft direction for both continuous and exhaust dyeing techniques. The color strength (ratio of absorption co-efficient (K) and scattering coefficient (S); K/S) showed an improvement of 100% and 20% for the exhaust and continuous dyeing techniques, respectively. Both the dyeing techniques showed a rising trend in color fastness to wash and color fastness to rubbing with an increment up to grade 5. The light fastness showed an improvement up to grade 6 for both the techniques. Fastness to rubbing showed an increment from 1 to 5 for both techniques.

Modification of bentonite nanoclay for textile application

The influence of the bentonite content (1, 3, 5 wt%) on the mechanical properties of lightweightcotton (C), polyester (P) and polyester-cotton (P/C 50/50) fabrics was investigated. Starch was used asa water-insoluble binder for coating fabrics. Bentonite nanoparticles were obtained by repeated hydration,decantation and evaporation of the water dispersion. The bentonite particle size was determinedby the XRD method using the Debye-Scherrer equation. The diffraction of the laser beam was used todetermine particles size distribution. The addition of bentonite nanoclay significantly improved tensilestrength (26-61% and 99–118% in the warp and weft direction, respectively) and tear strength (4‒13%and 5–24% in the wrap and weft direction, respectively) of coated fabrics. Their abrasion resistancehas also slightly increased. The biggest changes were noted for the cotton fabric, the smallest for thepolyester fabric, which may result from the low compatibility between starch and the polyester fabric.

Meso-Scale Finite Element Model for Rib-Stiffened Composites with Biaxial Weft-Knitted Reinforcements

Shell-rib structures made of textile-reinforced composites are used in a wide range of applications to increase bending, buckling and torsional stiffness. Such composites are usually manufactured in differential construction at the preform level by assembling several textile structures or at the component level by the subsequent joining of separately manufactured shells and stiffening structures. Integral preform production is one way to overcome the disadvantages of the forenamed methods, such as high manual effort, failure during assembling or fiber distortion. Weft-knitting technology is excellent for achieving integral preforms for shell-rib components with a strong connection between the shell and the rib, especially while producing biaxial weft-knitted fabrics (BWKF) with reinforcing yarns in the warp and weft direction to improve its mechanical behavior. In this work, the possibilities of the knitting technique are investigated, and a finite element model for comparing different variants is developed and validated. A meso-scale Finite-Element-Method (FEM) model of the BWKF is used. The simulation results with the meso-scale model show a good correlation with experimental data by a description of bending strength and stiffness of different FRP configuration variations. The model can be used in further investigation of fiber-reinforced polymer (FRP) made from BWKF.

Asymmetrical Emissivity and Wettability in Stitching Treble Weave Metafabric for Synchronous Personal Thermal-Moisture Management.

Developing textiles with passive thermal management is an effective strategy to maintain the human body healthy as well as decrease energy consumption. Personal thermal management (PTM)textiles with engineered constituent element and fabric structure have been developed, however the comfortability and robustness of these textiles remains a challenge due to the complexity of passive thermal-moisture management. Here a metafabric with asymmetrical stitching treble weave based on woven structure design and yarn functionalization is developed, in which the thermal radiation regulation and moisture-wicking can be achieved simultaneously throughout the dual-mode metafabric due to its optically regulated property, multi-branched through-porous structure and surface wetting difference. With simply flipping, the metafabric enables high solar reflectivity (87.6%) and IR emissivity (94%) in the cooling mode, and a low IR emissivity of 41.3% in the heating mode. When overheating and sweating, the cooling capacity reaches to ≈9°C owing to the synergistic effect of radiation and evaporation. Moreover, the tensile strengths of the metafabric are 46.18MPa (warp direction) and 37.59MPa (weft direction), respectively. This work provides a facile strategy to fabricate multi-functional integrated metafabrics with much flexibility and thus has great potential for thermal management applications and sustainable energy.

Three-dimensional orthogonal woven hybrid fabrics in X band frequency region for electromagnetic shielding effectiveness

The three-dimensional fabric structures with metallic yarns and different fibers offer additional opportunities to enhance the electromagnetic shielding potential. This study involves the manufacturing of a Three-Dimensional Orthogonal Woven (3DOW) hybrid conductive fabric to be potentially used in an electromagnetic shielding field. 3DOW fabric consisting of copper filament-based core-sheath hybrid yarn in the weft direction has been manufactured to obtain maximum shielding effect. Hybrid yarns were produced using the DREF-III spinning technique, having copper filament in the core and sheathing by Polyphenylene Sulfide (PPS) staple fibers. The experiment was designed using Box-Behnken method. The orthogonal fabric samples are tested in an electromagnetic frequency region of 8-12 GHz using Free Space Measurement System (FSMS) to estimate absorbance, reflectance, and transmittance. Hybrid yarn parameters such as PPS fiber diameter, copper filament diameter, and yarn linear density considerably affect electromagnetic shielding. 3DOW fabric’s electromagnetic shielding effect increase with the diameter of the copper core filament, as does PPS yarn’s diameter, showing a promising trend towards shielding. The findings of orthogonal structure can be further extended in other Three-Dimensional structures like multi-layer, angle interlock, draperies, and tops for civilians and soldierly applications.

Finite Element Analysis on the Anisotropic Characteristics of 3D Woven Resin Matrix Composites under Lateral Compression

3D meso-structural composites with three layers were constructed using 3D modeling software Pro/E, and the static anisotropic characteristics of the composites under lateral compression in warp and weft directions were simulated by using finite element analysis software ANSYS. The mechanical properties of the composites under lateral compression were predicted by analyzing the stress and strain distribution of fiber and resin in the composites under lateral compression load. The anisotropic characteristics of composites were then analyzed. Results showed that the lateral compression property of the composites was anisotropic, and the lateral compression performance in weft direction was better than that in warp direction. In the composite, fiber bears more load, and the resin undergoes greater deformation. Fibers whose axial direction is parallel to the lateral compression direction bears greater load, while fibers whose axial direction is perpendicular to the lateral compression direction bears less load.

The Longitude-Latitude-Loop Used for Complex Bankart Lesion Repair: An All-Arthroscopic Technique

The most frequent operation for anterior shoulder instability is the arthroscopic Bankart repair, which has a positive outcome and a low rate of complications. A variety of restoration procedures have been reported to reconstruct labral height and reproduce a dynamic concavity–compression reaction. The longitude–latitude loop is a knotless high-strength suture method that simultaneously tightens the joint capsule in the warp and weft direction and resists tearing. The suture method is safe and reproducible. This study aimed to present a longitude–latitude loop suture for joint capsule labral complex repair during Bankart arthroscopy surgery.

Comparative analysis of the mechanical performance of 3D woven honeycomb composites produced in warp and weft directions

This research work focuses on the design and manufacturing of 3D woven honeycomb fabrics and their composites in both warp and weft directions. An experimental investigation of the mechanical properties of these two composite materials was carried out. For this purpose, at first, a 3D woven honeycomb in both directions was fabricated on a customized multi-beam 3D weaving machine using E-glass fibers. The composites were created by VARIM (Vacuum assisted resin infusion method) process using epoxy resin and Aradur hardener. The mechanical characteristics such as compression, three-point bending, and in-plane impact of composite samples were investigated keeping cell parameters constant. There will be a change in composite properties as tension in warp and weft is different. Crimp and modulus will also be different. The comparison of mechanical properties of these two honeycomb composite samples revealed that warp way honeycomb shows better properties in edgewise compression and three-point bending test while weft way honeycomb shows higher energy absorption under flatwise compression and in-plane impact test. The direction of cell channels gives the direction of loading to the threads, which affects the mechanical properties.

Enhancing flame retardancy of polyphenylene sulfide nanocomposite fibers by the synergistic effect of catalytic crosslinking and physical barrier

AbstractProtective clothing with fascinating flame‐retardant features is urgently needed to reduce the large amount of smoke and heat released from combustion during fire protection. In this study, polyphenylene sulfide (PPS) nanocomposite resin with efficient flame retardancy is obtained by mixing a low content of graphene and Fe2O3via a twin screw extruder. Followed by, the PPS/G/Fe2O3fibers are fabricated via melting spinning. The PPS/G/Fe2O3nanocomposite resin with 0.3 wt% of graphene and 1.0 wt% of Fe2O3performs the best during the flame retardant tests, giving a shorter self‐extinguishing time, lower peak heat release rate (22.3 kW/m2), total heat release (11.3 MJ/m2) and total smoke production (1.32 m2) than others. The pyrolysis analysis indicates that a large number of products with fused rings are formed in the residual char layer, which effectively inhibit the release of heat and smoke and thus improve the flame retardancy of PPS nanocomposite resin. In addition, the flame retardant textile weaved with PPS/G/Fe2O3fibers gives a high‐limiting oxygen index (40.1%), zero after‐flame time, no droppings and small damaged length (114 mm in warp and 98 mm in weft direction) during the standard flame retardancy tests provided by a third‐party independent inspection organization. The fabrication of PPS fibers with effective and enhanced synergistic flame retardancy through melting spinning is facile and scalable, providing a promising strategy for advanced protective clothing.

Weft direction pseudo-thermomechanical fatigue behaviors of T300/ Polyimide-380 2.5D woven composites

This work elaborates the weft direction in-phase thermomechanical fatigue (IP TMF) behaviors of T300/PI-380 2.5D-WCs for the temperature variation between 100 and 300 °C for the first time. Results show that the IP TMF responses of 2.5D-WCs exhibit a low cycle fatigue characterization, which approximately linear decreases with the increase of cycle number. The hysteresis loops shifted to the right confirm an elongation of specimen during the IP TMF process. The residual stiffness and residual strength behaviors are also investigated in the case of TMF, and the corresponding numeric models are proposed based on the damage mechanics. Moreover, fracture morphologies of 2.5D-WCs under the IP TMF loading have been explored by means of SEM and X-rays observations. Finally, a probable failure mechanism for the weft direction IP TMF behaviors of 2.5D-WCs is proposed. This work provides a new benchmark in studying high-temperature fatigue properties of resin matrix 2.5D woven composites.

Analysis and prediction of tensile properties based on rule of mixtures model for multi-scale ramie plain woven fabric reinforced composite

Natural fibers are increasingly used as sustainable reinforcement for composites because of their carbon capture and renewability. Classical rule of mixtures (ROM) and ROM-based models have been widely used to predict the tensile properties of natural fiber reinforced composites with random or unidirectional oriented structures. However, the woven fabric reinforcement is interwoven by warp and weft yarns, which are spun by short fibers. The multi-scale composite structure made tensile properties challenging to predict. To provide the prediction of woven fabric reinforced composites, the macro and micro ramie fiber reinforced composites fabricated by multi-layer ramie plain woven fabrics, single-layer fabric, and detached yarn were analyzed. Results demonstrated that tensile properties of composites in the warp direction are lower than that in the weft direction due to yarn crimp and weaving damage. The linear fracture behavior of various composites confirms the hierarchical relationship between internal structure and tensile properties. The actual yarn volume fraction in fabrics or composites is calculated and introduced to the ROM model. The improved ROM model significantly enhances the prediction accuracy and efficiency of ramie plain woven fabric reinforced composites in five different areal densities and two interwoven directions.

Study on tearing strength of woven sisal fabrics for tents and polymer composite applications

ABSTRACT The use of plant fibers as a reinforcement in composites has increased daily owing to their favorable environmental considerations. Fabric properties play a significant role in alignment during composites processing, enhancing the composite properties. However, the fabric structures are formed by warp and weft yarns. These yarns are subjected to axial and shear loads, respectively. However, very limited work has been carried out on the study involving the tearing strength of the fabric. So it is necessary to study the effect of the tearing load of fabrics before converting them into composites. This paper focuses on the tearing strength of the sisal woven fabrics in both warp and weft directions. Two plain and one weftrib fabrics are prepared using sisal fibers, and their physical properties were characterized as per textile testing standards. Tear strength has been determined by Elmendorf Tear and Single Rip Tear Method by varying crosshead speeds. The result shows that woven patterns and number yarns significantly impact tearing strength. In the case of the weft rib pattern, the warp direction exhibits the highest tearing strength compared to the weft direction. Also, in the case of weftrib fabrics, the weft direction indicates better-tearing strength than another woven pattern.