Yarn Density Research Articles

Development of a Novel Three-Dimensional, Adjustable Weaving Reed

Weaving, as a parametric medium, involves various parameters, some of which can be altered while others remain constant. One constant parameter is the right angle between the weft and warp yarns, established by the weaving reed. The reed sets the warp density and the weave’s width. This paper presents a new concept of a three-dimensional, adjustable reed. This reed modifies the weaving structure by changing the density of the weft yarns across the fabric. Our reed is constructed to allow the dents to move forward and backward during the weaving process, with the position maintained by replaceable cardboard stencils. These stencils enable the reed’s dents to form different curves that transfer onto the weft yarns, impacting the weave architecture by allowing the weft yarns to deviate from a perpendicular alignment with the warp yarns. This innovative reed design offers new structural possibilities and properties for woven textiles, exemplified by a series of 3D textiles and a case study of a seamless, fully fashioned skirt. In this study, the weft yarns’ length along the skirt is extended using zig-zag-shaped stencils, resulting in a skirt with an A-line silhouette. The Variable Reed has the potential to improve efficiency by reducing production steps and minimizing waste in the manufacturing of seamless woven garments.

Experimental and numerical validation of high strain rate impact response and progressive damage of 3D orthogonal woven composites

Advanced three-dimensional (3D) woven composites for aerospace and automotive applications are commonly subjected to complex dynamic environments involving vibrations and impacts, resulting in examining their impact properties is extremely important. This paper first experimentally discussed the influences of strain rates, weft yarn densities and loading directions on the impact performances and failure mechanisms of 3D orthogonal woven composites (3DOWCs). Secondly, full-scale finite element models were developed to predict the stress distribution and interfacial damage evolution process. The predictions were well in agreement with the experimental results. This research revealed that the impact characteristics exhibited strain rate sensitivity. With increasing weft yarn densities, the high strain rate impact behaviors also improved. Particularly, the warp impact strength of 3DOWCs with a weft yarn density of 2 yarn/cm (W5-2) at 812 s−1 was 17.4% and 24.0% higher than that of 3DOWCs with a weft yarn density of 1.5 yarn/cm (W5-1) at 822 s−1. Meanwhile, warp impact strength consistently exceeded to that of the weft impact strength. Additionally, strain rates, weft yarn densities, and loading directions dramatically affected the stress distribution and interfacial damage evolution process of 3DOWCs. Significant warp yarns fracture and matrix cracking were the principal failure patterns in the warp impact, whereas the damage in the weft impact was dominated by localized fracture of weft yarns and interfacial debonding.

Analyzing the Effect of Yarn Tension, Weft Yarn Type, and Weft Yarn Density on Thermal Resistance, Thermal Conductivity, and Air Permeability of Plain Woven Fabric

ABSTRACT Uncomfortable feelings during wear highly affect human health, work efficiency, and mental satisfaction. This study evaluated the thermal comfort of woven fabrics made from 16Ne ring and rotor spun weft yarns(x1). The other variables involved are warp tensions (x2) of 1 kilo newton (KN) and 2 kN, weft tensions (x3) of PFT/B- and PFT/B+T, and weft densities (x4) of 14 picks per centimeter (PPC) and 18 PPC. Comfort properties such as thermal conductivity, thermal insulation, and air permeability were measured and analyzed. The fabric produced from rotor-spun weft yarn showed better thermal comfort properties than the fabric made from ring-spun weft yarn. The results of the analysis revealed that when warp and weft yarn tension increased and weft density decreased, thermal conductivity and air permeability also increased. However, thermal insulation of the fabric decreased as yarn tension increased. On the other hand, as the weft density increased, the thermal insulation of the fabric increased. Air permeability increased as weft tension increased from PFT/B- to PFT/B+T and it decreased as weft density increased from 14 PPC to 18PPC. The maximum thermal conductivity and minimum thermal resistance were attained at 14 PPC weft density and ring-spun weft yarn.

A progressive optimization of axial compression performance of 3D angle-interlock tubular woven composites through textile structure and yarn configuration innovations

Lightweight tubular composite materials with excellent compression performance are important structural components for load-bearing or energy absorption. Generally, outstanding performance depends on the structural design. Herein, a progressive structural optimization of 3D angle-interlock tubular woven reinforced composites (3DATWCs) is performed. The structural factors under consideration involve proportion of warp lining yarn, layers of weft yarn, surface constraint yarn and weft density. The axial compression performance and failure process of 3DATWCs with different structures are investigated through experiments and finite element method. The results indicate that increasing proportion of warp lining yarn can significantly improve the axial compression performance of 3DATWC. However, simply increasing proportion of warp lining yarn may decrease the straightness of yarn and constraint on warp yarns, leading to the performance reduction. The problem of performance reduction can be solved by introducing surface constraint yarn or increasing weft density. Finally, an optimization strategy is unveiled. Compared to ordinary structure, the ultimate load, plateau average load, ultimate stress, elastic modulus, total energy absorption and specific energy absorption of optimized 3DATWC increase by 101.88 %, 96.12 %, 77.46 %, 142.55 %, 119.06 %, and 77.39 %, respectively. Additionally, the axial compression performance is seriously affected by the fiber waviness, yarn waviness and interfacial properties, and can be further improved through reducing the waviness during the preparation of fabric preform.

Modeling The Started Tear Of A Linen Fabric: Case Of A White Woven Fabric

This article relates the behavior of the initiated tear of a white woven linen fabric. The initiated tearing of fabrics is represented by mathematical models and developed from the physical characteristics of the fabrics and the characteristics of the yarns constituting the fabric. Among the evaluation parameters we distinguish: the weight of the fabric, the yarn density in warp and weft of the fabric, the width of the fabric, the resistance of the yarns, the kilometric resistance of the yarns and the actual metric number of the yarns. The fabrics studied during this work are composed of 55% cotton and 45% also, tests and experiments were carried out with 66 fabric samples of the same composition in order to better understand the phenomenon of initiated tearing. The mathematical models given in this work are associated with their precision reflected by the relative and absolute errors.

Study of textile carpet combustion process

Currently, synthetic carpet products are widely used in the home, as they compare favorably with natural ones in terms of technical characteristics. This is due to their high durability, lack of tendency to rot, wide range of colors and relatively low cost of production. However, the ease, ignition and increased flammability of most synthetic carpet products result in rapid spread of fire through them, igniting other products and objects in the vicinity. The sources of the fire are usually matches, cigarettes, careless handling of fire, and short circuits. In this regard, the purpose of the study is to investigate the combustion process of textile synthetic carpet products of "Bal Textile" LLP with justification of the most rational methods of flammability and combustibility assessment. Subject of research: processes of thermo-oxidative destruction of modified polypropylene textile materials and their relationship with fire hazard properties, flammability of fiber-forming polymers. The combustion process of synthetic carpet products of Bal Textile LLP with different Heat Set yarn densities and pile lengths were investigated. Based on the research we have done, it has been concluded that the higher the pile of the carpet, the higher the level of combustion. Carpets melt when ignited and are also colored as a black liquid. The value of the conducted research is that on their basis it is possible to classify materials by degree of combustibility (flammability) and to develop requirements for synthetic carpet products of LLP "Bal Textile" of reduced fire hazard taking into account their possible application in practice.

Improvement of Mechanical And Light Transmittance Properties of Foam Coated Curtain Fabrics

In foam coating, the main factors are the foam density of the coating material and the compatibility among foam structure, the coating material and the fabric surface. In this study, the results of breaking strength, breaking elongation, tear strength and light transmittance testing were compared according to the fabric structure, coating recipes, foam density and the coat layer viscosity statistically. The high yarn density of warp threads per unit length in polyester woven fabric leads to an increase in tensile strength. The best results in tensile strength and elongation at break experiments were obtained at coating recipe 4. As a result, the minimum light transmittance value was 1.0347 and the maximum light transmittance value was 1.12 by using coating recipe 4, respectively. Consequently, the low filler content, soft binder ratio and foam density had a positive effect on the mechanical and light transmittance properties of foam coated fabrics.

Electrical conductivities and temperature distributions of carbon fiber 3D woven composites with different electric field direction

Electrical conductivities and temperature generations are related closely for carbon fiber composites under electric fields. Here we reported the current conductivity and electro-thermal behavior of carbon fiber reinforced 3D orthogonal woven structure composites (3DOWCs) along different current directions. The influence of woven architectures and contacts on electrical and thermal behaviors was analyzed with finite element analysis (FEA) model. We found that the conductivity was the highest along warp direction and the lowest along Z-binder direction. The conductivity increased with the increase of in-plane angles. The overall conductivity of Z-binder direction was affected by weft/Z-binder yarn interface. In-plane angle directions, the warp/weft interfacial conductivity affected overall conductivities, which had the largest temperature contribution. The maximum current density and temperature of warp yarns decreased with the increase of in-plane angles. The proportion of weft yarns in current density and temperature rise increased with the increase of in-plane angles.

Influence of Linear Density of Polyamide Plating Yarn on the Usage and Comfort Properties of Men’s Cotton Socks

Socks, being a necessary item of clothing, must be comfortable and maintain their quality throughout their life. Therefore, it is very important to select the yarns for their production. Usually, casual socks are made from a high percentage of cotton to ensure softness and comfort, and blended with polyamide to improve fit, durability and shrink resistance. The objective of this study is to compare five groups of black colored cotton calf-length men's socks produced under the same conditions in full plating with different textured polyamide 6.6 multifilament yarns, designated as: 22 dtex f7 × 2, 33 dtex f10 × 2, 44 dtex f13 × 2, 78 dtex f23 × 2, 110 dtex f34 × 2. The influence of the linear density of the polyamide plating yarn on the usage properties of the socks was evaluated by testing abrasion resistance and propensity to surface pilling with the Martindale abrasion and pilling tester, dimensional stability and color fastness to washing, perspiration and rubbing, as well as on comfort-related properties by testing moisture absorption, air permeability and thermal resistance with the Thermal foot manikin system. In addition, the basic physical properties of the socks, consisting of density parameters, mass and thickness were measured, all according to the standardized test methods. The results show that increasing the linear density of polyamide 6.6 yarns (i.e., increasing the amount of polyamide in the socks) has the following effects: increase in mass, thickness and structural change of sock plain knits, increase in abrasion resistance and change in dimensional stability of socks, decrease in moisture absorption, air permeability and thermal comfort of socks. From the obtained results, it can be concluded that when selecting the plating yarn for the production of cotton socks, it is necessary to take into account their linear density and structure, as well as the intended purpose of the socks, their specified comfort and the expected usage quality.

Wet Twisting in Spinning for Rapid and Cost‐Effective Fabrication of Superior Carbon Nanotube Yarns

AbstractCarbon nanotubes (CNTs) are promising blocks for building advanced yarns with unique structural and functional attributes. However, the complexity of fabrication and high cost has hindered the widespread adoption of CNT yarns. In this study, a rapid and continuous twisting wet spun yarn strategy to produce highly densified CNT yarns is presented. The method involves effectively dispersing CNTs in the surfactant dispersion, swiftly removing the surfactant in the coagulation bath and twisting treatment to effectively improve the density of yarn and the orientation of CNT. Detailed characterizations on the influence of each spinning conditions reveal that twisting treatment significantly enhances the packing density of yarns, improves the orientation of CNTs, and mitigates the impact of impurities on conductivity. The resulting CNT yarns exhibit a remarkable tensile strength of 600 MPa, a Young's modulus of ≈40 GPa, and a high conductivity of 8990 S cm−1. When utilized as a yarn heater, the CNT yarn demonstrates an ultra‐fast electrothermal response of over 1000 °C s−1 at a low operating voltage of 5 V. Impressively, the mechanical properties of CNT yarns show good stability during heating. This study provides a perspective of structural engineering for the large‐scale preparation of high‐performance CNT yarns.

Scalable Fabric‐Based Solar Steam Generator

AbstractSolar steam generation has emerged as a promising approach to address water scarcity issues globally. However, a few challenges remain, including high cost, limited scalability, and salt accumulation, before this technique can be adopted by the general population. Here, an all‐in‐one photothermal fabric is reported such as a solar steam generator (SSG), consisting of commercial hydrophilic superfine denier polypropylene fiber and water‐repellent expandable polyethylene foam, manufactured via a conventional weaving machine. By tailoring the yarn twist and density, optimized micro‐macro hierarchical channels can be created in the SSG to provide sufficient water supplementation and continuous steam generation. Due to the Marangoni effect introduced by the temperature gradient along the yarns water with high salinity transports to the bulk water, realizing a salt‐rejecting property. As a result, the SSG demonstrates a rapid evaporation rate of 1.408 kg m−2 h−1 and energy efficiency of 92.43% under 1 sun, as well as outstanding stability for desalination of high salinity brine (10 wt% NaCl). Furthermore, this strategy provides a new solution to achieve excellent cost‐effectiveness in clean water production at ≈1700 g h−1 $−1. This work provides a sustainable fabric‐based SSG for practical large‐scale clean water production, and can potentially inspire other textiles‐based water treatment.

The model of ring-spun slub yarn based on random fiber arrangement and its application: Part 2 Prediction of morphology parameters for slub yarn and simulation of slub fabric

The morphology parameters of slub yarn include slub length, base length, the length of the transitional segment, slub multiple, slub linear density, base linear density, and average linear density of slub yarn. These parameters have an impact on the appearance of both slub yarn and its fabric. This paper aims to predict the morphology parameters of spun slub yarn by utilizing the model proposed in Part 1 for ring-spun slub yarns. Once the slub generation mode was known, slub yarn could be simulated with the morphology parameters. The simulated slub fabric was obtained by arranging the simulated slub yarn in the warp and weft directions. According to our study, the prediction accuracy of each morphology parameter was over 80% by comparing the simulated parameters with the measured ones of spun slub yarn. The CV (coefficient of variation) of the slub segment number per unit area was utilized to assess the distribution of slubs in the simulated fabric. This research can facilitate the development of slub yarn and its fabric, providing guidance for technicians to enhance production technology.

Istraživanje nekih svojstva površinske hrapavosti tkanina proizvedene od održivih prediva

Biodegradable polymers have attracted attention in recent years owing to increased sensibility to waste management. Polylactic acid (PLA) fibers have been recently utilized in textile products owing to its being biodegradable with low environmental impact. PLA fibers decompose into simpler compounds, thereby minimizing their environmental impact. Woven fabrics produced from sustainable yarns such as PLA or its blends may be good alternative textile products with a sustainable manner. This research was carried out to compare the surface roughness characteristics of some woven fabrics which are plain, 2/2 twill, and 5/1 satin woven samples. Fabric samples were woven with different weft yarns (polyester, polylactic acid, and recycled polyester/Trevira) at various weft yarn densities but with the same warp yarn properties. Surface roughness values of the samples including arithmetic average height (Ra), mean height of peaks (Rpm), mean depth of valleys (Rvm) and mean slope of the profile (Da) were analysed. Effect of different raw materials and fabric properties such as warp/weft density, weave pattern on surface roughness were tried to be analysed within the study.

The effect of dyeing tubes’ structure on the colour difference of yarns

In the study, the effect of the structure of the dyeing tubes used in bobbin dyeing on the colour difference of the yarns was investigated. For this purpose, dyeing was done using 5 dyeing tubes with different dye permeability. Yarn samples were taken from the inner, middle and outer winding layers of the dyed bobbins. The colour difference of the yarns was measured with a spectrophotometer. It was observed that as the dye permeability of the dyeing tubes increased, the colour difference decreased and a more homogeneous dyeing was obtained. When the bobbins were evaluated in terms of diameter, it was seen that the colour difference was at least in the middle diameter. As the dye permeability increased, the colour distribution along the bobbin diameter became more homogeneous. In addition, it was determined that the colour difference decreased in fine yarn and high winding density.

The Potential of Double-Faced Polyester-Viscose Woven Fabric as a Porous Substrate for Direct-Coating and Multilayer Concept.

Textile-based sensors fabricated using the direct-coating method are the appropriate choice to meet the aspects of flexibility, non-invasiveness, and lightness for continuous monitoring of the human body. The characteristics of the sensor substrate are directly influenced by factors such as the type of weave, thread fineness, fabric density, and the type of polymeric constituent fibers. The fabric used as the sensor substrate, fabricated using the direct-coating method, must be capable of retaining the electrode paste solution, which has higher viscosity, on one surface of the fabric to avoid short circuits during the fabrication process. However, during its application, this fabric should allow the easy passage of analyte solutions with low viscosity as much as possible. Hence, an appropriate fabric construction is required to serve as the substrate for textile-based sensors to ensure the success of the fabrication process and the effectiveness of the resulting sensor's performance. The development of the structural design of the fabric to be used as a substrate for non-invasive biosensors with a multilayer concept is carried out by weaving and sewing processes utilizing polyester-viscose fibers. During the production process, variations are applied, such as weft yarn density, the characterization of wetting time, absorption rate, maximum wetted radius, spreading speed, and accumulative one-way transport index. The most suitable fabric for use as a substrate for non-invasive biosensors with a multilayer concept, such as in this research, is a fabric with a weft thread density of 70 strands per inch, along with the addition of an analyte transfer thread configuration.

Evaluation of the effect of structural parameters on the compression behaviour of woven spacer fabrics

In this study, six groups of woven spacer fabrics with different structural parameters such as the spacer yarn pattern (V and W pattern) and spacer yarn density (denting pattern) were produced, and their compressional behaviour was investigated. According to the experimental results, the V-pattern spacer fabrics revealed better compressional resistance compared to the W-pattern spacer fabrics. Besides, it was observed that the spacer fabrics produced with lower spacer yarn density, were more susceptible to compressional forces. Statistical analysis of results demonstrated that all compressional parameters, except relative compressibility and thickness recovery, were affected by the spacer yarn pattern and density. Finally, the compressional behaviour of woven spacer fabric was correlated by three viscoelastic models (Kelvin model, Maxwell model, and three-component model with a nonlinear spring) and also the Van Wyk Theory. The results of curve fitting exhibited that the three-component model with nonlinear spring well fitted the experimental data.

Taguchi-TOPSIS based optimization of comfort in compression stockings for vascular disorders

Compression stockings/socks are one of the most essential materials to treat vascular disorders in veins. However, the comfort of wearing such stockings over prolonged period of time is a major problem. There is limited research in the area of comfort optimization while retaining the compressional performance. The current work is carried out with an aim to determine the optimum level of the input factors e.g., knitting structure, plaiting yarn linear density and main yarn linear density for achieving desired stretch recovery percentage and thermo-physiological comfort properties of compression socks used in treatment of vascular disorders. Their optimum combination was determined by using Taguchi based techniques for order of preference by similarity to ideal solution i.e., TOPIS. In this study, thickness, areal density, air permeability, thermal resistance, over all moisture management capacity (OMMC), stretch and recovery % were optimized simultaneously by using Taguchi-TOPSIS method. The results showed that linear density of plaiting and main yarn has significant influence on all the comfort related properties for compression stockings/socks. The optimum sample had linear density 20 denier for Lycra covered by 70 denier of nylon 66 in the plaiting yarn. It also suggested 120 denier nylon 66 in the main yarn knitted into a plain single jersey structure. The percentage contribution of the factors i.e., structure, plaiting yarn linear density and main yarn linear density was obtained by using ANOVA which are 7%, 31% and 42% respectively. It is worth mentioning that in case of compression stockings, the main yarn linear density has more significant effect on comfort properties as compared to other independent parameters. The results were verified by experiment, and the accuracy was relatively high (maximum error 8.533%). This study helped to select suitable knit structure with the change of linear densities of plaiting yarn and main yarn for comfortable compression stocking/sock and will fulfill the potential requirement for treatment of venous/vascular disorders. The novel methodology involving TOPSIS method helped in analyzing the cumulative contribution of the input parameters to achieve optimum compression as well as comfort performance. This modern approach is based on contemporary scientific principles and statistical approximations. This study may provide benchmark solutions to complex problems involving multiple interdependent criteria.

Twistocaloric Modeling of Elastomer Fibers and Experimental Validation.

The twistocaloric effect is attributed to the change in entropy of the material driven by torsional stress. It is responsible for the torsional refrigeration of fiber materials that has been widely exploited as one of the solid-state cooling techniques with high efficiency and low volume change rate. The lack of theories and mathematical models of twistocaloric effect, however, limits broad applications of torsional refrigeration. In this work, a twistocaloric model is established to capture the relationship between twist density and temperature variation of natural rubber fibers and thermoplastic elastomer yarns. An experimental setup consisting torsion actuator and torque sensor coupled with a temperature measurement system is built to validate the model. Using the Maxwell relationship, twistocaloric coefficient is measured by quantifying the thermal effect induced by torsion under shear strain. The experimental characterization of the twistocaloric effect in natural rubber fiber and thermoplastic elastomer yarn are consistent with the theoretical predictions.

High-Resolution X-ray Spectromicroscopy Reveals Process-Structure Correlations in sub-5-μm Diameter Carbon Nanotube-Polymer Composite Dry-Spun Yarns.

A persistent lack of detailed and quantitative structural analysis of these hierarchical carbon nanotube (CNT) ensembles precludes establishing processing-structure-property relationships that are essential to enhance macroscale performance (e.g., in mechanical, electrical, thermal applications). Here, we use scanning transmission X-ray microscopy (STXM) to analyze the hierarchical, twisted morphology of dry-spun CNT yarns and their composites, quantifying key structural characteristics such as density, porosity, alignment, and polymer loading. As the yarn twist density increases (15,000 to 150,000 turns per meter), the yarn diameter decreased (4.4-1.4 μm) and density increased (0.55-1.26 g·cm-3), as intuitively expected. Yarn density, ρ, ubiquitously scaled with diameter d according to ρ ∼ d-2 for all parameters studied here. Spectromicroscopy probes with 30 nm resolution and elemental specificity were employed to analyze the radial and longitudinal distribution of the oxygen-containing polymer content (∼30% weight fraction), demonstrating nearly perfect filling of the voids between CNTs with a vapor-phase polymer coating and cross-linking process. These quantitative correlations highlight the intimate connections between processing conditions and yarn structure with important implications for translating the nanoscale properties of CNTs to the macroscale.

Mechanical performance of cementitious composites reinforced with weft-knitted spacer fabrics under static flexural and impact loading

Though weft-knitted spacer fabric made from high-performance continuous fiber offers great potential for lightweight composite with high energy absorption characteristic, it has yet to be substantially studied in the field of cement-based structural materials. In this paper, a series of newly developed aramid weft-knitted spacer fabrics were applied to reinforce the eco-friendly cementitious matrix. The mechanical properties and failure behaviors of composites were investigated via the three-point bending test and impact test systematically. XCT was then performed to reveal the underlying damage mode of composites. The experimental results indicated that aramid weft-knitted spacer fabrics were highly beneficial reinforcements for cementitious composites due to their great bonding and mechanical anchoring with matrix. The larger ductile deformation and higher damage tolerance of composites were obtained by the increase of spacer yarn density and surface yarn density. The asymmetrical structure corresponding to the different density of surface layer could further enhance bearing capacity by altering the stress transfer.