Knitted Structures Research Articles

Skin comfort of base layer wool garments. Part 2: Fiber diameter effects on fabric and garment prickle

Earlier studies on prickle have been largely fabric based and designed to elucidate mechanisms and also the relative importance of different parameters. The current work has importantly extended the study of prickle from fabric to garment giving for the first time extensive knowledge of wearer responses to garments for a particular market segment. Also the range of fabrics and garments has been extended significantly from the heavier 14-gauge knit structures that formed the basis for the majority of the earlier seminal studies to finer, lightweight 24-gauge structures. The observed prickle responses from the garment studies remain consistent with the existing mechanistic understanding of prickle and confirmed that the forearm fabric test can be used as a useful predictor of relative prickle levels. An analysis of the garment prickle data relative to an overall assessment of a like/dislike assessment of the garments identified that wearers are willing to experience a low level of prickle, that is, beneath a critical level without effecting an overall like/dislike decision. Analysis of the like–dislike data was able to generate, for the first time, quantitative information on the likely percentage of ‘satisfied wearers’ as a function of fiber quality.

Tension and tear behaviors of co-woven-knitted fabric with photograph investigation

Co-woven-knitted (CWK) fabric is a novel structural fabric which combines the woven and knitted structures together. In this paper, the tension and tear properties of CWK fabric along different directions are tested. The stress-strain curves for tension loading and load-displacement curves for tearing loading were well obtained. The high-speed camera also was employed to observe the whole damage process and series of still pictures were picked up to analyze the meso-scale mechanism of CWK fabric along various directions. The results indicated that the tension and tear properties of CWK fabric are closely related to the directions of loading.

Numerical Analysis of Functional Fabrics for Cycling Sportswear Design

Thermal functional design is a new trend of cycling sportswear design based on style and pattern design, which places the focus on creating clothing with desired thermal functions to offer thermal comfort. In this paper, a numerical system, which can investigate, simulate and preview the physical thermal behaviours in the sportswear, is firstly described. With this system, five fabrics with different knitting structure were numerically simulated through simulation cases, and the predicted thermal performance of the fabrics and the wearers in these was analyzed and compared in terms of temperature and relative humidity of the fabric, skin temperature, core temperature, thermal comfort and moisture comfort of the wearer. This numerical analysis of the thermal performance of the fabrics may offer helpful implication for the thermal functional design of functional cycling sportswear.

A Study on Ultraviolet Protection of 100% Cotton Knitted Fabric: Effect of Fabric Parameters

The effect of fabric parameters such as weight, thickness, and stitch density on the ultraviolet (UV) protection of knitted fabrics was studied. Different knitting structures such as plain, pineapple, lacoste, and other combinations of different knitting stitches of knit, tuck, and miss as well as half milano, full milano, half cardigan, full cardigan, 1 × 1 rib, and interlock were prepared. Experimental results revealed that weight was the most important factor that affected UV protection while thickness and stitch density were not the leading factor in determining UV protection.

カーリング・斜行現象を再現できる平編地の編目構造モデリング手法

In this paper, a modeling method of knitted loops in a plain stitch fabric, which can simulate its curling and wale skew, is proposed. First, a yarn is modeled as an elastic linear object whose cross-section is circular and does not change during deformation. Then, the shape of the yarn and its potential energy can be described by use of Euler angles based on the differential geometry and its stable shape can be derived by minimizing its potential energy under geometric constraints imposed on it. Applying this model, the shape of a knitted structure can be determined when only properties of a yarn such as the radius, flexural rigidity, and torsional rigidity and parameters for knitting such as the length of one loop, wale width, and course width are input. Curling/wale skew is phenomenon caused by decrease of the potential energy of a knit with an asymmetric structure/twisted yarns. Therefore, such phenomena also can be simulated with our proposed method in which the shape of a knit is determined by minimizing its potential energy. Computational results show the qualitative validity of our proposed method.

고신축성 압박의류제품의 편성조직 및 특성

This paper describes the first part of a study for obtaining useful data on the development of compression garments with high stretch knitted materials. Twenty types of compression garments sold in the domestic market were analyzed in terms of the knitting method and knit structure. After classifying these garment types into three elements of knit structure, a comparative analysis of the body part to which knit structure is applied was performed. Given the superior comfort of its finished product and seamless process productivity, the weft knitting technique was used more commonly than the warp knitting technique. All extracted knit structures were single-faced, and float and tuck were variously applied based on plain stitch. Plain stitch was applied on smooth body part surfaces, which do not require much compression. In the case of body parts that easily accumulate mass, such as the lower abdomen and sides, plain with float stitch was used by employing a mock rib structure to exert appropriate pressure on body and ensure a good fit. However, on body parts requiring a strong fit and pressure along with protection, plain with float stitch was used. Meanwhile, the structure in which float and tuck were combined based on plain stitch was applied for body parts with active muscles.

Assessment of body mapping sportswear using a manikin operated in constant temperature mode and thermoregulatory model control mode

Regional sweating patterns and body surface temperature differences exist between genders. Traditional sportswear made from one material and/or one fabric structure has a limited ability to provide athletes sufficient local wear comfort. Body mapping sportswear consists of one piece of multiple knit structure fabric or of different fabric pieces that may provide athletes better wear comfort. In this study, the 'modular' body mapping sportswear was designed and subsequently assessed on a 'Newton' type sweating manikin that operated in both constant temperature mode and thermophysiological model control mode. The performance of the modular body mapping sportswear kit and commercial products were also compared. The results demonstrated that such a modular body mapping sportswear kit can meet multiple wear/thermal comfort requirements in various environmental conditions. All body mapping clothing (BMC) presented limited global thermophysiological benefits for the wearers. Nevertheless, BMC showed evident improvements in adjusting local body heat exchanges and local thermal sensations.

Hierarchical architecture of active knits

Nature eloquently utilizes hierarchical structures to form the world around us. Applying the hierarchical architecture paradigm to smart materials can provide a basis for a new genre of actuators which produce complex actuation motions. One promising example of cellular architecture—active knits—provides complex three-dimensional distributed actuation motions with expanded operational performance through a hierarchically organized structure. The hierarchical structure arranges a single fiber of active material, such as shape memory alloys (SMAs), into a cellular network of interlacing adjacent loops according to a knitting grid. This paper defines a four-level hierarchical classification of knit structures: the basic knit loop, knit patterns, grid patterns, and restructured grids. Each level of the hierarchy provides increased architectural complexity, resulting in expanded kinematic actuation motions of active knits. The range of kinematic actuation motions are displayed through experimental examples of different SMA active knits. The results from this paper illustrate and classify the ways in which each level of the hierarchical knit architecture leverages the performance of the base smart material to generate unique actuation motions, providing necessary insight to best exploit this new actuation paradigm.

3D auxetic warp-knitted spacer fabrics

Auxetic fabrics have gained an increasing attention in the auxetic material area in recent years. Especially, auxetic fabrics fabricated based on both weft-knitted and warp-knitted structures have made some important progress. However, all the knitted auxetic fabrics reported so far are fabricated based on 2D knitted structures, although some of the weft-knitted auxetic fabrics are finally formed into 3D forms. This paper reports a novel kind of 3D auxetic fabric fabricated based on a warp-knitted spacer structure with adoption of a special geometrical configuration which is formed with parallelograms. The auxetic behavior of these fabrics is discussed in terms of tensile direction, geometrical parameter, and repeated extension. The shape fitting ability on a spherical surface is also demonstrated. The results shows that the 3D auxetic fabrics have auxetic behavior in all the fabric plane directions and the highest auxetic effect is obtained when stretched in the weft direction of the fabric. The 3D auxetic fabrics also display an excellent shape fitting ability, which makes them very attractive for various applications where fitting to the human body's shape is highly required, such as bra cups, protectors for knees and elbows, shoes covers, etc.

3D Modeling and Visual Simulation of Plain Knitted Structures

Weft knitted fabrics are widely used in clothing textiles and technical applications, such as sweater and underwear, etc. The geometrical modeling of weft knitted structures is useful to predict fabrics properties and for creating physical models. How to realize the realistic computer simulation of plain knitted structures, much research is still needed. By measuring the loop structure size of fabrics produced by the circular machine and flat machine, a 3D geometrical model of plain loop with combination of empirical and theoretical was developed. The loop model has a total of 17 data points. Cubic NURBS curve was used to generate central path of yarn in plain loop. The circle was selected as the cross-section of yarn. In Visual C++ and OpenGL environment, then the 3D computer simulation of plain knitted fabric was realized. The simulation results distinctly show the intermeshed loops effects of knitted structures in 3D space.

Core Conductive Yarn Based Integral Knitted ESD Garments Part II. Carbon Composite Yarns Investigation

A research regarding integral knitted structures for electrostatic discharge (ESD) protective garments with core conductive fibres is currently undergoing. In this paper, the second part of the research is presented, in which the integral knitted structures with carbon-based fibres were investigated. A number of 8 samples were manufactured and their ESD properties were analyzed. In this regard, the surface resistivity, volume resistivity, and charge decay time were determined, and based on the results, a bilayer knitted structure was proposed.

Core Conductive Yarn Based Integral Knitted ESD Garments Part I. Metallic Core Conductive Yarns Investigation

A research regarding the integral knitted structures for electrostatic discharge (ESD) protective garments with core conductive fibres is currently undergoing. The results of the research will be published in three papers. The current paper presents a study on the knitted structures made with metallic core conductive fibres. A number of 15 samples made with different types of fibres were manufactured and tested for their ESD characteristics. From the experimental results, conclusions were drawn about ESD performances of tested samples.

Effect of blend proportion on thermal behaviour of bamboo knitted fabrics

This study presents the thermal comfort properties of single jersey knitted fabric structures made from cotton, regenerated bamboo and cotton–bamboo blended yarns. Cotton, bamboo fibre and blends of the two fibres (100% cotton, 100% bamboo, 50:50 cotton:bamboo, 67:33 cotton:bamboo, 33:67 cotton:bamboo) were spun into yarns of identical linear density (20 tex). Each of the yarns so produced was converted to single jersey knitted fabrics with loose, medium and tight structures. The thermal conductivity of the fabrics was generally found to decrease with increase in the proportion of bamboo fibre. The relative water vapour permeability and air permeability of the fabrics were observed to increase with increase in bamboo fibre content. Statistical analysis also indicates that the results are significant for air permeability, thermal resistance, thermal conductivity and relative water vapour permeability of the fabrics.

Analysis of Compressibility Behavior in Warp Knitted Spacer Fabrics: Experiments and Van Wyk Theory

Spacer fabrics are mostly formed by two separated surface layers which are connected to each other by connector monofilaments or yarns. The middle layer in such fabrics gives a unique compressibility characteristic to them. These fabrics can be employed as the distributor or damper of pressure in the automobile industry, medical and technical textiles, and sport wear. In these applications, the compressibility behavior plays a significant role in the structural stability of fabrics. The compressibility behavior could be affected by different physical and geometrical parameters of knitted structures such as the density of monofilaments and fabric thickness. In the present work, the compressibility behavior of single and double layered warp knitted spacer fabrics (WKSF) was investigated. The work of compression and reversibility forces and hysteresis in single and double layered WKSF were experimentally obtained. The compression results for single layer WKSF are compared with the theoretical results obtained by Van Wyk theory. The comparison demonstrates that the results obtained by Van Wyk theory are consistently correlated with the experimental results. The compressibility and reversibility behavior and the hysteresis of double layered WKSFs were evaluated based on their single layer components at different cycles of loading.

Investigation of air permeability of core spun cotton/spandex weft knitted structures under relaxation

In this research work, air permeability variations of core spun cotton/spandex single jersey and 1×1 rib knitted structures were studied under relaxation treatments. Results are compared with similar fabrics made from 100 % cotton material. Even though cotton/spandex fabrics knitted with same stitch lengths, their structural spacing and stitch densities vary with the progression of treatments. Similar behavior was also observed with 100 % cotton knitted structures. Under higher machine set stitch lengths (i.e., lower fabric tightness factor), higher structural spacing and lower stitch densities were resulted and those variations significantly affected on the air permeability variations of knitted structures. 1×1 rib knitted structures showed significantly higher air permeability than single jersey structures and it is more prominent with cotton rib structures. However, cotton/spandex 1×1 rib and single jersey structures have not showed such significant deviations. Air permeability of cotton/spandex and 100 % cotton rib and single jersey knitted structures decreased with lower machine set stitch lengths (i.e., at higher fabric tightness factors). There was a correlation with fabric tightness, air permeability, areal density and fabric thickness such as knitted fabrics became tighter, their weight and thickness were higher, while their air permeability was lower. Thus, fabric areal density and fabric thickness are positively correlates to machine set stitch length−1 (fabric tightness factor). Air permeability of a knitted structure depends on material type, knitted structure, stitch length, relaxation treatment, structural spacing and stitch density.

Effect of Ring and Compact Cotton Spun Yarn characteristics on Physical and Comfort Properties of Knitted Fabrics

This study investigates the effect of ring and compact spun yarns such as Sussen Elite and Com4 spun yarn on the physical and comfort characteristics of single jersey, rib and plain interlock knitted fabrics. The physical characteristics such as fabric aerial density, tightness factor, spirality and pilling behaviour were studied and statistically analyzed using Multivariable ANOVA analysis. The comfort characteristics such as thermal insulation behaviour (TIV), water vapour permeability, wicking and air permeability were studied and reported. The test results showed that compact spun yarn knitted fabrics such as Sussen Elite and Com4 yarn fabrics demonstrated higher thermal insulation behaviour in all the knitted structures when compared to ring spun yarn knitted fabrics. The low stress mechanical characteristics such as shear and compressional behaviour of ring and compact spun yarn knitted fabrics were also reported.

Stretch sensing properties of conductive knitted structures of PEDOT-coated viscose and polyester yarns

Wearable textile-based stretch sensors for health-care monitoring allow physiological and medical evaluation without interfering in the daily routine of the patient. In our previous work, we successfully coated viscose and polyester (PES) fibers with the conjugated polymer poly(3,4-ethylenedioxythiophene) (PEDOT), using a chemical vapor deposition (CVD) process. In the present paper we report the possibility of producing a large quantity of PEDOT-coated conductive fibers with acceptable mechanical strength and frictional properties, so that knitted stretch sensors can be produced. In utilizing these knitted structures we have demonstrated the possibility of producing a textile-based monitoring device which is more readily integrated into wearable clothing than the previous metal-containing structures. The performance of viscose and PES knitted structures as stretch sensors has been investigated using a cyclic tester of our own design. For imitation of respiratory and joint movement, the variation in electrical properties of the knitted structures was examined at 5 to 50% elongation, and the performance of knitted viscose and PES structures was then compared on the basis of the cyclic testing results. In order to determine the effect of washing on PEDOT coatings and the knitted structures, two washing cycles were performed. After washing, the persistence of PEDOT coating on knitted structures was investigated using FT–IR spectroscopy and thermogravimetric analysis. In the case of PES fiber, it was revealed that stretch sensing behavior persisted even after the washing cycles. These structures thus have the potential to be utilized in medical textiles for monitoring the physiological activities of patients, such as breathing rate and joint movement.

An optimal artificial neural network system for designing knit stretch fabrics

In this paper, a computer-aided system for designing knit stretch materials is presented. It allows designers to optimize the structure of knit stretch materials according to the functional properties. This system aims at modeling the relation between functional properties (outputs) and structural parameters (inputs) of knitted fabrics. Thirteen features characterizing knit structures and operating parameters were taken as input parameters of the artificial neural networks (ANNs). These parameters were preselected according to their possible influence on the outputs which were the elongation, growth, and elastic recovery. In order to reduce the complexity of the models, an original fuzzy logic-based method was proposed to select the most relevant parameters which were taken as input variables of the ANNs. The selection procedure of structural parameters allows designers to focus on the most relevant parameters in order to conduct production experiments related to the new product. Then, two types of model are set up by utilizing multilayer feed forward neural networks, which take into account the generality and the specificity of the product families, respectively. The presented models have been validated with the use of experimental data concerning several families of knitted fabrics.

Loop Length of Plain Single Weft Knitted Structure with Elastane

For decades, scientists have been trying to define relationships among yarn parameters, knitted fabric parameters, and knitting parameters with loop models. Recently, the geometrical loop models have returned to focus as they assist finding the effective parameters which cause dimensional changes during relaxation. Furthermore, they help designing knitted structures for technical applications and obtaining computer simulations of knitted structures. In the past, geometrical loop models considered more or less porous structures and the yarns used were mostly conventional, without elastane. The behavior and characteristics of compact knitted fabrics made from elasticized yarns have been investigated only recently. In general, mostly the structures with plated elastane threads have been analyzed. The aim of the research was to study the geometrical parameters (yarn thickness, loop width, loop height, fabric thickness, loop length) of plain single weft knitted structures made from various elasticized yarns, in comparison to equivalent structures made from conventional yarns. In the study, the most frequently applied loop models for the loop length calculations were evaluated with the emphasis on their adequacy for elasticized knitted structures. A new loop model for an elasticized weft knitted structure based on the multiple linear regressions was defined.

Effect of surface treatment and knit structure on comfort properties of wool fabrics

The comfort properties of the pique and single jersey knitted wool fabrics were investigated using the Wool ComfortMeter (WCM). The fabrics were knitted in three cover factors and treated with either plasma or a silicone softening agent and were compared with untreated fabrics. Plasma treatment did not show significant effects on the comfort value. However, silicone polymer significantly reduced WCM values suggesting that the silicone coating reduced the number of protruding fibres on the fabric surface. Regardless of treatment used, pique fabrics showed a lower WCM value, and therefore were perceived to be more comfortable than the single jersey structure. While the effect of cover factor was not significant, in fitted model to predict the WCM value of fabrics, mass/unit area and fabric thickness were significant predictors along with fabric structure and finishing treatment.