Yarn Linear Density Research Articles

Determination of Pore Size, Porosity and Pore Size Distribution of Woven Structures by Image Analysis Techniques

Due to the complexity of fabric structure, modeling of pore structure and predicting the pore parameters are difficult. This paper presents a novel approach to determine textile pore size, porosity and pore size distribution by the application of the image analysis techniques. In this study, it has been attempted to establish a theoretical model for both the pore size and porosity of woven fabrics. For this purpose, a theoretical model of porous systems based on Poiseuille's law was used to predict the pore size of woven fabrics. Also a theoretical model was created to predict the porosity of a woven fabric depending on the geometrical parameters. The two characteristics of pore opening size and porosity were determined from image analysis and were compared to the results from laboratory tests. The validity of which was confirmed by experimental results using cotton plain woven fabrics produced from different yarn linear density and tightness. A new and accurate method of image analysis for pore size distribution (PSD) determination of woven fabrics is presented in this paper. The tested fabric sample could be ranked in a decrease order successfully.

Characterization and statistical modelling of thermal resistance of cotton/polyester blended double layer interlock knitted fabrics

The aim of this study was to analyse and model the effect of knitting parameters on the thermal resistance of cotton/polyester double layer interlock knitted fabrics. Fabric samples of areal densities ranging from 310-495 g/m2 were knitted using yarns of three different cotton/polyester blends, each of two different linear densities by systematically varying knitting loop lengths for achieving different cover factors. It was found that by changing the polyester content in the inner and outer fabric layer from 40 to 65% in the double layer knitted fabric has statistically significant effect on the fabric thermal resistance. Fabric thermal resistance increased with increase in relative specific heat of outer fabric layer, yarn linear density, loop length, and fabric thickness while decrease in fabric areal density. It was concluded that response surface regression modelling could be successfully used for the prediction of thermal resistance of double layer interlock knitted fabrics. The model was validated by unseen data set and it was found that the actual and predicted values were in good agreement with each other with less than 10% absolute error. Sensitivity analysis was also performed to find out the relative contribution of each input parameter on the air permeability of the double layer interlock knitted fabrics.

Understanding the influence of fibre, yarn and fabric parameters on UV protection of wool-knitted fabrics

This work investigated the influence of fibre, yarn and fabric parameters on the UV protection of fabrics. It proposed a model for UV interaction based on a theoretical hypothesis, targeted experimentation and statistical analysis. Undyed and untreated wool-knitted fabrics with varying mean fibre diameter, yarn linear density, yarn twist, fabric cover factor and fabric structure were examined. A statistical model was presented to report the relationship between fibre/yarn/fabric parameters and fabric UPF values. An optical model on the interaction between the UV light and a single jersey fabric was constructed to understand the penetration of UV light. The models were verified by the UV transmittance results of knitted wool fabrics. The results obtained from the statistical and optical models were used to propose a set of optimized parameters for lightweight summer/spring UV-protective knitted fabrics. Testing confirmed that these fabric parameters provided both high UV protection and good tactile comfort.

Development and comparison of artificial neural network and statistical model for prediction of thermo-physiological properties of polyester–cotton plated fabrics

AbstractThermo-physiological properties of textiles play a very crucial role in providing thermal equilibrium to human beings in changing ambient conditions and activity level and in turn dictate the overall wearer comfort. A number of prediction tools like mechanistic, statistical and stochastic (artificial neural network) models are finding application in textiles for reasonable prediction of various aspects of textiles before the actual commencement of fabric production and testing. In this study, thermo-physiological properties of polyester–cotton plated fabrics were predicted by two approaches: artificial neural network and response surface equations. A multilayered back propagation artificial neural network was developed with four input nodes corresponding to four selected input parameters: back layer yarn linear density, filament fineness, total yarn linear density and loop length and one output node corresponding to the predicted thermo-physiological property. Four individual networks working in tandem with common set of input parameters and each giving an individual output were developed such that the outputs of four networks were thermal resistance, thermal absorptivity, air permeability and moisture vapour transmission rate respectively. Network architecture gave good prediction performance with low values of mean absolute percentage error and high coefficient of determination. Response surface equations were developed to predict the thermo-physiological properties and good agreement between experimental and predicted values for all the properties was found with coefficient of determination over 0.9. Artificial neural network predicted the thermal resistance and air permeability of plated fabrics with good accuracy. However, the response surface equations served better prediction tool for thermal absorptivity and moisture vapour transmission rate prediction.

Influence of Textile Parameters on the Out-of-Plane Permeability of Carbon Fiber Non-Crimp Fabrics

Within the last years, liquid composite molding (LCM) is gaining more and more importance for the automotive industry due to weight saving of (semi-)structural car parts. In order to make carbon fibre parts economically more interesting for this area, short cycle times are necessary. Hence, one concept is the impregnation of carbon fibre parts in through-the-thickness direction. The behaviour of the impregnability depends mainly on the out-of-plane permeability of the fabric. The permeability of the fabric is mainly influenced by the fibre type, orientation of the fibres, and the stitching parameters. In this study the influence of textile parameters on the out-of-plane permeability of 45° and 0°/90° biaxial carbon fibre non-crimp fabrics (NCF) was investigated. The stitching yarn parameters (linear mass density and stitch length) were varied to see the influence on the out-of-plane permeability. The out-of-plane permeability was measured using a measurement cell based on flow front monitoring with ultrasonic technology at a minimum of three different fibre volume contents between 47 % and 63 % to show the decrease of permeability with respect to the fibre volume content. The results show that the out-of-plane permeability of the 0°/90° carbon fibre NCF are not significantly affected by the yarn linear mass density and the stitch length. Conversely the 45° carbon fibre NCF is affected by the stitch length, but not by the yarn linear mass density.

Effect of Lowering Twist Levels on Quality Parameters of Rotor Spun Cotton Yarn

Investigations were made to explore the influence of lowering twist level on quality characteristics of rotor spun yarn. Three levels of yarn linear density (i.e. 40, 35 and 30 tex) and five levels of twist (i.e. 700, 600, 550, 500, and 450) were employed during yarn spinning trials. Each twist multiple was investigated at all linear densities for tensile strength, elongation, total CVm (Coefficient of Mass Variation) imperfection index and hairiness. 100% cotton yarn samples were prepared on Reiter R-40 at rotor speed of 90,000 rpm. Determination of elongation, yarn strength, hairiness, mass variation, and total imperfections index was carried out on Uster Tensorapid-4 and Uster Tester-4 as per set standards of ISO standard test methods. Based on investigations it is established that yarn strength and elongation declined minutely (Insignificant) with lowering twist levels but still can be confidently used for knitting yarns. However, significant improvement in total imperfection index and marginal enhancement in CVm were experienced.

Twist requirement for blended yarns

The twist requirement of a yarn is defined by not only the number of twist turns per unit length of the yarn (T) but also the yarn diameter, which can be related to the yarn linear density (C) by assuming a constant yarn volume density. For yarns consisting of a single type of fibre, for example, pure cotton yarns, the twist requirement is commonly specified by the twist factor . For a blend of fibres with extreme difference in volume densities, for example, a blend of cotton and stainless steel fibres, the blended yarn volume density varies dramatically with the blend ratio, and the relationship between twist, yarn linear density and twist factor has to be adjusted accordingly. In this paper, we introduce a formula of equivalent yarn linear density that is simple to use for determining the twist requirement of blended yarns. The formula was used to calculate the twist settings required for the whole range of cotton/stainless steel fibre blend ratios to achieve approximately the same twist angle in the final blended yarns.

Prediction of the fabric’s crease recovery property with Taguchi design of experiment

The creasing characteristic of fabrics is affected by many factors like yarn twist, fabric density, fabric constructions, fabric thickness apart from the fiber type. In the first part of this study, the effect of yarn fineness, yarn twist, fabric tightness and weave construction factors on crease recovery was studied. In the second part of the study, in order to improve the creasing recovery of the fabrics, shape memory alloy (SMA) wires were used and the effect of shape memory alloy (SMA) wire on the crease recovery of cotton fabrics produced with different types of weave constructions were determined. Due to the high cost of SMA wire and the weaving operation adversity the two experimental plans were designed according to Taguchi design of experiment (TDOE). From the analysis of the first part, it was found that the yarn linear density had the greatest effect on fabric crease recovery compare to others. Twist coefficient was the second, weft density was third and the weave construction had the least significant effect on the crease recovery. The fabrics produced with coarser and low twisted yarns with high tightness and longer floats in the weave construction have higher crease recovery property. In the second part of the study, the application of the SMA wire significantly increased the crease recovery angle of the fabrics. The thickness of the SMA wire is very important and the effect depends on the wire thickness. The increase of the SMA wire thickness increases the crease recovery significantly. However it must be appropriate with the yarn and fabric properties. The distance between the SMA wire distances was expected to increase the crease recovery however the effect was found not significant. The fabrics produced with coarser yarns with longer floats in the weave construction have higher crease recovery property. However, statistically the effects of these parameters were found not significant due to the dominant effect of the wire thickness.

Research on the influence of yarn parameters on the ultraviolet protection of yarns

Considering both the yarn parameters and the light interaction (reflectance and transmittance) between two adjacent yarns, an optical model was presented to understand the ultraviolet (UV) light penetrating a single undyed yarn and a lot of yarns. The optical model was verified with results of diffuse reflectance spectra measurement on wool yarn samples. This optical model was used to predict the factors influencing UV protection, including fibre diameter, yarn linear density, yarn twist, transmittance index and refractive index. The statistical predictive model was also set up to show the relationship between the yarn parameters and the UV protection (UPF values) of the yarns. Yarns with the fine diameter, large yarn linear density and low yarn twist had the high UV protection.

Investigation of the Effect of Pile Height and Yarn Linear Density on the Performance Properties of Pile Loop and Cut-Pile Loop Knit Fabrics

This paper investigates the effects of fabric structural parameters such as pile yarn linear density (19.7, 22.7 and 24.6 tex), ground yarn linear density (100 and 78 dtex), sinker height (2.2 sinker; 2.5 sinker and 2.8 sinker) on the performance properties of pile loop and cut-pile loop knit fabrics. The effects of structural parameters on the performance properties of the fabrics, such as abrasion resistance, bursting strength, and air permeability, were analysed. To determine their relationship and significance, ANOVA and Pearson correlation analysis were conducted. A higher pile height increases the fabric surface weight and thickness, thereby improving the abrasion resistance of the fabrics. The bursting strength of the fabrics increases with thicker ground yarn. The thicker pile yarn decreases the air permeability of the fabrics. Pile loop knit fabrics have higher abrasion resistance and lower air permeability compared to cut-pile loop knit fabrics. There is not much difference between the bursting strength of pile loop and cut-pile loop knit fabrics if the linear density of ground and pile yarn is the same.

The effect of slub yarn descriptive parameters and yarn linear density on upholstery fabric abrasion resistance

Textile materials can be unserviceable because of several different factors and one of the most important causes is abrasion. In this study, it was aimed to achieve the minimum fabric abrasion with an optimization process on selected control factors of slub yarn descriptive parameters such as slub length, slub distance and slub thickness and yarn linear density. For this purpose, the Taguchi experimental design technique, analysis of variance, and signal‐to‐noise ratio were used. Instead of 81 (34) different slub yarn configurations, with respect to full factorial design, only nine yarn configurations with respect to Taguchi’s L9 orthogonal design were spun, woven and tested. As a result of these experiments, the optimum slub yarn descriptive parameters and yarn linear density values were determined which made a considerable improvement on the fabric abrasion resistance.

An investigation of the relationship between blend ratio, linear density and loop length on geometrical and air permeability properties of bamboo cotton-knitted fabrics

Air permeability is one of the most important aspects of clothing. This study presents the geometrical and air permeability properties of single-jersey-knitted fabric structures made from cotton, bamboo and cotton–bamboo-blended yarns. The objective was to determine the influence of blend ratio, yarn linear density and stitch length on geometrical and air permeability properties of bamboo cotton-knitted fabrics. Yarns with linear densities of 19.6, 23.6, 29.5 tex and with the same twist level were used to construct the fabrics of single-jersey structure with loose, medium and tight structures. The air permeability of the fabrics was observed to increase with an increase in bamboo fibre content. The anticipated increase in air permeability with a decrease in yarn linear density (tex) and an increase in stitch length was observed. Bamboo fibre in the fabric causes a reduction in fabric thickness and mass/unit area for all linear densities of yarn.

Prediction of Certain Low Stress Mechanical Properties of Knitted Fabrics from Their Structural Parameters

Knitted fabrics are preferred as clothing materials because of of their outstanding comfort quality. 16 plain knitted fabric samples were produced from 4 combed ring spun yarn of linear densities 29.5 Tex, 23.6, Tex 19.7 Tex and 17.4 Tex and 4 different stitch lengths from each yarn linear density were selected for this study. The fabric samples were relaxed and then tested for tensile shear and bending properties using Kawabata tester's. KES- FB1and KES- FB2. The effect of various fabric structural parameters on fabric low stress mechanical properties was studied. The fabric shear rigidity, bending rigidity, shear hysteresis, bending hysteresis, and tensile linearity were positively correlated with the fabric GSM, thickness, and tightness factor and negatively correlated with fabric linear Stitch modulus, areal stitch modulus, volume stitch modulus, and porosity. The fabric tensile elongation was positively correlated with the fabric linear stitch modulus, areal stitch modulus, volume Stitch modulus, and porosity and negatively correlated with the fabric GSM, thickness, and fabric tightness factor. The above properties were higher in course direction than in wale direction. Separate prediction equations were developed for fabric low stress mechanical properties from Tightness factor, Volume Stitch modulus, and Porosity

Shear properties of three‐dimensional woven composite reinforcements

This paper presents a comprehensive experimental study and detailed mechanistic interpretations of the shear deformation of three‐dimensional (3D) reinforcements. Six types of 3D angle interlock glass fiber preforms (3DAP) were fabricated using a range of weave parameters including the fabric density, fabric layer, and yarn linear density. A modified picture frame was developed to ensure a pure shear load during the test. Through a series of comprehensive tests, our results demonstrated that the fabric density played a key role in the mechanical properties of 3DAP and that the reinforcements with low fabric density and yarn linear density were easy to shear. The shear deformation mechanism was analyzed based on the meso‐structure. It is expected that this research will provide preliminary work for building a theoretical model of 3D woven preform. POLYM. COMPOS., 38:244–251, 2017. © 2015 Society of Plastics Engineers

Response of Slub Characteristics on Tensile Properties of Injected Slub Yarn

Injected slub yarn is one of the most promising among different types of slub yarns. Present study embodies the effect of some important parameters like base yarn twist level, number of base yarn, twist direction and injected fibre components on injected slub yarn performance in terms of tensile strength and breaking elongation. In case of single base slub yarn, final yarn tenacity and elongation increases with the reduction of base yarn twist level keeping final yarn twist multiplier constant. However, the effect of base yarn twist level is marginal in case of injected slub yarn made with double base yarn. Yarn tenacity and elongation significantly higher in case of double base injected yarns as compared to single base injected yarn. The aforementioned tensile parameters of single base injected slub yarns reduce with the reduction of yarn linear density. However, in case of double base injected slub yarns, highest tenacity and elongation value are achieved for 2/80s yarn having finest yarn liner density among 2/40s, 2/60s and 2/80s yarns. In case of single base injected slub yarn, tensile strength is slightly higher and elongation values are significantly higher when injection component fibres changed from 100 % cotton to 50/50 polyester/cotton blended fibres which is just opposite to that of double base injected slub yarn. Results also showed that the twist direction in the base and final yarn influence the strength and elongation of injected slub yarns.

A numerical investigation into the influence of fabric construction on ballistic performance

The use of high-performance fibres has made it possible to produce lightweight and strong personal body armour. Parallel to the creation and use of new fibres, fabric construction also plays an essential role for performance improvement. In this research, finite element (FE) models were built up and used to predict the response of woven fabrics with different structural parameters, including fabric structure, thread density of the fabric and yarn linear density. The research confirmed that the plain woven fabric exhibits superior energy absorption over other structures in a ballistic event by absorbing 34% more impact energy than the fabric made from 7-end satin weave. This could be explained that the maximum interlacing points in this fabric which help transmit stress to a larger fabric area, enabling more secondary yarns to be involved for energy dissipation. It was found that fabric energy absorption decreases as fabric is made denser, and this phenomenon becomes more pronounced in a multi-ply ballistic system than in a single-ply system. The research results also indicated that the level of yarn crimp in a woven fabric is an effective parameter in influencing the ballistic performance of the fabrics. A low level of yarn crimp would lead to the increase of the fabric tensile modulus and consequently influencing the propagation of the transverse wave. In addition, it was found that for fabrics with the same level of yarn crimp, low yarn linear density and high fabric tightness were desirable for ballistic performance improvement.

An Investigations of Sound Absorbance Properties for Weft Knitted Spacer Fabrics

Nonwoven fabrics have been used for many years in different technical applications; they have particularly been used as isolation materials in vehicles in order to reduce the noise heard within them, and they. They have achieved great popularity due to low production cost and good absorbance. However, the fabrics produced by making use of the nonwoven technique have some disadvantages including low resistance, low abrasion strength, poor aesthetic appearance and thickness. In order to eliminate these disadvantages, recent studies have reported that knitted fabrics could be an alternative to nonwoven fabrics. Various studies have focused on the impact on sound absorbance that the thickness and surface structure of knitted fabrics have. In this study, a number of knitted spacer fabrics, which had five different connection angles, were manufactured by using a plain knitting machine. The sound transmission loss levels of the developed fabrics were tested and analysed by Bruel and Kjaer tube instruments. At the end of the examinations, the sound absorbance behaviors at different frequencies were demonstrated in graphics based on the type of knitting. It was determined in the study that three factors have a major impact on the sound absorbance behaviour; thickness of fabric, micro porosity between fabric surfaces and yarn linear density in the interconnection of the fabrics.

Influence of Knits Structure on Flammability and Comfortability

Abstract Investigations of the influence of the knit structure, i.e. the loop length and the number of yarns in a loop, on flammability and comfortability are presented in this paper. The investigations were carried out using single jersey knits from Delta TA 18 tex × 2 yarns with five variants of a loop length. Single yarn as well as folded yarn from two single yarns was used in the investigations. Comparison of the results of single-layer knits flammability and air permeability with those of multilayer packet was made. The results obtained show that an increase in the loop length of the knit increases their permeability to air and decreases the burning time as well as increase in the number of layers decreases the air permeability and increases the burning time. Moreover, the similar burning time with significantly different permeability to air can be achieved changing the basic knitting parameters, i.e. the loop length and/or the yarn linear density.

The influence of fiber diameter, fabric attributes and environmental conditions on wetness sensations of next-to-skin knitwear

This study investigated the relationships between the sensations of sweaty, damp, muggy and clingy, as assessed by human response from wearer trial garment assessment, and fiber type, fiber, yarn and fabric properties and instrumental fabric measurements of next-to-skin knitwear. Wearer trial assessment of 48 fabrics followed a strict 60 minute protocol including a range of environmental conditions and levels of exercise. Adjusted mean weighted scores were determined using linked garments. Instrumental fabric handle measurements were determined with the Wool HandleMeter (WHM) and Wool ComfortMeter. Data were analyzed using forward stepwise general linear modeling. Mean fiber diameter (MFD) affected the sweaty, damp, muggy and clingy sensation responses accounting for between 23.5% and 56.2% of the variance of these sensations. In all cases, finer fibers were associated with lower sensation scores (preferred). There were also effects of fiber type upon sweaty, muggy and clingy scores, with polyester fiber fabrics having higher scores (less preferred) compared with fabrics composed of wool, particularly for peak sweaty scores in hot and active environments. Attributes such as fabric density, yarn linear density, knitting structure and finishing treatments, but not fabric thickness, accounted for some further variance in these attributes once MFD had been taken into account. This is explained as finer fibers have a greater surface area for any given mass of fiber and so finer fibers can act as a more effective sink for moisture compared with coarser fibers. No fabric handle parameter or other attribute of fiber diameter distribution was significant in affecting these sensation scores.

Prediction of warp and weft yarn crimp in cotton woven fabrics

The aim of this study was to develop statistical models for the prediction of warp and weft crimp percentage of cotton woven fabrics. The developed models are based on the empirical data obtained from carefully developed 60 fabric samples with different yarn linear densities, fabric densities, and weave designs. The predictability and accuracy of the developed models was assessed by correlation analysis of the predicted and actual crimp values of another set of eight fabric samples which was not used for the development of models. The results show fairly good capability and accuracy of the prediction models.