Computer simulation of plain woven fabric appearance from yarn photographs

This article proposes a method for simulating plain woven fabric appearance based on photographs taken by still camera of actual yarns along their lengths. The survey mathematically models the transformation of yarns from a straight circular cylinder to a flattened and crimped form in the fabric structure. The simulation is performed by yarn images that are obtained by image processing techniques and resized according to mathematical models developed by means of the software prepared. Transforming circular yarn cross-section to elliptical one for simulating yarn flattening and modelling the crimped shape of yarn by an elastica curve are both convenient and realistic. The simulation of plain woven fabric can be performed by a method based on raster graphics. This article provides a model for yarn shape in fabric structure as well as a method for simulating plain woven fabric appearance. This method may be used in textile industry for design and quality control.     

Theoretical and experimental analysis of bending rigidity of plain and twill woven fabrics

The study of bending behavior of woven fabrics is an important issue in textile scientific researches and its industrial applications. Different behavior of fabrics such as drape, comfort, and handling can be understood by this study. Bending rigidity of fabric depends on several factors such as weave geometry, bending rigidity of yarn, and yarn density. In this study, estimation of bending rigidity of woven fabric with different twill and plain structures, have been carried out using energy method. Generally, the woven fabric structure is divided into three different section lengths i.e. rigid, semi-rigid, and flexible sections. Thereafter, bi-component and tri-component models for predicting bending behavior of plain and twill woven fabric have been presented. Then, bending properties of fabric based on Shirley apparatus as well as weight per area as a physical property were measured. Good agreement between measured and predicted values, validated our theoretical models for obtaining bending rigidity, except considerable differences observed between experimental and predicted values using bi-component model of plain fabric. Therefore, using assumptions in calculation of the ratio of rigid section length to flexible section length (R₁), the modified model of plain fabric has been proposed.     

玻璃纤维织物结构参数对隔声性能的影响

为研究玻璃纤维织物的隔声性能,选择EW100、EW200和EW300 3种不同经纬密度、线密度和层数的玻璃纤维平纹织物,采用混响室一消声室法对织物的隔声性能进行测试,比较分析织物面密度、厚度、透气性、纱线单丝根数等参数对隔声性能的影响.结果表明:随织物面密度、厚度、纱线单丝根数的增加和透气性的减少,其隔声效果增强;玻纤织物对声波高频段的隔声好于中低频段的隔声;玻纤织物的隔声性能不但与织物的面密度有关,还与织物的透气性有关;在透气性较好时,其隔声量对织物的面密度具有一定的加和性,而在透气性较差时,其材料内部对声波的吸收所产生的隔声量贡献远大于面密度的贡献.     

棉/不锈钢长丝机织物的电磁屏蔽及折皱回复性能

为研究组织结构与磨损对织物屏蔽性能的影响,以及不锈钢长丝对织物折皱回复性的影响,使用自制的棉/不锈钢长丝包芯纱织制了3种不同组织的机织物,测试了织物在0.3~1 500 MHz频段上的电磁屏蔽性能,并使用平磨仪对各织物分别摩擦60、120、180、240 及300次后,测试了织物磨损后的电磁屏蔽性能;同时,采用视频序列法测试了织物的动态折皱回复角。结果表明：织物组织结构对电磁屏蔽性能有一定影响,平纹组织结构紧密,屏蔽效果好;经过若干次磨损后,织物的电磁屏蔽性能先小幅升高后逐渐降低;相同磨损条件下,试样耐磨性越好,屏蔽效能的降低幅度越小;由于不锈钢长丝的加入使织物的折皱回复性降低,可以采用浮长更长的组织改善织物起皱现象。     

PTT/PET双组分长丝织物拉伸性能测试与分析

为了解PTT/PET三维卷曲复合丝及其不同织物参数对织物拉伸性能的影响,通过改变PTT/PET复合丝比例、捻度、织物组织和纬密4个参数织造了33种织物,测试并分析了这些织物的拉伸性能指标。研究发现：PTT/PET双组分长丝织物拉伸断裂强力较低,而断裂伸长较高,低负荷条件下织物具有高伸长特性;在相同的条件下,随着纬纱PTT/PET含量提高,断裂强力呈下降趋势而断裂伸长相应提高,纬密主要影响织物拉伸断裂强力,对断裂伸长的影响不大,PTT/PET复合丝的捻度对低负荷条件下织物拉伸性能影响明显,因织物组织不同其拉伸性能也存在一定差异。     

Determinants of electrical resistance change of in situ PPy-polymerized stretch plain woven fabric under uniaxial tensile strain

Although the conductive stretchable woven fabric has been widely used as the sensitive material of strain sensors monitoring human motion, it is lack of a deep understanding of the determinants of its electrical resistance change under uniaxial tensile strain. This study chose two kinds of typical stretchable plain woven fabric, i.e. cotton/spandex core-spun yarn fabric and polyester/spandex filament yarn fabric, and they were coated by in situ polymerization of polypyrrole. Their electromechanical responses under certain uniaxial tensile loadings were measured and compared. Meanwhile, by a multi-architecture analysis, i.e. the intrinsic resistance of yarns, the contact resistance of interlacing yarns and the contact resistance of adjacent yarns in parallel, several hypotheses were proposed and tested to determine the determinants of electrical resistance change under tensile strains. The results showed that the resistance change in woven fabric with in situ polymerization of polypyrrole mainly depends on the contact resistance of the adjacent conductive yarns in tensile direction, and the electromechanical responses of the cotton/spandex core spun yarn are significantly different from those of the polyester/spandex filament yarn. It was concluded that the conductive yarn density and fabric structure are critical parameters of woven fabric as resistive strain sensor.     

机织物密度对字典学习纹理表征的影响

为探讨纺织品表观质量的客观、智能评定方法,使用不同密度的机织物图像,采用子窗口样本获取方式作为学习样本,以离散余弦字典作为初始学习字典,选择基于最小二乘的字典学习算法求解用于表征织物纹理图像的字典,再通过字典元素的线性组合对织物图像进行重构。以均方误差为指标,首先讨论织物图像灰度值分布对字典学习算法重构误差的影响,然后对图像灰度值进行标准化处理,在此基础上探讨织物经纬密度对重构图像误差的影响。实验结果发现,当字典个数等于9时,织物密度在150 ~ 360根/10 cm之间,随着织物密度的增加,平纹重构图像的均方误差先变大,以后不再增加,而斜纹重构图像的均方误差增大。     

New computer geometric modeling approach with filament assembly model for woven fabric structures

This paper presents a new computer geometric modeling approach for three-dimensional woven fabric structures. Pierce’s geometry of the weave fabric of yarn from an arc abscissa (Peirce’s) model is presented. Then, new algorithms with a filament assembly model for a single yarn composed of many filaments by twisting along the crimp shape in the warp/weft is developed. The concept of a virtual location is used to simulate the fiber distributions in the yarn cross-section. Each cross-section is rotated along the yarn length by a pre-determined amount to allow for the yarn twist. The curve of each filament in each two successive cross-sections is approximated by NURBS and then each curve is created by sweeping a closed curve along the centerline of the yarn path. The method described is demonstrated by the CAD model of woven fabrics with plain and twill weaves. The simulated woven fabrics using this approach can demonstrate a wider variety and improved visual simulations of real woven fabric and can then be further generalized for different and more complicated fabrics. The method is necessary as an input to many computational models, such as modeling the mechanical properties or the heat transfer of fabrics or composite parts.     

An investigation into the effect of fabric structure on the compressional properties of woven fabrics

Lateral compression is one of the most important mechanical aspects of fabrics, which reflects their handle. Fabric compressional features depend on the compressional characteristics of constituent yarns and the fabric structure. In order to consider the effect of fabric structural parameters on its compressional properties, woven fabrics with five different weave patterns (plain, hopsack 2/2, twill 2/2, twill 3/1, warp rib 2/2) were produced with three different nominal weft densities (12, 15, 18 cm^?1). The compressional properties of produced fabrics were evaluated at different pressure values using a conventional fabric thickness tester. It was observed that increasing the weft density leads to decrease in the dissipated compression energy as well as the compressibility of the fabric, while the thickness recovery of the fabric increases. Moreover, the plain woven fabric exhibited the lowest dissipated compression energy and compressibility, while the highest thickness recovery. Besides, at the low pressure level, the fabrics with the lower weft densities demonstrate the higher thickness. By increase in the pressure level, the fabric thickness decreases by decreasing the weft density.     

面料抗皱性能规律研究

为获得面料抗皱性能规律,用织布机自制45块面料,采用压皱实验测试面料抗皱性能,得到结论如下:面料密度显著影响面料抗皱性能,面料密度越大抗皱性能越差;面料组织对面料抗皱性影响略小,缎纹面料抗皱性最好,平纹面料抗皱性最差,斜纹面料居中。     

玻璃纤维织物结构参数对隔声性能的影响

 为研究玻璃纤维织物的隔声性能,选择EW100、EW200和EW300 3种不同经纬密度、线密度和层数的玻璃纤维平纹织物,采用混响室－消声室法对织物的隔声性能进行测试,比较分析织物面密度、厚度、透气性、纱线单丝根数等参数对隔声性能的影响。结果表明：随织物面密度、厚度、纱线单丝根数的增加和透气性的减少,其隔声效果增强;玻纤织物对声波高频段的隔声好于中低频段的隔声;玻纤织物的隔声性能不但与织物的面密度有关,还与织物的透气性有关;在透气性较好时,其隔声量对织物的面密度具有一定的加和性,而在透气性较差时,其材料内部对声波的吸收所产生的隔声量贡献远大于面密度的贡献。     

Modeling the effect of elastane linear density,fabric thread density,and weave float on the stretch,recovery, and compression properties of bi-stretch woven fabrics for compression garments

The aim of this study was to investigate the effect of elastane linear density, thread density, and weave float on the stretch, recovery, and compression properties of bi-stretch woven fabrics for compression garments. Fabric samples were produced using elastane core-spun cotton yarns both in the warp and weft. The elastane linear density, fabric thread density, and weave float size were used as input variables while fabric contraction, subgarment pressure, fabric stretch, and recovery were taken as response variables. Two different elastane linear densities, i.e. 44 and 78 dtex, two different thread densities, and three different weave designs, i.e. 1/1 plain, 2/2 z-twill, and 3/3 z-twill were used. The results of fabric samples were analyzed in Minitab statistical software. The coefficients of determinations (R-sq values) of the regression equations showed good prediction ability of the developed statistical models. The findings of the study may be helpful in deciding appropriate manufacturing specifications of bi-stretch fabrics to attain specific stretch, recovery, and compression properties.     

毛金属丝包缠纱针织物防屏蔽性能探析

从防辐射性能及影响针织物性能的主要参数入手,通过对毛与不同直径的金属丝包缠纺纱线、不同组织结构、不同密度针织物进行屏蔽性能测试,得出由不同工艺组合形成的针织物在不同微波环境条件下防辐射性能的效果。初步分析了影响毛金属丝包缠纱针织物屏蔽效能的因素,有利于设计与开发防电磁辐射毛针织物及产品的工艺优化,达到满足人们对毛针织品时尚、功能性的需求。     

不锈钢纤维/涤纶特种花式线及其电磁波屏蔽织物的开发

以不锈钢长丝和有色涤纶丝等为芯纱原料,纯棉纱线及彩色涤纶丝为饰纱原料,在HKV151B型花式捻线机上纺制出具有电磁波屏蔽特殊功能的23种花色的花式线;用SL7900剑杆小样织机进行小样试织,设计织制了10个规格系列的电磁波屏蔽功能织物小样。电磁屏蔽性能和常规性能测试的结果显示,花式线织物具有突出的抗电磁屏蔽性能,并可满足常规家用休闲防护服面料的基本服用性能和外观风格要求。     

Multi-response optimization of mechanical and comfort properties of bi-stretch woven fabrics using grey relational analysis in Taguchi method

The present paper envisages the multi-response optimization of certain factors like elastane linear density, fabric thread density and weave float on some mechanical, (i.e. stretch %, recovery %) and comfort (i.e. air permeability) properties of bi-stretch woven fabrics, under L₁₈ orthogonal array in Taguchi design. Fabric samples were produced using elastane core-spun cotton yarns both in the warp and weft. The elastane linear density, fabric thread density and weave float size were used as predictor variables, while fabric air permeability, stretch and recovery were taken as response variables. Two different elastane linear densities, i.e. 44 dtex and 78 dtex, 3 different thread densities and 3 different weave designs, i.e. 1/1 plain, 2/2 z-twill and 3/3 z-twill were used. The results have been analysed using grey relational analysis for the identification of an optimum level of process factors. Furthermore, using analysis of variance method, significant contributions of predictor variables were determined.     

Multi-response optimization of thermophysiological comfort properties of polyester filament woven fabrics

Microfilament woven fabrics are used in many products such as sportswear, rainclothes, windproof clothes, sleeping bags and surgical gowns and for these products, thermophysiological comfort properties are of prime importance. In this study, it is intended to investigate the effects of filament linear density and weft sett on thermophysiological comfort properties. Also, an optimization model was developed to determine the optimum filament linear density and weft sett for the best response variables of air permeability, water vapour permeability and thermal resistance. Four different weft sett and five different filament linear densities were applied in weft direction with three different weave types. In doing so, 60 woven fabric samples were produced. According to ANOVA results and experimental observations, it is observed that, the effect of filament linear density on air and water vapour permeability was minor on microfilament range, whereas the differences between conventional filament and microfilament sample groups are considerable. Also, higher weft sett causes decreasing of air and water vapour permeability. On the other hand, there is no obvious consistent trend for thermal resistance of samples with different filament linear density and weft sett.     

Prediction of fabric drape using the FAST system

In this study, we investigated the relationship between the fabric drape coefficient from the drape meter and mechanical properties tested on the fabric assurance by simple testing system (FAST). Different kinds of woven fabrics with two kinds of weave (plain and twill) were tested. Three regression models are proposed for each type of weave and for all fabrics using the multiple linear regressions. The regression results were analyzed in terms of correlation coefficients, T and p-values. A neural model is proposed using the neural networks and it is compared to the regression one.     

Total porosity,theoretical analysis,and prediction of the air permeability of woven fabrics

Air permeability is one of the most important properties of textile materials that ensure their comfort. For many materials for technical applications (filters, sails, vacuum cleaners, parachutes, etc.), this is one of the main properties that determine their quality. The air permeability of woven textile fabrics depends on many parameters of fabric. Thus, the determination of air permeability of woven fabric is highly complex and difficult. In this study, we attempted to establish a theoretical model for the porosity and predicted the air permeability of woven fabrics. A theoretical model was created to predict the total porosity and the air permeability of a fabric structure depending on the geometrical parameters such as pore size, warp density, weft density, fabric thickness, number of yarn, diameter of yarn, and fiber density. For the purpose, a theoretical model of porous systems on D’Arcy’s law was used, and the validity of the model was confirmed by experimental results using 100% cotton and 97/3 cotton/lycra woven fabrics. Since the amount of air passing through both the pores between yarns and the interstices in the fibers constituting the yarn structure was calculated, theoretical values of air permeability were obtained very close to the experimental values.     

氨纶丝预牵伸倍数对弹力织物性能的影响

为了解氨纶丝预牵伸倍数对弹力织物性能的影响,在一定的工艺设备与条件下,纺制了不同牵伸倍数的环锭弹力纱及转杯弹力纱,利用这些弹力纱作为纬纱,分别织制了环锭弹力纱织物和转杯弹力纱织物.为了进行对比,还织造了相同规格的纯棉织物.经织物性能测试表明:弹力织物除断裂强度比纯棉织物低外,断裂伸长率、弹性回复率、折皱回复率、透气性能均优于纯棉织物;环锭弹力纱织物除折皱回复性比转杯弹力纱织物低之外,断裂强力、断裂伸长率、弹性回复性、透气性能指标均优于后者;弹力织物除透气性外,断裂强度、断裂伸长率、弹性回复、折皱回复都随弹力丝预牵伸倍数的增大先增大后减小.