Utilization of the yarn pullout test in estimation of the reserved energy of rib knitted fabrics

The yarn pullout test is a prevailing and particular method to evaluate the effects of yarn properties and the structural characteristics of the fabric on the fabric mechanical performance. In this research, a theoretical model of yarn pull out is presented to determine the reserved energy of weft-knitted fabrics with rib 1 × 1 structure. This model is based on the fabric dimensional properties, i.e. stitch length, wale density, yarn diameter and contact angle of yarns. In order to appraise the proposed model, five different double jersey weft-knitted fabrics with rib 1 × 1 structure were produced and exposed to pullout test. Comparison between deviations of theoretical results from experimental results demonstrates that the presented theoretical model exhibits a rational estimation of the reserved energy in these fabrics.     

组织结构对涤纶经编织物卷边性的影响

为减少织物卷边对后道工序带来的影响,对各把梳栉的组织结构配置以及牵拉密度的选择进行了探讨。以55.5 dtex 24 f涤纶全牵伸丝(FDY)为原料,生产出7种不同组织和4种不同牵拉密度的两梳经编织物,对其卷边量进行测试,并结合显微镜下的线圈图进行分析。结果表明：随着牵拉密度的增大,经编织物横、纵向卷边量均不断减小,其中牵拉密度对横向卷边的影响要明显大于纵向卷边;两梳同向编织的织物横向卷边性要明显好于反向编织;当前梳组织不变,增加后梳延展线长度时,织物的横、纵向卷边量均不断减少,尤其是横向卷边量下降明显;而当后梳组织不变,增加前梳延展线长度时,织物的横、纵向卷边量均不断增加。     

影响竹浆纤维针织物起毛起球性的因素

为深入分析竹浆纤维针织物起毛起球性的影响因素,根据7种竹浆纤维纬平针针织物的基本结构参数和起毛起球性的测试结果,应用灰色关联分析法对织物基本参数与起毛起球性之间的关系进行了定性和定量分析.结果显示:对起毛起球性的影响程度依次为织物的面密度、纵密、厚度、纱线线密度、氨纶含量、织物横密和竹浆纤维含量;含氨纶纯竹浆纤维针织物...     

A relationship between dry-relaxed warp-knitted fabric structure and curling distance

This study provides us information about relationship between curling and knitted structure and density of two-guide bar warp-knitted fabrics. Five standard warp-knitted fabrics are produced with three densities (Tricot, Locknit, three-needle Satin, Reveres Locknit and three-needle Sharkskin). Certain cut lengths of sample fabrics in both wale and course direction are analyzed through image processing to define curling value. A mechanical model, a function of fabric structure and yarn parameters, is also suggested to predict the curling force. The results of experimental and theoretical results show a greater curling value for course-wise cut in comparison to that of wale-wise in all warp-knitted structures and densities. The lowest curling value is found for three-needle Sharkskin structure in both directions and all densities.     

Air permeability and bursting strength of weft-knitted fabrics from glass yarn. Part I: cam setting and number of yarn ply effect

This study revealed the effect of cam setting and number of yarn ply on air permeability and bursting strength of weft-knitted fabrics from glass yarn. Change in cam setting from loose to tight level increased fiber content, and stitch-density; while it decreased loop length. Fabrics with 3-ply yarn exhibited higher fiber content; lower stitch-density; and longer loop length than fabrics with 2-ply yarn. Cam setting showed more pronounced effect on physical properties of fabric than number of yarn ply. Fabrics knitted via tight cam setting level exhibited less air permeability, and higher bursting strength than fabrics knitted via loose cam setting. Fabrics from 3-ply yarn showed less air permeability and higher bursting strength than fabrics from 2-ply yarn. Loop length, wale density, and fiber content were determined as the most effective physical properties on permeability and bursting strength. A negative correlation was detected between air permeability and bursting strength.     

A novel approach for simulation of curling behavior of knitted fabric based on mass spring model

Edge curling is a unique property of knitted fabrics which affects on fashion such as using upper and side curling in cloth design. The purpose of this research is to present a new method to simulate drape behavior of knitted fabric considering difference between single and double jersey knitted fabrics. To this point, at first the bending and torsion moments that applied on the fabric edges and caused curling in single knitted fabric are determined. Also it demonstrated that these moments will be neutralized in double knitted and as the results, leads to a non-curling structure. Then, using the mass spring model, curling shape in fabric wale and course directions are simulated. To show efficiency of the proposed model, real 3D shape of single knitted fabric is compared with experimental results. Also, using the proposed model, the drape behaviors of single and double jersey knitted fabrics hanging from two fixed corners with different properties are simulated and then extend to simulation of skirt. Results of simulation are compared with 3D shapes of actual drape behavior in fabric samples which are achieved by depth camera. The simulated results show good agreement with 3D shapes of actual fabrics.     

基于形状记忆合金丝包覆纱的针织物致动器研究

为构建面向软体机器人应用的织物基人工肌肉,设计并制备了1种以镍钛形状记忆合金丝为芯丝、芳纶复丝为外包纤维的包覆纱,利用该包覆纱制备了1种可通过电阻热驱动的纬平针织物致动器,研究了此致动器循环致动特性及其结构参数与致动条件对其致动特性的影响。研究结果表明:针织物致动器受驱动后将沿线圈纵行方向产生弯曲变形;当致动器线圈横列数增加时,其沿织物平面线圈纵行方向输出的致动力值将呈近似线性关系显著增加,而在垂直于织物平面方向输出的致动力略有减小;针织物致动器线圈尺寸的增加将使其沿织物平面内线圈纵行方向输出的致动力增加;致动电流值的增加将使致动器输出的致动力增大;针织物致动器具有稳定、快速的循环致动能力。     

The effect of knit structures with tuck stitches on fabric properties and pilling resistance

The patterns of knit fabrics are designed by loops, tuck stitches, and float stitches and their combinations. The tuck stitch has important influences on fabric properties. It increases the fabric’s weight, thickness, and width and makes the fabric more porous than other fabrics. In this study, to determine the effects of knit structures which are made from the same cotton yarn with tuck stitches on fabric properties and pilling resistance, circular knit fabrics with different locations and number of tuck stitches were produced and dyed under the same conditions. In the evaluation process of the results, graphs were drawn and variance analyses were performed. At the end of the study, important findings were determined. The number and location of the tuck stitches and stitch length are effective factors on the structural, physical properties and the pilling resistance of knit fabrics. The fabrics with tuck stitches have much higher porosity, weight, and thickness compared to single jersey fabric. The dyeing process increases fabric weight. Single jersey has the lowest pilling resistance in comparison to fabrics having tuck stitches. The fabrics having more pores and larger pores show higher resistance to pilling. Dyeing and finishing processes decreased the pilling resistance of fabrics.     

Relations between Fabric Structure and Friction: Part II: Weft Knitted Fabrics

Abstract

In the earlier part of the series (Jeddi et al., 2003) the authors defined a new index for the structural asperity of woven fabrics and found the relationship between this index and fabric frictional parameters. In this part, the authors develop this definition for weft knitted fabrics and introduce a ‘Fabric Structural Asperity Index’ (FSAI) for interlock gating of knitted structures. This index, which can be explained as the ratio of miss stitches to the total number of needles in a structural knit cell, shows a good relation with frictional resistance parameters of the course over course direction of motion.

The experimental results show that the static and dynamic frictional resistances of the course over course motion are higher than the wale over wale motion. The values of frictional forces for different structures have no statistical difference in the wale over wale direction of motion. This paper also studies the effectiveness of the structural cell stitch length and fiber content on the frictional behavior of the fabrics.     

纤维组分与针织组织对针织物悬垂性的影响

悬垂性对针织物的外观及内在性能都有重要影响,而不同纤维组分纱线和不同组织的针织物悬垂性能也有很大区别。选用相同支数的纯羊毛纱、纯腈纶纱、羊毛/腈纶70/30纱3种典型的针织纱和纬平针组织、1+1罗纹组织、2+2罗纹组织3种常规的针织组织,利用正交试验法分析纤维组分与针织组织对针织物悬垂性能的影响。研究结果表明:混纺比例不同的纱线品种对针织物的悬垂性有一定影响,针织组织对针织物悬垂性的影响特别显著,因此在设计针织服装时应该有针对性地选用不同组分的针织纱和针织组织,以实现理想效果。     

Wickability behaviour of single-knit structures

Wicking is the spontaneous flow of a liquid in a porous substrate, driven by capillary force. This flow in aporous medium, caused by capillary action, is governed by the properties of the liquid such as surface tension, viscosity and density as well as the surface-wetting forces and geometric configuration of the pore structure such as yarn construction, number of fibres in the cross section, the randomness of the internal structure, twist and the fabric structure. In this study of wickability, the most widely used structures such as single jersey, single pique, double pique and honeycomb with two structural-cell stitch lengths have been considered. Wickability increases with structural-cell stitch length. Among the different structures of fabrics, single jersey with higher structural-cell stitch length shows better performance of wickability and absorption of water when drop is placed on the fabric. The wickability of knitted fabrics was also evaluated in different directions such as wale, course, and bias direction. Among these, wale-wise specimen shows better wicking behaviour. The effect of different liquids like distilled water, artificial sweat solution, tap water, hot water and so on was also tested. The distilled water shows good wicking behaviour as compared with other liquids.     

An analysis of the bending rigidity of warp-knitted fabrics: a comparison of experimental results to a mechanical model

This study focuses on the bending rigidity of warp-knitted fabrics as a function of knit structure (underlaps length), density (wale and course spacing) and yarn bending properties. Seven standard warp-knitted fabrics are produced with three different densities (Tricot, Locknit, three and four needles Satin, Reveres Locknit, three and four needles Sharkskin). The bending rigidity of the fabrics is measured using a Kawabata evaluation system and an automatic cyclic bending tester. Results show that the bending rigidity increases for the fabrics with a higher density and underlaps length of the front and back guide bars. In addition, a new mechanical model for the bending behaviour of warp-knitted fabrics using an energy method is presented. In this model, the knitted loop structure is assumed to consist of a series of straight and skew yarns simulating legs and underlaps while considering a rigid region lying in the direction of bending. Experimental results show that there is a reasonable agreement between the calculated and measured values for both wale and course directions.     

交织对无缝内衣面料结构与伸缩性的影响

本文选择了cooldry吸湿速干涤纶、Thermolite保暖涤纶和Tencel再生纤维及氨纶/锦纶弹力包芯纱分别为面纱和地纱,采用平纹添纱组织和N6上机密度设计与织造了4组16种交织物。对织物的纵横向密度、平方米重及厚度,拉伸伸长率及弹性回复率进行了测试与分析,并采用一元方差分析了交织对无缝内衣面料结构规格与伸缩性影响的显著性。结果表明,交织对织物纵横向密度、平方米重及厚度,拉伸伸长率影响均十分显著,对织物弹性回复率影响不显著;织物密度、单米重、厚度及拉伸率较大的交织方式为：面纱、地纱均为弹力包芯纱与非弹力纱间隔1根排列,或织物面纱为非弹力纱,地纱为弹力包芯纱。其研究结果对无缝内衣的设计与开发具有一定的参考价值。     

The use of micro-computed tomography to determine the fabric cross-sectional area and stress

Accurate measurement of the cross-sectional area of porous fabric is quite important to determine fabric strength. Many models using yarns cross-section were built to calculate the strength of woven and knitted fabrics, and the spaces between fibres in the yarns were always considered to be part of the cross-sectional area. In our previous study, using micro-computed tomography (CT) and reconstructed three-dimensional (3D) images and based on the evaluation of the pore diameter distribution across the thickness direction, a new method was established to accurately determine the fabric ‘surface’ and fabric thickness. In this study, we used this method to calculate the cross-sectional area of fabrics and the resulting fabric stress. Using a plain weave and a flat knit fabrics showed that the cross-sectional areas in warp (or wale) and weft (or course) directions of the fabrics change regularly based on fabric structures and yarns. The fabric stress, when calculations were based on the least cross-sectional area, were greater than that calculated based on the other methods, such as the stress calculated based on the Peirce yarn model, where yarns are regarded as solid cylinders. Other research and properties related to the fabric thickness and cross-sectional areas will benefit from this accurate determination.     

线圈转移对导电弹性针织柔性传感器的电-力学性能影响

为了理论指导弹性纬平针织物柔性传感器的设计,本文基于针织物的线圈结构对导电镀银纱弹性针织物的电-机械性能建立了电阻六角模型,并研究了电阻和导电针织物张力的关系,通过求解导电针织物电路方程组得到其等效电阻。研究结果表明：导电针织物电路是综合串联和并联的复杂电路网;沿纵行方向,它是一个并联电路;沿横列方向,它是一个串联电路。为了简化计算过程,只需要计算m横列╳1纵列线圈的等效电阻。从理论分析和实验研究可得,线圈纱段转移引起了导电弹性针织柔性传感器的电阻变化,并且是引起传感器灵敏度的关键因素;针织物的电阻随应变的增加而线性增加。此外,接触电阻、织物结构和纱线伸长也影响针织物传感器的性能。     

针织西服面料的挺括风格研究

为探讨针织面料在西服开发应用的要求与标准,寻找能够用于西服开发的针织面料,分别从弯曲长度、折皱回复性、悬垂性3个方面对针织面料的挺括风格进行量化分析。借助实验仪器以及数据处理得到弯曲刚度、折皱回复角、静态悬垂系数3项性能指标,以机织西服面料为参考标准,对针织面料的挺括风格进行研究分析。结果表明:6路变化罗马组织是较为适合针织面料开发西服的组织结构,其结构稳定性优于12路小提花组织以及变化间隔组织,降低纵向弯曲刚度与横向弯曲刚度的差异;织物厚度增加0.1 mm,折皱回复程度提高10%;织物密度控制在110~130线圈/(5 cm)时,悬垂程度达到机织西服面料的60%以上;6路变化罗马组织配合高织物密度能够使针织面料的挺括风格达到机织西服面料的80%。     

Modeling the mechanical and compression properties of polyamide/elastane knitted fabrics used in compression sportswear

A compression sportswear fabric should have excellent stretch and recovery properties in order to improve the performance of the sportsman. The objective of this study was to investigate the effect of elastane linear density and loop length on the stretch, recovery, and compression properties of the weft-knitted polyamide/elastane (PA/EL) stretchable fabrics used in sportswear. Two different tests were performed to study the stretch and recovery properties of the fabric 1st: under low power force and 2nd: cyclic loading under high tension force. Kikuhime pressure sensor was used to measure the pressure generated by different PA/EL knitted sample garment sleeves. It was found that with the increase in elastane linear density there is an increase in fabric course density, areal density, recovery percentage, and compression, and fabric stretch percentage and elongation percentage decreased in both course and wale direction. The results of fabric samples were analyzed in Minitab statistical software. The coefficients of determinations (R² values) of the regression equations showed good prediction ability of the developed statistical models.     

Modelling of thermal conductivity of knitted fabrics made of cotton–bamboo yarns using artificial neural network

Regenerated cellulosic fibre made from bamboo is gaining popularity for apparel use due to its improved functional properties. This paper presents the modelling of thermal conductivity of knitted fabrics made from blended yarns of cotton and bamboo fibres using an artificial neural network (ANN). Five parameters, namely knitted fabric structure type, yarn linear density, bamboo fibre proportion (%), fabric thickness and fabric areal density, were used as inputs to the ANN model. The developed model was able to predict the thermal conductivity of fabrics with very good accuracy. The trend analysis of the developed model revealed the influence of various input parameters on the thermal conductivity of knitted fabrics. These findings can be judiciously used for the selection of optimum material and structural parameters of knitted cellulosic fabrics for a particular end‐use.     

纬编粗细纱结构织疵分析与线圈力平衡研究

阐述粗细纱结构在成圈过程中线圈张力与织疵的关系。通过对粗斜纹、双面粗细针、起线大线圈等结构的剖析,研究分析了粗细纱结构的线圈受力情况及力平衡的控制方法,给出详细的编织工艺要点,列举了几种利用粗细纱结构来开发新型面料的思路和实施方法,如粗犷凹凸面料、凸纹提花保暖面料。针对粗细纱结构的原料粗细差异造成的力平衡失控等问题,指出可以通过合理选择原料、改变线圈长度及调整面料结构等方法来加以控制。     

羊毛畦编针织物尺寸特性分析

通过实验的方法,研究了横机编织的罗纹、半畦编和畦编羊毛针织物的尺寸特性,对3种织物的线圈长度、纵横向水洗收缩率、纵密及横密等各尺寸特性进行了分析与比较,实验得出,由于集圈线圈的存在,半畦编和畦编针织物的尺寸特性显著不同于罗纹针织物.通过建立尺寸变化率公式,计算出畦编织物与罗纹织物尺寸参数间的关系,可用于工厂实际生产设计时参考.