Ballistic performance of angle-interlock woven fabrics

The purpose of this paper is to investigate the ballistic performance of angle-interlock woven fabrics. Different fabric structures firstly have been compared to benchmark the ballistic performance of angle-interlock woven fabrics using the energy loss test. It has been shown that compared with other woven structures, angle-interlock woven fabric demonstrates low ballistic resistance as absorbing less impact energy. This is because angle-interlock woven fabric owns less interlacements than its counterparts. The interlacement plays an important role to help to transfer energy to the adjacent yarns: the more interlacements, the larger area the stress wave could propagate, and more projectile impact energy could be absorbed. After this systemic analysis of overall ballistic performance, more detailed parametric study of angle-interlock woven fabric is carried out. A group of 16 different structures have been tested and compared using the in-house firing range. The studies have revealed that the 3D angle-interlock woven fabric not only displays normal features of energy absorption mechanism, like yarn slippage, fibre fracture and cone formation, which 2D fabric usually demonstrates, but also shows the new property: the weaker gripping power on the constituent yarns. Besides, it also shows that the structural parameters of angle-interlock fabrics do not have a clear influence on the ballistic performance, due to the complicated factors which also have been theoretically explained from the four aspects: (a) the clamping state; (b) yarns hit by the projectile; (c) the impact angle of the projectile; (d) the impact velocity.     

Energy absorption of 3D orthogonal woven fabric under ballistic penetration of hemispherical‐cylindrical projectile

The non‐crimp features of warp and weft yarns impart the highest energy absorptions to 3D orthogonal woven fabric (3DOWF) than other kinds of 3D woven fabrics under ballistic impact. There are greater potential applications of the 3DOWF in ballistic protection. In this paper, an analytical model was proposed to calculate the energy absorption of the 3DOWF under ballistic penetration of a hemispherical‐cylindrical rigid projectile. The analytical model covers the calculations of the energies absorbed by the warp, weft, and Z‐yarns and the determinations of penetration time from the impact loading strain rate. The stress wave propagations in the warp, weft, and Z‐yarns were analyzed to formulate the fabric deformation and strain energy. The influence of strain rate on the residual velocities of the projectile was investigated. From the absorbed energy distribution calculated by the analytical model, the factors for improving ballistic performance of the 3DOWF are discussed.     

层-层正交角联锁机织物及其复合材料的结构及其层切破坏机制研究

采用无损高分辨率X射线成像(显微X-CT)技术对层-层正交角联锁机织物以及复合材料内部结构进行分析,并研究了层间剪切强度与结构之间的关系;通过三维重构展现了机织物的层-层正交角联锁的微观结构,观察到机织物内部的单丝扭转、挤压现象;依据机织复合材料中孔隙和高密度杂质在三维空间的分布,计算了其相应的占比。结果表明：层间剪切实验后的机织复合材料虽然宏观形貌保持了良好的完整性,但内部存在孔隙变形、分层、纤维弯曲、片层断裂等现象;层-层正交角联锁机织结构有效提高了复合材料的层间力学性能,内部的缺陷对复合材料的力学性能有较大的影响;无损高分辨X射线成像技术是研究纤维增强复合材料内部复杂结构特性的有利手段。     

Permeability and impact properties of warp-knitted spacer fabrics for protective application

An experimental investigation was carried out to study the effect of interlining material on the comfort and dynamic deformation characteristics of body armour. Suitable plies of interlining materials were selected based on the fabric comfort properties and the impact resistance specified for ballistic application. Kevlar woven fabric was used to block the projectile, and the spacer fabric was used as an interlining material to ensure wearing comfort and for imparting impact resistance. The yarn denier of the middle and bottom layers of the spacer fabrics was maintained constant, and three different deniers were used for the face layer. Three different plies of spacer fabrics were analysed by means of thermophysiological comfort properties to select the suitable interlining material for body armour. The experimental results confirm that the number of plies of spacer fabrics has significant influence on the ballistic armour characteristics than the face layer denier as proved by two-way ANOVA. The substantiated spacer fabric was used as an interlining material, and the depth and area of deformation were analysed. The research findings demonstrated that the three-plied warp-knitted polyester spacer fabric produced better results than single- and five-plied spacer fabrics. One-way ANOVA and Turkey’s HSD also confirmed the influence and interaction of different plies of spacer fabrics.     

Modeling and optimizing the frictional behavior of woven fabrics in climatic conditions using response surface methodology

Frictional characteristics of woven fabrics can determine smoothness and softness values of textiles. In this paper, we have studied the influence of factors such as temperature, relative humidity, fabric structure, type of fiber material, and direction of motion on roughness properties of fabric surface using response surface method (RSM). For this purpose, woven fabrics with plain, rib2/2, twill2/2, twill1/3, twill3/1, twill1/7, and twill7/1 were produced with polyester warp yarn and two different weft yarns (cotton and polyester). Then, a statistical model (RSM) was used for the experimental plan (with these variables) to determine the runs of experiment (or selected points). Next, the frictional forces measurement was carried out on the fabrics in those directions. The experimental results showed that fabric-to-fabric friction (static frictional resistance, kinetic frictional resistance, and smoothness of woven fabrics) is highly sensitive to factors like relative humidity, fabric structure, type of fiber material, and direction of motion while temperature factor (in the range 0–50°C) has no sensitive effect on frictional parameters.     

不同组织结构织物的拉伸、撕裂和冲击强力效果

织物的组织结构通过组织因子和交织指数表达,这些因素之间的联系是r=0.98,R2=0.97。研究了这些参数对织物拉伸、撕裂和冲击强力的影响。织物的拉伸性能受其参数和结构的影响。因此,这项工作可以帮助理解织物相关强度的决定因素。试验研究织物中纱线相互交织或交错模式对拉伸、撕裂和冲击强力的影响。以12种具有代表性的不同交织方式织成的织物作为研究的对象。本试验工作表明:在这些不同的组织结构中,平纹的组织因子和交织指数是12种组织中最高的,花式组织最低,表明织造类型影响织物的强度性能。利用方差分析帮助进行结果分析。     

三维正交机织复合材料的冲后压缩性能

为揭示纱线张力对三维机织复合材料抗冲击及冲后压缩性能的影响规律,基于多剑杆织造工艺,配置不同接结纱张力(25、50、100 cN)织造三维正交机织物,通过真空辅助树脂传递模塑成型工艺制备复合材料,并在室温下进行低速冲击及冲后压缩性能测试。结果表明：当接结纱张力为100 cN时,试样在冲击载荷下发生表层树脂大面积破裂和剥离并使纬纱失去支撑,同时,试样表层纬纱发生较大卷曲,促使压缩载荷发生屈曲失效;接结纱张力为100 cN试样的压缩性能相比接结纱张力为25 cN试样下降约50%;接结纱张力较高时易导致纬纱卷曲增大和树脂富集,并由此降低试样的弯曲刚度和冲后压缩性能。     

二维织物冲击响应模拟计算与分析

为说明织物在弹体冲击过程中的抗冲击能力,运用有限元软件ABAQUS模拟分析的方法,考察一种典型二维芳纶织物的抗冲击性能。绘制并分析弹体的速度曲线、能量变化曲线、应力在织物中的传播以及弹体冲击织物的过程,揭示这种织物抵抗冲击的性能与行为。二维织物在不足以将其击穿的弹体的冲击作用下,整个冲击过程被分为2个阶段,且冲击过程中主要发生系统动能与内能的相互转化。所作研究为防冲击织物的设计提供了一种有效的预测方法,同时也可将其扩展应用于其它结构材料的防冲击分析。     

Tensile characteristics and stress relaxation analysis of woven fabrics in terms of fabric direction

Abstract

Woven fabrics in various end uses are subjected to tensile loads in different directions, so investigation of the effect of fabric direction on the tensile behaviour and the stress relaxation performance of fabrics is important and needs to be considered. In this study, the tensile and stress relaxation properties of woven fabrics with five various weave structures have been analysed, in different directions. It was concluded that the tensile properties of fabrics such as Young’s modulus, breaking load and elongation and also the work of rupture were significantly affected by the fabric direction and weave structure. Moreover, it was determined that the fabric tensile stress relaxation (%) was considerably affected by the applied strain level, fabric direction and weave structure in the confidence range of 95% and it might well be expressed as a Gaussian function of sample direction.     

三维机织预型件的织造技术

纺织复合材料预型件的生产工艺有多种,其生产路径主要由最终用途决定。三维机织物是通过对传统织造原理改进加工而成的。二维机织复合材料是一种由二维织物构成的层合材料,而三维机织复合材料是复杂几何结构的整体构件。三维机织复合材料预型件有许多优点,最重要的优点是它避免了二维层合材料的分层现象。介绍了三维机织预型件的织造方法,为纺织复合材料的开发提供了有益的借鉴。     

三维正交机织物织造及复合材料成型工艺研究

详细阐述三维正交机织物的结构特征、织造原理及织造工艺,以三维正交机织物为增强体、环氧树脂为基体,采用真空辅助树脂传递模塑(VARTM)工艺成型,制成复合材料,并分析其内部结构。结果表明:由普通织机改造的多综眼多剑杆织机可以织造三维正交机织物,成型后复合材料内的纱线形状和位置未发生明显变化,树脂较好地渗透到织物内部,复合材料具有较高的纤维体积分数。研究结果为进一步研究三维正交机织复合材料的力学性能及应用奠定了基础。     

芳纶/阻燃粘胶/阻燃锦纶混纺织物制备及其性能

为获得长效阻燃、高强、耐磨且服用性能好的织物,将芳纶1414、阻燃粘胶与阻燃锦纶3种本质阻燃纤维混纺织造,探讨了混纺比、纱线捻度、织物组织结构和黏合剂种类对纱线及其织物力学性能、阻燃性能和色牢度的影响。结果表明：芳纶1414/阻燃粘胶/阻燃锦纶(30/45/25)混纺纱线同时具备优异的力学性能和阻燃性能,阻燃锦纶的加入使三元混纺纱线断裂强度相比芳纶/阻燃粘胶二元混纺纱线提升56%,耐磨次数提升58%,其纱线的力学性能随着捻度增加先增强后降低,峰值捻度为680捻/m;织物采用斜纹组织结构时,其阻燃性能和力学性能优于平纹和缎纹组织;采用非离子型丙烯酸酯共聚物G-BD作为印花浆料黏合剂,可使得到的高强耐磨阻燃织物水洗20次后变色牢度级数仍保持在2级以上。     

玻璃纤维织物的自动几何建模研究

织物的组织结构与其性能有很大的关系。通过设计并织造了四种不同组织(二维方平组织、3/1斜纹组织、双层斜纹组织,以及三维角连锁组织)、不同厚度的玻璃纤维织物,并对它们的几何形态进行模拟。结果表明,根据纱线的物理结构参数和织物的实际照片创建织物几何模型可行,且模型能够反映纱线的空间结构。     

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.     

改性聚丙烯酸类纤维吸湿发热机织物的开发

为研究吸湿发热保暖机织物的热湿舒适性,开发了6种不同结构的改性聚丙烯酸类纤维吸湿发热机织物。通过热湿舒适相关性能测试与分析,得出不同机织物结构参数对透气性、热阻、芯吸高度、液态水分管理以及吸湿发热性能的影响规律,为设计出兼具吸湿发热和导湿排汗性能的热湿舒适机织物提供参考。经测试发现:蜂巢组织能明显改善织物的保暖性和透气性,且织物由内层向外层形成回潮率递增的梯度结构,对水分管理和提高单向导湿性能有积极作用,三层蜂巢组织在提升织物吸湿发热性能上具有一定潜力。     

改性聚丙烯酸类纤维吸湿发热机织物的开发

为研究吸湿发热保暖机织物的热湿舒适性,开发了6种不同结构的改性聚丙烯酸类纤维吸湿发热机织物。通过热湿舒适相关性能测试与分析,得出不同机织物结构参数对透气性、热阻、芯吸高度、液态水分管理以及吸湿发热性能的影响规律,为设计出兼具吸湿发热和导湿排汗性能的热湿舒适机织物提供参考。经测试发现:蜂巢组织能明显改善织物的保暖性和透气性,且织物由内层向外层形成回潮率递增的梯度结构,对水分管理和提高单向导湿性能有积极作用,三层蜂巢组织在提升织物吸湿发热性能上具有一定潜力。     

Effects of spandex drawing ratio and weave structure on the physical properties of cotton/spandex woven fabrics

In this experimental study, we investigated the effects of spandex filament drawing ratio and weave structures on the properties of cotton/spandex woven fabrics. One-way analysis of variance was used to explore the significant effects of the independent variables on the fabric properties. A regression analysis was also used to derive regression relationships between each of fabric properties and spandex filament drawing ratio. Our findings show that the spandex drawing ratio and structures of the woven fabrics significantly affect the physical and mechanical properties of the cotton/spandex woven fabrics. Cotton woven fabrics containing spandex show higher contraction, crease recovery, and flexural rigidity with increasing spandex drawing ratio, whereas the rest of fabric properties decreases with the increasing drawing ratio. Because of higher contraction and then higher weight, thickness, and cover factor of cotton/spandex fabrics, unexpected results of fabric air permeability and breaking elongation were detected.     

二维与三维机织复合材料力学性能的实验研究

对超厚三维正交机织复合材料及二维要织层合板人别进行了拉伸和压缩实验,研究比较了两种复合材料刚度和强度特性的差异研究发现无论是三维机织材料的拉压还是二维层合板的拉压应力应变曲线都近似为直线,而且具有脆性破坏的特点;三维复合材料的拉压强度要高于二维层合板.这主要是由于材料不同的增强相结构及纤维含量造成;不同的破坏模式对材料强度影响很大.     

针梭织面料拼接前后物理性能的对比分析

探讨针织、梭织面料拼接前后的物理性能。选取几种常用于拼接的针织、梭织面料试样,利用FAST风格测试仪和KES-FB4表面测试仪测试试样拼接前后的压缩、弯曲、拉伸及表面摩擦、表面粗糙度等物理性能,运用SPSS软件的非参数检验方法,结合具体图表对其进行对比分析。结果表明,针织、梭织面料拼接后的物理性能与拼接前试样存在显著差异。     

Role of weave design on the mechanical properties of 3D woven fabrics as reinforcements for structural composites

3D fabrics as reinforcement can be manipulated in discrete numbers of weave designs in order to earn maximum gain so that the desired mechanical properties of the composites can be achieved eventually for particular end use. Thus interest has been focused to investigate tensile, impact and knife penetration properties of 3D orthogonal and interlock structures of different weave designs by varying their binder interlacement patterns keeping stuffer binder ratio constant. The tensile properties were effectively influenced by the linear densities as well as crimp of load bearing tows, which were determined by the weave design of the fabric. The compact structure generated from regular weave pattern in case of 1 × 1 plain orthogonal and 1 × 1 plain interlock fabrics exhibited better impact energy absorption. Owing to higher values of peak energy in the knife penetration test, it is revealed that more is the number of fibres in the in-plane direction better is the protection.