多轴向经编增强材料的拉伸性能

为优化企业实际生产中的织物结构参数,提高织物的拉伸强力提供参考依据,采用电子织物强力仪对多轴向经编针织物进行0°、90°、±45°方向上拉伸性能的测试研究,以探明织物的面密度、各层衬纱的面密度、层数、铺层顺序、纱线的线密度、机号、筘密以及线圈长度等结构工艺参数对织物拉伸性能的影响.结果表明:织物面密度是影响其断裂强力的...     

多轴向经编增强材料的拉伸性能

为优化企业实际生产中的织物结构参数,提高织物的拉伸强力提供参考依据,采用电子织物强力仪对多轴向经编针织物进行0°、90°、±45°方向上拉伸性能的测试研究,以探明织物的面密度、各层衬纱的面密度、层数、铺层顺序、纱线的线密度、机号、筘密以及线圈长度等结构工艺参数对织物拉伸性能的影响。结果表明:织物面密度是影响其断裂强力的主要因素,随不同方向纱线层面密度的增加,其断裂强力也增加;在织物纱线层具有相同面密度的条件下,织物铺层层数越多,每层纱线层的断裂强力会降低;机号越高,线圈长度越小,织物越紧密,织物的断裂强力就越大。     

纬编双轴向多层衬纱织物增强高性能头盔

介绍了MBWK织物(纬编双轴向多层衬纱织物)的结构以及拉伸、弯曲等力学性能.比较了该织物与经编双斜向(±45°)、双轴向(0°/90°)、多轴向(0°/90°/±45°)织物,UD材料及机织物的成型性.分析了MBWK织物在开发高性能头盔方面的优势.MBWK织物继承了经编轴向织物的力学优点且成型性颇佳,其纱线潜能利用率高,幅宽可以加大,上机操作灵活.     

纬编双轴向多层衬纱织物半球形成型后的形变研究

为了分析纬编双轴向多层衬纱(MBWK)织物对半球形薄壳体的形变影响,首先需要了解该织物本身的变形趋势,这需要进行织物成型试验和撤销外力后织物的变形试验。通过快速摄影法及图像处理分析得出MBWK织物在成型后撤销外力时的变形趋势,即在45°和225°方向向外扩张,在135°和315°方向向里收缩,同时赤道平面会产生扭曲变形。其主要原因是在半球成型过程中织物的对角线上有大量的纱线和线圈聚集,产生相当大的内应力,从而影响织物的变形。     

纬编双轴向抽纱织物的圆柱面成型

为解决深度冲压复杂曲面制件边缘和局部出现的设计上不能接受的纱线拥挤、堆积和起拱、起皱现象,进行了纬编双轴向抽纱织物的圆柱面成型性实验,比较了全部衬纬/衬经和部分衬纬/衬经纬编双轴向织物的剪切变形角和成型性。研究结果表明：纬编双轴向抽纱织物的圆柱面成型性能优于纬编双轴向满穿织物,而且成型高度提高25%以上;与满穿织物成型相比,抽纱织物达到成型高度极限时,其相应的剪切变形极限角显著减小,大约为20°。     

机织物在各个方向上的剪切性能

剪切性能是影响机织物外观及力学行为的重要特性之一。本文在Kilby等人工作的基础上建立模型 ,预测机织物在各个方向上的剪切刚度。基于现有文献 ,我们发现剪切刚度 (G)、0 5°及 5°角的剪切滞后有明显的线性关系。因此通过比较理论结果与实验数据 ,并将它们在极坐标图上展现出来 ,证明该模型亦可用于预测大范围类型机织物的剪切滞后。实验结果表明 ,剪切刚度与剪切滞后的这种线性关系不仅存在于经、纬两个主方向上 ,也存在于与经纬向成各种夹角的方向上。在实验中还发现 ,机织物剪切刚度的最大值出现在与经纬向成± 45°夹角的方向上。…     

局部衬纬经编组织规律及分析方法研究

介绍了局部衬纬经编组织的一般规律,重点探讨了地组织与衬纬经编组织的交结规律,得出衬纬纱与地纱针背反向垫纱时,交叉点较多,织物结构稳定,适宜编织非绒类织物;而同向垫纱时,交叉点较少,便于起绒。最后以实例的形式说明了局部衬纬经编组织的分析方法,如分析地组织、衬纬纱针背横移针距数、垫纱数码等。     

天然纤维纬编双轴向织物力学及透气性能研究

为了改善纬编双轴向多层衬纱织物原材料废弃后难降解的问题,采用天然棉纤维作为衬经纱、衬纬纱,涤纶低弹丝作为捆绑纱织造纬编双轴向多层衬纱织物,并对织物的机械力学性能和透气舒适性进行测试。结果表明:采用棉纤维织造的纬编双轴向多层衬纱织物拉伸断裂强力较高,纵向拉伸断裂强力明显高于横向,除纵向棉纱含量稍高于横向外,1+1罗纹捆绑纱也起了重要作用;轴向拉伸断裂强力优于斜向拉伸断裂强力,主要因为拉伸断裂机理的变化。此外,通过对织物压缩、弯曲性能测试,表明织物具有良好的压缩回弹性及弯曲性能,织物透气量可达800 mm/s,具有良好的透气舒适性。     

湿阻法测试织物各向异性导湿性能

根据织物润湿后电阻的变化,以金属探针作为传感器,自制了1台织物各向异性导湿性能测试仪,该仪器可同时测试液态水沿织物经向、纬向及45°方向的导湿性能。试验结果表明:液态水沿织物扩散速率除了与织物品种、组织结构有关外,还和织物厚度、扩散方向等因素有关;液态水沿织物各向扩散位移的平方与扩散时间基本成线性关系。     

仿钩纱织物的织造研究

我厂在研制装饰用布过程中,研制了45°涤棉仿钩纱织物十余个规格,经过小批量生产,获得有关设计生产资料,即将批量投产。它具有黑白分明,图案清晰,挺括柔软,透气性好的特点,别具一格。可用作窗帘、抬布及各种装饰用遮布;亦可用于衣着。与同样大小的钩纱织物相比,其价格仅为六分之一;且久洗不易变形,坚牢度好。但其图案变化,有一定局限性,是其不足之处。一、仿钩纱织物的特点仿钩纱织物,是透孔组织与平纹组织两者的结合体。其织物在透孔组织处,呈黑色阴影;平纹组织处呈白色;透过光线或放在深色底板上,黑白分明,图案清晰,而有钩纱的感觉。     

Effect of seam angle on seam puckering in lightweight woven fabrics

Displacement puckering is the major cause of seam puckering, while sewing lightweight woven fabrics. In this paper, effect of seam angle (0°–90° to the weft) on the seam puckering has been studied for cotton and polyester fabrics at different stitch lengths. Puckering is estimated by measuring a difference between the thickness of seamed and unseamed fabrics. It is observed that seam puckering decreases and then increases as the seam angle to the weft increases. Seam puckering is the lowest at seam angle of 30° for cotton fabrics and 69?g/m² polyester fabric; at 45° for 88?g/m² polyester fabrics, depending upon the warp and weft yarns covered in the seam and yarn linear densities, which can be represented as effective relative cover. Seam puckering is the lowest at a seam angle, when the effective relative cover is highest.     

基于线圈面积的罗纹织物半球成形研究

为研究纬编轴向织物的成形性能,分别采用芳纶、涤纶和超高分子量聚乙烯纱线在手摇横机上编织1+1罗纹织物,并铺覆在不同直径的半球上,测量织物试样在不同直径半球的不同高度上局部线圈面积的变化情况,探讨纱线自身力学性能、织物成形高度及球体直径对织物局部线圈面积变化的影响。结果表明,纱线的弯曲性能越好,在相同直径的球体上,织物局部线圈的相对面积变化越小;成形球体直径越大,织物局部线圈的相对面积变化越小;同一织物在同一半球体上,织物局部线圈的面积变化不均匀,与成形高度相关。该研究有助于纬编轴向织物三维成形的理论研究。     

Electromagnetic shielding effectiveness of carbon/stainless steel/polypropylene hybrid yarn-based knitted fabrics and their composites

In this study, a range of conductive hybrid knitted fabrics and their composites have been investigated for shielding effectiveness in the frequency ranges of 50 MHz to 1.5 GHz (low frequency) and 4 to 8 GHz (C-Band). Carbon and stainless steel (SS) filaments were combined in Dref-3 spinning machine and different hybrid yarns were prepared. The plain- and rib-knitted fabrics were made in V-bed flat knitting machine from the prepared hybrid yarns. The composite laminate was prepared by sandwiching a ply of fabric between the polypropylene films in compression moulding machine at 180 °C for 5 min under a consolidation pressure of 12 bar. All the fabrics and composites were tested for shielding effectiveness (SE) in coaxial transmission line and C-band waveguide with the help of vector network analyser. It was observed that fabric having both conductive loop and inlaid yarns exhibited higher SE of 20.2 dB than other fabrics in low-frequency range. However, in the composite form, carbon composite with SS inlaid yarn showed better SE of 45 dB than other composites. In C-band frequency range, conductive loop fabric structures yielded high shielding effect in course direction compared to wales direction. Compared to fabric form, the composite showed higher SE for all frequency ranges. This study proposes that knitted fabrics and their composites can be utilized as electromagnetic shields in wide frequency ranges.     

机织针织复合织物与多层双轴向纬编织物拉伸性能对比

选用玻璃纤维作经纱、纬纱和高强涤纶作针织纱分别编织机织针织复合(CWK)织物和多层双轴向纬编(MBWK)织物,测试两种织物的横向、纵向的拉伸性能,分析比较拉伸负荷和位移特征曲线。研究表明：在拉伸过程中,CWK织物MBWK织物均先由其中的经纱或纬纱,在较低的伸长下,承担较高的负荷,直至经纱或纬纱断裂,然后由针织结构,在较高的伸长下,承担较低的负荷,直至针织结构破坏;经纱和纬纱以交织形式衬入针织结构中,使得CWK织物的轴向的拉伸强度稍低于MBWK织物,但起到一定的“预牵伸”作用,可使针织纱对经纱和纬纱捆绑效果更好。     

Inspecting anisotropy in wrinkle recovery angle of woven fabric

In this paper, the anisotropic wrinkle recovery properties of plain and twill fabrics are explored by studying the variations of the wrinkle recovery angle with sample orientation angle. Orientation angle is the angle measured counterclockwise from the weft direction to the sample’s long axis, that is, the crease direction. This study focused on inspecting anisotropy in wrinkle recovery to find more effective test angles for different woven fabrics. A dynamic wrinkle recovery tester was used to measure the recovery angles of specimens automatically which were cut in various directions. The trend of plain fabrics shows that its recovery angle generally increases at first and then decreases with the increase in the orientation angle. The trend of twill fabrics differs in folding ways. The experimental results revealed that the wrinkle recovery angles of the woven fabrics had the lowest values near the orientation angles of 0° and 90°, i.e. the warp and weft directions, and therefore these two traditionally used directions in the standard test method did not best reflect the wrinkle recovery yielded from both warps and wefts. The diagonal direction (45°) was proven to be the optimal orientation angle for a balanced plain fabric, while the two orthogonal directions, i.e. the twill direction and its perpendicular direction, were found to be more relevant for a twill fabric. Optimal orientation angles used to test the wrinkle recovery angle of a woven fabric should be associated with its structure.     

Effect of surface modification and knife penetration angle on the Quasi-Static Knife Penetration Resistance of para-aramid fabrics

The focus of this paper is to describe the effect of change in surface friction of single layer para-aramid (Twaron^®) square woven fabric and change in knife penetration angle on its Quasi-Static Knife Penetration Resistance (QSKPR). The surface friction of fabric was changed by depositing SiO₂ on its surface by using water glass as a precursor. Six different knife penetration angles (0°, 22.5°, 45°, 67.5°, 90° and 135°) were selected. Untreated and treated fabric samples were compared for change in QSKPR. It was observed that the deposition of SiO₂ on the surface of Twaron^® fabric increased the surface friction which resulted in the increase in QSKPR. The response of fabric against QSKPR changed from partial yarn cutting to individual yarn cutting in fewer steps and load was distributed to a larger area due to decrease in yarn slippage. The change in penetration angle changed the distance, knife cutting edge travelled to cut each next yarn(s) and when this distance increased, the QSKPR was reduced. The post-penetration image analysis of damaged fibres showed that the load distribution among warp and weft yarns was complementary and change in penetration angles changed the distribution of stabbing load among the warp and weft yarns. When yarns with higher tensile strength and less slippage were loaded, the fabric showed highest resistance to penetration. A QSKPR prediction model was also proposed at the end.     

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.     

玻璃纤维经编成圈编织性能

针对玻璃纤维纱线在经编成圈编织时易受损、不易形成织物的现象,通过对不同生产机型、不同规格纱线的编织试验,探讨了经编成圈机构、送经机构和牵拉机构、纱线捻度、捻向及玻纤浸润剂类型等因素对玻璃纤维编织性能的影响,分析了玻纤纱因捻度和捻向造成的织物单边烂边问题,阐述了玻璃纤维在经编机上生产的关键技术,总结出淀粉型玻璃纤维纱线在复合针特里科经编机上采用积极送经方式可以正常成圈编织成玻纤布。     

常用高性能纱线弯曲刚度的测量和表征

由于轴向织物增强薄壳体复合材料越来越成为研究的热点课题。衬纱是轴向织物的重要组成部分,弯曲变形是织物变形的主要形式,因此,衬纱的弯曲刚度对织物的三维成型性能有着重要影响。本文借助KES织物风格仪,通过测量最大弯矩值M_max和拟合斜率值s,表征四种常用高性能纱线的弯曲刚度。实验结果表明：在相同线密度下,高性能纱线的弯曲刚度大于传统纱线的弯曲刚度,四种高性能纱线的弯曲刚度由大到小依次是碳纱线、玻璃纱线、高强聚乙烯纱线、芳纶纱线;高性能纱线的弯曲刚度受纱线中单丝的排列、聚集状态影响,并且随着进入角度的增加而减小。