干燥时受力状态对皮革得率和透水汽性的影响

以牛蓝湿革为原料,通过戊二醛复鞣和MK加脂后制得了坯革试样。在常压干燥和真空干燥2种干燥方式下,分别对试样施加单向拉伸和双向拉伸的应力作用。通过改变拉伸程度,研究了不同应力状态的力对皮革结构与性能的影响,重点研究了得革率、透水汽性能的变化规律。结果表明:干燥时拉伸可以提高皮革的得革率和透水汽性能;在双向拉伸应力状态下干燥,皮革的得革率及透水汽性能远高于在单向拉伸应力状态下干燥的试样。坯革试样的得革率与其厚度的变化率有一定关系,而透水汽性能与试样的最终厚度密不可分。     

多层多向机织复合材料细观结构建模及其性能

为分析多层多向机织复合材料的细观结构,基于多层多向机织工艺及不同于传统机织结构的纱线空间运动规律,推导了工艺参数与结构参数之间的关系,建立了细观结构分析模型;为研究多层多向机织复合材料的拉伸性能和失效机制,采用多层多向机织工艺、树脂传递模塑复合工艺,以碳纤维和环氧树脂为原材料制备了2种不同结构的多层多向机织复合材料,采用万能试验机和非接触全场应变仪对材料进行了0°和90°方向的准静态拉伸性能测试,并与正交三向机织复合材料进行了对比分析。结果表明:斜向纱的存在对多层多向机织复合材料的拉伸破坏模式和断口形貌有较大影响,斜向纱一定程度上阻碍了裂纹和应变沿承载方向扩展,0°方向拉伸试样断口处经纱层内经纱全部断裂,90°方向拉伸试样断口处纬纱层内纬纱全部断裂,2个方向的拉伸试样斜向纱层中均存在部分斜向纱纤维未断裂,拉伸试样非完全断裂。     

定型应力状态对皮革与皮胶原热稳定性的影响(续)

以牛蓝湿革为原材料,通过复鞣、加脂后制得坯革试样。在常压干燥和真空干燥2种干燥条件下,分别对试样施加单向和双向拉伸作用。主要研究了干燥时受拉伸试样的耐湿热性能、耐干热性能及热解性能,并借助红外光谱法探讨了皮胶原纤维内部氢键在拉伸前后的变化。结果表明:干燥时拉伸试样的耐湿热性能与耐干热性能都有一定程度的降低,其中薄皮片的耐干热性能优于其中胶原纤维的耐干热性能。拉伸往往伴随着其中部分氢键的断裂。     

定型应力状态对皮革与皮胶原热稳定性的影响

以牛蓝湿革为原材料,通过复鞣、加脂后制得坯革试样。在常压干燥和真空干燥2种干燥条件下,分别对试样施加单向和双向拉伸作用。主要研究了干燥时受拉伸试样的耐湿热性能、耐干热性能及热解性能,并借助红外光谱法探讨了皮胶原纤维内部氢键在拉伸前后的变化。结果表明:干燥时拉伸试样的耐湿热性能与耐干热性能都有一定程度的降低,其中薄皮片的耐干热性能优于其中胶原纤维的耐干热性能。拉伸往往伴随着其中部分氢键的断裂。     

棉针织物结构与拉伸收缩性能的关系

探讨了棉针织物结构与拉伸收缩性能的关系。利用图像法测试6种不同纱支、组织结构、织物密度的棉针织试样在10%、30%、50%、70%定伸长条件下的拉伸收缩性能。利用Auto cad软件处理试样横向收缩的实物图片后,分析在同一拉伸伸长率下不同结构针织物的横向收缩分布规律。结果表明:针织面料布边收缩曲线可由抛物线模拟,抛物线开口越大,面料布边收缩越严重;织物纵向拉伸得到的布边曲线的弯曲程度要大于织物横向拉伸后得到的布边曲线的弯曲程度;纱线根数越多,织物密度越大,横向收缩越小,织物保形性越好;罗纹组织结构面料保形性能优于半畦编组织和纬平针组织织物。     

疲劳对机织压延类柔性复合材料剥离性能的影响

对机织压延类柔性复合材料进行定伸长疲劳试验,测试了经疲劳处理后试样的剥离性能,分析了试样的定伸长疲劳对其剥离性能和织物结构、试验方法对柔性复合材料疲劳性能的影响.结果表明,材料疲劳后的剥离强力与定伸长比例和拉伸次数密切相关,且随着定伸长比例和拉伸次数的增加,其剥离强力明显下降.     

撕裂性能增强型阻燃面料的制备与研究

以轶纶95聚酰亚胺双股纱线为原料、2/2和3/3方平组织为织物组织结构,制备防护服外层阻燃面料试样,并对其热防护性能、拉伸断裂强力和撕裂强力进行测试.结果表明,所制备的试样可满足防护服热防护性能的要求.2/2方平组织试样的经纬向拉伸断裂强力分别达1 337.3 N和1 252.8 N,经纬向撕裂强力性能显著提高(分别为146.3 N和133.9 N).3/3方平组织试样经纬向的撕裂强力更好,分别为195.6 N和177.7 N,可很好地满足阻燃防火面料的使用要求.方平组织阻燃面料有望在消防等领域发挥更大的作用.     

涤塔夫拉伸过程的动态分析与机制研究

对7种不同盖覆紧度涤塔夫织物的经纬向分别拉伸,同时用高速摄像机记录拉伸的全过程,分析织物拉伸变形直至断裂过程中的数字化信息,研究结果表明:试样拉伸初始阶段属于力学高模量区,纵向伸长缓慢,但是宽度明显减小;拉伸曲线的中间区域属于力学低模量区,纵向伸长速度加快,试样宽度减小的速度减缓;尾部阶段沿受力方向纱线伸长、纤维间出现相互滑移,模量增高,试样宽度变化较平稳.经向第1个特征点试样宽度残留率变化幅度比纬向大,经向前2个阶段宽度变化率随着盖覆紧度增大呈增大趋势.     

拼接对针织物拉伸性能和服装压力的影响

为了分析拼接工艺对针织物服用性能的影响,通过对15种锦纶/氨纶弹性针织物分别进行10%、20%、30%、40%、50%、60%拉伸率下的拉伸力值测试。从15种织物中优选3种进行拼接组合,并测试其拉伸性能,建立了单种针织物拉伸力值和拼接针织物拉伸力值的回归方程;测试了不同拉伸率下单种针织物试样和拼接针织物试样的服装压力,并建立了拉伸力值、拉伸率和服装压力的回归方程,总结了织物拉伸力值与服装压力的相互关系,能够辅助预测弹性针织物拼接后的拉伸力,为针织服装压力的相关研究提供参考和指导。研究结果表明:弹性针织物纵向与横向的拉伸率呈高度正相关。拼接针织物试样拉伸力与单种针织物试样拉伸力间存在显著相关性,且拼接针织物拉伸力受2种织物中拉伸力较大织物的影响大。通过拉伸率、拉伸力及服装压力的回归方程能够较好的预测服装压力。     

阻燃棉织物结构与性能关系研究

以8种阻燃棉织物为试样,分析并测定织物组织、面密度、织物密度、纱线线密度和织物紧度等织物结构参数,以及拉伸性能、耐磨性、透气性、透湿性、刚柔性、悬垂性和阻燃性能等服用性能,并采用多因素方差分析、回归分析,探讨织物结构参数对服用性能的影响,最后通过模糊决策分析方法综合评价服用性能的优劣程度及织物适用性。结果表明织物组织和面密度对织物的拉伸性能、刚柔性、阻燃性能均有显著影响,且面密度与阻燃性能呈线性正相关;织物组织相同时,随着织物经密和纬密的增加,织物透湿率下降;6#试样适宜用作阻燃防护服,5#和6#两个试样都较适用于装饰用织物。     

An experimental investigation into structure and properties of 3D-woven aramid and PBO fabrics

Three-dimensional (3D) fabrics are the focus of recent developments due to their versatile physical, structural attributes, and application scopes. These fabrics can be manufactured in various architectures which offer a great deal of opportunity to modify the weight, physical and mechanical properties, and cost of the various products. The potential usage of 3D woven fabrics in the ballistic protection applications was the main motivating factor of this research work. Thus, interest has been focused to investigate the structure and properties of 3D woven orthogonal fabrics with aramid fiber and PBO fiber in comparison with 2D fabrics. The investigation of ballistic properties of these fabrics showed that 3D woven fabrics are superior in terms of breaking load and energy absorption as compared to those of 2D woven fabrics. The specific ultimate tensile strength of 3D woven fabric was observed to be lower than 2D fabrics, which may be due to less number of load bearing yarns in the loading direction. The crimp percentages of the load bearing tows in 3D fabric are very less than that of 2D fabrics. Owing to the higher values of work at peak and load at peak, in knife penetration test, it is revealed that 3D fabrics offer better protection than 2D fabrics.     

Effect of structural parameters of porous yarns and fabric on air permeability and moisture transfer of double-face woven fabrics

In this study, effect of fabric structural parameters of double-face woven fabrics including kind of porous yarn namely micro-porous yarn and hollow yarn, hole size of hollow yarn, percentage of these yarns in double-face woven fabric structure, and finally weft density on air permeability and moisture transfer of woven fabrics was evaluated. These yarns were produced by using water-soluble continuous polyvinyl alcohol filaments as core part for hollow yarns and as doubling yarn in micro-porous yarn. Results revealed the effect of kind of porous yarn, hole size of hollow yarn, and weft density on air permeability and moisture transfer of woven fabrics. The percentage of porous yarns as weft did not show obvious trend. Analysis of variance was used to study the effect of these variables on air permeability and moisture transfer of double-face woven fabrics statistically.     

整体褶裥机织面料的织造新方法

为增强机织面料的立体造型效果,提出了具有较强立体肌理特征的褶裥结构设计与织造方法。针对整体褶裥一次成形织造中存在经纱张力大幅波动的技术难题,通过分析机织整体褶裥的成形原理和过程,分析了整体褶裥成形的关键技术,设计了一种具有自适应功能的送经系统。送经机构设计及产品织造结果表明：褶裥部分织造时,地轴经纱停止送经,但受花经打纬时钢筘往复移动的影响,其张力在45 cN 上下波动,而花轴经纱张力在20 cN上下波动,可满足褶裥织造对经纱张力要求,且能实现整体褶裥的高效稳定织造;同时,整体褶裥的每褶长度可在0 ～23 mm之间变化,具有较明显的立体效果。     

Finite element analysis of monofilament woven fabrics under uniaxial tension

Mechanical behavior of woven fabrics under tensile load is complex because their deformation could result from the combined effects of tension, compression, bending, and shear. In this study, the tensile behavior of woven fabrics is simulated using finite element method. The input parameters are the mechanical properties of constituent yarns obtained from tensile and friction coefficient tests and the geometry of woven fabric repeating unit. First, a 3D geometric model of the repeating unit based on Pierce’s model was built using computer-aided design tools. Then, finite element analysis which incorporates material properties, frictional contact, and periodic boundary conditions was implemented using ANSYS. A non-linear mechanical behavior was defined. Frictional contact algorithm for the cross-sectional zone of the repeating unit and periodic boundary conditions to the contour of the repeating unit was implemented. Numerical simulation data and experimental data were compared, which showed good agreement.     

玄武岩包芯织物的制备及吸声性能

针对玄武岩纤维集束性差且可纺可织性低的缺点,使用涤棉纤维与玄武岩纤维制备3种线密度的赛络包芯纱线,并测试其基础性能。分别使用3种纱线织制平纹、蜂巢2种不同组织的机织物,探讨不同材料、厚度及排列方式对于织物吸声效能的影响。结果表明:所纺不同线密度包芯纱的质量均良好稳定,不同材料中包芯玄武岩织物的平均吸声性能最好;玄武岩平纹织物叠加到厚度3 mm的吸声性能时良好,但随着厚度增加,中低频吸声系数稍有下降;将2种组织织物交替复合的方式形成不同梯度的多孔结构,可显著提高织物的吸声性能,低中频的平均吸声系数在0.2以上,高频吸声系数可达0.7。     

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.     

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。     

锥形管状预成型机织物的织造方法研究

分析了三种锥形管状预成型机织物的织造方法。平面织造法以管状织物组织为基础,通过在织物边部有规律地增(减)经纱,可以形成近似于锥形的预成型织物,但织物的结构欠均匀。环形立体织造采用专用的环形立体织机,可以织造高质量的锥形多层织物,为保证织物的经纱密度均匀,需在织造过程中增(减)经纱,生产效率较低。仿形织造法采用纱架供纱,锥形辊控制织物的卷绕成型,可按照锥形件的外廓形状生产单层环形织物,生产效率高,设备费用低,生产的预成型织物可以方便地缠绕成型锥形复合材料。     

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.     

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.