Influence of Weave Structures on the Tribological Properties of Hybrid Kevlar/PTFE Fabric Composites

The existing research of the woven fabric self-lubricating liner mainly focus on the tribological performance improvements and the service life raised by changing different fiber type combinations, adding additive modification, and performing fiber surface modification. As fabric composites, the weave structures play an important role in the mechanical and tribological performances of the liners. However, hardly any literature is available on the friction and wear behavior of such composites with different weave structures. In this paper, three weave structures （plain, twill 1/3 and satin 8/5） of hybrid Kevlar/PTFE fabric composites are selected and pin-on-flat linear reciprocating wear studies are done on a CETR tester under different pressures and different frequencies. The relationship between the tensile strength and the wear performance are studied. The morphologies of the worn surfaces under the typical test conditions are analyzed by means of scanning electron microscopy （SEM）. The analysis results show that at 10 MPa, satin 8/5 performs the best in friction-reduction and antiwear performance, and plain is the worst. At 30 MPa, however, the antiwear performance is reversed and satin 8/5 does not even complete the 2 h wear test at 16 Hz. There is no clear evidence proving that the tensile strength has an influence on the wear performance. So the different tribological performance of the three weave structures of fabric composites may be attributed to the different PTFE proportions in the fabric surface and the different wear mechanisms. The fabric composites are divided into three regions： the lubrication region, the reinforced region and the bonding region. The major mechanisms are fatigue wear and the shear effects of the friction force in the lubrication region. In the reinforced region fiber-matrix de-bonding and fiber breakage are involved. The proposed research proposes a regional wear model and further indicates the wear process and the wear mechanism of fabric composites.

Sliding Wear of the Hybrid Kevlar/PTFE Fabric Reinforced Phenolic Composite Filled with Nano-titania

The Kevlar/polytetrafluroethylene（Kevlar/PTFE） fabric composite can be used as a self-lubricating liner of the self-lubricating bearing.Many types of nano-particles can improve the tribological performance of the polymer-based composite.Unfortunately,up to now,published work on the effect of nano-particles on the tribological performance of the fabric composite which can be used as a self-lubricating liner is quite scarce.Therefore,for the purpose of exploring a way to significantly improve the tribological performance of the fabric composite,the tribological performance of the Kevlar/PTFE fabric composite filled with nano-titania is evaluated by using the block-on-ring wear tester.The scanning electron microscopy is utilized to observe the morphologies of worn surfaces of the fabric composites and the counterparts.The tensile properties of the composites are evaluated on the universal material testing machine.The test results show that the addition of nano-titania at a proper mass fraction of the matrix resin improves the wear resistance and the tensile strength,decreases the friction coefficient,and makes the wear volume of the composite reach a relative steady state more quickly;plastic deformation and microcutting are important for the wear of the fabric composite;a lubricating layer is formed on the worn surface of the composite during sliding,and the lubricating layer is critical for the tribological performance of the composite;the formation and properties of the lubricating layer are influenced by the nano-titania particles.The proposed study on the effect of nano-titania on the tribological performance of the Kevlar/PTFE fabric composite,especially on the evolution of the worn surface of the composite,provides the basis for further understanding of the influence mechanism of the nano-particles on the tribological performance of the composite and explores a method of improving the tribological performance of the composite.

A Study on the Initial Fracture Behavior of CF/GF Intra-Hybrid Woven Fabric Reinforced Composites

In this paper, woven fabrics of glass fiber/carbon fiber intra-hybrid in plain structure were used to fabricate fiber reinforced plastic (FRP) composite by hand lay-up method. The investigation on tensile property was carried out on specimens in 7 orientations including 0°/5°/15°/75°/85°/90° in previous works. With the specimen parameters and experimental data, FEM model was built by the software of Marc. By combining the experimental results and finite element analysis, the modulus was simulated and calculated at the first stage. Then interfacial stress of the 0 degree and 90 degree was also calculated. By the initial fracture stress data from experiment as well as the simulation value of interfacial strength of 0 and 90 degree, the initial fracture stress of the off-axial specimens wascalculated and predicted. The result shows that the interfacial strength of the glass fiber bundle is higher than that of the carbon fiber bundle in transverse direction. By using the interfacial strength and according to the Von Mises yielding criterion, the initial fracture stress was predicted, which can be a contribution to the design or predict of the material properties.

Effect of Aramid/Carbon Hybrid on the Tensile Properties of Multilayered Biaxial Weft Knitted Fabric Reinforced Composites

The effects of aramid/carbon on tensile properties of multilayered biaxial weft knitted( MBWK) fabric reinforced composites are analyzed by experiments. The tensile tests are inducted by the SHIMADZU AG-250 KNE universal material testing machine and Aramis V6 digital image correlation( DIC) technique.More specifically,the composite samples own four hybrid ratios(Na∶ Nc= 12∶ 0,8 ∶ 4,6 ∶ 6 and 4 ∶ 8). The results showed that the aramid/carbon hybrid MBWK fabric reinforced composites showed nearly linear response until reaching the maximum load and the inserting yarns distribution on the surface of MBWK fabrics reinforced composites had a great influence on the strain pattern distribution. Besides,the tensile strength,the tensile modulus and the elongation at breakage of 0° samples and 90° samples increased with the decreasing of aramid/carbon hybrid ratio. In a word,the changes of tensile strength, tensile modulus and elongation at breakage have a lot to do with the difference of aramid/carbon hybrid ratio.

Electrospun MgO/Nylon 6 Hybrid Nanofibers for Protective Clothing

Magnesia(MgO) nanoparticles were produced from magnesite ore(MgCO3) using ball mill. The crystalline size, morphology and specific SSA were characterized by X-ray diffraction analysis, transmission electron microscopy and Brunauer-Emmett-Teller method, respectively. MgO nanoparticle-incorporated nylon6 solutions were electrospun to produce nanofiber mats. Surface morphology and internal structure of the prepared hybrid nanofiber mats were examined by scanning electron microscopy and high-resolution transmission electron microscopy, respectively. The fire retardancy and antibacterial activity(Staphylococcus aureus and Escherichia coli) of coated fabrics made from MgO/nylon 6 hybrid nanofiber are better than those from nylon6 nanofiber.

Skin-inspired interface modification strategy toward a structurefunction integrated hybrid smart fabric system with self-powered sensing property for versatile applications

Fabric-based composites with superior mechanical properties and excellent perceptive function are highly desirable.However,it remains a huge challenge to attain structure-function integration,especially for hybrid fabric composites.Herein,a skin-inspired interface modification strategy is proposed toward this target by constructing a hybrid smart fabric system consisting of two types of smart fabrics:carbon nanotube(CNT)/MXene-modified aramid fabrics and zinc oxide nanorod(ZnO NR)-modified carbon fabrics.Based on that,flexible piezoelectric pressure sensors with skin-like hierarchical perception interfaces are fabricated,which demonstrate superb sensitivity of 2.39 V·kPa^(-1)and are capable of various wearable monitoring tasks.Besides,the interface-modified hybrid fabric reinforced plastics can also be fabricated,which are proven to possess 13.6%higher tensile strength,10.1%elastic modulus.More impressively,their average energy absorption can be improved by 111.9%,accompanied with inherent damage alert capability.This offers a paradigm to fabricate structure-function integrated hybrid smart fabric composites for the smart clothing and intelligent aerial vehicles.

玄武岩织物-钢-PVA工程水泥基复合材料单轴受压力学性能研究

本文研究了玄武岩织物和混杂短切纤维(钢纤维及PVA纤维,短切纤维总体积掺量为2%)复合作用对玄武岩织物-钢-PVA工程水泥基复合材料(BTR-HyECC)单轴受压力学性能的影响,并通过圆柱体单轴受压试验测得各试件受压性能指标,并绘制出应力-应变曲线。结果表明:当钢纤维掺量为0%(体积分数,下同)时,随着玄武岩织物的加入,试件的抗压强度、峰值应变以及抗压韧性显著提高;当钢纤维掺量增加到1%时,试件抗压强度和弹性模量达到最大;当钢纤维掺量为1.5%时,试件变形能力和抗压韧性达到最佳。基于试验数据,建立了适用于BTR-HyECC的单轴受压本构方程,拟合曲线与试验曲线吻合较好。

“面料检测与分析”课程多元混合式教学模式研究与实践

在“互联网+”教育的时代背景下,多元混合式教学模式在高职教学中得到广泛应用。“面料检测与分析”课程是纺织类专业的核心课程,基于“课程知识项目化、教学资源阶段化、教学流程层次化”建设基本思路,“课前导学、课中研学和课后促学”三环节设计教学活动,通过多元混合式教学改革与实践,学生的学习兴趣和自主学习能力得到明显提升,有效地促进“教”与“学”双向互动。

基于VARTM的碳纤维单向与三维编织混杂织物树脂灌注工艺

为探究碳纤维单向与三维编织混杂增强环氧树脂基复合材料地铁转向架侧梁的树脂灌注成型工艺,首先基于渗透率理论模型采用非饱和径向流法分别测试得到碳纤维单向与三维编织织物的渗透率。通过数值模拟的方法对典型复合材料方形管结构进行缩比建模与网格划分,并利用PAM-RTM软件对树脂灌注成型过程进行仿真分析,预测了制备复合材料方管所需的灌注时间、灌注压力以及树脂流动过程缺陷的产生。最后根据模拟的灌注方案通过真空辅助树脂传递模塑(VARTM)成型工艺制备了碳纤维单向和三维编织混杂织物增强环氧树脂复合材料方管结构件。结果表明,通过PAM-RTM模拟VARTM工艺制备复合材料方管时树脂的流动,预测得到灌注时间为3897 s,VARTM工艺实际制备复合材料方管的灌注时间为4052 s,误差约为3.8%,在合理误差范围内。方管内部灌注压力随着与注胶口距离的增加而逐渐减小。模拟与实验的误差可能是由于实际铺层和灌注过程中树脂流动引起织物的剪切变形以及真空度的差异导致渗透性能产生变化。仿真模拟和实际制备复合材料方管均无明显缺陷产生,证明径向法织物渗透率的理论模型计算测试和仿真结果具有可靠性。

SiCp 与 Gr 混杂增强 Al 基复合材料的制备和摩擦磨损性能

利用真空压力浸渍工艺制备了ＳｉＣｐ增强和ＳｉＣｐ、Ｇｒ（石墨）混杂增强铝基复合材料，Ｇｒ能降低复合材料的摩擦系数，减少偶件的磨损，但Ｇｒ的片状和针状外形对其耐磨性不利。

CF/PTFE纤维混编织物增强环氧复合材料干摩擦特性

采用碳纤维与聚四氟乙烯纤维(CF/PTFE)混编织物增强,制备了环氧树脂基自润滑复合材料,研究了钢背衬复合材料与45钢在环-环端面干摩擦状态下的摩擦学特性,考查了纤维织物、摩擦热、载荷、速度对材料摩擦磨损性能的影响,用红外热像仪、热电偶及风冷方式对摩擦副温度进行监控,用激光共聚焦显微镜和扫描电子显微镜对复合材料及偶件磨损面进行了观察与能谱分析.结果表明:与碳织物相比,混编纤维织物大大改善了复合材料的摩擦学性能,改善效果极大依赖于摩擦温度、载荷和速度参数.PTFE纤维磨损后在树脂基体及偶件表面形成减摩型转移膜层,材料表现为疲劳磨损特征.摩擦高温使复合材料摩擦学特性改变,黏结磨损加剧,偶件钢环表面出现氧化磨损,树脂基体塑性流动,摩擦力增大.混编纤维的排布方式影响复合材料的摩擦磨损性能,摩擦面上大量破碎的碳纤维易使偶件表面转移膜受到破坏,复合材料转变为以磨粒磨损为主,减摩主要源于磨屑中的润滑组分.

用混编布带缠绕薄壁圆筒的研究

用F - 12 /碳纤维混编布带干法缠绕成型了Ф15 0mm薄壁圆筒 ,测试了薄壁圆筒的轴压力学性能 ,着重分析了布带预热温度、缠绕张力以及压辊压力等缠绕工艺参数对薄壁圆筒层间结构的影响。试验结果表明 :当工艺参数选择适当时 ,用混编布带缠绕成型的Ф15

高性能纤维混杂织物增强混凝土应用研究

对碳／ 芳纶纤维混杂编织物增强混凝土梁的性能进行了试验和理论分析，主要是集中在纤维混杂编织物混凝土的强度分析以及找出混杂纤维织物增强混凝土结构应用的可行性．

制作工艺对复合材料胶—螺混合连接接头传力机理及承载力的影响分析

根据制作过程中胶层固化的时机,复合材料胶—螺混合连接接头可分为两种制作工艺。目前对两种工艺制作的胶—螺混合连接接头的研究中均存在传力机理不清,缺乏承载力计算方法等问题。对于两种工艺所制作的胶—螺混合连接接头,对比分析其承载变形过程中传力机理及胶—螺之间变形协调条件的差异。基于接头的传力机理及胶—螺之间的变形协调条件,分别推导此两种工艺所制作胶—螺混合连接接头各自的承载力计算方法。利用该方法对采用两种工艺分别制作的各一组接头试件进行承载力计算和试验对比,理论值与试验值吻合较好,验证理论分析的正确性。

TiC和TiB混杂增强钛基复合材料研究新进展

混杂增强是获得高性能复合材料的有效方法,它可以兼顾2种或多种增强体的特点,使之起到相互弥补的作用,特别是由于产生的混杂效应将明显提高或改善单一增强材料的某些性能,从而扩大材料设计的自由度。因此,对于TiB与TiC原位自生混杂增强钛基复合材料方面的研究将很有意义。本文从制备方法、界面与组织及性能方面对TiC和TiB混杂增强钛基复合材料进行了详细阐述。

混杂增强铝基复合材料的研究进展

从制备方法、力学性能、热物理性能、高温性能综述了国内外对混杂增强铝基复合材料的研究现状 。

纳米杂化氟硅疏水织物整理剂的制备及应用

用聚甲基(3,3,3-三氟丙基)/甲基含氢硅氧烷与烯丙基缩水甘油醚、全氟辛基乙烯进行硅氢加成反应,先制得侧链含全氟烷基和环氧基的氟硅聚合物(PFAMS),再与氨基改性的纳米SiO2进行接枝共聚反应,制备了一种纳米杂化氟硅聚合物(PFAMS-SiO2)并将其用于织物整理,获得了对水静态接触角达160.91°的超疏水棉织物.用红外光谱(FT-IR)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和静态接触角测量仪等仪器研究了PFAMS-SiO2的结构、在棉纤维表面的微观形态以及织物的疏水性能.结果显示,PFAMS-SiO2与预先设计的分子结构一致;经PFAMS-SiO2整理的棉纤维表面存在一层低表面能的氟硅疏水膜和大量仿荷叶的纳米微凸起,此即织物达超疏水的主要原因.

(Gr_f+SiC_p)/Mg的热膨胀性能

采用挤压铸造技术制备了石墨纤维织物与SiC颗粒混杂增强镁基复合材料,研究了其微观组织与热膨胀性能。结果表明,复合材料的的线胀系数随温度升高而降低,经退火后复合材料在20-100℃的平均线胀系数约为3×10^-6/K。纤维二维正交排布条件下复合材料热膨胀性能的各向异性特征得到有效改善。

聚丙烯酸类共聚物/SiO_2硅织物有机-无机杂化材料的合成与表征

以γ-缩水甘油氧丙基三甲氧基硅烷为偶联剂,通过溶胶-凝胶法制备了聚丙烯酸类共聚乳液/SiO2硅织物的有机-无机杂化材料,利用FT-IR、SEM、DSC及TG等手段对其进行了结构表征。SEM照片显示有机组分与无机组分间分布较均匀,并出现了相互贯穿;DSC表明Tg为206℃;对比法测得的比表面为81.61m2/g。实验结果证实该硅织物杂化材料中存在-Si-O-C-共价键,热稳定性较好。

梳状氟硅共聚物-纳米SiO2杂化材料的合成与表征

用硅氢化加成和氨解开环反应先制备侧链带有全氟酯基、三氟丙基和硅乙氧基的改性聚硅氧烷(FPFAS)中间体,再利用硅乙氧基水解产生的Si-OH与硅溶胶间的原位缩合反应,制得一类梳状氟硅共聚物-纳米Si O2杂化材料(FPFAS-Si O),并将其用于棉织物的超疏水整理。探讨了FPFAS-Si O2 2的制备条件,并用红外光谱仪(IR)、核磁共振仪(1H NMR)、热重分析仪(TGA)和接触角测量仪等手段对产物结构、耐热稳定性和疏水性能进行表征。结果表明,产物具有预期结构;纳米Si O2的加入可显著提高FPFAS的耐热稳定性;当FPFAS的Si-H键含量为0.23%、黏度为580 m Pa·s,纳米Si O2平均粒径为134.3 nm时,处理后棉织物具有良好的超疏水性能,织物表面水静态接触角最大可达163.5°。