Statistical and ANN analysis of thermal and evaporative resistances of multilayered fabric ensembles

In this paper, thermal and evaporative resistance of multilayered fabrics meant for cold weather conditions have been reported. Polyester hollow fibers of 6 denier and 15 denier were used to produce needle-punched fabrics. Full factorial experimental design was used to produce 30 different needle-punched nonwoven fabrics from two different linear densities of fiber by varying mass per unit area and punch density at three and five different levels, respectively. The needle-punched nonwovens were used as insulative middle layer. Single jersey knitted fabric and polytetrafluoroethylene-coated fabric was used as inner and outer layer, respectively. The multilayered fabric ensembles were evaluated for thermal and evaporative resistance using sweating guarded hot plate (SGHP) system. Regression equations were developed to draw the contour plots and to analyze the effect of different parameters on thermal and evaporative resistance of fabrics. Two independent one-way analysis of variance (ANOVA) were conducted to find the significance of linear density of fiber and effect of inner and outer layers on thermal and evaporative resistance of fabrics. The two-way ANOVA was conducted to analyze the effect of mass per unit area and punch density on thermal properties of fabrics and ‘F’ values were calculated. Mean square values of pure error and lack of fit were studied to analyze the fitness of the developed model for thermal properties of fabrics. An artificial neural network (ANN) model was developed to predict the thermal and evaporative resistance of multilayered fabrics and compared with the experimental values. It has been observed that the ANN model predicts the thermal and evaporative resistance of multilayered fabrics with high degree of accuracy.     

Thermo-physiological comfort properties of double-face knitted fabrics made from different types of polyester yarns and cotton yarn

Double-face knitted fabrics with hydrophobic inner and hydrophilic outer layers are characterised by their advantageous thermo-physiological comfort property that facilitates the transport of sweat from skin to outer fabric layer where it can be evaporated easily. In this study, for the production of double-face knitted fabrics, cotton yarn as hydrophilic yarn type and five different polyester filament yarns consisting of standard polyester, hollow polyester, micro polyester, textured polyester and textured micro polyester as hydrophobic yarn type were used. In order to determine the thermo-physiological comfort properties of the fabrics, air permeability, water vapour permeability, thermal conductivity, thermal resistance and overall moisture management capacity were measured. The results were comparatively analysed using statistical methods. The experimental results demonstrated that the polyester-type yarns and the combinations of them with the cotton yarn in fabric layers affected the thermo-physiological comfort properties significantly. The fabrics with polyester-type inner face and cotton outer face showed the best moisture transmission properties.     

经编间隔织物多层复合材料的防刺性能

针对目前国内防弹防刺复合插板的防刺性能仍需加强的要求,本文通过采用传统层压复合工艺将间隔织物与现有警用防弹防刺插板中材料(芳纶无纬布/芳纶机织布)相结合,在涂覆不同的黏合剂后,考察其在准静态与动态穿刺状态下的防刺性能。实验结果表明：芳纶平纹机织布由于其紧密的结构特征,可以被用来作为间隔织物的上表面进行有效防刺,同时间隔织物的下表面设计需较为紧密,这样有利于阻止刀尖的持续下刺,另外间隔织物的间隔丝可以有效将刀尖锁住,起到抗刺作用。研究也发现黏合剂对间隔织物及其夹层结构的防刺性能影响较大,采用强度、韧性、和粘结度高的胶有利于材料的防刺性能提高。     

Investigating the effect of material and weave design on comfort properties of bilayer-woven fabrics

The paper focuses on the development of a bilayer-woven fabric and investigating the effect of weave design and material type on its comfort properties. Face layer was plain woven with cotton yarn, while two different weave designs (2/2 and 3/1 twill) and four different materials (cotton, polyester, micropolyester and nylon) were used for the back layer. The comfort properties of fabric, including air permeability (AP), thermal resistance, water vapour resistance and overall moisture management capacity, were determined. It was found that both the layers of fabric as a whole contribute to the comfort properties of bilayer fabric. The highest AP was exhibited by fabrics having both layers of cotton, while 3/1 twill samples have a lower value of thermal resistance as compared to the 2/2 twill samples. The results further showed that micro polyester woven in 3/1 twill weave exhibits better comfort properties.     

Soft body armour

Abstract

A detailed and timely progress of soft body armour against stab and ballistic impact is presented in this monograph. The classification and the evolution of body armour is briefly presented, demonstrating the change of material choice with time. The energy absorption capacity of soft body armour and the mechanisms by which this energy is absorbed or dissipated are dependent upon various parameters and a detailed review is highlighted to best understand the material and structural influence. Various stab and ballistic resistance standards against which armour is currently evaluated are presented in detail. Additionally, the different techniques used to evaluate the performance of armour, from a single layer high-performance fabric to a full armour panel assembly are explained in depth, focusing on yarn pull-out, dynamic impact and ballistic test. Further, different approaches adapted to improve the impact or ballistic response of a high-performance fabric used for soft armour panels is reported exhaustively, with special attention drawn to the application of natural rubber, shear thickening fluid (STF) and surface modification of fibre. Among these, the use of STF is given greater importance, minutely exploring the mechanism of shear thickening, the factors affecting shear thickening behaviour and the methods adopted to improve the thickening or viscosity of STFs. Furthermore, emphasis is laid upon the failure mechanisms of a single high-performance fabric to low velocity impact and of an armour panel to high velocity impact, both for neat and STF treated structures. Moreover, the effectiveness or applicability of soft body armour is valid only when certain conditions are met, a list of which is concisely outlined. Finally, with new techniques and approaches being explored at research level, a futuristic and revolutionalised concept of soft body armour is anticipated- the application of nanomaterials, the use of smart textiles and the concept of biomimetics in armour design.     

Study on thermal and evaporative resistances of multilayered fabric ensembles

The present work deals with the study on thermal and evaporative resistance of multilayered fabric ensembles meant for cold weather applications. Three-layered structure is used to study the thermal comfort properties. Knitted fabric and polytetrafluoroethylene coated fabrics were used in inner and outer layer, respectively. Needle punched fabrics produced from polyester fibre were used in middle layer. Fifteen different non-woven fabrics were produced according to Box and Behnken experimental design for three variables and three levels by varying mass per unit area, punch density and depth of needle penetration. The produced fabrics were evaluated for thermal and evaporative resistances with and without inner and outer layer fabrics. Thickness, air permeability, bulk density and porosity of the needle punched fabrics were studied. The properties of the fabrics were analyzed for statistical significance by using ‘Design-Expert’ statistical software. Artificial neural network model was developed to predict the properties of fabrics and validation of model was done with the testing data-set. The performance of prediction was evaluated by mean square error, mean absolute error percentage and correlation coefficient. It was concluded that the predicted properties of fabric correlated well with the experimental results.     

纬编间隔织物的编织工艺与压缩性能探讨

采用涤纶单丝作为间隔纱和低弹涤纶长丝作为表层纱,在双面圆纬机上编织了几种不同规格的纬编间隔织物,并探索了编织工艺.对这些织物的压缩性能进行了测试,分析了压力-变形曲线和影响压缩变形和回复性能的因素.实验结果表明,在其它条件都相同时,间隔纱细度、织物密度、筒口距离的增加,有利于减小织物的压缩变形和提高回复性能.     

Hybrid panels from woven Kevlar® and Dyneema® fabrics against ballistic impact with wearing flexibility

.This paper reports on a study of hybrid ballistic panels consisting of plain-woven fabrics made from Kevlar® and Dyneema®, aiming to achieve protective and flexible ballistic panels. Experimental and numerical approaches were adopted for this research. Ballistic penetration tests indicated that the single-phase Kevlar® fabric panels was more energy absorbent than that of the Dyneema® fabric panels at low areal density. When the areal density reached around 1.4 kg/m2, the Kevlar® woven fabric panels started to outperform the Dyneema® counterpart in terms of energy absorption. Accordingly, hybrid panels from the two types of fabrics were engineered and such panels were associated to the higher specific energy absorption than the single-phase panels. It was also found that placing the Kevlar® fabric layer close to the impact face and the Dyneema® fabric layers towards the back face resulted in an improvement of around 16% in ballistic performance over the panels constructed in the reverse sequence. In this investigation, the optimum ratio of the two types of fabrics in hybrid panels was found to be 1:1.     

Impact resistance behaviour of silicone coated warp knitted spacer fabrics used for protective clothing

This paper aims to analyse the effect of coating, fabric layers and structural parameters on the impact resistance behaviour of warp knitted spacer fabrics used for protective clothing. For this purpose, six warp knitted spacer fabrics were produced by varying thickness and mesh structure and were coated with a silicone substrate. A drop-weight impact tester was used to determine the impact resistance characteristics of the samples. The results indicate that, the impact resistance properties of warp knitted spacer fabrics can be improved considerably by coating as reducing approximately 10 kN of the peak transmitted force. Also, the structural parameters such as fabric thickness and mesh structure have significant effects on impact resistance behaviour of the samples. The fabrics with higher thickness and smaller size mesh on the outer layers have better impact resistance properties. Additionally, the lamination of spacer fabrics can effectively improve the impact resistance characteristics of the spacer fabrics. The warp knitted spacer fabrics can be used as an energy absorbing material for body protection by varying their structural parameters, fabric lamination and/or by coating.     

Prototyping and analyzing physical properties of Weft knitted spacer fabrics as a substitute for wound dressings

In this research, the required physical properties of weft knitted spacer fabrics, as an alternative for wound dressings have been investigated. For this purpose, weft knitted spacer fabrics with five different fabric structures have been produced on the electronic flat knitting machine. Moreover, in order to compare the properties of the produced fabrics with available wound dressings in the market, two kinds of wound dressing have been prepared from the market. Then, the physical properties of the spacer fabrics and the wound dressings such as air permeability, water vapor permeability, thermal conductivity, compressibility and absorbency have been measured and compared. The results show that in weft knitted spacer fabrics with the same fabric structure of the outer layer and different inclination angle (the angle formed between the outer layer and the spacer yarn), by decreasing the inclination angle, the fabric air permeability, water vapor permeability and absorbency decrease and the thermal conductivity and compressibility increase. Moreover, the use of tuck stitches in the outer layer of the spacer fabric leads to an increase of air permeability, water vapor permeability, absorbency and thermal conductivity and decrease of compressibility. The wound dressings also exhibit less air permeability and compressibility than weft knitted spacer fabrics. On the other hand, they possess higher water vapor permeability and absorbency. According to the results, among the examined weft knitted spacer fabrics in this research, the fabric with the tuck stitches in the outer layer is specified as the most appropriate alternative for wound dressing, in case of wounds with low exudates.     

织物湿扩散系数的实验研究

为了对人体着装稳态情况下织物内水分传输特性的进行有效的测定及评价。本文采用三步法分别实验测试了不同液面高度下装置的总湿阻、织物上表面空气层1湿阻、织物下表面与水表面之间的空气层2湿阻,利用回归方法确定水蒸汽在空气层2的等效扩散系数,进而计算出有空气层存在情况下织物的有效湿扩散系数。此方法能有效规避空气层对织物透湿性测试精度的影响,测试结果能深刻反映出织物传质的特性,为深入研究织物的舒适性提供了实验基础。     

经编间隔织物的拉伸特征

为探讨经编间隔织物的拉伸特征,选取4种不同结构的织物进行拉伸试验,分析了各织物及其上下表面层的断裂强力、断裂伸长和拉伸曲线特征,解释了经编间隔织物的拉伸机制和三维尺寸变化规律,并从织物层角度讨论对拉伸强力和断裂伸长的影响。实验结果表明:间隔织物三维尺寸的变化在拉伸过程中呈现出不同的规律;断裂伸长较小的间隔织物表面在拉伸过程中会率先发生断裂;间隔层对间隔织物的拉伸强力和断裂伸长影响较小,但会延长间隔织物拉伸断裂过程;上下表面层的强力和伸长数值及其大小关系共同决定着间隔织物的断裂强力和断裂伸长。     

基于皮肤拉伸的跑步紧身裤样板优化

研究基于女子人体下肢带结构特点、腿部皮肤形变规律,提出了女子跑步紧身裤结构样板的优化方案。通过样板设计、面料应用,得到适体性和舒适度均良好的跑步紧身裤。通过测量体表标识点间距离并计算得到腿部各区域皮肤的形变拉伸率,分别从纵向、横向统计分析,将拉伸率相近区域做合并处理,为跑步紧身裤结构的分割设计提供理论依据。同时根据合并区域不同的拉伸率值,选择拉伸回复性能与之相近的弹性面料,制作优化的跑步紧身裤,并通过人体穿着和主观评价对比结构优化的紧身裤与未优化的紧身裤的外观合体度、穿着舒适度以及运动舒适度等。通过以上对人体皮肤形变规律的观察,提出紧身裤装结构优化方案,结合适当的弹性面料,制作合体塑形的紧身裤,同时使之具备良好的运动性能,为运动功能性裤装的研究和开发提供理论参考。     

真丝面料热缩率变化规律的探究

在同一温度不同时刻以及不同温度条件下分别对未粘衬及粘着不同衬料的真丝面料的经、纬向热缩率进行了测试,结果显示,面料本身性能、熨烫冷却后的放置时间、熨烫温度、熨烫粘合温度及粘合衬的种类均会影响面料的热缩率。     

二种特殊真丝绸的环保型精练工艺

探索了天然黄色真丝绸和粗纤度真丝绸的高温高压环保型精练工艺。实验结果表明 :高温水精练是一种高效快速的精练工艺 ,在有效脱胶的基础上 ,有利于丝胶回收和环境保护。其中天然黄色真丝绸的最佳精练工艺为 120℃、30min、浴比 1∶100 ;粗纤度真丝绸的最佳精练工艺为 120℃、60min、浴比 1∶300。     

Investigation on thermo-physiological and compression characteristics of weft-knitted 3D spacer fabrics

The thermo-physiological comfort and compression properties of knitted spacer fabrics have been evaluated by varying the different spacer fabric parameters. Air permeability and water vapor transmission of the fabrics were measured using the Textest FX-3300 air permeability tester and PERMETEST. Thermal behavior of fabrics was evaluated by (TCi) thermal conductivity analyzer and overall moisture management capacity was evaluated by moisture management tester. Spacer fabrics compression properties were also tested using KES-FB3. In the KES testing, the compression resilience, work of compression, linearity of compression, and other parameters were calculated from the pressure–thickness curves. Analysis of variance was performed using new statistical software named QC expert trylobite and Darwin in order to compare the influence of different fabric parameters on thermo-physiological and compression behavior of samples. This study established that the raw materials, type of spacer yarn, density, thickness, and tightness of surface layer have significant influence on both thermal conductivity and work of compression in spacer fabrics. The parameter which mainly influences the water vapor permeability of these fabrics is the property of raw material i.e. the wetting and wicking properties of fibers. The Pearson correlation between moisture capacity of the fabrics and water vapor permeability was found.     

经编贾卡提花间隔织物的顶破性能

为探讨不同经编提花间隔织物结构的顶破性能差异,采用在拉舍尔双针床贾卡经编机上编织的8种不同提花结构的织物进行顶破性能试验,分析不同织物的顶破强力大小和顶破曲线特征,解释了经编间隔织物的顶破机制,并从提花面结构角度讨论对织物顶破强力的影响。结果表明：平布层和提花层分别影响间隔织物顶破过程的第1、2阶段;间隔层结构决定间隔织物顶破高度;提花面结构决定间隔织物顶破强力大小,厚组织顶破强力大于薄组织,顶破强力与网孔尺寸成反比关系;在鞋用经编提花间隔织物的设计中,可根据鞋面部位和功能需求进行灵活的组织搭配,丰富鞋材的花纹图案。     

Mechanical properties of double-layered woven fabrics used in car seat upholstery

The objective of this study is to examine mechanical performance of double-layered woven fabrics used in car seat upholstery. For this purpose, 450 denier polyester yarns were supplied to produce double-layered woven fabrics. For the production of the fabrics, full weft connection, which is warp yarn of the top layer makes a connection with the weft yarn of the bottom layer, was used. To produce such a fabric, four different factors such as bottom layer pattern, number of interlacing warps in a unit report, number of interlacing picks per top warp and number of weft skips were investigated using Taguchi experimental design. After weaving stage, fabrics were stentered. Mechanical and physical properties of the fabrics were measured before and after stentering and the results were analysed with regard to Taguchi experimental analysis.     

酚醛纤维织物热湿舒适性的灰色聚类分析

为了解酚醛纤维织物的热湿舒适性,将酚醛纤维织物应用于消防领域,以酚醛纤维织物及消防服常用的阻燃棉布、芳纶1313 织物、聚酰亚胺织物为研究对象,对隔热性、保温性、透湿性、透气性和输水性这5 个指标进行测试,研究相同面密度的不同种类织物的热湿舒适性。利用灰色聚类分析理论对5 个指标进行聚类分析,对这4 种织物在不同环境下的热湿舒适性能做了综合评价。结果表明：在高温条件下,酚醛纤维织物具有较好的热湿舒适性,聚酰亚胺织物与阻燃棉布次之,芳纶1313 织物最差;在低温条件下,酚醛纤维织物也具有良好的热湿舒适性,聚酰亚胺织物次之,芳纶1313 物与阻燃棉布最差。     

Application of artificial neural network (ANN) for the prediction of thermal resistance of knitted fabrics at different moisture content*

Thermal resistance of the fabrics is one of the decisive parameters in terms of comfort; however it can change due to wetting. Therefore, thermal resistance of wetted fabric is important for comfort performance of garments. In recent years, artificial neural networks (ANN) have been used in the textile field for classification, identification, prediction of properties and optimization problems. ANNs can predict the fabric thermal properties by considering the influence of all fabric parameters at the same time. In this study, ANNs were used to predict thermal resistance of wetted fabrics. For this aim, two different architectures were experienced and high regression coefficient (R²) between the predicted (training and testing) and observed thermal resistance values were obtained from both models. The obtained regression coefficient values were over 90% for both models. Then it can be said that ANNs could be used for predicting thermal resistance of wetted fabrics successfully.