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1

Moisture and Thermal Transport Properties of Different Polyester Warp-Knitted Spacer Fabric for Protective Application

Chen Qing, Shou Dahua, Zheng Rong, Tang Ka-Po Maggie, Fu Bailu, Zhang Xiaoting, Ma Pibo

Autex Research Journal

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2021

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Vol. 21, no. 2

182--191

EN

Warp-knitted spacer fabrics are generally used for sportswear, functional clothing, protective clothing, and other applications. This article studied the heat and mass transfer properties of polyester warp-knitted spacer fabrics from low thickness (2 mm) to high thickness (20 mm), from low mass (247.34 g/m2) to high mass (1,585.9 g/m2), and surface structure in plain or mesh construction. Water vapor permeability, air permeability, water absorption, and thermal insulation property were conducted to evaluate the spacer fabrics. The results revealed that with increasing volume density the water vapor permeability of spacer fabrics decreased, but the water absorption ratio increased. The water vapor permeability of fabrics increased when thickness decreased and volume density increased. It was further found that spacer fabrics with mesh worn nearby the skin and plain structure worn far from the skin could facilitate water vapor and air transmission. The difference of 8.82% for water vapor permeability and 14.19% for air permeability were found between testing mesh side up and down for the spacers (2.56 and 3.37 mm), respectively. Thermal insulation ratio was highly and significantly correlated with heat transfer coefficient at −0.958 and with thickness at 0.917. Thermal insulation ratio is highly and significantly correlated with air permeability at 0.941.

2

Changeover Process Assessment of Warp-Knitting Let-Off Equipped with Multispeed Electronic Let-Off System

Ji Yong, Jiang Gaoming 1, Tang Mengting

Autex Research Journal

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2021

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Vol. 21, no. 3

299--304

EN

Warp-knitted fabrics have gained increasing attention due to their excellent properties, and their production is strongly dependent on the warp-based electronic let-off system. Most of the existing control systems are single speed electron let-off structure, which brings a series of issues such as broken yarn, missed needle, and running thread caused by let-off delay, making it hard for manufacturer to produce the required fabrics. To fill the gap, this article proposes a new framework of a multispeed electronic let-off system for warp knitting based on closed-loop control strategy. As a demonstration of the capacity and generalizability of this newly proposed methodology, the 01-type four-channel acoustic vibration analyzer is used to test and analyze the time of switching, the let-off amounts, and the change in warp tension during the process of switching let-off amounts, including the explanation and comparison of difference values of let-off quantities. It is shown that the proposed method for the production of warp-knitted fabrics is a useful method for achieving digital manufacture of warp-knitted fabrics.

3

Study of the Flexural Behaviour of Warp Knitted Reinforced Ferrocement Composites

Paramasivam S., Rameshkumar M., Malathy R., Prakash C.

Fibres & Textiles in Eastern Europe

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2019

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Vol. 27, no. 4 (136)

94--101

EN

This paper presents the effect of warp knit textile reinforcement in ferrocement laminates. In general, steel wire mesh is used as ferrocement reinforcement, which is often known aschicken mesh. The need for the replacement of steel mesh is the problem of corrosion, which reduces the durability of ferrocement laminate. High performance synthetic fibres and fabrics are constantly used in various research works as reinforcement in concrete. In this paper, an attempt was made to incorporate three different nylon warp knit mesh structures in the place of chicken mesh. Ferrocement composites were produced with chicken mesh and nylon warp knit fabrics. The flexural properties of ferrocement laminates were analysed in terms of the first crack load, ultimate load, energy absorption capacity and ductility factor. Nylon square mesh with 3 layers in the reinforcement has a 2.5 kN first crack load and 3.36 kN ultimate load, which is higher than chicken mesh reinforcement in ferrocement laminate. The results show that there is an improvement in the flexural properties of ferrocement laminates reinforced with a nylon warp knit structure. The flexural parameters have a direct relationship with the number of layers used in the reinforcement.

PL

W pracy przedstawiono wpływ zbrojenia z dzianiny osnowowej na właściwości siatkobetonu. Siatka z drutu stalowego jest często stosowana jako wzmocnienie szkieletu. Z powodu korozji, która zmniejsza trwałość laminatu stalowego, istnieje potrzeba wymiany siatki stalowej na inny materiał. Wysokiej jakości włókna syntetyczne i tkaniny są stale wykorzystywane w różnych pracach badawczych jako wzmocnienie stosowane betonu. W pracy podjęto próbę włączenia trzech różnych struktur siatkowych z osnową nylonową w miejsce standardowej siatki. Kompozyty siatkobetonowe zostały wyprodukowane z siatki i dzianiny z osnową nylonową. Właściwości zginania laminatów żelaznych analizowano pod kątem obciążenia do pierwszego pęknięcia, obciążenia końcowego, zdolności pochłaniania energii i współczynnika ciągliwości. Nylonowa siatka z 3 warstwami w zbrojeniu uzyskała następujące wyniki: obciążenie do pierwszego pęknięcia – 2,5 kN i obciążenie końcowe – 3,36 kN. Wyniki pokazały, że właściwości zginania laminatów żelbetowych wzmocnionych strukturą dzianiny osnowowej nylonowej uległy polepszeniu, a parametry zginania miały bezpośredni związek z liczbą warstw stosowanych we wzmocnieniu.

4

Three-Dimensional Deformation of Warp-Knitted Spacer Fabrics Under Tensile Loading

Sun Wan, Miao Xuhong, Raji Rafiu King, Ma Pibo

Autex Research Journal

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2019

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Vol. 19, no. 4

381--386

EN

This paper puts forward a new method for measuring the three-dimensional deformation of warp-knitted spacer fabrics under tensile stress. The three-dimensional deformation mechanisms of warp-knitted spacer fabrics have been analyzed using stress–strain curves. Poisson’s ratio of the three-dimensional deformation has also been analyzed. The stress–strain curves obtained for tests in the warp-ward direction and weft-ward direction show a characteristic initial large deformation, followed by minimal-to-no deformation. The stress–strain curves obtained for tests in the thickness direction exhibit different characteristics due to the differences in stretch directions. In the weft-ward direction, the curve shows an approximate linear change with minimal strain. In the warp-wise direction, the curve shows a large stress with small strain, and subsequently, a small stress yielded a large strain. During the stretching process, the surface deformation perpendicular to the direction of tensile force is greater than the tensile deformation, and the deformation in the thickness direction is also minimal compared to that in the direction of the tensile deformation.

5

Calculation and Analysis of Horizontal and Vertical Lapping Angles in Tricot Warp Knitting

Zhang Lingjie, Miao Xuhong, Wan Ailan

Autex Research Journal

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2019

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Vol. 19, no. 2

173--180

EN

The lapping angle, which affects the style and quality of production, has been studied as a parameter of weft knitting. But the importance of the lapping angle has not been considered during the warp-knitting cycle. This paper shows that the lapping angle exists in the process of warp knitting and can be divided into horizontal and vertical lapping angles. Models for the lapping angles of closed and open loops were devised, and the lapping angles (horizontal and vertical lapping angles) of closed and open loops were calculated and analyzed. Furthermore, the paper seeks to investigate the factors that influence the lapping angle of tricot warp-knitted fabrics and summarize the rules. Moreover, the vertical lapping angle can affect the loop coverage. Results reveal that the decrease in number of underlaps and an increase in take-off density enables loops of the front guide bar to show on the face of the fabric. Moreover, it is also advantageous for an apparent front loop visibility when the front guide bar knits in open loop.

6

Finite Element Modeling for the Uni-Axial Tensile Behaviour of Metallic Warp-Knitted Fabric

Xu H.-Y., Jiang J.-H., Chen N.-L., Lin F.-B., Shao H.-Q.

Fibres & Textiles in Eastern Europe

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2018

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Vol. 26, no. 2 (128)

49-54

EN

The finite element analysis method (FEM), for its advantages of lower time and economic costing in predicting the mechanical properties of fabrics, was applied to warp-knitted fabrics. In this paper, two bar warp-knitted fabric knitted with wires was used as reflecting mesh antennas. Firstly the loop unit of the metallic warp-knitted fabric was simulated in 3-D by TexGen software. Secondly the 3-D loop unit model was inputted into ABAQUS software to form a model of the metallic warp-knitted fabric sheet for uni-axial tension analysis. Thirdly numerical results were obtained after setting the parameters in ABAQUS. Finally numerical results were verified by uni-axial tensile experiments on the metallic warp-knitted fabric. The results showed that the simulation was in good agreement with the experimental tensile process, where the transfer of yarns between loops when in low fabric elongation and in yarn elongation when in high fabric elongation were simulated by FEM of warp-knitted fabric in the tensile process. Also the same trend of tensile force was found in experiment and FEM results. Therefore it can be concluded that FEM can be used to predict the mechanical properties of warp-knitted fabric with a complex structure.

PL

Do przewidywaniu mechanicznych właściwości dzianin metalicznych zastosowano metodę elementów skończonych (FEM). Symulacji 3D dzianin dokonano przy użyciu dwóch rodzajów oprogramowania: TexGen i ABAQU. Wyniki symulacji zweryfikowano eksperymentalnie. Stwierdzono, że symulacja charakteryzowała się zgodnością z eksperymentalnie przeprowadzonym procesem rozciągania. Na podstawie wyników stwierdzono, że metoda elementów skończonych (FEM) może być z powodzeniem wykorzystywana do przewidywania mechanicznych właściwości dzianin o złożonej strukturze.

7

Application of Knitting Structure Textiles in Medical Areas

Zhang X., Ma P.

Autex Research Journal

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2018

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Vol. 18, no. 2

181--191

EN

There are many kinds of medical textiles, such as woven textiles, non-woven textiles, braided textiles and knitted textiles. Non-woven medical textiles constitute more than 60% of the total medical textiles used, but are almost disposable ordinary medical textiles. While knitted fabrics forms a small part of the medical textiles, but are greatly applied in high-tech medical textiles, containing artificial blood vessels, hernia patches, cardiac support devices, knitted medical expandable metallic stents and tendon scaffolds. Knitting structures, including weft knitting structure and warp knitting structure. The knitted textiles are popular for their loose structure, greater flexibility, higher porosity, more flexible structure and better forming technology. The present article will introduce some knitting structures and materials applied in the medical textiles in accordance with non-implantable, implantable, extra-corporeal textiles and healthcare and hygiene products.

8

The Effect of Knitting Parameter and Finishing on Elastic Property of PET/PBT Warp Knitted Fabric

Chen Q., Ma P., Mao H., Miao X., Jiang G.

Autex Research Journal

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2017

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Vol. 17, no. 4

250--260

EN

This study investigated the elastic elongation and elastic recovery of the elastic warp knittedfabric made of PET (polyethylene terephthalate) and PBT (polybutylene terephthalate) filament. Using 50/24F PET and 50D/24F PBT in two threadingbars, the tricot, locknit and satin warp knitted fabrics were produced on the E28 tricot warpknitting machine. The knitting parameters influencing the elastic elongation under 100N wereanalyzed in terms of fabric structure, yarn run-in speed and drawing density set on machine.Besides, dyeing temperature and heat setting temperature/time were also examined in order toretain proper elastic elongation and elastic recovery. The relationship between elastic elongationand knitting parameter and finishing parameter were analyzed. Finally, the elastic recovery of PET/PBT warp knitted fabric was examined to demonstrate the elastic property of final finishedfabric. This study could help us to further exploit the use of PET/PBT warp knitted fabric in thedevelopment of elastic garment in future.

9

Flexural Properties of Syntactic foam Reinforced by Warp Knitted Spacer Fabric

Zhi C., Long H.

Autex Research Journal

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2016

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Vol. 16, no. 2

57--66

EN

The aim of this study was to investigate the flexural behaviours of syntactic foam reinforced by warp knitted spacer fabric (SF-WKSF). Seven kinds of SF-WKSF samples were fabricated by warp knitted spacer fabric (WKSF) with structural parameters including surface layer structures, inclination-angle and fineness of spacer yarns, different microballoons types and contents. The flexural tests were carried out and the bending properties of SF-WKSF were analysed based on the strength and modulus values obtained from the test results. It is indicated that the SF-WKSF shows higher flexural strength and modulus compared to neat syntactic foam with almost no impact on the density of composites. The results also demonstrate that the surface layer structure, inclination-angle of spacer yarns, microballons content and type have significant effects on the flexural responses of SF-WKSF. The composites exhibit better antibending capacities by selecting larger inclination-angle, closer surface layer structure, higher density and relatively higher content of S60HS microballoons.

10

Moisture Comfort and Antibacterial Properties of Elastic Warp-Knitted Fabrics

Yu Z. C., Zhang J. F., Lou C. W., He H. L., Chen A. P., Lin J. H.

Autex Research Journal

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2015

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Vol. 15, no. 1

60--66

EN

Multifunction elastic warp-knitted fabrics were fabricated on a crochet machine with the use of metal composite yarns/viscose yarn and bamboo polyester/ crisscross-section polyester hybrid yarns as the front face and back face of the knitted fabric structure, respectively. We investigated the effect of the blend ratio of bamboo charcoal/ crisscross-section polyester multiply yarns on the fabric's moisture comfort properties, such as water vapour transmission (WVT), water evaporation rate (WER), and water absorbency. The results showed that blending ratio significantly influenced WVT and WER. Moreover, antibacterial activity of the elastic warp-knitted fabric was tested against Staphylococcus aureus and Escherichia coli in accordance with AATCC 90-2011. Finally, the extension-stress value curves were used to analyse the elastic stretching property, and the fabric exhibited greater breaking elongation and lower stress value in the walewise than in the weft direction.

11

Experimental Investigation on the Stab Resistance of Warp Knitted Fabrics

Miao X, Jiang G, Kong X, Zhao S

Fibres & Textiles in Eastern Europe

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2014

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Vol. 22, no. 5 (107)

65--70

EN

The stab resistance of two guide bar warp knitted fabric made from ultra-high molecular weight polyethylene was characterised by a maximum load, and energy at the maximum load and load versus displacement curves under quasi-static test conditions are presented. Penetration angles and side were designed. Samples with different lapping, densities and layers were tested, with a woven fabric used as the original reference. The results showed that warp knitted fabric with a moderate density and longer underlaps on the front guide bar performed better. The penetration angle and side have no observable influence on warp knitted fabrics’ stab resistance. Furthermore the performance of warp knitted fabrics during a knife penetration shows the difference from woven fabric in the damage process.

PL

W artykule stwierdzono, że odporność na przebicie specjalnych dzianin osnowowych wykonanych z włókien polietylenowych o ultra wysokim ciężarze cząsteczkowym można charakteryzować poprzez maksymalne obciążenie przy przebiciu, energię w chwili maksymalnego obciążenia i krzywymi obciążenia w funkcji przemieszczenia w warunkach testowych quasi statycznych. Między innymi określono kąty penetracji . Przygotowano próbki o różnej strukturze, masie liniowej i ilości warstw. Wyniki porównywano w stosunku do wyników uzyskanych dla tkaniny. Wyniki wskazują, że dzianiny osnowowe o średniej masie liniowej i dłuższych łącznikach oczek są bardziej odporne na przebicie. Natomiast nie stwierdzono wyraźnego wpływu kąta przebicia. Ogólnie stwierdzono wyraźną różnicę zachowania się dzianin w stosunku do tkanin przy penetracji nożem.

12

Automatic Identification of Jacquard Warp-knitted Fabric Patterns Based on the Wavelet Transform

Jiang G. M., Zhang D., Cong H. L., Zhang A L, Gao Z.

Fibres & Textiles in Eastern Europe

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2014

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Vol. 22, no. 2 (104)

53--56

EN

In view of the fact that the design of jacquard warp knitting patterns is time-consuming, this paper proposes a rapid segmentation method to divide the multi-textural regions of jacquard warp-knitted fabric which could be used for automatic identification of fabric patterns to improve the efficiency of design. After pretreatment, the images scanned were decomposed by a two-layer two-dimensional wavelet transform and the standard deviations of five channels were extracted as the eigen values. Then, after giving the cluster centers, a multi-channel clustering was made combined with a K-means clustering algorithm. Finally the removal of noises caused by classification errors was needed , after which an accurate identification image was obtained. The experiments show that this method can achieve automatic texture segmentation of jacquard warp-knitted fabric with more than three textural regions. The identification results have high regional consistency, and the segmentation accuracy is up to 92%. The method can also adapt to a variety of mesh regions. Besides this, the approach is fast and can simplify craft personnel’s traditional process of pattern tracing classification when it is combined with CAD. Through this method, the efficiency of jacquard warp-knitted product designing can be improved a lot.

PL

Biorąc pod uwagę, że określenie wzorów żakardowych dzianin osnowowych jest czasochłonne, zastosowano metodę szybkiej segmentacji wzorów dla wydzielenia wielostrukturalnych rejonów dzianin, które mogłyby zostać wykorzystane dla automatycznej identyfikacji wzorów dzianin i usprawnieniu procesu projektowania. Po wstępnej obróbce zeskanowane obrazy zostają podzielone poprzez dwuwarstwową, dwuwymiarową transformacje typu „wavelet”, następnie określa się odchylenia standardowe dla pięciu kanałów i ekstrahuje się jako wartość własną. Następnie przeprowadza się wielowarstwową analizę klastrów opartą na specjalnym algorytmie. W końcu usuwa się szumy spowodowane przez błędy klasyfikacyjne co pozwala na dokładną identyfikację obrazów. Eksperymenty wykazują, że opracowana metoda pozwala na automatyczną segmentację struktury osnowowych dzianin żakardowych z więcej niż trzema regionami strukturalnymi. Opracowana metoda zapewnia identyfikację z dokładnością do 92% i znacznie usprawnia proces projektowania dzianin żakardowych.

13

Three-Dimensional Simulation of Warp-knitted Fabric

Cong H., Ge M., Jiang G.

Fibres & Textiles in Eastern Europe

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2009

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Vol. 17, no. 3 (74)

66--69

EN

With detailed research on the structure of warp-knitted fabric, the spatial yarn position of a 3D loop structure was discussed, and the dimension of each parameter was ascertained. After establishing the basic control points of the loop, a 3D model of warp-knitted fabric was created. By calculating the control points of this model in reverse, a more exact control polygon was attained. By utilizing the program Visual C++ and the developing tools of Open GL, using Non-Uniform Rational B-Spline surfaces, spatial yarn can be described exactly, and a virtual reality of warp-knitted fabric can be realized on a computer screen.

PL

Szczegółowo przeanalizowano strukturę dzianiny osnowowej, przestrzenne usytuowanie przędzy w oczku 3D oraz określono wartości wszystkich istotnych parametrów. Po określeniu wszystkich podstawowych punktów konturu oczka sporządzono model 3D dzianiny osnowowej. W wyniku przeliczania pozycji punktów kontrolnych modelu sporządzono precyzyjny kontrolny wielobok. Dzięki wykorzystaniu programu Visual C++ oraz narzędzi Open GL i Non-Uniform Rational B-Spline Surfaces przestrzenne położenie przędzy może być opisane a także można stworzyć wirtualny obraz dzianiny osnowowej za pomocą komputera.

14

Textile composite materials for small intestine replacement

Deichmann T., Michaelis I., Junge K., Tur M., Michaeli W., Gries T.

Autex Research Journal

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2009

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Vol. 9, no. 4

105--108

EN

Down to the present day there are no sufficient techniques for a small intestine replacement, mostly because of the high standards for such implants. An indication for the need of novel operation techniques is the small patient survival rate of just 80 % for isolated small intestine transplantation and 62 % for combined liver-small intestine transplantation. The five year survival rates of the patients are merely 42 %. In order to overcome these limitations the authors are developing a partly resorbable textile-foam-composite for small intestine replacement The novel implant consists of a non resorbable textile PVDF mesh which is foamed with a micro porous, resorbable, and drug loaded polymer. The resorbable polymer serves on the one hand as initial sealing, therefore no intestine substance and bacteria can leak out into surrounding tissue, on the other hand it needs to be micro porous in order to ensure cell ingrowth. For the macro porous textile mesh warp knitting technology is used. The warp knitted tubular structure remains inside the body as a long term implant and provides mechanical support to ingrowing cells. In order to evaluate biomechanical properties of the warp knitted tubular PVDF meshes to compare them to the mechanical characteristics of small intestine tissue, tensile tests were conducted. Results of tensile tests on warp knitted structures with three different loop densities of 8, 12, and 16 loops per cm were compared to tensile tests on native small intestine tissue probes. The recorded curves of small intestine and warp knitted structures showed similar characteristics. The two characteristic Young Modules as well as the curve progression of the warp knitted structure with 12 loops per cm showed good accordance to the values of the native small intestine. Morphological analysis of the textile structures by digital image processing showed adequate pore size and porosity of the textile mesh.

15

Analysis of Warp Knitted Fabrics' Relative Cover with the Use of Computer Technique of Image Processing

Mikołajczyk Z.

Fibres & Textiles in Eastern Europe

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2001

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Vol. 9, no. 3 (34)

26--29

EN

The coverfactor of decorative warp knitted fabrics is critical in selecting the proper design of any textile and an optimisation criterion of important parameters of the knitted fabric structure. In the designing process there is no instrumental method of coverfactor z determination. The presented method of measuring z is based on digital segmentation of the image of a knitted fabric surface in a 2D system. The method has been verified for a jacquard weft knitted fabric.

PL

Współczynnik powierzchniowego zapełnienia dzianin kolumienkowych dekoracyjnych jest podstawowym czynnikiem wyboru koncepcji plastycznej wyrobu oraz kryterium optymalizacji istotnych parametrów budowy dzianiny. W procesie projektowania brak instrumentalnej metody wyznaczenia współczynnika zapełnienia. Przedstawiona metoda pomiaru tego współczynnika opiera się na cyfrowej segmentacji obrazu powierzchni dzianiny w systemie 2D. Metodę tę zweryfikowano dla dzianiny żakardowej wątkowej.