Xuhong Miao

Mechanical properties of co-woven-knitted fabric/epoxy composites incorporating carbon nanotubes

The mechanical properties of co-woven-knitted (CWK)/epoxy resin composites with various carbon nanotubes (CNTs) contents along different directions had been investigated. The tensile failure mode of CWK composites with various CNTs contents also was reported. The results indicate that the stress strain curves are influenced by the CNTs contents obviously, and the failure stress, failure strain and absorbed energy composites with various CNTs contents are linearly increased with the CNTs contents. The tensile failure modes of CWK composites with various CNTs contents tend to be in shear deformation and fiber breakage together, and the failure modes of CWK composites with high CNTs contents mainly are resin shear deformation.

Computer simulation for warp-knitted brushed fabric with patterned piles

Warp-knitted brushed fabrics are special pile fabrics with uneven and declining piles that consist of broken filament ends. It is difficult to predict the finial pattern of the pile surface in the process of the design of patterned fabric. There are few researches on computer simulation of the fabric because of their complicated and fuzzy characteristic. This paper focuses on computer simulation of this group of pile fabrics. Firstly, the characteristics of warp-knitted brushed fabric and the factors that influence the pile are discussed. Secondly, a simplified line model is proposed to represent the shape of the pile by some lines in a certain titling angle, radial angle and length. A two-dimensional matrix is used to describe the position and color of piles in one pattern repeat. Finally, based on the mathematic model, a program is developed by VC++.NET to realize the simulation of the brushed fabric with a patterned pile. By the input of some parameters that were adjusted according to the craft, the two-dimensional computer simulation of the pile surface was found to be similar to the actual patterned pile fabric. It is proved that the method is feasible and contributes to the development of a computer-aided design system to realize the design and simulation of the warp-knitted brushed fabric.

Compression behaviors of carbon woven composites with carbon nanotube-filled epoxy resin under high strain rates

The compressive properties and compressive failure mode of multi-layer carbon woven/epoxy resin composites with various carbon nanotube (CNT) contents at quasi-static and high strain rates loading have been investigated in the present paper. The results indicate that the stress–strain curves are strain rate sensitive, and the compressive stiffness and compressive failure stress of composites with various CNT contents are significantly influenced by the strain rates and CNT content. The compressive failure modes of woven composites without CNTs tend to be in shear deformation, delamination fiber breakage and matrix cracking, and the failure modes of woven composites with higher CNT contents are mainly delamination, matrix cracking and shear deformation.

Manufacture and filtration of the PM2.0 of microfiber warp-knitted mesh fabrics dealing with tourmaline

Tourmaline can enhance filtering efficiency to PM2.0 of microfiber warp-knitted mesh fabric. In this paper, microfiber warp-knitted mesh fabrics were designed with different mesh structures and mass fraction of tourmaline solution respectively. The effect of tourmaline concentration on filtering efficiency of fabrics was investigated. After the tourmaline solution, the strength of mesh fabrics and durability of tourmaline’s conglutination to the mesh fabrics were explored at the same time. The results shown that the filtering efficiency of microfiber warp-knitted mesh fabrics dealing with tourmaline was resentful. Breaking strength of fabrics decreases with increasing mass fraction of tourmaline solution. The resistant efficiency of fabrics and tourmaline adhesive on the mesh fabrics were still stable along with the increasing mass fraction of tourmaline.

The Comfort Properties of Two Differential-Shrinkage Polyester Warp Knitted Fabrics

Abstract Single-layered warp knitted fabrics were produced by the 60D/36F (containing 36 filaments) polyester yarn with differential shrinkage (DS) property in this study. Due to the differential shrinkage property, the fabric becomes curly and bulkier, simulating cotton fabric in terms of its appearance and fabric handle. The performance and appearance of these DS polyester warp knitted fabrics were evaluated objectively and subjectively. The testing results demonstrated that the DS polyester warp knitted fabric had better abrasion property, worse pilling resistance due to the mechanical property of polyester yarn when compared with 100% cotton warp knitted fabric. Meanwhile, lower water vapour permeability and air resistance were found for DS polyester warp knitted fabric resulting from the dense structure of yarn shrinkage after heat-moisture treatment. Besides, the fabric handle was evaluated by Kawabata evaluation system and subject to trial under dry and wet fabric condition. DS polyester warp knitted fabrics provide better recovery under low stress mechanical pressure. The subjective evaluation result shows that the warp knitted fabrics made of DS polyester had similar handle against cotton warp knitted fabric in terms of prickle, smooth, comfort and dry feeling in both dry and wet testing conditions.

Influence of Rib Structure and Elastic Yarn Type Variations on Textile Piezoresistive Strain Sensor Characteristics

Production parameters have been established to play a fundamental role in dictating the physical characteristics and sensing properties of knitted sensors. This research studied the influence of elastic yarn type and rib fabric structure variation on the physical, tensile and conductive properties and sensitivity performance of knitted underwear strain sensors to be used for breathing mensuration. Four different structures in 1×1, 1×2, 1×3 and 2×2 mock ribs were knitted using covered elastic (CY) and bare strand elastic yarn (BS) combinations. These two parameters proffered unique physical, conductive and tensile characteristics to the samples. Wear and machine tests were conducted to ascertain the sensor’s piezoresistive responses. The machine test showed a higher piezoresistive response, with an average peak value (APV) from 1.70 Ω to 0.24 Ω, while those for the wear test recorded were around 0.0110 Ω to 1.867 Ω for all sample categories. However, sensors knitted with covered elastic yarns produced the best breathing test results (APV of 1.089 Ω – 1.86 Ω) compared to bare strand elastic yarns (APV 0.0027 Ω – 0.0790 Ω) when used in a wearable environment. Fabric structure variation had influences on both conductive and tensile characteristics; however, the effects on the piezoresistive response were negligible. The influences of the unique characteristics provided by these core parameters on sensor resistance values, piezoresistance, aging, ease of deformation and dimensional stability have also been discussed.

Analysis of yarn tension based on yarn demand variation on a tricot knitting machine

To date, the trend in the development of knitting promotes higher requirements for warp tension control, and the fluctuation of knitting warp finally comes down to the imbalance between yarn demand and feed while forming every loop. According to warp knitting machine characteristics, four typical points are chosen to calculate the value of yarn demand, and in this way a model is built to obtain and plot the overall change trend in yarn demand in one knitting cycle. Combined with the theoretical tension curve calculated based on the yarn demand and the measured one, it is verified as coincident. The model is useful for analyzing the factors causing warp dynamic tension variation, and lays the groundwork for accurate active tension compensation.

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

Abstract 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 ofPET/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.

Post-treatment and evaluation of polyester filament cotton-like fabric

Alkali reduction treatment was found to reach the imitation of cotton fabric and improve the wear ability of polyester fabric in this paper. Four main factors on the wearable ability were analyzed and through a set of orthogonal tests the optimal treatment parameters were received that alkali dosage of 25 g/l, handing time of 50 min, bath ratio of 1:15 and treatment temperature of 110 °C. Under the optimal conditions, samples were processed and then compared with raw ones via SEM to conclude differential appearances of fibers. Furthermore, preferential performances of the processed fabrics were analyzed by a group of tests in terms of tensile, shear and compressive properties. The experimental results proved that with the treatment of alkali, polyester fabrics could show soft handle, mild glossiness and superior texture which were in high uniformity with cotton fabrics.

Comparative study on the mechanical behavior of carbon weft-knitted biaxial fabrics stitched by polyester fibers and preoxidized polyacrylonitrile fibers

The carbon weft-knitted biaxial fabrics stitched by polyester fibers and preoxidized polyacrylonitrile fibers were prepared respectively. Tensile and tearing tests of two types of carbon biaxial weft-knitted fabrics stitched by different fibers were carried out. Stress–strain and load–displacement curves were obtained according to the testing data. The high-speed camera was employed to observe the whole testing process and series of still images were picked up according to the time nodes to analyze the meso-scale mechanism of the extension and displacement of tows on oriented layers and stitching yarns. The properties of the two fabrics were compared based on the research of the stitching yarns mechanical performance. The researching results indicated that preoxidized polyacrylonitrile fiber exhibit higher mechanical behaviors, and its fabric bond displays excellent performance.