Yarn Cross-section Research Articles

スリット型インターレーサの寸法がインターレース糸の生成挙動に及ぼす効果の高速度ビデオ画像による解析

In order to obtain knowledge of interlacers generating a high number of tangles, the yarn motion was observed in slit-type interlacers with various sizes with high-speed video cameras. Results obtained are as follows: (1) Interlaced yarn is generated by the iteration of closed, dispersion and twisting states of running yarn independent of size of interlacer. (2) Interlacers generating a high number of tangles are supposed to have the following characteristics: Yarn passage region, where the airflow velocity is low, is small. In addition, the twin vortex has high dynamic pressure, filaments disperse to the whole yarn passage, plural twists generate in a yarn cross-section by the twisting action of the twin vortex, and a series of entanglements with different twist types occurs in the direction of yarn axis. Hence, strong entanglements between filaments are formed.

Engineering Fiber Volume Fraction of Natural Fiber Staple - Spun Yarn Reinforced Composite

There is a large demand for high fiber volume fraction natural fiber reinforcement polymer composites. Among many parameters affecting the mechanical properties of a composite, the fiber volume fraction is the most decisive factor. The effect of fiber volume fraction on the physical and tensile properties of aligned natural fiber staple spun yarn composites has been intensively investigated. However, there have been no direct studies on determining the relation between composite fiber volume fraction and the yarn fiber volume fraction for fiber staple-spun yarn composite. With the intention to improve the utilization of most fibers of the yarn cross section in the composite, the variation of the yarn diameter in staple-spun yarn reinforced composite is investigated in this study. The analysis of the yarn diameter indicates that it has a high variability that necessitates an increase in the composite diameter to envelope all the yarn body leading to reduction in its fiber volume fraction. A model for the determination of composite fiber volume fraction was driven, grounded on the analysis of the yarn diameter variability along its length. An equation has also been developed to calculate the diameter of the composite to cover majority of yarn cross section

Evaluation of the Correlation between the Structure and Quality of Compact Blend Yarns

Pneumatic compact spinning is the most widely used compact spinning technology at present, which is implemented by using negative airflow to condense the fibre bundle and decrease the spinning triangle. Roller-type and Lattice apron-type compact spinning are two major kinds of pneumatic compact spinning now. In this paper, blend yarn qualities spun by one kind of roller-type compact spinning: complete condensing spinning (CCS), and one kind of Lattice apron-type compact spinning: 4-line rollers compact spinning (FRCS) were studied and analysed comparatively. First, 28.1, 18.5 and 12.3 tex JC60/T40 blend yarns and 18.5, 14.8 and 11.8 tex JC35/T65 blend yarns were spun on two kinds of compact spinning systems, respectively, and the effects of the blending ratio on yarn qualities were discussed. Then another two kinds of cotton blended yarns - JC60/R40 and JC60/M40 were spun. 28.1, 18.5, 14.8 tex JC60/R40 and 18.5, 14.8, 11.8 tex JC60/M40 were spun on two kinds of compact spinning systems, respectively. Meanwhile the qualities of spun yarns were analysed by using two methods. First with a high speed camera system - OLYMPUS i-speed3 (OLYMPUS Image Co., Ltd., Japan), the condensing process of a fibre strand in the condensing zones were captured and analysed. Second the cross sec tions of the spun yarns were presented using a Y172 Hardy’s thin cross-section sampling device (Nantong Hongda Experiment Instruments Co., Ltd. , China). The corresponding Hamilton Index was then calculated, and the fibre radial distributions in the yarn cross section were analysed. The results show that the fibre condensing effects are increased with an increase in the ratio of cotton fibre on the blended yarn for both kinds of compact spin ning, especially the FRCS. Meanwhile with an increase in the ratio of polyester fibre on the blended yarn, the advantage of CCS with respect to yarn qualities increased. For both JC60/R40 and JC60/M40, cotton fibres are transferred to the outer part of the yarn body. However, the fibres in JC60/R40 yarn spun by CCS and those in JC60/M40 yarn spun by FRCS are distributed more randomly.

Complex description and measurement of two-ply yarn transversal proportions

A diameter of single yarn is well known as one of the main geometrical descriptive characteristics of yarn formation. Many experimental methods also measure and define this parameter while assuming cylindrical shape of a single yarn. Very rare information exists in the case of two-ply yarn geometrical parameters. This paper, in its first part, introduces the geometrical parameters of two-ply yarn from a mathematical ideas point of view. The second part presents the longitudinal view method of their measurement. The longitudinal view method is functional also for single yarn diameter evaluation. Contribution proves the method on a set of five single polypropylene yarns variable in fineness and on a set of five polypropylene two-ply yarns different in ply twists, while two-ply yarn fineness stays constant. The third part of this paper presents a cross-sectional method of linear textiles, here of two-ply yarn and single yarn. Images of two-ply yarn and additionally single yarn cross-sections are used to measure transversal proportions of two-ply yarn and single yarn equivalent diameter. Results are discussed in terms of the set of five two-ply polypropylene yarns and some outputs are compared to those from the longitudinal view method.

Evaluation of the integrity of 3D orthogonal woven composites with embedded polymer optical fibers

Due to their high flexibility, high tensile strain and high fracture toughness, polymer optical fibers (POF) are excellent candidates to be utilized as embedded sensors for structure health monitoring of fiber reinforced composites. In 3D orthogonal woven structures yarns are laid straight and polymer optical fiber can be easily inserted during preform formation either as a replacement of constituents or between them. The results of the previous paper indicated how an optic fiber sensor can be integrated into 3D orthogonal woven preforms with no signal loss. This paper addresses whether incorporating POF into 3D orthogonal woven composites affects their structure integrity and performance characteristics. Range of 3D orthogonal woven composites with different number of layers and different weft densities was fabricated. The samples were manufactured with and without POF to determine the effect of embedding POF on composite structure integrity. Bending, tensile strength tests, and cross section analysis were conducted on the composite samples. Results revealed that integrity of 3D orthogonal woven composite was not affected by the presence of POF. Due to its high strain, embedded POF was able to withstand the stresses without failure as a result of conducting destructive tests of the composite samples. Micrograph of cross-section of composite samples showed that minimum distortion of the yarn cross-section in vicinity of POF and no presence of air pocked around the embedded POF which indicates that 3D woven preform provided a good host for embedded POF.

A variable metric stochastic theory of textile composites with random geometric parameters of yarn cross-section

A variable metric stochastic theory of the elastic constants of textile composites with stochastic yarn (or tow) geometry has been developed in the current study. A variable metric coordinate transformation is utilized in this theory to introduce the cross-section shape fluctuations of yarn into the compliance of textile composites. Six parameters are defined to describe the positioning and cross-section shape of yarn completely. Then, the Taylor expansions of the local stochastic variable metric basis and the compliance of yarn are executed. Finally, the volumetric averaging method is employed to obtain the elastic properties of textile composites. The numerical simulations show that the fluctuations of geometric parameters may affect the elastic response of textile composites considered. The example of single straight yarn proves the validity of the theory and presents the explicit formulas of influence of stochastic yarn geometry on elastic constants. Within the example of plain weave composite, random yarn cross-section shape and twist degrade all of the elastic constants except the shear moduli and Poisson’s ratios in 1–3 and 2–3 directions, which are determined by the comprehensive effect of the stochastic scaling and twist.

Process–structure relationship of carbon/ polyphenylene sulfide commingled hybrid yarns used for thermoplastic composites

Commingling is a prospective manufacturing process for the production of hybrid yarn in which a reinforcement material and a thermoplastic matrix in the form of filaments are mixed to form continuous filament yarn. In this work, hybrid two-component carbon/ polyphenylene sulfide (PPS) yarns designed for high-performance thermoplastic composites were developed. Experiments were carried out to investigate the manufacturing process of commingled yarn and quantify the homogeneity of distribution of carbon and PPS fibers in cross section of commingled hybrid yarns. The effect of process parameters in commingling including degree of overfeeding, production speed, and air pressure on the filament distribution in the cross section of commingled hybrid yarns was investigated. The results show that process parameters play a large part in improving blend uniformity and filament distribution in hybrid commingled yarns. A correlation between the observed homogeneity and the process parameters was established.

Geometric model for 3D through-thickness orthogonal interlock composites

The elastic properties of 3D through-thickness orthogonal interlock composite materials are affected by the curvature of the yarns caused by compaction during the manufacturing process. However, most of the models in the literature do not take into account this fact resulting in not so accurate predictions. A novel geometric model accounting for the compaction and curvature effects on the cross-section and distribution of fill and warp yarns in 3D through-thickness orthogonal interlock composite materials is presented in this work. The model assumes sinusoidal functions to represent the curvature along the length of the fill and warp yarns due to binder. Then, with only a set of preform parameters combined with few geometric measurements in optical micrographs of specific sections the geometry of the material can be fully determined. The model is compared and validated with the real geometry and fibre area fraction of the warp and fill yarns of a 3D through-thickness orthogonal interlock carbon/epoxy composite and the predictions of an analytical model present in the literature. After the comparison, it can be concluded that the model is a useful tool to describe the real geometry and can be used with finite element analyses to obtain its elastic properties.

An analytical approach to the deflection analysis of woven preforms and composites under tensile loading using the Winkler theory of curved beams

In this article, a new analytical approach for the deflection analysis of yarns in woven materials under tensile loading is presented. A unit cell of a warp yarn surrounded by adjacent weft yarns is modeled using curved beams. Next, using the Winkler theory of curved beams, the warp yarn strain energy under tensile loading is derived; followed by the implementation of the variational method to obtain the governing equations as well as related boundary conditions. The exact displacement field solution was found and using the continuity of deflection condition at crossover points, the normal inter-yarn contact force was estimated. In the proposed analytical approach, shear forces and potential slippage of yarns at contact points are neglected. The validation of the solution was checked by comparing results of a benchmark example on steel textile preforms to two sets of finite element simulations. For further evaluation of the approach, the uniaxial extension response of a polypropylene/glass woven fabric composite with a noncircular yarn cross section is also considered under large deformation and predictions are compared to earlier data in the literature.

Theoretical estimation of structural parameters in 2/2 twill woven structures

It has been shown through various experimental works that the geometry of woven fabrics will change after it is released from looms due to the contraction forces resulting in changed structural geometry in their fully relaxed state. In this work, an appropriate three dimensional unit cell is proposed for 2/2 twill woven structure. The proposed model covers all angles and lengths between warp and weft yarns in the three dimensional unit cell of the structure in its fully relaxed state assuming straight line path and circular cross-section of yarns. At first, a theoretical solution for estimation of skewness angle in float region of 2/2 twill fabrics is proposed by defining the JJ ratio index to consider different amount of contraction in float and crimp region of unit cell. Then the proposed theory is extended to include the weave and skewness angle of yarns in crimp region of woven structures. By applying this theory, the skewness angle of 2/2 twill weaves will be incorporated in structural modelling of woven fabrics which can be used in predicting the thickness and areal mass of the 2/2 twill woven structures. Besides the confirmed validation of model in predicting the areal mass, the results for estimating the thickness of fabrics are in close agreement with the measured ones in the fabrics with worsted and coarse cotton yarns.

Drape behavior of 3D woven glass‐epoxy composites

This article deals with the drapability of 3D woven glass fabrics for composite applications. The study focuses on forming a 3D fabric over the mold, the result is a preform, which generally is then injected with a polymer matrix by so called Liquid Composite Molding (LCM) technique. When draping pre–impregnated composites, the fabric is embedded in the epoxy resin as matrix material. Various drape models for dry and pre‐impregnated fabrics have been proposed in the work. Solidworks and ANSYS are the software used for modeling and simulation of 3D woven fabric composites. Given the linear density (tex) and density of E‐glass fiber, the radius of the yarn was calculated. So far the cross section of yarn is assumed to be perfectly circular in shape, keeping the perimeter of yarn constant the circular cross section was deformed into a race track shape which is a much more practical and realistic shape of a yarn cross section. After calculating all the required dimensions, all the three 3D woven structures namely angle interlock, warp interlock and orthogonal were developed in solidworks. All the parameters like total number of warp and weft yarn per unit distance and thickness of the fabric were kept constant in all three structures. The analysis is based on first principles and the parameters of yarn and fabric construction. Results obtained through simulation are reported. These are validated with experimental composite samples. The model used to predict drapability of 3D woven glass‐epoxy composite gives good results. Orthogonal structure proves to be the best as far as resistance to deformation is concerned. However, if a relatively more flexible and formable prepreg is desired, it is advisable to use angle interlock or warp interlock structures. Warp interlock 3D structure proves most beneficial for draping on a mold. POLYM. COMPOS., 37:472–480, 2016. © 2014 Society of Plastics Engineers

Research on the Molding Condition of 3D Braided Nozzle Throat Fabric

3D braided fabric lining mandrel weaving, throat is the key part of nozzle which should meet the requirements of molding. This paper based on the research between geometry and knitting yarn array of 3D braided nozzle fabric, proposed the basic conditions which influence the molding performance of nozzle. Theoretical derivation the formula of reasonable yarn array and cross-section parameters of yarn. Verify its correctness by actual production of 3D braided nozzle fabric. The CT scan image and the moire pattern of fiber volume percentage showed that the throat size of fabric and roundness well matched with mandrel, fiber volume percentage changed uniform which satisfied the requirement of engineering application.

이상적인 수분 제어 기능을 갖는 섬유 구조체에 대한 연구

This study investigates specific fabric structures with the optimal moisture transfer properties of moisture absorbency and dryness depending on the yarn type. Experiments were performed on the moisture absorbency and dryness of yarns with different cross sections (four channels, six channels, and regular round), yarn counts (i.e., denier), filament counts, textures (i.e., textured vs. flat), and structures (e.g., double-layer construction with different densities between the face and back sides). Polyester fiber was identified and determined to fulfill the above functions. Experiments were also performed to determine factors that affect the absorbency function of cotton and polyester microporous spun yarns: the yarn count (mono denier), total yarn denier, absorbent chemical concentration, and yarn cross-sectional shape. Finally, experiments were carried out to compare the moisture absorbency and dryness of different yarn cross sections: four channels, six channels, and regular round.

A volume averaging and overlapping domain decomposition technique to model mass transfer in textiles

A new three scale approach for textile models is suggested: a one-dimensional fiber model and a fabric model, with a meso-level in between, i.e. the yarn scale, Goessens et al. (2012). For loose textile substrates this seems appropriate as the yarn level plays an important role. This is because the saturation vapor pressure will influence the release rate from the fibers, and its value will vary over the yarn cross section. Therefore, in this work we present two upscaling techniques for the three step multiscale model. The active component is tracked in the fiber, the yarn, and finally at the fabric level. At the fiber level a one-dimensional reduction to a non-linear diffusion equation is performed, and solved on an as needed basis. The outcome is upscaled via the volume averaging method and used as an input for the yarn level. At this level a one-dimensional model can be applied to calculate the concentration, which on its turn is upscaled using the overlapping domain decomposition as an input for the fabric level model.

X-ray microtomography applications for quantitative and qualitative analysis of porosity in woven glass fiber reinforced thermoplastic

A three dimensional representation of woven glass fiber reinforced thermoplastic composite has been obtained by means of X-ray microtomography. Various methods of image segmentation were applied to classify microtomography results. Segmented images were used to perform complete qualitative and quantitative analysis of porosity present in material. Several image processing tools were developed to precisely define porosity distribution on the global, layer and single yarn scale. A 3D mesh representing fiber, resin and porosity geometry has been obtained to better visualize localization of various forms of porosity and serve as a base for future mechanical simulations. A problem with yarn impregnation has been identified in one principal direction of material and has been precisely described regarding to orientation of yarns and location in thickness of material along with topographic description of resin deficiency in single yarn cross-section. Additional verification was provided by observation of the samples by Scanning Electron Microscopy.

A theoretical model of maximum hairiness of staple ring-spun yarns

This paper proposes a theoretical model for maximum hairiness, defined as the number of fiber ends with a certain length in the surface layer of a unit length of ring-spun yarn. These fiber ends have the potential to become protruding hairs, that is, form hairiness of the spun yarn. With consideration of yarn twist, but excluding loops and wild fibers, this model predicts the maximum yarn hairiness or maximum numbers of potential fiber ends with various lengths, which is derived by employing kernel estimation of fiber length distribution. A hairiness contribution factor is introduced as the ratio between the number of fiber ends in the surface layer that potentially contribute to yarn hairiness and the total number of fiber ends in the yarn cross-section. Previous and the present models associated with hairiness or fiber ends are discussed and compared with the measured number of hairs to verify the proposed theoretical model for maximum hairiness of ring-spun yarn.

Engineering Geometry Method for Modeling the Structure and Performance Characteristics of Fabric Articles for Technical Purposes. Part 1. Structure Modeling Method

We propose an engineering geometry method for modeling the structure of dryer fabrics made from polyethylene terephthalate yarns for the papermaking industry. The models can allow us to determine the following parameters: the shape and dimensions of the yarn cross section; the positioning of the yarns in the structure; the length increment and crimp increment for the yarns; the thickness of the structure; the linear, surface, and bulk coverage by the yarns; the surface and bulk porosity; the surface and bulk density.

Methods for adhesion/friction reduction of novel wire-shaped actuators, based on shape memory alloys, for use in adaptive fiber-reinforced plastic composites

For fiber-reinforced plastic composites, fiber-matrix adhesion is a significant aspect of composite properties. While conventional lightweight structures are always aiming for high fiber-matrix adhesion, innovative and unconventional functional constructions require different concepts. The research work treating adaptive fiber-reinforced plastic composites with shape memory alloy wires presented here uses the approach of actuators freely movable within the composite. This is supposed to prevent mechanical tensions in the interfaces of actuator and composite structure, which would otherwise cause damages of the composite. This work examines hybrid yarns based on friction spinning technology, with shape memory alloy wires as their core component as well as glass fibers, and partly polypropylene, as their sheath component. Additionally, the surface properties of the shape memory alloy wires being used are modified by sanding and coating. The results of a characterization by pull-out testing clearly show that a coating of the shape memory alloy wires with an abherent causes considerable decrease in adhesion and friction in the interface and leads to the mobility of the shape memory alloy wires in the later composite. An even greater effect is attained by sheathing the hybrid yarns in an additional layer of polypropylene, compacting the yarn cross-section. Thus, the pull-out force could be reduced to 35–40% of the reference structure.

Pilling properties of wool single jersey made of compact and conventional ring yarns after anti-felting treatment

This work studied the differences between wool single jersey made from compact and conventional ring-spun yarns composed of surface-modified fibers with different anti-felting treatments. Wool yarns (100%), produced from the fibers modified by two commercial chemical treatments, Basolan®88 and Kroy-resin, were spun according to compact and conventional ring-spinning systems in two different twist factors of spun yarn. The surface morphology and physical properties of wool fibers and conventional and compact ring yarns and the pilling properties of these fabrics were examined and compared with each other before and after the chemical treatment. The breaking strength of modified fibers decreased if compared with the control. Results indicated that the surface morphology of wool fiber changed by Basolan®88 and Kroy-resin treatment, and a lower friction coefficient increased with the differential frictional effect value. The hairiness index ( S3) of compact yarn was a reduction by 60% and the strength and elongation percentages were higher compared with conventional ring yarn. The fiber packing density of compact yarn was 30% higher from the fiber distribution pattern in the yarn cross-section. Another important finding was that the fabric produced with compact yarn showed better anti-pilling property and more mass loss.

Micro-CT analysis of the internal deformed geometry of a non-crimp 3D orthogonal weave E-glass composite reinforcement

An investigation at the unit cell level of the sheared geometry of a single layer E-glass non-crimp 3D orthogonal woven reinforcement (commercialized under trademark 3WEAVE® by 3Tex Inc.) is performed by X-ray micro-computed tomography (micro-CT) observations. The aim is to observe, understand and quantify the effect of in-plane shear deformation on the composite reinforcement geometry, at meso-scale (i.e. unit cell level). It was observed that, increasing the shear deformation, Z-yarns maintain unchanged the distance between the yarns and as consequence the yarn cross-section has a reduced variation of width, mainly in the weft direction.Furthermore, the effect of the shear angle on the textile thickness during compression is measured, this being an important parameter after the forming and molding phases of a composite component production. Compression tests and micro-CT measurements of the thickness show similar values and are in agreement with the prediction obtained assuming the theoretical invariance of the volume in the considered range of shear deformations.