Yarn Length Research Articles

Thermo-physiological properties of polyester chenille single Jersey knitted fabrics

This article sheds light on the important construction parameters of chenille yarn that characterize chenille single Jersey knitted fabric thermo-physiological properties. The study investigates the influence of selected yarn and fabric construction parameters, namely yarn twist, pile height of chenille yarn and loop length on the geometrical, physical and, thermo-physiological properties of chenille outerwear used in cold climates. Moreover, the effect of yarn and fabric parameters on the fabric abrasion resistance was studied as it is one of the main fabric defects. Furthermore, the study optimizes the knitted chenille fabric thermal properties to find out the most suitable for winter knitted outerwear. So, 40 tex chenille yarns were produced at 700 and 850 twist per meter and three levels of pile height, 1, 1.2, and 1.5 mm. Eighteen single Jersey knitted fabric samples were produced at three different loop lengths 1, 1.2, and 1.4 cm. Results revealed that the most prominent factor that influences the tested fabric properties at the given setting range is the fabric loop length followed by chenille yarn pile height then the chenille yarn twist level. As pile height and twist increase, the thermal resistance and conductivity increase while air permeability and water vapor resistance decrease.

Nondestructive Test Technology Research for Yarn Linear Density Unevenness

Abstract Yarn linear density and linear density unevenness between fragments involve the mass and mass variation of yarn per unit length, which are important indices to reflect the uniformity of yarn thickness. Aiming at the shortcomings of the traditional testing method, which uses a yarn length tester to test these indices by counting length first and then cutting and measuring weight, a testing device that measures weight and counts length synchronously is designed and developed, so that the yarn can be continuous, recyclable, and reusable. Length counting is conducted by a length-counting disk connected to a photoelectric coded disk, and the result of length counting can be accurate to 0.01 m. The original skein frame with a perimeter of 1 m is replaced, so that the error caused by yarn overlapping is avoided. Through program control, the testing of a plurality of groups of linear density values can be completed at one time to calculate the linear density unevenness of different fragments of yarn, and the yarn can be led to a recovery spool through a yarn guide cylinder to form a new package. Polyester/viscose 65/35 blended yarn was taken as a test sample and subjected to statistical analysis using SPSS software. It is found that the results of the newly developed device are closer to the arbitration value; the whole experiment is completed at one time, which avoids the secondary error and reduces the labor intensity; and the raw materials can be recycled, which saves labor and raw material costs. The device has high value for industrialization and popularization.

Flexible Theoretical Calculation of Loop Length and Area Density of Weft-Knitted Structures: Part II.

A simple and flexible method for theoretical calculation of the main structural parameters of various weft-knitted fancy and combined patterns is presented in this article. It is especially important for patterns containing different elements, such as loops, floats of different lengths, tucks, and tuck stitches. Measurement of an actual average length of the loop in these fabrics is complicated because it is necessary to disassemble precisely one pattern repeat to measure the yarn length and divide it by the number of elements in this pattern repeat. For large and complex pattern repeats, this is difficult and usually gives a high number of errors. It is very important to have lengths of structural elements as it helps to predict the main physical properties of knitted fabrics and their mechanical behaviour, which is especially important for protective textiles. The main idea of the proposed method, based on Čiukas geometrical model, is to calculate lengths of various structural elements or even their parts separately, taking into account the number of needle bars and their formation principle, which gives great flexibility to such modelling. The proposed theoretical formulas can be used for various patterned weft-knitted structures containing not only loops but tucks, floats of different lengths, or additional yarns; they give very few errors in empirical calculations and are easy to use.

Geometric Characterization of Three-Dimensional (3D) Woven Jute Fiber Preforms for Composites

Fiber-reinforced composite materials have many advantages in various engineering applications when compared to traditional materials such as glass, metals, ceramics and unreinforced plastics. Recently, textile-reinforced composites are increasingly used in various industries including aerospace, construction and automotive. This study aims to investigate the geometric characteristics of three-dimensional (3D) woven preforms which are used as reinforcement materials in composites. To this end, 3D woven preforms with three different weave types were produced namely 3D orthogonal, 3D plain z-orthogonal and 3D satin z-orthogonal. The effect of weave pattern and the number of layers on the geometric characteristics of the produced fabrics was investigated. For this purpose, yarn-yarn distances and density, yarn lengths and yarn angles were measured. The effect of the number of layers on the geometric parameters was limited. Yarn-to-yarn distances in plain-weave fabrics were found to be greater when compared to other types of fabrics whereas the yarn density decreased in plain woven fabrics due to a large number of interlacements. This shows that in composite form, the fiber volume fraction in the filling and z-directions will be lower in the semi-interlaced fabrics when compared to the non-interlaced orthogonal structures. It was also shown that filling and warp angles are a function of weave type while z yarn angle is associated with the weaving operations such as beat-up, multi-layer filling insertion and warp yarn let off.

Serialized gradient chromatography for the digital blending of colored fibers and spinning of gradient colored yarn

Gradient colored yarns are manufactured by controlling the blending ratios of three-primary-colored fibers in a slight distribution of gradients along the yarn length, thereby resulting in a continuous natural variation in mixed colors of the fibers throughout the whole yarn. The spinning of gradient colored yarns still remains a challenge, which requires the reliance on digital blending theory of colored fibers and the supporting of multi-channel computer numerical control (CNC) spinning technique. This paper constructed a three-primary-colored fiber gridded color mixing model and its mass mixing matrix and color mixing chromatography matrix by mass discretization and coupling pairing with a 10% gradient for the three-primary-colored fibers. With the aim of continuous natural gradient of mixed colors, the blending ratio gradient path of three-primary-colored fibers was planned based on the mass mixing matrix, and a method of regulating the gradient of color difference between adjacent color segments was proposed. In order to realize the natural gradient of color of the forming yarn, the spinning mechanism of gradient colored yarn was established based on three-channel CNC spinning mechanism and the time-series yarn simulation model, and the time-series spinning processing parameters of three-channel CNC spinning machine were devised. Four gradient colored yarns with different gradient paths were designed and prepared, the linear density, twist, unevenness, surface hairiness, and tensile strength of the spun yarns were measured, compared, and analyzed, and knitted fabrics with color gradient effect were fabricated by small circular knitting machine to obtain continuous and natural color transition with a dreamy and mysterious color effect.

Strength and Deformation Characteristics of Fiber Reinforced Longdong Loess and Experimental Study of Modified Duncan -Chang Model

Fiber yarn reinforced loess is prepared through mixing plain loess with a certain proportion of polyester fiber yarn, which is formed by loosening, carding and cutting waste synthetic textile polyester fabric and has rough surface properties and good acid-alkali corrosion resistance. The strength and deformation characteristics of Longdong Loess reinforced by fiber yarn were studied. The test results show that the uniaxial compressive strength of fiber yarn reinforced loess increases with the increase of fiber yarn proportion and fiber yarn length, and decreases with the increase of fiber yarn fineness. Combined with the uniaxial compressive strength data of fiber yarn reinforced loess under the optimal water content and liquid limit water content, an index which can comprehensively reflect the reinforcement performance of fiber yarn reinforced loess is proposed-- Fiber reinforced index. The shear stress-strain relationship of triaxial consolidation drainage of fiber-reinforced loess with different proportion of fiber yarn is strain hardening type. The hypothesis of hyperbolic form is in accordance with Duncan Chang model. By discussing the relationship between the parameters of fiber yarn reinforced loess and plain loess model, the empirical expression of model parameters considering the influence of fiber yarn reinforced loess is obtained. A modified Duncan-Chang E-B model reflecting the influence of different fiber yarn blending ratio was constructed. The rationality of the model is verified by comparing the test curve with the model prediction curve.

Novel Approach for Determining Diameter of A Yarn with Unknown Count.(Dept.T)

This research work presents a perfect method to determine yarn diameter based on scientific understanding of things nature and avoiding the obstacles of classical methods of yarn diameter measuring by magnification or calculating it from empirical formulae. The suggested method presented here dep ends on putting yarn in a geometrically well defined form and getting use of the relation between yarn length, yarn diameter, and yarn weight through this selected form. Yarn length, in this state, is a common factor between the selected geometrical form and the weight of the formed yarn. The relation between yarn weight and yarn length is well known through the count. As count is unknown, yarn is formed with changing length of its pattern, By this arrangement, two sets of informations are obtained. Yarn count, being a common factor between the two sets, can be cancelled. This results in a simple relation from which yarn diameter can be determined to the nearest 0.1 micron or more accurate. Details of forming device called EYDM (Estimated Yarn Diameter Meter) and testing procedure are indicated.

Determinning Count of Yarn without Measuring Its Length (Dept.T)

A new method for measuring yam count is presented in this research work. This method depends on weight measurements. Yarn length measurement is avoided because of problems associated with it. The new test method is built on replacing yarn length measuring by weight measuring and then through pure mathematical relations yam count can be calculated. Yarn count is expressed as a function of yam weight and diameter of a cylinder. Before yarn is tested, it goes through a forming process using cylinders of a known diameter to get a new shape which can be mathematically assessed. Formed yarn is weighed. This procedure (forming and weighing) is repeated for another part of the same yam after being formed using cylinders of another diameter. A proven formula is used to determine yam count. The way of yam forming and a way of generating a large number of readings from a small number of procedures are described.

Development of 3D auxetic structures using para-aramid and ultra-high molecular weight polyethylene yarns

In recent times, auxetic woven structures gained considerable attention from the researchers due to their excellent impact properties in high-performance areas. Researchers have done much work on the auxetic behavior of the natural and low-performance yarns in two-dimensional structures. Keeping in view the structural application of auxetic structures, in this work, three-dimensional (3D) woven auxetic fabrics were developed on conventional weaving machines with high-performance yarns. Effect of high-performance yarns (Para-aramid and UHMWPE) as the main structure and binding threads on the auxeticity of 3D fabric structures and the impact properties of their corresponding composites were discussed. For this purpose, eight different orthogonal 3D woven structures were produced with para-aramid filament yarn as warp and weft, whereas ultra-high molecular weight polyethylene (UHMWPE) filament yarn was used as a binder. The tensile load was applied to the 3D fabrics to check their auxeticity, and a change in thickness was recorded. The results showed that as the float length of binder yarn and warp yarn increases with the equal and same ratio, the auxeticity also increases. While auxeticity decreases as the difference between the float length of binder yarn and warp yarn increases. The Negative Poisson's Ratio (NPR) of 3D woven fabrics ranged from −0.9 to −2.98. In the second step, these 3D woven fabrics were fabricated into their composites using unsaturated polyester resin, and the hand-layup technique. Their impact strength was measured using the Charpy test method. Auxetic woven composites made of high-performance yarns structures showed impact strength ranging from 55.64 kJ/m2 to 158.46 kJ/m2. Highlights High-performance yarns (Para-aramid and Ultra-high molecular weight polyethylene) were used to create eight 3D woven and composite samples with enhanced auxetic behavior. The result shows that samples having maximum binding yarn float length and fewer intersection points show maximum auxeticity and increased energy absorption. The maximum auxeticity and impact energy absorption obtained was -2.98 and 158.46 kJ/m2, respectively. The current research has applications in protective textiles and bulletproof composite panels.

Determining the loop length during knitting and dyeing processes

Loop length is one of the most relevant variables to control while producing knitted fabrics because the final characteristics of the finished fabric depend on it to a great extent. The procedure followed to calculate it is based on standard UNE-EN 14970, and it is cumbersome, time-consuming and requires yarn-measuring equipment. This study investigated several single jersey and 1 × 1 rib structures produced with different yarn counts and 100% cotton yarns, and a 1 × 1 rib structure that was half-plated in alternating courses by defining four relaxation states of the different fabrics: two knits (knitting and dry relaxation and knitting and wet relaxation) and two dyed (dyed and dry relaxation and dyed and wet relaxation). The most significant dimensional variables were characterized in all the relaxation states and models were presented that explain the variability of the yarn length absorbed by the loop using other variables that are much simpler to analyze.

Inspection and feature specification of the fancy yarns using diffraction limited incoherent imaging

Chenille yarn features (pile yarn length, twist, hairiness, defect length, coefficient of diameter variation) were determined by diffraction limited incoherent imaging (DLIM) allowing to simulate sensor plane irradiance. The predicted image irradiance used in determining these features were obtained by deconvolving the captured image irradiance with incoherent point spread function designated by rectangular aperture. In twist values obtained by proposed DLIM, mean absolute relative error (|RE|mean) was determined as 0.822% by comparing Uster Twist Tester results. The DLIM in determining diameter provided better results with 0.8194% |RE|mean, compared to that 2.044% of optoelectronic method. The determination of hairiness fibers exceeding the ordinary lengths of pile yarns using Fourier domain high pass filtering (HPF) whose size is designated by the cut-off frequencies is proposed. These cut-off frequencies were determined in response to mean diameters obtained by image processing. The results of hairiness indices of HPF were compared with image processing results.

Modelling loop length in weft-knitted fabrics with an interlock structure after the dyeing process with a stitch density, Wales and courses per centimetre analysis

One of the variables that we need to know in knitted fabrics in order to explain variations in dimensions in their different relaxation states, which might occur during the production process, is the yarn length that a loop forms, known as loop length. To experimentally calculate it, quite a lengthy process is required and the following need to be identified: direction of wales, direction that samples unreave in, counting the number of loops in the fabric length, separating and measuring yarn with specific measuring equipment, and repeating these 10 times, according to regulation UNE-EN 14970. Thus, depending on the structure type to be analysed, the whole process can take a relatively long time to do this calculation. This study proposes a calculation system that simplifies the process, for which the yarn length absorbed by an estimated interlock structure was modelled, as was loop length, without having to follow such a time-consuming process.

Određivanje dužine pređe u petlji na bazi tehnoloških parametara mašine

Yarn length in a loop is one of the most important technological parameters in knitwear structure analysis. Therefore, determination of the accurate values of yarn length in a loop is of great importance in knitwear structure parameters projection. This paper presents comparative results of the determination of yarn length in a loop based on the loop row height, loop row width and calculated yarn diameter, as well as determination of loop length based on machine technological parameters taking into account needle pace, platinum and needle diameter, platinum and needle curved radius, span angle of yarn with needle and platinum and projected cooling depths. The results obtained show various values of yarn length in a loop.

Parameter Analysis of CNT Yarns in Smart 3-D Braiding Composites

Abstract An important method for making smart three-dimensional (3-D) braiding composites is to use embedded carbon nanotube (CNT) yarn sensors with 3-D braiding technology. According to the braiding structure of 3-D six-direction braiding composites, the mathematical model of carrier movement of braiding machine is constructed. The method for calculating the number and length of embedded CNT yarns with intelligent composites is proposed. The characteristics of resistance changing for CNT yarns under loading are analyzed. Experiments show that the error of the length and actual length of the CNT yarn calculated by the Bezier curve is less than 1 %. When the tensile strain exceeds 2 %, the strain of the embedded CNT yarns begins to appear nonlinear. The loading and unloading of the specimen have some influence on the resistance change of the CNT yarn. After the load is unloaded, the CNT yarn will produce the residual resistance.

NEW PARTNENCLONES OF BOOMBYX MORI L. FROM THE COLLECTION OF GENETIC RESOURCES OF UKRAINE

The purpose of the research is to investigate the ability to heat the parthenogenesis of new breeds silkworm T–1, T–2, D–1 silkworm breeds and to establish the reproductive, biological and technological parameters of the T–1clone, T–2clone and D–1clone created on their basis. Materials and methods of research. The research was conducted on the basis of the laboratory of silkworm and technical entomology of the National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine" during 2016–2018. For the study of the ability of new breeds of silkworm D–1, T–1, T–2 to the thermal parthenogenesis, the females of the aforementioned silkworms were used. Activation of the gravel to ameiotic parthenogenesis (complete thermal pathogenesis) was carried out using the method B. L. Astaurov The reproductive parameters of parthenoclon were studied: the ability to parthenogenesis (%), the total number of eggs (pieces), the weight of one egg (mg), the output of caterpillars from eggs (%). The economic-valuable and technological indicators of the created clones were investigated: viability of caterpillars (%), cocoon yields of 1 g of caterpillars (kg), silkworm cocoons (%), cocoon mass (g), length of filaments (m), length of continuous- unwound thread (m), raw silk output (%). The main results obtained. It is established that the new clones of silkworm silk created by the ability to parthenogenesis are at the control level. In terms of the viability of caterpillars in 2018, they are somewhat inferior to Ukr.28, but according to the results of three years of research, this indicator is at a level, and T–2clone even exceeds control by 4.84% (p < 0,05). Similar results are obtained on the basis of the weight of the cocoon. By the cocoon yield, the new Parthenoclon exceeds control in 2018 by an average of 0.44 kg and for three years of research – by 0.50 kg. The indicator of silk worminess of cocoons in T–1clones and D–1clones was at the level of the indicator Ukr.28clones, at T–2clone – was higher than the parameters of part-clones and control at 0.83–2.73%. The length of the thread, the length of the continuously unwound yarn and the output of raw silk is dominated by T–2clone – its values exceed the similar indicators of T–1clone and D–1clone, dominated by control indicators – Ukr.28clones. Thus, the new clones of silkworm, adapted to the changed climate in Ukraine, were introduced and evaluated. They can be components for the creation of new clone-breed hybrids with high biological and technological performance. The stands of silkworm hybrids will provide domestic branches of production of organic raw materials for the production of modern products. This will allow import substitution of organic goods for everyday use to our country's inhabitants. Domestic production of organic products in the form of clothing, medical and cosmetic products will provide the work of thousands of compatriots and reduce the cost of goods in comparison with imported ones. Prospects for further scientific research are the creation of new clone-breed hybrids with high biological and technological indices for Ukraine. Conclusions. 1. Three new high-yield silkworm clones with the optimal combination of silk productivity and ability to ameiotic parthenogenesis, characterized by the following biological indices, are derived: T–1clone – caterpillar livelihood 84.13%, cocoon yield 3.76 kg, cocoon mass 2.30 g, silkiness 21.62%; T–2clone – caterpillars' survivability 88.94%, cocoon yield 4.23 kg, cocoon mass 2.53 g, silicone 24.25%; D–1clone. – The viability of the caterpillars is 85.52%, the cocoons are 4.08 kg, the cocoon mass is 2.41 g, and the silicone content is 21.62%. The estimation of reproductive indices of created T–1clone, T–2clone and D–1clone clones was made and their ability to heat parthenogenesis was determined. The highest ability to ameiotic parthenogenesis has D–1clone – 72.73%. Parthenoclones T–1clone, T–2clone and D–1clone for reproductive characteristics are at the level of the control clone Ukr.28clones and are promising for clone- breed hybridization. The technological parameters of the new clones are established: the T–2clone is the leader in the length of the filament (1432m), the length of the continuous unwound yarn (734 m) and the output of raw silk (46.3%) – its parameters exceed the similar indicators in T–1clone and D–1clone at 2.5% and prevail over control indicators – Ukr.28clones – by 5.5%.

New computer geometric modeling approach with filament assembly model for two-ply yarns structures

This article presents a new computer geometric modelling approach for three-dimensional of two-ply yarn structures with filament assembly model. The geometric of individual filaments in two-ply yarn structures with uncompressed and compressed states were studied. In the uncompressed state the filaments in ply yarns have the form of coaxial double wound helices; we simulate the paths of these filaments in the ply yarns. In the compressed state the transformation of the initial filament distribution from the uncompressed state into the distribution after compression by a transverse force. The ply yarns cross-section uses the concept of virtual locations to simulate the filament distributions. Each cross-section is rotated along the single yarn and the ply yarn length. The curve of each filament in each two successive cross-sections is approximated by NURBS and then each curve is created by sweeping a closed curve along the centerline of the single yarn and ply yarn path. The method described is demonstrated in the uncompressed and compressed state of two-ply yarns by the CAD model using geometric parameters of the double-rove acrylic-fiber yarns. The simulation using this approach can demonstrate more realistic and improved visual simulations of real two-ply yarns.

New computer geometric modeling approach with filament assembly model for woven fabric structures

This paper presents a new computer geometric modeling approach for three-dimensional woven fabric structures. Pierce’s geometry of the weave fabric of yarn from an arc abscissa (Peirce’s) model is presented. Then, new algorithms with a filament assembly model for a single yarn composed of many filaments by twisting along the crimp shape in the warp/weft is developed. The concept of a virtual location is used to simulate the fiber distributions in the yarn cross-section. Each cross-section is rotated along the yarn length by a pre-determined amount to allow for the yarn twist. The curve of each filament in each two successive cross-sections is approximated by NURBS and then each curve is created by sweeping a closed curve along the centerline of the yarn path. The method described is demonstrated by the CAD model of woven fabrics with plain and twill weaves. The simulated woven fabrics using this approach can demonstrate a wider variety and improved visual simulations of real woven fabric and can then be further generalized for different and more complicated fabrics. The method is necessary as an input to many computational models, such as modeling the mechanical properties or the heat transfer of fabrics or composite parts.

Interactive design of periodic yarn-level cloth patterns

We describe an interactive design tool for authoring, simulating, and adjusting yarn-level patterns for knitted and woven cloth. To achieve interactive performance for notoriously slow yarn-level simulations, we propose two acceleration schemes: (a) yarn-level periodic boundary conditions that enable the restricted simulation of only small periodic patches, thereby exploiting the spatial repetition of many cloth patterns in cardinal directions, and (b) a highly parallel GPU solver for efficient yarn-level simulation of the small patch. Our system supports interactive pattern editing and simulation, and runtime modification of parameters. To adjust the amount of material used (yarn take-up) we support "on the fly" modification of (a) local yarn rest-length adjustments for pattern specific edits, e.g., to tighten slip stitches, and (b) global yarn length by way of a novel yarn-radius similarity transformation. We demonstrate the tool's ability to support interactive modeling, by novice users, of a wide variety of yarn-level knit and woven patterns. Finally, to validate our approach, we compare dozens of generated patterns against reference images of actual woven or knitted cloth samples, and we release this corpus of digital patterns and simulated models as a public dataset to support future comparisons.

Strain sensing fabric integrated with carbon nanotube yarn for wearable applications

Textiles, as a desired platform for wearable smart technology, can be integrated with smart elements in the hierarchical levels of the fabric structure. In this study, a new way to make strain sensing fabric was developed by embedding a single strain sensing carbon nanotube (CNT)-based yarn into the woven structure. To overcome the abrasion during insertion, the yarn was coated with poly(vinyl alcohol) (PVA) to achieve higher mechanical performance. The gauge factor of the yarn was improved from 0.91 to 1.64. The sensing properties of CNT/PVA yarn integrated strain sensing fabric showed a gauge factor of over 1.1, a degree of linearity of more than 97% and good stability and repeatability during cyclic loading. Fabric with different integrated yarn lengths, patterns and output connections has also been investigated. The results showed that the yarn length and bend over section had a great influence on the strain sensing properties of the fabric. Furthermore, the fabric strain sensor exhibited a quick and precise response to the finger motion detection, demonstrating potential in wearable electronics.

Yarn speed and length measurement using optical method in real time

Yarn speed and length are two important parameters in the winding process. A noncontact method is proposed to measure the speed and length of the microtension moving yarn automatically in the winding process. A moving yarn could vibrate sharply in the microtension range. With a line laser illuminating the moving yarn, a linear charge-coupled diode camera was used to capture the images. Based on different laser reflection of the yarn texture, we calculated the speed and length of the moving yarn by extracting different features of yarn texture. Yarns with different materials were used to prove the validity of the proposed method under different winding speed. Experiment works have been performed and compared with a direct contact sensor, and the results proved that the proposed method is effective.