Variation of Poisson’s ratio of fabrics woven with helical composite auxetic weft yarns in relation to fabric structural parameters

2019 ◽  
Vol 50 (2) ◽  
pp. 149-169
Author(s):  
Asal Lolaki ◽  
Mohsen Shanbeh
Keyword(s):  
Poisson’S Ratio ◽  
Structural Parameters ◽  
Processing Technique ◽  
Poisson's Ratio ◽  
Image Processing Technique ◽  
Weft Yarn ◽  
Warp Yarn ◽  
Dimensional Changes ◽  
Weft Direction ◽  
Yarn Count

Auxetic textiles are defined as textiles with negative Poisson’s ratio. These textiles possess unique properties that render them suitable for special applications. This work aims to investigate the effect of fabric structural parameters such as thread densities, weave design and warp yarn count. Thus, 30 fabric samples were woven at 3 weft and 2 warp densities, respectively. Two warp counts and three weave designs of plain, basket 3/3 and weft-backed satin 6 were used. The samples were uniaxially loaded in weft direction and dimensional changes at various strains levels were evaluated. The evaluation was carried out using the image processing technique based on MATLAB software. The weft yarns used were found to exhibit auxetic behavior at the whole spectrum of the strain level used. The least weft yarn Poisson’s ratio was found to be −0.9. It was established that in general the fabric samples exhibit auxetic effect within the stated range of strain. Additionally, it was concluded that while fabric thread densities together with warp count influence the minimum fabric Poisson's ratio, auxetic behavior of the samples is not dependent on weave design alone. Rather, it was illustrated that the combined effect of weave design in association with stated structural parameters on auxetic feature cannot be ignored.

scholarly journals Effect of Fabric Structure and Weft Density on the Poisson's Ratio of Worsted Fabric

2013 ◽  
Vol 8 (2) ◽  
pp. 155892501300800 ◽  
Author(s):  
Nazanin Ezaz Shahabi ◽  
Siamak Saharkhiz ◽  
S. Mohammad Hosseini Varkiyani
Keyword(s):  
Poisson’S Ratio ◽  
Uniaxial Extension ◽  
Poisson's Ratio ◽  
Weft Yarn ◽  
Combination Effect ◽  
Weft Direction ◽  
Weave Structure ◽  
Fabric Structure ◽  
Fabric Structures ◽  
High Linear Correlation

This paper investigates the impacts of weave structures and weft density on the Poisson's ratio of worsted fabric under uniaxial extension. In this study nine groups of worsted fabrics comprising of three weave structures (twill 2/2, twill 3/1 and hopsack 2/2), each produced in three different weft densities were examined. Samples were extended in weft direction uniaxially and the Poisson's ratio of fabric in various extensions was measured. Analysis showed that the effect of both weft density and weave structure are significant with no combination effect on the Poisson's ratio. It was found that there is an exponential correlation between warp and weft crimp during fabric extension. For the worsted fabrics used in this research in all three fabric structures, fabrics with higher weft yarn density have higher value of Poisson's ratio. It was also concluded that for the fabrics with the same condition but only different in structures, this ratio is related to the structural firmness of fabric. In all three fabric structures the value of the Poisson's ratio were following the same pattern of twill 2/2, twill 3/1 and hopsack 2/2 from highest to lowest value. It was revealed that there is a high linear correlation between the crimp interchange ratio and Poisson's ratio.

The Effects of Jacquard Woven Fabric Constructional Parameters and Elastane Yarn on Bending Rigidity

2015 ◽  
Vol 10 (2) ◽  
pp. 155892501501000
Author(s):  
Gülcan Süle
Keyword(s):  
Woven Fabrics ◽  
Experimental Results ◽  
Woven Fabric ◽  
Weft Yarn ◽  
Bending Rigidity ◽  
Warp Yarn ◽  
Weft Direction ◽  
Bending Property ◽  
Yarn Count ◽  
Overall Bending

In this research, the bending property of jacquard woven fabrics and the effects of weft density, weft yarn count, weave, and Lycra inclusion in weft yarn on this property were investigated. Viscose filament warp yarn and polyester and polyester/Lycra weft yarns were used for weaving fabrics, and 4/1 and 7/1 satin weaves with the same jacquard design were used as the ground weave. Experimental results show that the bending rigidities of the fabrics in the warp directions increase as the weft density increases and the weft yarn gets thicker. The bending rigidities of the fabrics woven with a 4/1 satin weave in the warp direction are higher compared to the bending rigidities of the fabrics woven with a 7/1 satin weave in the same direction. Similar to the bending rigidities in the warp direction, as the weft density increases and the weft yarn gets thicker, the bending rigidities of the fabrics in the weft directions increase. When the weft yarn includes Lycra, the bending rigidity values of the fabric decrease in the weft direction. Additionally, similar to the bending rigidity in the warp direction, the jacquard woven fabrics with a 4/1 satin weave have a higher bending rigidity in the weft direction compared to the jacquard woven fabrics with a 7/1 satin weave. It was observed that when the weft density increases, the overall bending rigidities of the fabrics increase. Despite fabrics woven with a polyester/Lycra weft yarn having a thicker weft yarn and heavier weight with the same weft density and weave compared to fabrics woven with a polyester weft yarn, the bending rigidity values in the weft direction have a lower overall fabric bending rigidity.

A study of tubular braided structure with negative Poisson’s ratio behavior

2017 ◽  
Vol 88 (24) ◽  
pp. 2810-2824 ◽  
Author(s):  
Ning Jiang ◽  
Hong Hu
Keyword(s):  
Poisson’S Ratio ◽  
Structural Parameters ◽  
Uniaxial Extension ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Yarn Diameter ◽  
Wrap Angle ◽  
Negative Poisson's Ratio ◽  
Braided Structure ◽  
Braiding Angle

Textile structures with negative Poisson’s ratio (PR) behavior are called auxetic textile structures. They have received increasing attention in recent years and have been designed and fabricated through spinning, knitting, weaving and non-woven methods. However, auxetic textile structures fabricated using braiding method have not been reported so far. This paper reported a novel type of auxetic braided structure based on a helical structural arrangement. The geometry of the structure and its deformation mechanism were first introduced and described. Then a special manufacturing process was developed by the modification of commonly used tubular braiding technology. Various auxetic braids were fabricated with different structural parameters and yarns and tested under uniaxial extension conditions. The results showed that all manufactured braids exhibited high negative PR behavior and maintained this behavior until the fracture of the component wrap yarn. Among three structural parameters discussed, namely wrap angle, braiding angle and braiding yarn diameter, the wrap angle had more effects on the tensile properties of auxetic braided structure than the other two parameters. The success of fabricating auxetic braids with commercially available yarns in this study provides an alternative way to manufacture auxetics from positive PR materials.

Design and modeling of an electromagnetic launcher for weft insertion system

2018 ◽  
Vol 89 (5) ◽  
pp. 834-844 ◽  
Author(s):  
Emad Owlia ◽  
Seyed Abbas Mirjalili ◽  
Mostafa Shahnazari
Keyword(s):  
Numerical Procedure ◽  
Processing Technique ◽  
Experimental Methodology ◽  
Image Processing Technique ◽  
Weft Yarn ◽  
The Finite Element Method ◽  
Projectile Velocity ◽  
Electromagnetic Launcher ◽  
The Relationship ◽  
Specific Amount

An electromagnetic launcher can be used as an accelerator for yarn attached to a ferromagnetic projectile. As a result, yarn endures a specific amount of tension. In addition to the yarn variables and the type of weft insertion system, the parameters of the weft yarn accelerator strongly affect the weft yarn velocity, its tension, and consequently the fabric quality. An applicable model that can represent the relationship between input and output parameters of this weft insertion system is very useful for predicting the strike of the projectile. Therefore, in this research a 3D imitating launching model was developed by the finite element method. A coil electromagnetic launcher was employed. An experimental methodology using an image-processing technique was also utilized to measure the projectile velocity. Numerical results were compared with experimental results to verify the numerical procedure. A validated model can be a reliable tool to investigate the effects of many process parameters on the strike of the projectile and to optimize them. Therefore, the system parameters can be scientifically defined by this model to insert a weft yarn.

DFT study of SmXO3 (X = Al and Co) for elastic, mechanical and optical properties

2018 ◽  
Vol 32 (32) ◽  
pp. 1850362 ◽  
Author(s):  
A. Afaq ◽  
Abu Bakar ◽  
Sajid Anwar ◽  
Waheed Anwar ◽  
Fazal-e-Aleem
Keyword(s):  
Optical Properties ◽  
Poisson’S Ratio ◽  
Density Functional ◽  
Structural Parameters ◽  
Poisson's Ratio ◽  
Published Data ◽  
Generalized Gradient ◽  
Elastic Parameters ◽  
Functional Theory ◽  
Anisotropic Factor

The first-principles study of cubic perovskites SmXO3 (X = Al and Co) for elastic, mechanical and optical properties is done in the framework of density functional theory (DFT). Optimized structural parameters are obtained first to find mechanical and optical properties of the materials. These obtained structural parameters are in accordance with the published data. The cubic elastic parameters C[Formula: see text], C[Formula: see text] and C[Formula: see text] are then calculated by using generalized gradient approximation (GGA) as an exchange correlation functional in Kohn–Sham equations. Poisson’s ratio, shear modulus, Young’s modulus and anisotropic factor are deduced from these elastic parameters. These compounds are found to be elastically anisotropic and SmAlO3 is brittle while SmCoO3 is ductile. Their covalent nature is also discussed by using Poisson’s ratio. In addition, optical properties like absorption coefficient, extinction coefficient, energy loss function, dielectric function, refractive index, reflectivity and optical conductivity are studied. This study predicts that SmAlO3 and SmCoO3 are suitable for optoelectronic devices.

Tuning the Optical Properties Through Bandgap Engineering in Si-Doped YAuPb: ab Initio Study

2021 ◽  
Author(s):  
Fida Rehman ◽  
A. Dahshan ◽  
Muhammad Shariq ◽  
Pervaiz Ahmed ◽  
Y. Saeed
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Poisson’S Ratio ◽  
Density Functional ◽  
Structural Parameters ◽  
Poisson's Ratio ◽  
Optical Parameters ◽  
Full Potential ◽  
G Ratio ◽  
Band Gap Structure

Abstract In order to probe the band gap engineering to tune optical properties in YAuPb1-xSix (x = 0, 0.25, 0.50, 0.75 and 1) alloys, we used all electron full-potential linearized augmented plane wave (FP-LAPW+lo) method within the frame work of the density functional theory. The optimized structural parameters were in good agreement with other theoretical and experimental results. The calculated results of elastic constant satisfy the condition for mechanical stability at each composition for cubic symmetry. In addition, the study of elastic parameters are summarized for the calculation bulk modulus, Young’s modulus, shear modulus, Kleinman parameters, Poisson’s ratio and Lame’s co-efficient. To predict the brittle (ductile) nature of this composition, the Cauchy pressure, Poisson’s ratio and B/G ratio were also calculated. Using modified Becke and Johnson GGA, the band gap values of each composition were computed precisely. Further, it was observed that for 0.25 < x < 0.75, band gap structure revealed a direct band gap configuration. In order to analyze the electronic structure of each composition, the total and partial densities of states have been investigated in detail. Furthermore, the investigation of optical parameters in terms of dielectric functions revealed the potential of these alloys for optoelectronic devices.

Tensile property of highly twisted cotton yarns under varied relative humidity

2016 ◽  
Vol 28 (4) ◽  
pp. 390-399 ◽  
Author(s):  
Htet Htet Htike ◽  
Jian Kang ◽  
Sachiko Sukigara
Keyword(s):  
Relative Humidity ◽  
Tensile Tests ◽  
Woven Fabric ◽  
Weft Yarn ◽  
Content Type ◽  
Weft Direction ◽  
Yarn Twist ◽  
Cotton Yarns ◽  
Yarn Count ◽  
The Difference

Purpose – The traditional Japanese cotton-crepe fabric chijimi has been used for summer clothing for over a century because of its good skin comfort. The high extensibility of this fabric relies on the high-twist cotton yarns used in the weft direction. The purpose of this paper is to show the effect of environmental humidity on the extensibility of highly twisted cotton yarns to help in choosing weft yarn suitable for woven fabric. Design/methodology/approach – Four highly twisted cotton yarns are examined under 10-90 percent RH and in 25°C water. Cyclic tensile tests are performed to obtain the tensile energy, resilience, extensibility at maximum applied load (EM), and residual strain. Findings – Comparing the same yarn-count samples Y1 and Y2, the EM of Y2 (2,200 T/m) is larger than that of Y1 (1,000 T/m) under all RH conditions, and the difference increases at humidity over 60 percent RH. For fabric crepe samples woven by Y1 (warp) and Y2 (weft), the extensibility (EM-1) in the weft direction is in the range 16-26 percent, which is equivalent to that of outer-knitted fabrics. The extensibility and recovery of chijimi is largely dominated by the twist of weft yarns, which is also influenced by changes in relative humidity. Originality/value – The skin comfort of Takashima chijimi has been of interest, but the high extensibility of this cotton fabric has not been given much attention. The results of this study show that yarn twist is key to controlling extensibility in high-humidity environments.

Static and Dynamic Loading Behaviour of Auxetic Thermoplastic Foams

Aerospace ◽  
2004 ◽  
Author(s):  
Paolo Pastorino ◽  
Fabrizio Scarpa
Keyword(s):  
Poisson’S Ratio ◽  
Thermoplastic Polyurethane ◽  
Constant Strain Rate ◽  
Image Data ◽  
Processing Technique ◽  
Polyurethane Foams ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Stress Strain ◽  
Negative Poisson's Ratio

The paper describes the manufacturing and tensile testing of auxetic (negative Poisson’s ratio) thermoplastic polyurethane foams. The foams are produced from conventional flexible polyurethane basis following a manufacturing route developed in previous works. The Poisson’s ratio behavior over tensile strain has been analyzed using an Image Data processing technique based on Edge Detection from digital images recorded during quasi-static tensile test. The samples have been subjected to tensile and compressive tests at quasi-static and constant strain-rate values (up to 12 s−1). Analogous tests have been performed over iso-volumetric foams samples, i.e., foams subjected to the same volumetric compression of the auxetic ones, without exhibiting a negative Poisson’s ratio behavior. A model describing the compressive stress-strain behavior of the auxetic foams has been developed considering the stress-strain performance of single unit cell and making use of statistical distributions of relative densities and buckling loads on auxetic foam cells during loading.

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