Study on the structure formation and heat treatment of helical auxetic complex yarn

Liu, Sai; Pan, Xingxing; Zheng, Dongfang; Du, Zhaoqun; Liu, Gui; Yang, Shu

doi:10.1177/0040517518760754

Cited by 17 publications

(22 citation statements)

References 21 publications

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“…Development of the DHY includes an auxetic plied yarn [212], auxetic braided structure [160], and a DHY where the 'wrap' fibre is stitched in place to offer more control over its behaviour by preventing fibre slippage [213]. Heat treatment has also been utilised to solve the issue of slippage [214]. The initial angle at which the wrap fibre is spun around the core fibre, and the diameter ratio of wrap to core fibre influences the value of the NPR, whereby a lower yarn wrap angle increases the magnitude of NPR [215][216][217].…”

Section: Fabricating Auxetic Textilesmentioning

confidence: 99%

Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection

Duncan

Shepherd

Moroney³

et al. 2018

Applied Sciences

230

151

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Following high profile, life changing long term mental illnesses and fatalities in sports such as skiing, cricket and American football-sports injuries feature regularly in national and international news. A mismatch between equipment certification tests, user expectations and infield falls and collisions is thought to affect risk perception, increasing the prevalence and severity of injuries. Auxetic foams, structures and textiles have been suggested for application to sporting goods, particularly protective equipment, due to their unique form-fitting deformation and curvature, high energy absorption and high indentation resistance. The purpose of this critical review is to communicate how auxetics could be useful to sports equipment (with a focus on injury prevention), and clearly lay out the steps required to realise their expected benefits. Initial overviews of auxetic materials and sporting protective equipment are followed by a description of common auxetic materials and structures, and how to produce them in foams, textiles and Additively Manufactured structures. Beneficial characteristics, limitations and commercial prospects are discussed, leading to a consideration of possible further work required to realise potential uses (such as in personal protective equipment and highly conformable garments).

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Section: Fabricating Auxetic Textilesmentioning

confidence: 99%

Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection

Duncan

Shepherd

Moroney³

et al. 2018

Applied Sciences

230

151

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“…However, it remains to be a challenge to produce stable helical yarns, with matched lengths of the two yarn plies, that influences yarn auxeticity in a great extent. Recently, to overcome the yarn slippage problem causing dismatched ply lengths, Liu et al worked on the heat treatment for their two‐ply auxetic yarns with a thermal melting component, to improve the structural stability . Another method is using circular braiding technology for making auxetic yarns, where the stiffer ply was directly braided onto the core helically.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, to overcome the yarn slippage problem causing dismatched ply lengths, Liu et al worked on the heat treatment for their two-ply auxetic yarns with a thermal melting component, to improve the structural stability. [22] Another method is using circular braiding technology for making auxetic yarns, [23] where the stiffer ply was directly braided onto the core helically. Researchers worked on yarns with more plies, and these yarns exhibited auxetic effect as well.…”

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confidence: 99%

Manufacture and Evaluation of Auxetic Yarns and Woven Fabrics

Gao

Liu

et al. 2020

Physica Status Solidi (b)

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Auxetic materials expand in the transverse direction under tensile loading in the longitudinal direction, or contract when compressed, in contrast to the conventional materials. [1] Negative Poisson's ratio (NPR) was reported in natural materials by Viogt in the late 19th century. [2] Evans et al. advised that NPR structures and materials could be renamed as "auxetics" for convenience from the Greek word "auxetos." [3] The auxetic characteristics have been reported on fundamental theory in 1989, [4] and different structures including re-entrant structure, [5] folded structure, [6] and honeycomb structure. [7,8] Also, many auxetic materials have been discovered up to date. Iron pyrites were found auxetic with the Poisson's ratio of À0.14, [9] polyurethane foams were reported for a NPR value of À0.7, [5] and warp-knitted and weft-knitted fabrics were found to demonstrate NPR effect too. [10,11] Alderson and Evans experimented on microporous ultrahigh molecular-weight polyethylene (UHMWPE) and found the Poisson's ratio ranged between 0 and À1.24. [12] There are two general approaches for making auxetic textiles. The first one is using the conventional yarns with specially designed fabric structures, such as the reentrant structures and rotating structures for knitted fabrics [13] and bistretch auxetic woven fabrics with re-entrant hexagonal geometry. [14] The other approach is to use auxetic yarns directly to make fabrics. Some researchers produced auxetic woven fabrics using double helix yarns, and their studies showed that such fabrics demonstrated the some level of auxeticity and increased porosity. [15,16] An out-of-register double helical yarns were used to produce double-pick woven fabrics by Miller et al. [17] which showed that the two-layer fabric assembly had the auxetic effect with the Poisson's ratio to be À0.1. In addition, Hu and coworkers [18,19] created an auxetic yarn with a fourply structure with the Poisson's ratio of about À2.0, and it was used to make woven auxetic fabrics which demonstrated much smaller auxeticity. It has to be said that despite the progress in making fabrics from auxetic yarns, the responses of the fabrics under tensile loading need further clarification. High modulus fibers together with an elastic core element are the most commonly used materials for manufacturing auxetic yarns. Helical auxetic yarns (HAYs) are one type of the most promising yarns for exploitation according to Hook. [20,21] HAYs have been made of two or more plies of component yarns with different diameters and with extremely different elastic moduli. These plies were twisted together, with the thinner and stiffer yarn wrapping over the thicker and more elastic core ply. When stretched, the two types of plies would swap their roles, leading to a situation where the thinner and stiffer ply became the straight core and the thicker and more elastic ply turned into the binder, as shown in Figure 1. However, it remains to be a challenge to produce stable helical yarns, with matched lengths of the two yarn plies, t...

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“…14 The structural problem of the yarn was overcome, but the auxeticity of the braided yarn needs to be further investigation. Recent research by Liu et al 15 proposed a heat treatment for HAYs, where a polyamide (PA) filament with a melting point of 80 C together with the wrap ply were wrapped around the core ply. Then after the 120 C heat treatment in an oven, the melted PA improved the contact state between the two plies without tension.…”

mentioning

confidence: 99%

Experimental and numerical study of helical auxetic yarns

Gao

Chen

Studd

2020

Textile Research Journal

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Auxetic materials, including textiles, exhibit a negative Poisson’s ratio (NPR), which is of interest for many applications. This research aims to optimize the structural parameters of helical auxetic yarns (HAYs) and to evaluate the auxetic performance of these yarns. The research reports on the improvement of auxetic yarn quality and the yarn auxeticity through studying the effect of helical angles, diameter ratio and tensile moduli of the two plies, as well as the binder filament feeding. The maximum NPR of the optimized auxetic yarns was experimentally achieved as low as –9.6, with the helical angle of around 14.0° on average using the optimal machine setting. The optimized yarn parameters enabled the making of high-quality auxetic yarns with a wider range of machine settings than before. In parallel, theoretical and numerical studies were carried out for the engineering design of auxetic yarns, which enabled comparisons among the experimental results, calculated results and results from finite element analysis. The comparison showed that a lower initial helical angle, higher tensile modulus of the wrap ply and lower tensile modulus of the core ply led to a higher auxetic effect. A new finding is reported in that a concave relationship between the diameter ratio and the NPR was discovered. The results of this study could assist researchers in producing HAYs, and this type of HAY could be used for many potential applications, such as filtration and impact protection.

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Study on the structure formation and heat treatment of helical auxetic complex yarn

Cited by 17 publications

References 21 publications

Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection

Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection

Manufacture and Evaluation of Auxetic Yarns and Woven Fabrics

Experimental and numerical study of helical auxetic yarns

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