The Torsional Behaviour of Singles Yarns. Part I: Theory

Tandon, S. K.; Carnaby, G. A.; Kim, S. J.; Choi, Fook Choon

doi:10.1080/00405009508631326

Cited by 13 publications

(14 citation statements)

References 20 publications

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“…[The measured deflections have been converted into a torque value using equation (1).] This demonstrates that the technique can be used successfully to measure the torque per strand independent of the size of the hank.…”

Section: Properties Of the Torque Per Strandmentioning

confidence: 99%

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Torque in Worsted Wool Yarns

Mitchell¹,

Naylor²,

Phillips

2006

Textile Research Journal

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A direct technique developed for measuring yarn torque is explored for the case of worsted wool yarns. The technique balances the torque in a yarn hank against a wire of known torsional rigidity. It is shown that this technique gives a reliable measure of the torque per strand independent of the size of the hank. The torque per strand was found to be linearly dependent on the applied external tension and a finite torque exists even at zero applied tension. This leads to the concept of resolving the torque into two components, (a) the torque due to the applied tension and (b) the intrinsic torque that exists in the untensioned yarn. The torque due to the applied tension does not depend on the yarn history but only on yarn geometric factors such as the yarn twist and linear density. By comparison the intrinsic torque depends on factors such as the level of yarn set as well as the twist and linear density. These components of torque due to tension and intrinsic torque are shown to be consistent with literature models and lead to estimates of yarn specific volume, yarn packing fraction and relative fiber relaxation moduli after steaming.

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Section: Properties Of the Torque Per Strandmentioning

confidence: 99%

“…In the case of a yarn, theoretical considerations indicate that this torque, arising from external forces, dominates the total yarn torque under even moderate tensions [1,10,11].…”

mentioning

confidence: 98%

Torque in Worsted Wool Yarns

Mitchell¹,

Naylor²,

Phillips

2006

Textile Research Journal

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“…The torque due to tension was remodeled by Bennett and Postle (1979) to allow for the effect of fibre migration and showed that the torque due to tension dominates the total yarn torque under even moderate tensions; see also Tandon et al (1995) and Grishanov et al (1997). The…”

Section: Yarn Torquementioning

confidence: 99%

Predicting torque of worsted singles yarn using an efficient radial basis function network-based method

Tran

Phillips

2007

Journal of the Textile Institute

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The torque in single-spun yarns is an inherent property of the twisting and bending of staple fibres during the formation of yarn combined with the effect of applied tension on the yarn.The consequences of yarn torque are well known and are widely observed as yarn instability, e.g., yarn rotation under tension; local snarling and entanglement at low loads, and as distortion in fabric, i.e., edge-curl and skewing in knitted fabric. In this paper, a method for predicting the yarn torque based on the radial basis function networks is presented and evaluated. This method uses a "universal approximator" based on neural network methodology to minimize noise during training of the network and to approximate the yarn torque as a function of the geometrical and physical parameters of yarns (twist, linear density) and the applied load. The current method is an integral radial basis function network-based approach suitable for textile engineering and gives very good prediction of yarn torque across a range of yarn structural parameters and test conditions.

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“…With Equation 6. the theoretical stress-strain curve can be easily worked out, so the job left is to determine the boundary of integration.…”

Section: Yarn Modelingmentioning

confidence: 99%

A New Tensile Model for Rotor Spun Yarns

Jiang

Postle

2002

Textile Research Journal

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This paper reports a refined model to predict the tensile behavior of rotor spun yarn from the knowledge of specimen specifications and yarn strain. Fundamental approaches used in modeling include a discrete fiber-modeling principle, an energy method, and a "shortest-path" hypothesis. The study is based on a coaxial-helix structural model, taking account of nonuniform yarn packing density. Most importantly, a changing-pitch system is introduced for the first time in yarn modeling. A pitch function is thus determined with the aid of a nonlinear regression method and a curve-fitting approach using images obtained from a tracer fiber technique. The model is also compared with experimental data, together with a theoretical analysis of fiber strain distribution, confirming that, due to the introduction of the changing-pitch system, the model is very successful in explaining the experimental observations.The study of yarn structure and the positioning of constituent fibers to form a continuous strand have attracted the attention of many textile researchers [4, 5j. However, most current yarn models are developed for general use, and little attention is paid to the difference between yams produced on various spinning systems. A typical example is that pitch, the yarn axial length within a whole twist, has always been identified by previous researchers as the reciprocal of twist level, a machine . data product. This is, of course, not appropriate when considering the inherent variations in different yam types. For instance, twist insertion in rotor spun yarn operates layer by layer. As a result, its twist magnitude from yam axis to yam surface cannot be a constant and thus cannot be obtained from machine twist data, as we often do with ring spun yarn. This phenomenon has never been included in previous models known to us and hence has become one of the subjects of this work. .A prominent feature of our work is that it adopts the energy method, which has been successfully used in modeling the mechanical deformation of textile fiber assemblies [!-3, 6, 7]. Moreover, the packing density of a yarn cross section is no longer considered uniform but a function of radial position. We also include Camaby's &dquo;shortest-path&dquo; hypothesis jt]―under tensile load, a yam will be separated into two regions, a jammed region and an unstrained region surrounding it. The jammed region implies that the packing density of this region has reached a prescribed maximum value. Tensile strain can only be accumulated within fibers in this region because fibers outside can readily move inward or outward to avoid being strained. Based on these considerations, we attempt here to postulate the phenomena likely to occur, to construct a model that represents them, and to test the validity of that model against experimental observations.

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The Torsional Behaviour of Singles Yarns. Part I: Theory

Cited by 13 publications

References 20 publications

Torque in Worsted Wool Yarns

Torque in Worsted Wool Yarns

Predicting torque of worsted singles yarn using an efficient radial basis function network-based method

A New Tensile Model for Rotor Spun Yarns

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