2—the Mechanics of Staple-Fibre Yarns Part I: Modelling Assumptions

Luijk, C. J. van; Carr, Athol J.; Carnaby, G. A.

doi:10.1080/00405008508631774

Cited by 17 publications

(14 citation statements)

References 8 publications

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“…For decades, textile scientists worldwide have been studying the mechanics of flexible fiber assemblies and investigating the effect of fiber properties on yarn properties, especially tensile properties [1][2][3][4][5][6][7][8][9][10][11]. Several models have been developed to understand the mechanics of yarn formation and failure [2,5,8,10,111.…”

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confidence: 99%

Influence of Fiber Length Distribution on Strength Efficiency of Fibers in Yarn

Zeidman

Sawhney

2002

Textile Research Journal

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The tensile and tear strengths and hence the durability of a cotton fabric are greatly influenced by the length and strength of cotton fibers in addition to the fabric structure. This is so because fiber length to a large extent determines yam strength, which ultimately contributes to fabric strength. Also, fiber length and its distribution affect fiber processing and hence yarn performance during subsequent mechanical processing, including knitting and weaving. Therefore, fiber length distribution and its ultimate effect on the yarn strength are important. To better understand the length-strength relationship in cotton fibers, we have tried to model the strength of fibers assemblies in a yarn, based on some simple assumptions. In this model, we address an important issue of friction among adjacent fibers in a yarn structure and also introduce and derive a new parameter called the "strength efficiency" of fibers in a yarn, which may contribute to an understanding of the yarn failure mechanism. The paper should be helpful to the scientific community involved in improving the properties of cotton fibers, yarns, and fabrics.Although fiber migrations and the resulting entanglements are very important in yarn formation, fiber length, fineness, and strength and their respective distributions/ consistencies are even more critical parameters in determining the effectiveness of the ultimate fibrous assembly (yarn). For decades, textile scientists worldwide have been studying the mechanics of flexible fiber assemblies and investigating the effect of fiber properties on yarn properties, especially tensile properties [1][2][3][4][5][6][7][8][9][10][11]. Several models have been developed to understand the mechanics of yarn formation and failure [2,5,8,10, 111. For example, a semi-empirical expression developed from work by Grosberg and Smith on worsted rovings to predict the breaking strength of low-twist woolen-spun yarn reveals the relative importance of the contribution of fiber length and fiber strength to estimated yarn strength [ 10]. They examined the effect of carbonizing in altering fiber strength and entangling and showed that fiber length has the most marked influence on yarn strength. Tests have also shown that fiber slippage is an important part of the yarn failure mechanism. Van Luijk et al. developed a model for the long-gauge behavior of staple-fiber yarns based on Hearle's work incorporating fiber migration and slippage [ 11 ]. The tensile strength of the model stems from frictional forces, which are calculated using the Grosberg theory of fiber-withdrawal force from a sliver. The governing equations of the staple fiber/yarn model have been formulated and solved using the finite element method.Since fiber length and strength greatly influence yarn , strength, we have tried to develop a model to express yarn strength as a function of the accumulated strengths of the individual fibers in the yarn cross section. In this research approach, we use the following simplifying assumptions: First, the fibers are quasi...

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Influence of Fiber Length Distribution on Strength Efficiency of Fibers in Yarn

Zeidman

Sawhney

2002

Textile Research Journal

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“…The number of fibres aiding the withdrawal of the fibre at the location of the section will be all those that will ultimately move to the left but with shorter tails than L, namely: L Hence [7,8], since * Grosberg [4] has shown that ^i' is given by The value of P can be obtained by locating the maximum normal G tress on any plane parallel to the z-axls. Let a and a be the transverse stresses on the previous increment in two orthogonal directions x and y lying in a plane perpendicular to the sliver axis z.…”

Section: Conditioh For Grippingmentioning

confidence: 99%

“…Hearle [6] has provided a derivation for C for the case of a yarn composed of fibres all of the same length, and van Luijk et al [7,8] have carried out an analysis that applies to specific migration paths in spun yarns, again on the assumption that all the fibres have an Identical length. The following analysis allows for the more realistic case where the fibres are of various lengths as defined by the length-biassed fibre-length distribution, N^(L).…”

Section: Conditioh For Grippingmentioning

confidence: 99%

“…The maximum force, WF, that can be exerted on a shorter slipping tail of lengtii L will be given [7][8][9] where P = transverse pressure on the silver, WF -withdrawal force per unit length when P " 0, )i' = propor tlonall ty f ac tor (with dlmens ions of length )*, and C -proportionality factor accounting for the fact that, whereas some fibres In contact with the tail will oppose its withdrawal, others will aid it.…”

Section: Conditioh For Grippingmentioning

confidence: 99%

“…If we are given the stresses and strains from the previous increment, the critical length can be calculated by using the principles of single-fibre withdrawal theory previously used by Hearle [6] and van Luijk et al [7,8].…”

Section: Conditioh For Grippingmentioning

confidence: 99%

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