Mechanistic Role of Yarn and Fabric Structure in Determining Tear Resistance of Woven Cloth

Abstract

The goal of this study is to acquire an understanding of the manner in which cotton yam properties (including structure) contribute to the tear resistance of woven fabrics as measured by the tongue tear test. Our approach to this overall goal is a three step process. First, we examined samples during and after failure to identify the important phenomena that contribute to tearing strength, termed the subcomponents of tear. Next, we designed tests to observe the isolated contributions of pull-in (of yams into the del zone), pull-ahead (of yams towards the untorn fabric), and yam tenacity. Finally, in Part II of this paper, we will describe a model based on a mechanical spring analogy that will allow us to predict load-displacement responses of woven fabrics being torn.Whereas tensile strength might be seen as a minimum strength requirement that ensures the quality of raw materials and finishing processes, tearing strength can be considered an assessment of the serviceability of a fabric [ I 0 ] .Tearing strength (in conjunction with abrasion resistance) should be a concern of potential buyers as an indication of the useful life they should expect from their purchase. Although there are a variety of ways to measure the strength of a fabric that is tearing, predicting these results from a knowledge of more basic constituent yarn and fabric properties is key. This is not a trivial matter, especially when one considers the number of variables to be considered. Beyond the weave texture adjustments, which can be made in the mill by appropriate loom adjustments, are the &dquo;microscopic&dquo; properties such as compaction, bending rigidity, and frictional properties of yarns, all of which depend on the spinning technology used to form them. These factors, in turn, influence in-fabric behavior such as crimp interchange, shear transfer, interyarn normal forces, and the like. The goal of this work is not to derive a completely predictive model of tear, but rather to isolate the primary factors that contribute to the resistance to fabric tear. These factors can then be analyzed, assessed for relevance, and integrated into a predictive model. Past modeling attempts have not been successful in the jump from yarn / fabric structure and behavior to tear strength prediction. The approach we have taken here is put forth as a first step toward developing a completely predictive model. '

Stochastic modelling of tear behaviour of coated fabrics

“…load arresting the crack propagation. The trend of the curve agrees qualitatively with results reported in existing literatures [18,19]. figure 7, to the effect that, with the increase of fabric strength A, the initial tear load T I increases almost in a linear manner, reflecting the fact that a greater load is needed to break a stronger fabric, while the arrest load T A remains almost constant to retain the crack.…”

“…As a critical indicator of the serviceability of a fabric, tearing strength is rigorously examined when estimating the useful life of the fabric. Although there are simple ways to measure such strength, theoretical prediction and modelling continue to be difficult, due to the many variables that contribute to the complicated mechanisms involved in the tearing process [16][17][18][19]. Examples include the development of a del-zone in a tongue tear test (see figure 1).…”

Accelerated Weathering of Firefighter Protective Clothing Containing Melamine Fiber Blends

“…The number of transverse yarns in the Del zone, which support the applied load, is thus reduced. However, this trend is not straightforward and discrepancies may arise due to differences in the failure mechanisms [28]. The slightly higher tear strength value for BKP (113 N ± 6 N) as compared to BK fabric can be attributed to the presence of PBO fibers in the fabric blend and the weave of the fabric.…”

Wing Tear: Identificationn of Stages of Static Process

“…The application of previous models was not fully satisfactory for different variants of fabric structure. Then the problem was analyzed by Seo (Scelzo et al, 1994a), who broaden the Taylor's (Taylor, 1959); (Letters to the Editor, 1974) model by the proposed by him parameters of the tearing zone geometry. The common feature of both models was an existence of such parameters as: the friction coefficient (thread by thread in a fabric), mean thread breaking force, distance between the axes of neighbor threads.…”

“…Scelzo, Backer and Boyce (Scelzo et al, 1994a); (Scelzo et al, 1994b) proposed the description of phenomenon taking place in the cotton fabric during the tearing basing on the tearing zone shape analysis and adapting the rheological model consisted of spring arrangement for a description of tearing process. Now, the resistance on the static tearing is one of the most important assessment criteria of strength parameters of fabrics destined for the work and protective clothing, high-tech textiles, technical and interior textiles, upholstery and daily used clothing.…”