Chegg soru görüntüleme hk

SORUNUN CEVABI


yarns of woven fabric is not still completely investigated. The aim of this work was to establish which of the weave factor is most suitable to describe slippage resistance of yarns at a seam in woven balanced weave fabrics. Fifteen wool fabrics were weaved for investigations, which differ only on weave. They all were weaved with rapier “Vamatex” looms from the same back rest. So all the fabrics were weaved with the same setting and technological parameters. They all have the same linear density of warps and wefts – 12.5 tex×2, warps setting is 300 dm –1 , wefts – 260 dm –1 . The warp ends were drawin-in on 12 heald frames straight pass and fifteen balanced weaves, which can be weaved on 12 heald frames were chosen. The weaves were chosen in such a way that they could be woven at the same loom settings (see Fig. 1). Slippage resistance of the yarns at a seam in woven fabrics was measured with a tensile testing machine Zwick/Z005, according to international standard “Determination of the slippage resistance of yarns at a seam in woven fabrics – Part 1: Fixed seam opening method” (LST EN ISO 13936-1: 2004) and according Woolmark test method (TM 117 “Seam slippage of woven fabrics”) at 78 N force distance between yarns after slippage has been measured. In this research only tests of seam slippage in the weft direction were carried out (warp yarns slipping over weft yarns). All results were statisticallyharacteristics are influenced by its structure. There are seven parameters influencing woven fabric structure: the raw material of the warp and the weft, the linear density of warp and weft, the warp and weft setting and the weave of the fabric [1 – 3]. All seven parameters of the fabric’s structure can be evaluated by integrated fabric structure factors. Various scientists proposed different evaluations of all these fabric parameters. According to the methods of evaluation of these parameters, two groups of integrated factors are distinguished: the first is based on the Peirce theory and the second on the Brierley theory. Peirce’s group factors express the covering of a fabric surface with threads, and Brierley’s group factors are defined as a ratio of analysing fabric density with standard fabric density [4, 5]. This group also includes average float length F, which was offered by Ashenhurst and weave factor P offered by V. Milašius. It is well known factor – the average float length F, which was offered by Ashenhurst [6, 7]. It was very simple and widely used factor. Later it was observed that this factor didn’t describe all the properties of a weave, which are important from a technological and end-use point of view. This factor could not evaluate the difference between types of weaves (it is well known that the weaves twill 7/1, satin 8/3 and panama 4/4 have a different tightness, but are still counted with the same only a single thread float, but an interlacing of adjacent threads too and can be calculated for all the types of the weaves. Weave factor P describes beating-up process very well [8] and it measures fabric structure describing some of its properties, such as elasticity, air permeability and other [1 – 3]. However, factor P is very good for balanced weaves but it cannot evaluate the difference between unbalanced weaves – warp rib 4/4 and weft rib 4/4 have the same value, P = 1.205. Later V. Milašius proposed factor P1, calculated in the warp direction [1]. It covers most of the weaves used. Such technological and constructional parameters as position of back rest, heald levelling advance, geometry of shed, weft and warp yarns stress in general meaning, may influence on fabric structure. It was measured in previous work, that properties of fabrics with the same setting pa-rameters, but weaved with not identical technological parameters, are different [9]. Such properties of fabrics as air permeability, strength, elongation, etc. were investi-gated by many authors. Many studies have been performed on the woven fabric structure influence on different fabric properties. Investigations showed that woven fabric structure influences on fabric