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  • Author: Iva Mertová x
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Abstract

Fabric properties and fabric structure prediction are important in each industry domain. Generally all professional CAD packages for woven textiles system will be able to achieve basic fabric simulation and production output. A good CAD system should enable you to create design (dobby and jacquard woven fabric) ideas quickly and easily to enhance the way you work. The differences among competing systems fall mainly into the following categories: ease of use; speed of operation; flexibility of operation; advanced features; technical support; and ongoing software development. Computer simulation or prediction is oriented on standard woven fabrics, technical textiles, and composites. This article focuses on the presentation of software ProTkaTex and its use in the prediction of woven fabric properties. The software implements a generalized description of the internal structure of woven fabric on the unit cell level, integrated with mathematical models of the fabric relaxed state. User can calculate selected mechanical and end-use properties of dobby and jacquard woven fabric as well as can evaluate fabric behavior before real weaving. The major challenge is to develop software that industry will use in design centers for creation and development of new fabric structures for technical as well as clothing application.

Abstract

The article focuses on a new approach for characterization and evaluation of lateral yarn deformation. A small review about theoretical description and measurement possibilities will be introduced. The evaluation of yarn compression will be done by three innovative methods (lateral deformation of yarn between two parallel plates, simulation of binding point of fabric, cross-sectional analysis of real fabric). The analysis of yarn deformation will be carried out for a set of samples in combination of fiber material, yarn count and given fabric structure.

Abstract

This paper analyzes the relationship between technological parameters of spinning of 100% CV Vortex yarns of different counts and its selected geometrical parameters (a lead of helix of wrapping fibre ribbon, yarn diameter) as well as yarn properties. The number of twist of wrapping fibre layer is determined. The effect of the yarn delivery speed, hollow spindle diameter, and the main draft on the hairiness, mass irregularity, tenacity, elongation, resistance to abrasion and bending rigidity of Vortex yarn is observed. The yarn properties are compared with the properties of open-end rotor spun yarns. Slivers of the same spinning lot were used for the production of both kinds of yarn. The results showed that the delivery speed in combination with spindle diameter affects yarn diameter, hairiness and abrasion resistance. Mass irregularity and imperfections of yarn is mainly affected by the main draft of drafting unit. Technological parameters of spinning do not affect the level of bending rigidity of the Vortex yarn. Tested rotor spun yarns had a larger diameter, higher hairiness, lower tenacity and higher elongation, lower mass irregularity and number of imperfections, higher abrasion resistance and lower bending rigidity compared to tested Vortex spun yarns.

Abstract

Owing to twisting of filament fiber bundle, the structure and consequently various parameters and properties of a fiber bundle are changed. The aim of the work is to verify the effect of multifilament yarn twist (or twist coefficient) on selected mechanical properties such as multifilament tenacity, breaking elongation, and coefficient of fiber stress utilization in the yarn. Furthermore, the influence of twist on structural parameters such as the angle of peripheral fibers, the packing density, and the substance cross-sectional area of fiber bundle is observed. Two multifilament yarns with different filament cross-section shape and material were used for the experiment. Experimentally obtained data was compared with the known model dependencies derived decades ago based on the helical model. It can be stated that multifilament yarn retraction can be predicted based on the angle of peripheral fibers using the Braschler’s model. The coefficient of fiber stress utilization in the multifilament yarn determined experimentally corresponds with a theoretical curve, constructed according to Gégauff and Neckář, in the area of Koechlin’s twist coefficient α > 54 ktex1/2 m−1. Results as well as possible causes of deviations of experimental data from the theoretical one are discussed in this work.