STUDY OF THE PROCESS OF STRECHING IN THE COURSEWISE DIRECTION OF DIFFERENT KNITTING RIB STRUCTURES

Abstract

Study of the process of deformation of rib knits, which occurs due to the application of tensile forces in the course direction. Methodology.  During  the  study,  methods  of  theoretical  analysis,  a  camera,  a  stretching  frame, Microsoft Excel software and Autodesk AutoCAD were used.
Findings. For producing rib knit samples, a 10th class flat-bed knitting machine PVRK was used. Samples of knitwear were made with repeatable unit patterns of 1x1, 2x2, 3x3, 4x4, 5x5 and 6x6 from bamboo
yarn of linear density 29x2 tex, woolen yarn 32x2 tex, half-woolen yarn 31x2 tex and Polyacrylonitrile yarn 32x2 tex. To carry out uniaxial stretching of knitted fabric samples along the line of stitch rows, a stretching frame was used. After fixing the opposite ends of the sample on the needle set of the frame holders, the distance between them gradually increased with an interval of 20 mm. At each stage of stretching, the samples were photographed together with a calibration ruler. Sample photos imported into Autodesk AutoCAD software. After calibration, for each state of stretching of the sample, such characteristics were determined as: the average value of the width of the repeatable unit pattern, the average value of the width of the convex part of
the pattern, as well as the visible section of its concave part. The study showed that at the first stages of stretching,  there  is  a  mutual  displacement  of  the  sections  of  the  pattern,  belonging  to  different  layers  of knitwear and a decrease in the twisting of the sections of the smooth surface. Further application of the tensile force leads to a more uniform deformation of the ivestigated structural parts of the pattern.
Scientific novelty. The change in the geometric characteristics of rib knits with various repeatable units patterns made from various types of raw materials is experimentally determined. Practical value. The characteristics of knitwear, obtained in the course of the study, were used to form
a database necessary for the construction of three-dimensional models of rib knits with bamboo, woolen, semi-woolen, and polyacrylonitrile yarns.