FRAME MODEL OF UNIAXIAL STRETCHING OF WEFT-KNITTED STRUCTURES IN THE WALE DIRECTION

Abstract

The purpose of this study is to develop a frame model for stretching the weft-knits in the wale direction, suitable for further integration into the algorithm for building a three-dimensional knitwear model in a stretched state and modeling of interactive deformation dynamics. Methodology.  Methods  of  theoretical  analysis,  basics  of  knitting  theory,  topological  model  of knitwear, methods of geometric modeling and parameterization were used in the research process. Findings. Modeling the physical and mechanical behavior of knitwear in a computer environment is one of the promising ways to increase the level of conformity of knitted products with the requirements of comfort and functionality. However, the complexity of the internal structure, the anisotropy of properties and the instability of the parameters of the loop structure determine the need to find non-trivial ways to solve the problem of mathematical description of the three-dimensional model of the thread, knitted in the knitwear, considering the stretching deformations. During  the  study,  a  frame  model  of  a  uniaxial  stretching  of  knitwear  in  the  wale  direction  was developed. The basis of the frame model is the idea of a knitted structure, represented as a logically organized set of elements, each of which is interlaces with other elements in accordance with the topology of knit. The
frame of the jersey fragment is described as a set of bars and hinges. The hinges are located at the interlacing points of the loop heads and loop feet, and each rod in the model is an imaginary element representing a
complex of force factors that prevent the change of distance between the hinges connected to the given rod. In the process of stretching, the geometrical characteristics of the elements change, while the logical
connections remain unchanged. The wireframe model allows to define coordinates of interlacement points in the coordinate system of the sample, relative position of coordinate systems of each elementary fragment, which correspond to  given  loops,  coordinates  of  characteristic  points  of  a loop  for  transition  to  a three-dimensional model of a knitted structure. Scientific novelty. For the first time, a frame model of deformation of the knit, suitable for three-dimensional modeling of its structure, considering deformation of the thrust, was developed.
Practical value. The developed model can be used as mathematical support of systems of automated designing of knits.