Use of computer tools in forecasting the properties of knitwear

Попри значні досягнення у сфері моделювання структури текстильних матеріалів, задача забезпечення можливості застосування програмно-аналітичних комплексів для прогнозування властивостей трикотажу ускладнюється великою кількістю невирішених питань, серед яких відсутність стандартизованих методик досліджень у сфері 3D моделювання та симуляції фізичних процесів у текстильних матеріалах, способів верифікації моделей, відсутність баз даних фізико-механічних властивостей текстильних матеріалів. У ході роботи проаналізовано сучасні підходи до створення моделей структури трикотажу та вимоги до таких моделей з точки зору можливості їх подальшого використання у віртуальних експериментах. Розроблено загальну схему прогнозування властивостей трикотажу з використанням тривимірних геометричних моделей його структури. Сформульовано та запропоновано дотримуватись таких п’яти принципів моделювання структури трикотажу як: принцип виробничої доцільності, принцип параметризації, принцип декомпозиції, принцип реалістичності та принцип раціонального використання інформаційних ресурсів. Для реалізації принципу раціонального використання інформаційних ресурсів розроблено алгоритм дворівневого проєктування з використанням моделей мезо- та макрорівнів. Відомо, що дослідження властивостей трикотажу за допомогою його тривимірних геометричних моделей не завжди потребують деталізації на рівні ниток. Текстильні полотна відносяться до гетерогенних систем. Дворівневе проєктування передбачає необхідність використання моделей з деталізацією на рівні ниток (моделей мезорівня) на початковому етапі для виокремлення елементарного структурного фрагменту, за допомогою якого можуть бути розраховані гомогенізовані фізичні характеристики. На наступному етапі трикотажне полотно або виріб подається у систему проєктування у вигляді макромоделей, як оболонка заданої товщини, фізико-механічні характеристики якої приймаються з розрахунку попереднього етапу.The paper presents the results of analysis of scientific research and publications in the field of development of three-dimensional geometric models of knitted structures, current issues of designing knitwear with given properties, the capabilities of modern computer tools. Despite significant advances in 3D modeling of textile materials, the challenge of providing the possibility of using simulation software to predict the properties of knitwear is complicated because of a large number of unresolved issues, including the lack of standardized research methods in 3D modeling and simulation of physical processes in textile materials, verification methods, lack of databases of physical and mechanical properties of textile materials, etc. Modern approaches to the creation of models of knitted structures are being explored as well as the requirements to such models from the point of view of the possibility of their further use in virtual experiments. A general diagram for predicting the knitwear properties by means of three-dimensional geometric modeling has been developed. The following five principles of three-dimensional geometric modeling of the knitted structures are suggested as follows: the principle of production feasibility, the principle of parameterization, the principle of decomposition, the principle of realism, and the principle of rational use of information resources. To implement the latter principle, a two-level design algorithm using meso- and macro-level models have been developed. As is known, the study of the properties of knitwear using its three-dimensional geometric models may not always require the use of yarn level models. Textile fabrics belong to heterogeneous systems. Two-level design presupposes the need to use the yarn level models (Meso level models) at the initial stage to explore the elementary structural fragment, which can be used to calculate homogenized physical characteristics. At the next stage, the model of the knitted fabric or product is transmitted into the design system under the form of macro models, as a shell of a given thickness, the physical and mechanical characteristics of which are taken from the calculation of the previous stage

A proposal to model ancient silk weaving techniques and extracting information from digital imagery - ongoing results of the SILKNOW Project

Three dimensional (3D) virtual representations of the internal structure of textiles are of interest for a variety of purposes related to fashion, industry, education or other areas. The modeling of ancient weaving techniques is relevant to understand and preserve our heritage, both tangible and intangible. However, ancient techniques cannot be reproduced with standard approaches, which usually are aligned with the characteristics of modern, mechanical looms. The aim of this paper is to propose a mathematical modelling of ancient weaving techniques by means of matrices in order to be easily mapped to a virtual 3D representation. The work focuses on ancient silk textiles, ranging from the 15th to the 19th centuries. We also propose a computer vision-based strategy to extract relevant information from digital imagery, by considering different types of images (textiles, technical drawings and macro images). The work here presented has been carried out in the scope of the SILKNOW project, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 769504.Three dimensional (3D) virtual representations of the internal structure of textiles are of interest for a variety of purposes related to fashion, industry, education or other areas. The modeling of ancient weaving techniques is relevant to understand and preserve our heritage, both tangible and intangible. However, ancient techniques cannot be reproduced with standard approaches, which usually are aligned with the characteristics of modern, mechanical looms. The aim of this paper is to propose a mathematical modelling of ancient weaving techniques by means of matrices in order to be easily mapped to a virtual 3D representation. The work focuses on ancient silk textiles, ranging from the 15th to the 19th centuries. We also propose a computer vision-based strategy to extract relevant information from digital imagery, by considering different types of images (textiles, technical drawings and macro images). The work here presented has been carried out in the scope of the SILKNOW project, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 769504

Using high-fidelity virtual reality to study perception in freely moving observers

Technological innovations have had a profound influence on how we study the sensory perception in humans and other animals. One example was the introduction of affordable computers, which radically changed the nature of visual experiments. It is clear that vision research is now at cusp of a similar shift, this time driven by the use of commercially available, low-cost, high- fidelity virtual reality (VR). In this review we will focus on: (a) the research questions VR allows experimenters to address and why these research questions are important, (b) the things that need to be considered when using VR to study human perception, (c) the drawbacks of current VR systems, and (d) the future direction vision research may take, now that VR has become a viable research tool

FRAME MODEL OF UNIAXIAL STRETCHING OF 1x1 RIB KNITS

One of the nowadays challenges is the development of scientific sound models of knitwear deformations. The paper is devoted to developing an algorithm for constructing a frame model of rib 1x1 knits stretched in the course or wale direction. In the process of uniaxial stretching, the shape of the sample depends on the tensile forces orientation. A frame model of a deformed knitted structure, and an algorithm of construction of a mesh frame, are developed during the study. The frame model makes it possible to find coordinates of intermeshing points of every stitch. Then yarn characteristic points can be determined that, in turn, serve as input data for the construction of 3D model of rib 1x1 structure under uniaxial tensile deformations at the yarn level of detail. The study provides a graphical tool for formalization of geometric transformation that happen during 2D deformations of knitted structures, characterized by gradual change of the specimens width crosswise to the loading direction. This model is intended to become a part of a general deformation model of knitted fabrics

Macro-Modelling of Rib-Knitted Tubular Parts

The aim of the research was to improve the process of knitted products design. The use of modern software helps us predict the physical and mechanical behaviour of materials, using their three-dimensional models. A macro-model of rib-knitted tubular parts was developed in the study. This model allows its implementation into algorithms, describing the peculiarities of the stretching process. Recent findings in the field of 3D modelling and simulation of knitwear behaviour aim at working with models of different scales of structural hierarchy. The use of macro-models provides the opportunity to simplify the geometry and significantly reduce the time required for simulation. Rib stitch structures are among the most popular weft-knitted ones. When using threads of usual stretchability (with breaking elongation that does not exceed 10–12%), the stretchability of some rib stitch structures in the course-wise direction can reach up to 350% and even more. When stretched in the course direction, rib-knitted stitches undergo a number of stages. The stretching process includes: decreasing the width-wise curling; mutual shifting of knit and purl stitches; reducing the curvature of the loop feet and loop heads; pulling the yarn from the loop legs to the loop feet; stretching of the yarn. The assumption was made that such parts of knitted garments as cuffs and borders on sweaters, cuffs on socks, where rib stitch patterns are used, can be described as thin-walled elastic shells. A part of a human body surface, covered with a rib-knitted garment part, can be approximated by a truncated cone. The mid-surface of the shell can be represented as a ruled surface created upon a set of Bezier curves, located along the circumference of the upper and lower bases of the truncated cone. The mathematical description, elaborated in the course of the research, was used for the computer program LastikTube, which was developed to create 3D macro-models of ribbed tubular garments

Image Processing Based Pattern Recognition and Computerized Embroidery Machine

In the last decades, embroidery getting much attention in industries and academics. Although the technique is very old, it is still very much adopted. The current era of machine learning and smart devices makes this method even more attractive, easy to adopt and high accuracy. The proposed research work aims to highlight the implementation of new smart devices in this field, and the work is based on microcontrollers. Adopting the proposed work will be very easy and feasible to transform from the old sewing machine to a new smart method. Using smart devices, it is very easy and precise to get the embroidery fulfilling the user's demands. It gives simple raster images, which are used to convert into digital images to portray any new product. The current work is a novel idea of generating simple images rather than complicated ones, which are difficult to draw. In our method, we introduce the digitization process to input any image file used for vectorizing raster images, where vector images can easily convert into a DST embroidery file, a commonly used embroidery format originally from Tajima. It also has a Gcode file. The machine runs on a Gcode file which can be easily generated and runs on a product

PEMBUATAN KAIN RAJUT BULKY DENGAN MENGGUNAKAN MESIN RAJUT DATAR

Kain yang terbuat dari benang bulky memiliki berbagai keistimewaan, dan hal inilah yang membuatnyamenarik untuk diproses dengan berbagai metode, salah satunya adalah dengan menggunakan Mesin Rajut Datar(MRD) Single Bed, Gauge 6 merek Brother buatan Jepang. Tujuan penelitian ini, adalah untuk membuat kain rajutbulky dengan metode baru yaitu melalui proses perajutan dan pemantapan dengan menggunakan uap panas.Pembuatan kain rajut bulky ini menggunakan bahan baku benang kapas Ne1 40 dan benang poliester 150 D, yangdirajut masing-masing dengan tiga variasi skala stitch cam, serta menggunakan dua variasi kondisi dalam prosespemantapan panas.Hasil penelitian menunjukkan bahwa kondisi optimum diperoleh pada kain rajut poliester yangmenggunakan metode pemantapan panas dengan kondisi 70C, relaksasi 30 menit, tiga kali proses, yangmenghasilkan nilai tertinggi pada ketebalan kain (2,108 mm) dan crimp benang (131,56 %). Hasil uji ketahananjebolnya dan perubahan dimensi dari kain rajut tersebut memenuhi persyaratan SNI 2367. Selanjutnya dampak hasilpenelitian ini diharapkan dapat digunakan sebagai salah satu alternatif untuk substitusi bahan baku impor dalampembuatan kain rajut bulky yang dapat diaplikasikan pada industri kecil dan menengah