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Many users relate additive manufacturing (AM) directly with fast and high-quality prototyping and manufacturing. Nevertheless, already within the different printing techniques there are significant...

The Covid-19 pandemic has had a major impact on higher education across the world. In this paper we consider how textile education has been impacted and what approaches have been employed to maintain quality education and laboratory experience when traditional methods are not appropriate. This paper considers three different countries – United States, South Africa and Germany. Each has been affected in a different way, has a different sociological makeup, and has developed distinct solutions to the challenge. Methods related to HyFlex, flipped classrooms, and blending learning have been applied by all three institutions. Lectures have been presented as pre-recorded videos, synchronous video conferencing, and hybrid. Similarly, laboratory and studio experiences have been handled through pre-recorded video, guided “at home” experiments, and modified in-person experiences. This paper gives an overview of the laboratory and studio experiences, time spent in preparation, and reaction of the students to remedies. It also addresses best practices from each country in the three continents.

Braided structures are widely used in numerous contexts including everyday practice. In most cases, rope ends are knotted to form various types of loops or tie them to rigid body parts; however, knots take up space that may not be available in some application scenarios, thus making them unsuitable for certain purposes. Hence, this paper introduces first development steps of a method for the numerical simulation of rope ends connected by sewing stitches.

The purpose of this study is to investigate pregnant women’s maternity dress in relation to their body image at each stage of pregnancy. Firstly, in order to create pregnant body Blender software is used. Then Lectra ModarisV8R2 allows to create a pattern. Finally, Lectra 3D Fit simulate and visualize projects. The paper explains, how to gain pregnant body in Blender and how to prepare a project for visualization in Lectra. The result is pregnancy dress project in 4 sizes and tailored to each stage of pregnancy.

This chapter provides an overview of the different approaches for constructing the geometry of textiles at mesoscale level. Particular attention is paid to the topology-based methods, where 3D sketch of the fabrics is created based on information from contact points between the yarns. Several examples for woven, braided, and knitted structures are demonstrated. The yarn cross section does not remain constant within the textile structures and its definition for solid and multifilament yarns is demonstrated. Finally, some methods for transferring the 3D sketch to more realistic geometry are stated.

This paper presents latest development of a modelling algorithms and simulation results, related to 3D braiding machines with individually driven switches and horn gears. The early developed 3D braiding machines and the current software from the braiding producer covers only rectangular sets of horn gears. Based on complete emulation of the braiding process with the carrier motion, a generalized method for the simulation of any configuration of horn gears with different sizes was developed and reported earlier by the author. In this work, an extension of the algorithms with individually controlled switches is presented. These switches allow production of profiles for textiles reinforced composites with complex cross section, changing during the production. The machine emulation can be coupled with FEM based braiding process simulation and the complete product can be virtually produced and analyzed.

An empirical survey was conducted, manually evaluating the relative haptic preference of patterns in weft knitting for winter garments in Mönchengladbach, Germany. Thirty-six patterns were compared in a blind test using ranking orders with respect to six primary hand values (thickness, softness, warmth, weight, stiffness, and smoothness) and general preference for winter garments by 35 participants. Traits of popular patterns included softness and smoothness as well as tucked stitches, rib structures, and float stitches on the surface. On the other hand, unpopular patterns included lace, purl stitches, and ripples.

High X-ray absorption and, therefore, excellent X-ray protection properties are related to heavy chemical elements. Therefore, a composite fiber for X-ray protection applications was developed consisting of an organic cellulose part and an inorganic part. Whereas the preceding part provides the common properties connected to fibers and the latter part ensures the X-ray protection effect. The treatment of this composite fiber along the whole textile chain is presented and the possible usage as a common textile fiber in spinning and knitting processes is impressively demonstrated. Textile properties such as air permeability and abrasion stability are successfully tested. Furthermore, the microscopic structure is characterized by means of optical and scanning electron microscopy. The X-ray protective properties are determined by transmission experiments. The realization of a textile product is shown by production of a glove, where protective properties are impressively shown by 3D X-ray tomography. A...

This paper deals with performance properties related to human thermo-physiological comfort of three-layer textile systems used for the production of outerwear for cold protection. The transfer of heat and fluids through the compound single layers (woven and non-woven) is investigated and compared to the heat and mass transfer of the systems for clothing. Six characteristics are measured for both single layers and systems of layers: thermal resistance, air permeability, water vapor resistance, relative water vapor permeability, the accumulative one-way transport index and overall moisture management capacity. For each of the characteristics, regression analysis is applied to prove or reject the proposed mathematical dependencies between the transfer abilities of the single layers and the respective systems. The results obtained showed that the fluid transfer abilities of the single layers applied in clothing for cold protection strongly affect the fluid transfer ability of the system of layers, while the heat transfer of the system is dominated by the heat transfer ability of the thermo-insulating layer. The proposed approach for assessment of the transfer processes through a system of layers for the production of outerwear for cold protection could be successfully applied in the design of other textile and clothing items, produced by using systems of different textile layers.

Results are presented from a study on the prediction of the insulation abilities of outerwear clothing for cold protection from the point of view of the thermophysiological comfort of the wearer. The Required Clothing Insulation (IREQ) index is used to simulate the abilities of 14 assemblies of layers designed for the production of winter jackets to protect the body in different cold environments. The calculations allow to assess the limits of applicability of the garments in terms of the thermophysiological comfort assured, the activities performed and the weather conditions. Discussions are presented on the correspondence between ISO11079:2007 and the online JavaScript code for calculation of IREQ based on it. The results predicted and their analysis have a practical use, as they allow to estimate the cold protection effectiveness of the textile layers used in an assembly at the design stage, thusgiving room for necessary changes depending on the conditions of its use.

One of the key lessons learned during the pandemic of COVID-19 is that the digital education and adaptation of Information and Communication Technologies (ICT) should not be viewed as an island on its own but should be considered as an integral part of all education and training. The ICT-TEX project is an EU-funded project which aims to integrate ICT in online education of textile and clothing. Within the framework of this project, deficiency areas have been identified with a comprehensive survey conducted across the project partner countries. A new course curriculum has been developed based on desk research, field research, surveys, and Gap Analysis. Eight modules (around 16 courses) according to the needs of the textile and clothing industry (TCI) will be developed within the framework of the project. This paper discusses the methodology of applying ICT in new course content for Apparel Design and Production which is a pilot course and serves as a benchmark for further development of other courses.

This paper presents a comprehensive experimental study, conducted on a series of woven and non-woven fabric samples from different materials (cotton, polyester, and polyamide) and 14 three-layer systems of textile materials, used for production of outerwear clothing for protection from cold. Heat and mass transfer properties, related to the thermophysiological comfort of the outerwear clothing, namely conductive thermal resistance, water vapor resistance, relative water vapor permeability, air permeability, accumulative one-way transport of liquids, and overall moisture management capacity, were determined for the system of layers and the compound single layers. The transfer properties of the single layers were presented as a function of their thickness, mass per unit area, and areal porosity. The transfer properties of the system of layers were presented as a function of the thickness, mass per unit area, and bulk density of the systems. Regression analysis was applied to derive regression equations. The results obtained allowed assessment of the existence and trend of the influence, as well as evaluation of the strength of the dependences.

Larger set of warp knitted structures can be represented as set of knot points (loop heads) and linear connected between these. Suitable mechanical representations of these are truss frameworks. This chapter presents the model building, finite element method based calculation rules, implementation, boundary conditions, extension for double needle bed structures. The dependance betweeen the solvability of the equation and the boundary conditions is investigated. Some drawbacks, connected to the elasticity module and type of the structural elements is presented.

This chapter presents the fundamental approach of the description of the yarn paths in weft and warp knitted structures using selected key points. For most of the common structural elements, rules for calculation of the coordinates of their key points are defined, depending on the size of the loop, yarn and depending on the neighbor elements. Some problems and disadvantages of the method for specific elements are described. The approach builds the theoretical core of the modern CAD systems for 3D representation of knitted structures. Its efficiency is proven by its implementation in professional software.

This chapter represent applications of the topologically generated geometries of textile structures as initial geometry for FEM computations, performed by the author or his students. Reported are examples of knitted structures with HyperWorks and LS-Dyna and braided structures with Impact-FEM and VTMS. Examples of homogenisation of textile reinforced composites are reported using Voxelisation or using the method of inclusions within TexComp.

This chapter presents the modelling and programming issues about the storage of the structures on computer. After analysis of the textiles it is found, that two basic types of objects are required—virtual fibers and group of fibers. As the group of fibers can contain recursivelly another groups of fibers, it can be used for representation of the complete assembly. An overview about the possibilites of the TexMind suite, developed by author and the another textile based software is given.

This first chapter of the book introduces the different types of yarn based textile structures and gives short overview about the main works related to their modelling. The main modelling strategies for textiles are discussed and the difference between the topology, geometry, and mechanics based models is given. Finally, the structure of the book is explained.

The cloths and other ready to use products are normally represented as 2D objects. For thier modelling are used shell or plate elements, which elastic behaviour has to be identified bevore the modelling. The yarn level is seldom modelled until now for the ready structures, but with the increasing computational power this will become possible. This chapter presents a method of the structural cells, as topological units of the yarn level structure. Some direct applications in the area of spacer fabrucs and tubular fabrics are demonstrated. Issues of the modelling of cutting of fabrics are discoussed.

Common textile materials as cotton or polyester do not possess reliable X-ray absorption properties. This is due to their morphology and chemical composition in particular. Common fibers are built up from organic polymers containing mainly the elements carbon, hydrogen, oxygen and nitrogen. These “light” elements only have low X-ray absorption coefficients. In contrast, inorganic materials composed of “heavy” elements with high atomic numbers, e.g. barium or bismuth, exhibit X-ray absorption coefficients higher by up to two orders of magnitude. To obtain a flexible yarn with high X-ray absorption properties both these materials, the organic polymer and the inorganic X-ray absorber, are combined to an inorganic/organic composite fiber material. Hence, as the organic component cellulose from modified Lyocell-process is used as carrier fiber and blended with inorganic absorber particles of low toxicity and high absorption coefficients, as bariumsulphate, bariumtitanate or bismuthoxide. A content of inorganic absorber particles equally distributed in the whole fiber of up to 20% is achieved. The composite fibers are produced as staple or filament fibers and processed to multifilament or staple fiber yarns. The staple fiber yarns are rotor-spinned to increase the comfort of the subsequent textile material. Several woven fabrics, considering multilayer structure and different warp/weft density, are developed. The energy dependent X-ray shielding properties are determined in dependence on the different yarn compositions, yarn types and structural parameters of the woven fabrics. As a result, a production process of textile materials with comfortable and dedicated X-ray absorption properties is established. It offers a promising opportunity for manufacturing of specialized textiles, working clothes or uniforms applicable for medicine, air craft and security personal, mining as well as for innovative composite materials.

This works presents a numerical investigation about the production and simulation of braided products with complex cross section. The geometrical modelling of tubular and flat braids is already well described in the literature and implemented in several scripts and commercial software like TexMind Braider. In the literature are reported as well several works about the modelling of 3D braided structures, created using different 3D braiding techniques. For the case of complex maypole braiding machine with horn gears are reported some works with the software TexMind Braiding Machine Configurator, which emulates the carrier motion for the creation of the 3D geometry of the braids. This work presents evaluation of the possibilities of the software for designing machines with large number of horn gears in custom arrangements and at the same time presents the results of a large set of tests of the possible combinations for arrangements of horn gears with different size for the production of complex multilayer braided structures like T-, and double-T-profiles. The investigation shows, that the possibilities for carrier arrangement are directly connected with the topology of the tracks of these carriers and for structures with multiple tracks more empty places in the arrangement is required. For the cases, where for such structures suitable machine configuration and carrier arrangement is found, an simplistic 3D geometry of the braid is generated and can be used for FEM calculations, relaxation and other computations of the properties.

Triaxial braided reinforcements are extensively used as main constituent materials in various biomedical and composite applications. The material parameters, and the choice of process parameters during the braiding process, have a significant influence on the geometrical and mechanical properties of these reinforcements. In this study, the manufacturing on a braiding loom of triaxial braids with a large range of braiding angle is presented. On these samples geometrical properties, as bias yarn length, crimp, linear mass, are experimentally identified in function of the braiding angle. From uniaxial tests, the specific tensile behavior of these braided fabrics is characterized. These results are compared with analytical models described in the literature. Associated to this experimental approach, the geometry of these triaxial braids is numerically modeled thanks to TexMind Braider software dedicated for three-dimensional creation of braided structures. Comparison between characteristics experimentally identified and computed is analyzed.

About the 3D Modelling of Jacquard Warp Knitted Structures This paper presents a method for extending the algorithms for 3D modelling of warp knitted structures, which allows 3D simulation of jacquard warp knitted structures. It starts with short overview of the state of the art and presents some modelling issues and two simulated examples of jacquard structures.

International audience; In the production of body armor panels, multilayer aramid fabrics are normally used. A main problem of these panels is the high weight and consequential lower comfort for the wearer. In a recent survey it was shown that most officers in the United States would prefer an improved comfort and also reduced weight in their ballistic vests. To reduce layers with a concomitance of the same safety standards, the panel has to be improved. One solution is to reduce the slippage of the yarns during the penetration of the knife and with this to increase the absorbed impact energy. The tests showed that the placement of a layer of wool fabric on the top of the aramid panel changes the penetration behavior. The main goal of this work is the investigation of the influence of the woven wool structure over the penetration of aramid panels. For this investigation, the stab resistance of five aramid fabrics with different properties and patterns combined with one layer of wool on the top and bottom of the panel has been tested and compared against pure aramid panels, according to the VPAM test instruction “Stab- and Impact Protection”. In addition, an optical evaluation of the stab tests has been done using a high-speed camera. Also, the stab recess in the aramid layers was evaluated optically, using a digital microscope. The experimental results confirm that wool can increase the stab resistance of body armor panels, but results are dependent on the properties and pattern of the aramid fabrics, too.

Designing and developing braids requires specific knowledge about the structure, properties of the yarn, settings of the machine and other parameters. There are several works in the scientific literature that provide a large number of equations to calculate unknown braid parameters if some of the other values are known. Most of these works are useful for a scientific approach, but are often not practical for the everyday use in an industrial workspace environment. It would simply take too much time and effort for an engineer in a braiding company, to solve integrals in order to find the mass of a braid or another parameter. This paper presents an evaluation of the software TexMind Braider, which implements the above-mentioned scientific equations and performs several calculations automatically for the user. The benchmark has the goal to check and identify possible applications of this software, to find errors in the implementation or in the theories behind the equations and to state the general limitations of using geometrical models for modelling. The comparison will include a tubular braid with a monofilament yarn, a tubular braid with a multifilament yarn and a flat braid with a monofilament yarn.

In recent years, conventional garments and electronic components have been combined to produce wearable diagnostic systems for monitoring vital signs in medical applications, or novel fashion effects, visual displays, or audio and computing systems. Another area of interest is the integration of sensors and actuators into fibers as the development of high efficiency conducting polymer actuator fibers and conducting polymer fibers with chemical sensing is about to be realized. Sophisticated smart textiles and wearable systems will, however, require wearable energy-storage capabilities. There is a great need to develop fiber-based batteries that contribute to a deeper integration of active smart components in textiles and hence to realize a stand-alone smart textile system. We followed this approach and present in this paper our first results on textile-based batteries. We used combination of different metal coated textile structures serving as electrodes. On both electrodes thin gel-like layers of gelatine-based electrolyte filled with a metal salt were applied. Finally, I-V curves of different structures were measured.

Warp knitted fabrics are widely used in medical and technical applications, as well as for clothing textiles. To predict their properties, it is useful to have knowledge about the yarn geometry and the yarn interactions within these fabrics. The geometrical modelling of warp knitted structures from single bed knitting machines is documented in the literature. This text concentrates on a computation of the geometry of warp knitted structures, which have complex 3D forms or which are draped over similar ones. The topological information about the structure produced on the machine, is used to create the basic geometry of this structure. After creating the basic geometry, it is transferred to a 3D deformed state of the relaxed fabric. The paper starts with a short overview of the research papers about simulation of warp knitted structures. General theoretical remarks about the transformation from basic structure to 3D structure are given. Examples of spacer fabric with constant or non-constant thickness and tubular fabrics are included. All the results concentrate on the topological representation of the geometry and at this stage do not take into account the influence of internal and external forces exerted on the fabric.

This article presents the theoretical background for the arrangement of horn gears in maypole braiding machines in order to act as equivalent larger gears. The theoretical analysis is verified with numerical simulation and experiments. After review about the state of the art, an analysis of the process for one specific configuration of horn gears is given. This analysis demonstrates how a set of horn gears can be arranged to work as an equivalent to a larger one horn gear. The braiding equation is checked as remaining valid for such extended configurations, too. The theoretical result is verified using numerical simulation for all cases and practical validation for several variants. The theoretical rules give a clear extension of the current braiding knowledge and make the design of complex configurations of braiding machines more systematic and clear.

Three dimensional structures can be produced on jacquard warp knitting machines with double needle bed. This work presents theoretical considerations about the modelling and simulation of these structures. After that a method is described, how to obtain production parameters from the simulation data. The analysis demonstrates, that the automated pattern creation of 3D structures is not always possible and not all mathematical solutions of the problem can be knittable.

This chapter presents the basic methods for the modelling and simulation of woven, braided and knitted fabrics and wound packages. All these structures are built by yarns and thus there are several common aspects during their modelling. emphasis is given to the geometrical methods for the calculation of the yarn paths of these structures. some possible extensions of the models for consideration of the mechanical interactions between the yarns are discussed and examples of the capabilities of some commercially available CAD systems for design and simulation of textile structures are presented.

This chapter describes the basics of the finite element method (FEM) and its application for modelling of textile structures. It gives a brief introduction to the basics of the modelling of mechanical systems in the static and dynamic cases, some of the ideas behind the finite element method and a short overview of FEM software.

In this chapter an overview is presented of modelling methods for warp and weft knitted structures. The chapter begins with basic information about knitted structures, their classifications and the observation scales. After this introduction, the basic structural elements as main modelling elements at the meso-scale level are explained, followed by the basic problems and required steps during the modelling. The model generation is discussed in three main parts, checking the input data, topology generation and mechanics of the structure. For the mechanical model, two paths are presented, continuum and discrete. Some additional problems connected with the form of the yarn cross-section, yarn unevenness and contact treatment are followed. Finally, different ways of postprocessing the data are explained, including yarn volume rendering, visualization and other calculations, based on the modelled data and some application areas.

The textile fibers and yarns are usually modeled as one dimensional continuum of beams or as a system of particles, connected by springs. The governing equation of motion of such systems has many solutions, which switch in between depending on the available energy of the system. Effective modeling of problems with bifurcations like these, applicable for more general geometries is rarely reported. In the present work we demonstrate, that using a system of particles and an appropriate change of variables, a successful time step integration either by the Leap-Frog or the Verlet algorithms is possible.

In this paper two methods for 3Dimensional modeling of the plain weft knitted structures are presented. The aim is models to be more realistic concerning yarn cross section properties. The first model is based on the assumption that yarn cross section changes to ellipse-like form in the areas with high curvature. The second one is a discrete particle model of the loops, which takes into account the local changes of the yarn following from the contact forces. It calculates actual yarn geometry on the contact places iteratively, as general nonlinear compression behavior of the yarn is assumed.

Mathematical model for calculation of the stress-strain behavior of the wound package is presented. It uses the split of the body of cylindrical layers with finite thickness under assumption for orthotropic, linear elastic behavior of the single layers. The numerical results demonstrate, that in certain cases the windings and layers lose their tension forces, where the winding package loses its stability. Wound structures are widely used in the textile production for storing (depositing) and transporting of textile yarns during the production of textiles. Each package usually consists of only one yarn, which is wound over the cylindrical or conical tube. The wound structure is stable because of the light tension in the yarn. The stability of the structure depends on a large number of processes and material parameters. These parameters and their interactions are still not investigated completely [1]. Well known are stability conditions for piece of yarn over certain surface, based on the static friction coefficient and the geodesic angle of the surface. These conditions do not describe completely the stability of the whole package. In some cases, the inner or outer layers of the bobbin are being deformed significantly and the package is no more usable. In order to analyze and predictthe conditions, where the package loses its stability, the stress-strain behavior of wound packageshas to be investigated. There are works in some particular fields, for instance for the cases of filament winding and warp beams winding [2], [3], [4], [5] etc., as well as for fabric rolls [6]. Here we use the same mathematical model to obtain the stress-strain distribution, but the winding layers are represented as orthotropic (not isotropic, as in many in earlier works) material. The higher orthotropy causes numerical problems. They are avoid by using analytical solution with software MAPLE.