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Sewing stitches are used to connect two or more textile structures. Their modelling is required at the places, where the yarn level model has to contain all elements. This chapter represent the topological rules for modelling the main types of stitches. Considerations about the number of keypoints and the type of the interpolation of the curve between these are given.

The topological methods, described in the previous chapters, can be used for representation of an idealized geometry of the textile structures. In order the relaxed state of these structures to be achieved, mechanical compuations has to be performed. This chapter presents few mechanical methods, developed by the author and applied for calculation of the mechanical equilibrium of textile structures. The yarn is modelled as diskretized model and the dynamics equilibrium equation is integrated in the time using Verlet algorithm. Application of the algorithm for unwinding yarn and for knitted structures are demonstrated.

This chapter presents algorithms for the topological modelling of braids with complex cross sections. These can support the development of the machine configurations, needed for the braiding process of profiles with an arbitrary cross section form, using the may pole braiding technique. The composite profiles, made from carbon, glass or natural fibers, are used more commonly and in various application areas. This is the case, because of their lower weight compared to the metal profiles and the natural connection between the yarns in the given form. In order to produce a cross section form, the engineers have to arrange large numbers of horn gears on the machine plate, to define the tracks and the arrangement of the carriers without collision. Experimental trials of such tasks are very time and resource consuming and trials on paper are not very effective as well. The presented original algorithms model the key machine parts and their interaction—horn gears with their sections hold the carriers which move along the tracks—in a way that the motion of the machine can be simulated and evaluated.

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.

The geometry of the tubular and flat braided structures is predictable using parametrical relations between the carrier arrangement, machine configuration and some yarn parameters. This chapter presents generalized topological algorithm for calculation of the interlacing points of tubular and flat braids with arbitrary floating length and yarns in a group. Some drawbacks of the algorithm for larger or smaller than 45\(^\circ \) braiding angles and for multiple yarns in a group are presented and possible solutions for these cases are discussed. Placement of the yarns in triaxial braids and the yarn configurations at different types of flat braid structures are analyzed and included in the models.

The woven structures are significantly more and deeper investigated than all other textile structures. This chapter gives short overview about the topological, geometrical and mechanical models of woven structures for the sake of completeness of this work. Still, some important issues related to the coding of woven structures are discoussed.

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.

The textile yarns are often modelled as tubes for simplicity, but in the reality the yarns have their internal fiber based structure. This chapter presents a method for filing the yarn volume with predefined set of filaments, following the yarn axis. The natural twist of the curve is indepenent from the textile related twist, which has to be considered during the sweeping the cross section. Another point is the way of the interpolation of the yarn axis between the key points. Discussed are the advantages and drawbacks of generalized parametric modelling and of the exact function description of the curves between each two points.

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.

This paper presents an overview about the patterning possibilities of the new variational braider of the company Herzog GmbH. Presented are two practical examples with the sequences of their programing and some issues about the programming with the user interface. Some configurations for production of flat braids are checked using simulation software TexMind Braiding Machine Configurator. It is found that regular flat braids with three carriers and irregular flat braids with four carriers can be produced with the machine as well.

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.

The following study deals with the main interlacement variations and possibilities of the new covering technology D-3F. There are well-known processing technologies for the covering of extruded hoses or other tubular cores in order to increase their radial stiffness, like braiding or spiraling. The main disadvantage of the spiraling layers is the limitation in stability of the single windings, caused by missing interlacements. An advantage might be the fiber deflections and the resulting directed mechanical properties in combination with the achieved productivity. On the other hand, it is impossible to cover cores with changing diameters and resulting local angles higher than the friction angle of the current materials. These forming cores or profiles are often covered by the more suitable braiding technology. Braided structures can be produced stably based on proper interlacement between the two or three thread systems inside. In fact, the braiding technology has its limitations concerning the productivity. The interlacement of the thread, which stabilizes the structure from one side, is the reason for broken filaments as a result of the deflection of the threads from the other side. The number of broken filaments is proportionally increasing with the speed of the braiding process. In order to combine the advantages of both spiraling and braiding into a new productive and fiber-friendly technology, a new machine concept was developed and patented. The new weaving-like binding structure “D-3FG” (“Denninger-3Faden Geflecht”) combines the properties of two layers and weaving-like interlacements.

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.

Woven belts and tapes are used in wide area of technical applications and as reinforcement for composites. Contrary to the art design of the woven fabrics, where the colour and pattern appearance is more important than the mechanical parameters, in the technical products the strength, stiffness, compressibility and other mechanical properties have the importance.

This work presents an investigation about the bending rigidity of double braided ropes. The braid structure is subjected to bending condition by fixing one end and leaving the other end to hang freely and bend under its own weight to a set deflection limit and its length is measured. The length and deflection are then used to calculate the bending stiffness and bending moment using the beam deflection equation. The bending behavior of single braided and double braided tubular ropes is also studied and compared. Highest bending rigidity was obtained with double braided tubular ropes compared to single braided tubular ropes. It is observed that, braided structures are very weak under transverse loading, their strength are improved when more structural layers are braided together. High braiding angle of braid structures is observed to improve bending stiffness and bending moment.

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.

In this study, the mechanical behavior of double braided tubular ropes under tensile loads is studied experimentally and analytically. The outer braid is referred as the braid cover and the inner braid is considered as an elastic tubular braid core. A predictive model of the mechanical response of the braids based on the constituent monofilament (yarn) properties and braid geometry based on known research works was used. The model has accounted for the changes in the braid geometry, including braid angle and diameter. Both braid angle and diameter are found to be critical design parameters. Image analysis is employed to experimentally characterize the structural parameters of the braids and their deformation. The structures are tested in tension and their stress–strain response is recorded. The experimental results have been compared to the theoretical stress–strain curves of braid cover-core structures and the results have been observed to agree well between them, though the theoretical model underestimates the Young’s modulus of the braid cover-core structure.