Experimental and numerical studies of thermoregulating textiles incorporated with phase change materials

Phase change materials (PCMs) provide thermal management solution to textiles for the protection of wearer from extreme weather conditions. PCMs are the substances which can store or release a large amount of energy in the form of latent heat at certain melting temperature. This research reports practical and theoretical studies of textiles containing PCMs. Mono and multifilament filaments incorporated with microencapsulated phase change material (MPCM) have been developed through melt spinning process. Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) have been performed for the characterisation of MPCM polypropylene filaments. The parameters for optimum fibre processing and their effect on mechanical properties of filaments with respect to the amount of MPCM have also been studied. A plain woven fabric has been constructed using the developed MPCM multifilament yarn. The heat transfer property of the multifilament yarn and fabric has been investigated using finite element method. The time dependent thermoregulating effect of yarn and fabric incorporated with MPCM has also been predicted according to the validated models. The synthesis of Nanocapsules containing mixture of paraffins and Glauber’s salt as PCM and its characterisation using DSC and SEM has also been carried out. Polypropylene monofilament incorporated with the nanoencapsulated paraffins was developed and its properties have been compared to its MPCM counterpart. Furthermore the developed nanocapsules were applied on a cotton fabric via a pad-dry-cure process and the resultant fabric was evaluated using DSC and SEM in comparison with MPCM treated fabric. The research work described in this thesis has established a better understanding of use of phase change materials in textiles, the evaluation and application. It is anticipated that this research will broaden the understanding and potential use of encapsulated phase change materials in textiles especially in the field of active smart textiles

Three dimensional finite element modelling of non-Newtonian fluid flow through a wire mesh

Monofilament cloths are used as the separation media in filtration; woven wire cloths or screens are also used as the media in filters or to enhance the integrity of the filter medium in, for example, filter cartridges. A better understanding of the flow pattern in the woven structure is essential in examining the initial stages of cake filtration as well as the effect of weaves on fouling phenomena within a filter cloth. Due to the complex geometry of a woven cloth, three-dimensional modelling is necessary to correctly visualize the structure of the flow and hence to predict pressure losses. The modelling in a three-dimensional domain was handled using a finite element method which is known to cope with flow domains in complex geometries very effectively. The governing equations of continuity and momentum were solved by a mixed U-V-W-P finite element method and in conjunction with a first order Taylor-Galerkin scheme for temporal discretization. A secondary solution scheme based on a continuous Penalty finite element method in conjunction with theta time stepping method was also used to solve the governing equations. Two robust and reliable computer tools based on these sound and robust numerical techniques have been developed to simulate Newtonian and non-Newtonian fluid flow through a woven wire mesh. Purpose-designed test cases were used to validate the capability of the developed algorithms and were found to give expected numerical predictions. A selection of domains was used to investigate the effect of weave pattern, aperture to diameter ratio and Reynolds number on flow pattern and pressure drop. Based on these domains, simulations were successfully conducted to investigate fluid flow through four basic pore types in a plain weave, twill weave and satin weave. The flow fields in the interstices were illustrated using a commercial graphics software package. The results showed that the weave pattern has a profound effect on the fluid flow pattern and pressure drop across the wire mesh. Simulation results showed that plain weave gives the lowest pressure drop, while satin weave gives the highest pressure drop across the woven cloths. Fluid flow through a plain weave was further investigated in conjunction with the experimental studies of Rushton (1969) using water and Chhabra and Richardson (1985) using shear-thinning fluids. Simulations were tested against experimental data extracted from both studies. The close agreement of the results to those of the available experimental data in literature showed the accuracy and the reliability of the predictions. Personal communication with industrial experts and woven cloth manufacturers have confirmed industrial practice, whereby a plain weave is primarily used due to its lowest flow resistance. This showed that the developed model is capable of generating accurate results for flow of both Newtonian and non-Newtonian fluids through filter media. The model can be used by design engineers as a convenient and effective Computer Aided Design (CAD) tool for quantifying effects of pressure drop. The model can also be extended to describe particle capture on/in the wire mesh and woven filter cloths

Development of a ballistic hybrid fabric model for aeroengine fan blade containment application

Ce mémoire présente les travaux de recherche effectués au sein du département de Génie Mécanique de l’Université Laval dans le cadre du projet « Impact modeling of Composite Aircraft Structure », IMCAS du Consortium de Recherche et d’Innovation en Aérospatiale (CRIAQ). Le but de ces travaux était de créer une loi de comportement pour les composites tissés sec mous et de les implanter dans un élément coque reproduisant le comportement dynamique d’un croisement de fibres dans un pli typique sous impact balistique et en fonction de certains paramètres géométriques propres au tissé. La création d’une loi de comportement de l’usager dans le logiciel d’analyse par éléments finis Abaqus a été nécessaire pour mener à bien ce projet. La méthodologie de développement de la sous-routine de l’usager, qui définit le matériau tissé et est utilisée en conjonction avec l’élément shell S4R, est basée sur les récents travaux de Grujicic et al (1) et Shahkarami et al (2). La validation de ce modèle a été réalisée en vérifiant la validité de sa réponse à certaines sollicitations rencontrées dans des études simples d’impact. Le résultat final de ces tests numériques d’impact a permis de démontrer que nous obtenons des résultats similaires à ceux de Shahkarami pour les mêmes paramètres d’expérimentation. Enfin, après cette dernière validation, nous avons appliqué l’outil développé à l’étude, en dynamique explicite, de l’impact d’une pale de soufflante sur un caisson de confinement hybride. Ce caisson est composé d’une première couche intérieure en coque métallique et sur laquelle s’empilent plusieurs couches de kevlar. Tout au long de ce mémoire, nous avons détaillé toutes les hypothèses, les démarches et les outils utilisés pour réaliser ce travail. Nos résultats montrent finalement qu’il est possible de reproduire les phénomènes physiques à une échelle méso-mécanique lors d’un impact haute vitesse sur un matériau composite tissé multicouche tout en minimisant le temps de calcul nécessaire.This thesis presents the work that has been carried out inside the Mechanical Engineering Department of Laval University within a CRIAQ project related to Impact Modeling of Composite Aircraft Structure (IMCAS). The main goal of this work was to develop a dry fabric model for ballistic impact application and to implement it into a shell element capable of reproducing the dynamic behavior of a yarn crossover point with due account of some specific geometric and material parameters. The development of a material user subroutine (VUMAT user subroutine) was necessary to carry out this project. The methodology employed for the development of the user subroutine to be used with the S4R shell element available in Abaqus is based upon the works of Grujicic et al (1) and Shahkarami et al (2). The validity of the mesomechanical model created was carried out in order to assess the accuracy of its behavior under elementary loadings. Subsequently, using the same parameters to set up the analysis, the developed model has been applied in simple impact problems in Abaqus to demonstrate that we are able to obtain the same results as in the work of Shahkarami (2) used as a reference. Finally, after this last validation, the model is used in the impact study of an aeronautical engine’s fan blade containment problem using a hybrid casing. In our problem the casing’s inner shell is metallic and multiple Kevlar fabric layers are wrapped around it to contribute to the energy absorption and containment of the fan blade debris released outward at high speed. In this thesis all the assumptions, process and tools necessary to carry out every analysis have been described in details. Our results demonstrate that it is possible to capture the physical phenomenon happening at the yarn’s mesoscopic level during a high-velocity impact on a dry fabric while minimizing the computation time

Multiscale simulation methodology for the forming behavior of biaxial weft-knitted fabrics

Trotz der guten Drapierbarkeit ist das Formen von flachen Mehrlagen-Gestricken (MLG) zu 3D-Preforms für schalenartige Faser-Kunststoff-Verbund (FKV) Bauteile immer noch eine Herausforderung, da einige Defekte wie Falten, Gassenbildung oder Faserschäden nicht vollständig vermieden werden können. Daher ist vor der Massenproduktion eine Optimierung erforderlich. Die virtuelle Optimierung des Umformprozesses mit Hilfe von Finite-Element-Methode (FEM) Modellen ist ein attraktiver Ansatz, da die Rechenkosten immer geringer werden. Dazu wurde ein auf Kontinuumsmechanik basierendes Makromodell erfolgreich für MLG implementiert. Der makroskalige Modellierungsansatz bietet angemessene Rechenkosten und kann gängige Defekte wie Faltenbildung vorhersagen. Weitere Defekte wie Faserversatz, ondulierte Fasern, Knicken von Fasern, Faserschädigung und Gassenbildung können jedoch mit dem Makromodell nicht vorhergesagt werden. Da die Komplexität von Bauteilen aus FKV und die Qualitätsanforderungen an die 3D-Preforms zunehmen, sind FEM-Modelle mit höherem Darstellungsgrad erforderlich. Im am weitesten entwickelten mesoskaligen FEM-Modell für MLG verhindert die zu starke Vereinfachung des Strickfadensystems mit Federelementen jedoch die Fähigkeit dieses FEM-Modells, Faserverschiebungen und Gassenbildung bei großer Verformung zu beschreiben, wobei das Gleiten zwischen den Fäden berücksichtigt werden muss. Ziel ist daher die Entwicklung, Validierung und Anwendung eines mesoskaligen FEM-Modells für MLG, um die derzeitigen Einschränkungen zu überwinden. Es werden neue Modellierungsstrategien für biaxiale MLG auf der Mesoskala entwickelt. Die mechanischen Eigenschaften von MLG werden durch eine Reihe von textilphysikalischen Prüfungen charakterisiert und analysiert, die alle notwendigen Daten für den Aufbau sowie die Validierung der FEM-Modelle liefern. Es sollen zwei Ansätze zur Modellierung des Verstärkungsgarns implementiert und verglichen werden: durch Balken- und durch Schalenelemente. Die validierten Modelle können für die Umformsimulation verwendet werden. Es folgt eine Benchmark-Studie über die Kapazität und Zuverlässigkeit der verfügbaren Makromodelle und der entwickelten Mesomodelle durch Umformsimulation. Als Grundlage für die Benchmark-Studie werden Umformversuche durchgeführt. Das zweite Ziel der Arbeit ist die Modellierung von FKV auf verschiedenen Skalen. Die Modellierung von FKV auf der Makroebene wird mit den Daten der Faserorientierung durchgeführt, die aus der Umformsimulation gewonnen werden. Eine Mapping-Methode hilft dabei, die vorhergesagte Faserorientierung aus der Umformsimulation von dem MLG Mesomodell auf das FKV-Makromodell zu übertragen. Um den FKV zu charakterisieren und die Parameter für das FKV Modell vorzubereiten, werden Versuche mit FKV durchgeführt und ausgewertet. Basierend auf dem Mesomodell des MLG wird eine weiteres FKV-Modell vorgeschlagen, wobei Garn und Matrix getrennt modelliert werden. Dieses mesoskalige FKV-Modell enthält auch eine Kontaktformulierung, mit der die Delamination im FKV-Bauteil vorhergesagt werden kann. Prüfungen von Schale-Rippen Strukturen dienen als Grundlage für die Modellvalidierung. Das validierte Modell wird erfolgreich zur Vorhersage des mechanischen Verhaltens weiterer Schale-Rippen Strukturen mit unterschiedlicher Höhe und Anordnung der Rippen verwendet.:Kapitel 1 stellt die Einleitung und Problemstellung von dem Thema FKV vor. Kapitel 2 gibt eine Übersicht über Stand-der-Technik von den Hochleistungsfasern, Herstellung von textilen Verstärkungen und Halbzeugen, Fertigung von FKV sowie von Prüftechnik für Textilien und FKV. Zunächst wurden in Kapitel 3 eine Einführung in die Modellierung mit FEM allgemein und Stand-der-Technik der Modellierung von technische Textilien gegeben. In Kapitel 4 wurden die Zielsetzung und das Forschungsprogramm festgelegt. Die experimentellen Arbeiten werden in Kapitel 5 vorgestellt. Der erste Schritt ist die Auswahl des Materials und der Konfiguration für die MLG. Sowohl das Ausgangsmaterial als auch die produzierten MLG sollten systematisch getestet werden. Als Referenz wird auch ein Leinwandgewebe in die Prüfprogramme aufgenommen. Neben der Charakterisierung von textilen Flächengebilden sollen auch deren gleichwertige FKV geprüft werden. Das erste Ziel des Forschungsprogramms wird in Kapitel 6 erreicht, wobei verschiedene Ansätze zur Modellierung von MLG vorgestellt und validiert werden. Die entwickelten und validierten FEM-Modelle werden für die Benchmark-Studie der Umformsimulation in Kapitel 7 verwendet. Kapitel 8 befasst sich mit der Modellierung von FKV in verschiedenen Skalen. Zunächst wird das Mapping-Verfahren vorgestellt. Es wird ein Mapping für ein schalenförmiges T-Napf-Bauteil durchgeführt. Die trukturanalyse für das T-Napf-Bauteil erfolgt für übliche Lastfälle. Zweitens wird ein mesoskaliges FEM Modell für MLG-verstärkte FKV vorgeschlagen. Dieses Modell wird auf der Grundlage der Prüfdaten aus Kapitel 5 validiert. Das validierte Modell wird dann zur Vorhersage des mechanischen Verhaltens eines Schale-Rippen-FKV-Bauteils unter Biegebelastung verwendet. Kapitel 9 gibt eine Zusammenfassung von den Forschungsergebnissen und Vorschlägen für mögliche weitere Forschungen rund um dem Thema MLG als Verstärkung für FKV. Die Kombination von vorhandenen Makro-und Mesomodellen in einer einzigen Simulation kann die Berechnungskosten senken, ohne die Vorhersagenfähigkeiten des Modelles kompromittiert zu werden

Structure and geometry of single and two layer stitched woven fabrics

Existují různé způsoby výroby textilií. Jednou z možností výroby je výroba na základě technologie tkaní. Kde tkanina vzniká vzájemným provázáním osnovních a útkových nití. Geometrie a struktura tkanin má významný vliv na její chování. Tkaná struktura je tvořena vzájemným silovým působením a parametry vstupujících soustav nití. Tkaniny jako jeden ze tří plošných útvarů jsou klíčové výztuhy, které nabízejí snadnou manipulaci, tvárnost a zlepšují rovinné vlastnosti. Většina kompozitů je vyrobena vrstvením z tkaných materiálů, kde může nastat separace jednotlivých kompozitních vrstev výztuže. Tento problém může být řešen pomocí použitím vícevrstvé tkané výztuže spojkové, místo jednoduché tkaniny. Ve struktuře vícevrstvé tkaniny spojkové dochází k propojení jednotlivých vrstev už při samotném procesu tkaní. Struktura a vlastnosti tkanin jsou závislé na konstrukčních parametrech, jako je jemnost nití, dostava (osnovy a útku), vazba, setkání atd. Jak je známo, tkaniny možné popsat pomocí matematických forem založených na jejich geometrii. Lze idealizovat obecné charakteristiky materiálů do jednoduchých geometrických tvarů a fyzikálních parametrů, k vytvoření matematické formulace. Modely mohou popisovat vnitřní geometrii tkanin popisem některé části vazné vlny. Avšak my potřebujeme model, který dokáže popsat vaznou vlnu jako celek - celou střídu vazby. V této studii se usiluje o vytvoření teoretického modelu geometrie jednoduché a dvouvrstvé tkané struktury a jejich ověření s experimentálními výsledky. První část práce se zabývá vývojem modelu a druhou částí je zpráva o ověření tohoto modelu. V první části, je líčen základní popis geometrie tkanin. Křížení osnovy a útku vytváří základní vaznou buňku tkaniny pro všechny typy provázání. Řada výzkumníků učinila mnoho pokusů najít vhodný model pro popis vazebné buňky. Byly vytvořené matematické modely pro vyjádření tvaru vazebné vlny v příčném řezu plátnového provázání v ustáleném stavu. Tyto geometrické modely byly také studovány z hlediska nalezení jejich limitních hodnot provázání. Po obsáhlých studiích byla geometrie vazné buňky (pro jednoduché a dvouvrstvé tkaniny spojkové) prezentována jako teoretické hodnocení využívající Fourierových řad. Tato studie ukazuje některé zajímavé matematické vztahy mezi konstrukčními parametry jednoduché a dvouvrstvé tkaniny spojkové.Ve druhé části této práce, byl ověřen teoretický model pro popis vzájemného provázání nití ve struktuře jednoduchých tkanin s plátnovou vazbou s využitím Fourierových řad. Teoretické modely byly porovnaný s experimentálními hodnotami získanými z reálné vazné vlny pomocí obrazové analýzy. Vnitřní geometrie tkaniny a deformace nití ve struktuře tkaniny s jednou a dvěma vrstvami byly hodnoceny metodou analýzy obrazu. Pro jednoduchou a dvouvrstvou tkaninu spojkovou v podélném a příčném řezu byla provedena analýza využitím Fourierových řad, kde vstupní funkce k vyjádření popisu byla použita lineární funkce f(x). Spektrální charakteristika, včetně popisu střednice vazné vlny získaných pomocí Fourierovy řady (teoretické) byla porovnána s experimentálními hodnotami, které jsou v podélném pohledu a příčném průřezu velmi blízké. Hodnocením geometrických parametrů osnovních a útkových nití v reálném průřezu tkaniny je možné porovnávat s teoretickým tvarem vazné vlny pomocí analýzy jejích jednotlivých souřadnic. V rámci práce bylo provedeno hodnocení a porovnání provázání a struktury tkaniny pro různé opakované velikosti střídy dvou-vrstvé spojkové tkaniny. Jak je patrné z výsledného hodnocení, poloha a velikost spojky přímo určuje tvar spektrální charakteristiky vycházející z daného rozvoje Fourierovy řady použitého pro konkrétní popis tvaru vazné vlny spojkové dvouvrstvé tkaniny.There are different ways of making fabrics but the most common method of producing woven fabric is by interlaced yarns. The woven fabric geometry and structure have significant effects on their behavior. The woven structures provide a combination of strength with flexibility. At high strains the yarns take the load together giving high strength, whereas at small strains the flexibility is achieved by yarn crimp due to freedom of yarn movement. Woven fabrics are key reinforcements which offer ease of handling, moldability, and improved in plane properties. Most of the composites are made by stacking layers of woven performs over each other which can cause the delamination failure in composite materials. This problem has been tackled by using multilayer woven perform as reinforcement, instead of single layer woven fabrics. In the multilayer woven structures, multiple layers of distinctive woven fabrics are being stitched during the weaving process.The structure and properties of a woven fabric are dependent upon the constructional parameters such as thread density, yarn fineness, crimp, weave etc. As we know, woven fabrics are not capable of description in mathematical forms based on their geometry because these are not regular structures; but many researchers believe that we can idealize the general characters of the materials into simple geometrical forms and physical parameters to arrive at mathematical deductions. It is always assumed that the variation of the fabric structure is insignificant in the analysis. The models given by these researchers can describe the internal geometry of woven fabric by describing some part of the binding wave. But we need a model that can describe binding wave in whole repeat and the validation is good from left or right side. We need to obtain not only geometry of binding wave but also spectral characterization for analyzing individual components, which can react on deformation of the shape of binding wave.In this study, an attempt is made to create a theoretical model on the geometry of plain single and two layer woven structures and verify them with experimental results. The first part of the work deals with the model development and the second part reports on model validation. In the first part, the basic description of the geometry of woven fabric has been described. The interlacing of one warp and one weft yarn creates the binding cell of the woven fabric. Many attempts have been made by different researchers to find a suitable model for describing the binding cell. They have worked mathematically to express the shape of the binding wave in a given thread crossing in a woven fabric in a steady state. The geometric models have been studied to find out their limitations as well. After a comprehensive study, the geometry of binding cell in plain weave for single and two layer stitched woven fabrics have been presented for theoretical evaluation by Fourier series. This study shows some interesting mathematical relationships between constructional parameters of single and two layer stitched woven fabrics, so as to enable the fabric designers and researchers to have a clear understanding of the engineering aspects of single and two layer woven fabrics.In the second part of the work, the theoretical model for the description of mutual interlacing of threads, in multifilament woven fabric structure using Fourier series, derived from plain woven structure has been validated with experimental results. The internal geometry of the woven fabrics and the deformation of the shape of the binding wave in the single and two layer stitched woven structures has been evaluated by the cross-sectional image analysis method. The approximation using the linear function f(x) in Fourier series along longitudinal and transverse cross-section has been performed for single layer and two layer stitched woven fabrics cross-section, which fits well to the experimental binding wave. The spectral characteristics of b

Through thickness air permeability and thermal conductivity analysis for textile materials

Woven fabrics have found enormous application in our daily life and in industry because of their flexibility, strength and permeability. The aim of this work was to create a general model for through thickness air permeability and thermal conductivity for different types of textile fabrics because of their applications in industries and everyday life. An analytical model to predict through thickness air permeability was developed. The objective was to create a model which will take into consideration the two primary mechanisms of air flow in fabrics: through the gaps between yarns and through the yarns. Through thickness air permeability was measured according to British Standard BS EN ISO 9237: 1995. Several fabrics were tested including plain weave, twill weave and satin weave fabrics. The analytical model is a combination Kulichenko and Van Langenhove's analytical model which predicts the permeability through gaps between yams with Gebart's model to predict permeability within yams. Analytical predictions were compared to the experimental data. Computational modelling of through thickness air permeability using Computational Fluid Dynamics CFD software is presented in this thesis. The Polymer Composites Research Group in the University of Nottingham has created a textile schema, named TexGen. The prerequisites of this software were to be able to model various types of textile structures. A CFD model using CFX 11.0 was developed to be able to predict fabric permeability. In addition, an analytical model was developed for fabrics deformed by shear, compaction and tension. Experimental work for through thickness air permeability of sheared fabric was used to verify predicted results. An analytical model for thermal conductivity of fabrics was developed including the influence of moisture content on thermal conductivity. Two existing approaches for single-layer fabrics are described and compared: rule of mixtures and thermal resistance approach. A me6iod for thermal conductivity prediction for multiple layer fabrics is presented. The results are compared to the experimental data and analysed. Some predicted results were in excellent and good agreement with experimental data whereas other predicted results were in poor agreement with experimental data as they were dramatically affected by the assumptions made in the analytical model

Progress in experimental and theoretical evaluation methods for textile permeability

ABSTRACT: A great amount of attention has been given to the evaluation of the permeability tensor and several methods have been implemented for this purpose: experimental methods, as well as numerical and analytical methods. Numerical simulation tools are being seriously developed to cover the evaluation of permeability. However, the results are still far from matching reality. On the other hand, many problems still intervene in the experimental measurement of permeability, since it depends on several parameters including personal performance, preparation of specimens, equipment accuracy, and measurement techniques. Errors encountered in these parameters may explain why inconsistent measurements are obtained which result in unreliable experimental evaluation of permeability. However, good progress was done in the second international Benchmark, wherein a method to measure the in-plane permeability was agreed on by 12 institutes and universities. Critical researchers’ work was done in the field of analytical methods, and thus different empirical and analytical models have emerged, but most of those models need to be improved. Some of which are based on Cozeny-Karman equation. Others depend on numerical simulation or experiment to predict the macroscopic permeability. Also, the modeling of permeability of unidirectional fiber beds have taken the greater load of concern, whereas that of fiber bundle permeability prediction remain limited. This paper presents a review on available methods for evaluating unidirectional fiber bundles and engineering fabric permeability. The progress of each method is shown in order to clear things up

FIBER-TEX 1992: The Sixth Conference on Advanced Engineering Fibers and Textile Structures for Composites

The FIBER-TEX 1992 proceedings contain the papers presented at the conference held on 27-29 Oct. 1992 at Drexel University. The conference was held to create a forum to encourage an interrelationship of the various disciplines involved in the fabrication of materials, the types of equipment, and the processes used in the production of advanced composite structures. Topics discussed were advanced engineering fibers, textile processes and structures, structural fabric production, mechanics and characteristics of woven composites, and the latest requirements for the use of textiles in the production of composite materials and structures as related to global activities focused on textile structural composites

Textile materials

In this specialised publication, the reader will find research results and real engineering developments in the field of modern technical textiles. Modern technical textile materials, ranging from ordinary reinforcing fabrics in the construction and production of modern composite materials to specialised textile materials in the composition of electronics, sensors and other intelligent devices, play an important role in many areas of human technical activity. The use of specialized textiles, for example, in medicine makes it possible to achieve important results in diagnostics, prosthetics, surgical practice and the practice of using specialized fabrics at the health recovery stage. The use of reinforcing fabrics in construction can significantly improve the mechanical properties of concrete and various plaster mixtures, which increases the reliability and durability of various structures and buildings in general. In mechanical engineering, the use of composite materials reinforced with special textiles can simultaneously reduce weight and improve the mechanical properties of machine parts. Fabric- reinforced composites occupy a significant place in the automotive industry, aerospace engineering, and shipbuilding. Here, the mechanical reliability and thermal resistance of the body material of the product, along with its low weight, are very relevant. The presented edition will be useful and interesting for engineers and researchers whose activities are related to the design, production and application of various technical textile materials