On-line optical measurement and monitoring of yarn density in woven fabrics

This paper describes a vision-based system that monitors the yarn density of woven fabrics on-line. The system is described in terms of its two principal modules, namely, the image acquisition and the image analysis subsystems. The image acquisition subsystem is implemented with standard components on a low-cost personal computer platform. These components consist of a line-scan camera, a DSP-based image acquisition and processing card, and a host personal computer. The image acquisition process is controlled by a software module that runs on the DSP board and accumulates a 2-D image suitable for the density measurement algorithm. The image analysis sub-system, which also runs on the DSP board, implements a novel, yet straightforward, algorithm that utilizes the discrete Fourier transform for monitoring the yarn density of the fabrics from the acquired images. In this algorithm, the Fourier spectrum of the images is covered by contiguous, concentric annular regions that have a prespecified width. The spectrum values within each annular region are summed, normalized, and subsequently used to produce a 1-D signature. Simple statistics of the obtained signatures are the basis for characterizing the fabric in terms of its yarn density. The described system is tested on seven fabrics with common properties but varying yarn densities and has shown to be accurate within 2 yarns per inch in either direction. It is also shown that the obtained accuracy, which is primarily a function of the image resolution, can be greatly improved

Fabrication and properties of woven structures for biomedical applications

The purpose of this work was to manufacture a dense structure with small pores for biomedical studies. The structures are made of fine multifilament yarn by weaving. The aim was to get the yarn densities as high as possible, which would decrease the pore size of the structure. Nine samples were woven by using different weave patterns and different warp densities. Pore sizes and evenness of the structures were compared by microscope imaging. Mass per unit area, thickness and tensile strength of the samples were compared. Two of the best structures were woven with the help of paraffin oil as a lubricant to get even higher warp densities and to reduce the friction between the yarns, thus preventing them from breaking. Contact angles of the same samples were measured to get a better view of the permeability and porosity. The best weave patterns had several evenly distributed interlacing points. Best results were achieved by using the paraffin oil; there were only few through-going openings. They were only a few micrometres in size and they were distributed randomly around interlacing points.Työn tarkoituksena oli valmistaa biolääketieteen tutkimuskäyttöön tiivis pienihuokoinen alusta kutomalla hienoa multifilamenttilankaa. Työssä pyrittiin saamaan kudotun rakenteen lankatiheydet mahdollisimman suuriksi, mikä pienentäisi siten rakenteen huokoskokoa. Rakenteita kudottiin käyttämällä yhdeksää erilaista sidosta eri loimitiheyksillä ja mahdollisimman suurella kudetiheydellä. Näytteiden huokoskokoa ja tasaisuutta vertailtiin käyttäen apuna mikroskooppia. Lisäksi näytteiden neliömassat, paksuudet ja vetolujuudet olivat vertailtavina. Kaksi parhainta näytettä näistä yhdeksästä kudottiin myös käyttäen apuna parafiiniöljyä voiteluaineena, jotta loimitiheyksiä saatiin vielä suuremmiksi. Parafiiniöljyä käytettiin kudonnan aikana vähentämään loimilankojen välistä kitkaa ja siten estämään niiden katkeamista. Myös kontaktikulmat mitattiin näistä kahdesta parhaasta näytteestä, mikä kertoi enemmän niiden läpäisevyydestä ja huokoisuudesta. Parhaimmat sidokset olivat nimenomaan ne, joissa sidospisteitä oli tiheässä ja ne olivat tasaisesti jakautuneet kankaan pinnalle. Voiteluainetta apuna käyttämällä saatiin parhaat tulokset; läpimeneviä huokosia oli hyvin vähän, ne olivat jakaantuneet satunnaisten sidospisteiden ympäristöön ja ne olivat kooltaan vain muutamia mikrometrejä

Hybridní tkané struktury

Tato disertační práce poskytuje podrobnější informace o vlastnostech čedičových vláken vedle běžně používaných vláken, a to pro návrh a vývoj hybridních tkaných textilií určených pro výrobu kompozitních materiálů, zejména betonu vyztuženého textilií (TRC). Zkoumány jsou různé kombinace čedičové hybridní tkaniny s ohledem na mechanické, tepelné, akustické, elektrické a jiné vlastnosti, přičemž vliv hybridizace a struktury tkaných textilií je studován detailněji. Mechanické vlastnosti jsou predikovány s použitím a strukturální modely korelovány s výsledky získanými z provedených experimentů. Čedičová vlákna jsou velmi perspektivním materiálem díky jejich ohnivzdornosti spojené s lávovým původem, vynikajícím mechanickým vlastnostem a relativně nízké ceně. Na druhou stranu, tato vlákna doposud nebyla podrobena rozsáhlejšímu průzkumu, protože je možno je považovat za relativně nový typ vlákna. V technických článcích je možno nalézt jen omezené množství údajů o jejich chování po zpracování, jež je spojeno se stárnutím materiálu. Disertační práce prozkoumává možnosti využití čedičových vláken v kombinaci s jinými typy přízí a následně také vliv hybridní tkané struktury na nosnost kompozitu a dobu jeho životnosti. V této studii je vyšetřeno nosné chování TRC kompozitu (kompozitní systém tvořený jemnozrnnou betonovou matricí a výztuží složenou z vysoce funkčních vláken zpracovaných do plošné textilie) při jednoosém namáhání tahem. Průzkum je zaměřen na výztužnou schopnost hybridní tkané struktury. Při začleňování textilní struktury do betonu je zřejmé, že veškeré příze nejsou impregnovány cementovou matricí kompletně, což vede k heterogenitě systému beton - příze přispívajícímu ke komplexní nosnosti a defektnímu chování TRC kompozitu. Hlavním cílem této práce je tedy průzkum hybridizačních efektů na nosné chování TRC kompozitu.This thesis conveys a better insight into characteristics of Basalt fibers specifically, alongside commonly used fibers to design and develop hybrid woven fabrics for TRC composite materials. Various combinations of basalt hybrid fabrics are investigated with respect to mechanical, thermal, acoustic, electrical and other functional properties. The influence of hybridization and structure of woven fabric is studied in detail. The tensile properties are predicted by using structural model and correlated to the results obtained through experiments. Basalt fibers are very promising materials due to their fire resistance related to magmatic origin, superior mechanical properties and relatively low cost. On the other hand, being a relatively new kind of fiber, they are still not studied extensively. There are very few indications in technical papers about their behavior after aging treatments. The current study investigates the possibility of using basalt with other types of yarns and consequently the effect of hybrid woven structure on load bearing capacity and durability. In the present work, the load-bearing behavior of Textile Reinforced Concrete (TRC), which is a composite of a fine-grained concrete matrix and a reinforcement of high-performance fibers processed to textiles, when exposed to uniaxial tensile loading was investigated. The investigations are focused on reinforcement of hybrid woven fabrics. When textile yarns are embedded in concrete, they are not entirely impregnated with cementitious matrix, which leads to associated heterogeneity of the concrete and the yarns to a complex load-bearing and failure behavior of the composite system. The main objective of the work is the investigation of hybridization effects in the load-bearing behavior of TRC

Visual Prototyping of Cloth

Realistic visualization of cloth has many applications in computer graphics. An ongoing research problem is how to best represent and capture appearance models of cloth, especially when considering computer aided design of cloth. Previous methods can be used to produce highly realistic images, however, possibilities for cloth-editing are either restricted or require the measurement of large material databases to capture all variations of cloth samples. We propose a pipeline for designing the appearance of cloth directly based on those elements that can be changed within the production process. These are optical properties of fibers, geometrical properties of yarns and compositional elements such as weave patterns. We introduce a geometric yarn model, integrating state-of-the-art textile research. We further present an approach to reverse engineer cloth and estimate parameters for a procedural cloth model from single images. This includes the automatic estimation of yarn paths, yarn widths, their variation and a weave pattern. We demonstrate that we are able to match the appearance of original cloth samples in an input photograph for several examples. Parameters of our model are fully editable, enabling intuitive appearance design. Unfortunately, such explicit fiber-based models can only be used to render small cloth samples, due to large storage requirements. Recently, bidirectional texture functions (BTFs) have become popular for efficient photo-realistic rendering of materials. We present a rendering approach combining the strength of a procedural model of micro-geometry with the efficiency of BTFs. We propose a method for the computation of synthetic BTFs using Monte Carlo path tracing of micro-geometry. We observe that BTFs usually consist of many similar apparent bidirectional reflectance distribution functions (ABRDFs). By exploiting structural self-similarity, we can reduce rendering times by one order of magnitude. This is done in a process we call non-local image reconstruction, which has been inspired by non-local means filtering. Our results indicate that synthesizing BTFs is highly practical and may currently only take a few minutes for small BTFs. We finally propose a novel and general approach to physically accurate rendering of large cloth samples. By using a statistical volumetric model, approximating the distribution of yarn fibers, a prohibitively costly, explicit geometric representation is avoided. As a result, accurate rendering of even large pieces of fabrics becomes practical without sacrificing much generality compared to fiber-based techniques

Woven sounds / Design exploration and experimentation of acoustic curtain fabrics

Sound conditions are a top priority when it comes to designing an indoor space, since good sound conditions enhance the purpose the space is built for. There are several solutions for improving room acoustics, and one of the newest inventions in the market are lightweight acoustic curtains. This thesis examines such woven curtain fabrics, that have the appearance of conventional lightweight curtains, but that are able to absorb medium and high frequency sounds. Acoustic curtains belong to the group of functional textiles, where a particular function is integrated as a primary design criteria for adding value to otherwise conventional textiles. The goal of this practice-based research is to understand how and why lightweight acoustic curtain fabrics are designed and produced, and to adapt that knowledge in a design process of acoustic curtain fabrics. The work is done in collaboration with an Italian weaving mill Lodetex and their clients. The design process is based on a thorough background research, and a comprehensive ideation and conceptual design work. The aim of the design work is to create a versatile set of prototype fabrics in order to find the best possible design solutions for sound absorptive fabrics. The theoretical research provides the necessary information for understanding the basics of sound and acoustics. Sound is the concept of the work, and it acts also as an inspiration and a sketching tool in the visual design work. The theoretical research also covers a review on lightweight acoustic curtains and what are the factors that influence the sound absorption properties of those fabrics. Lastly the theoretical research is utilized in the design practice of experimental development work of woven acoustic curtain fabrics. Since the work is a practice-based research, the documentation of the design process is as important outcome as the presented idea collection of the designed prototype fabrics. The prototypes were created within two development cycles that included phases of prototyping, testing, analyzing and developing. The work reveals the complexity of designing sound absorbing fabrics. There are several microstructural factors that affect the sound absorption performance both individually and as a combination. Therefore the design work of woven acoustic fabrics should be based on several prototyping and testing phases in order to discover the most suitable material and structural solutions. This work establishes a design practice, that combines a thorough technical exploration and a creative experimentation. The relevance of this work is to provide new knowledge of functional acoustic fabric design to the manufacturing company Lodetex and to their clients. The presented idea collection offers a variety of fabric designs that possess a potential for even highly performative acoustic curtain fabrics. This practical study is a starting point to a development work, that most likely continues as a more advanced design practice in the future with some of Lodetex’s clients.Hyvät ääniolosuhteet tekevät tilasta monikäyttöisemmän, ja siksi huoneakustiikka on tärkeää sisätilojen suunnittelussa. Äänen absorbointiin on useita ratkaisuja, joista yksi uusimmista on ohuiden akustoivien verhokankaiden käyttö sisustuksessa. Tämä opinnäyte tarkastelee tällaisia kudottuja verhokankaita, jotka eivät ulkonäöllisesti juurikaan eroa tavallisista verhokankaista, mutta jotka kykenevät absorboimaan keskitaajuuksien ja korkeiden taajuuksien ääntä. Akustoivat verhokankaat ovat funktionaalisia tekstiilejä, joiden suunnittelussa toiminnallisuus on tärkein kriteeri. Tämä myös nostaa tekstiilin arvoa entisestään. Practice-based-tutkimustyön tavoitteena on ymmärtää miksi ja miten ohuet akustoivat verhokankaat on valmistettu, ja sitä kautta toteuttaa akustoivien verhokankaiden suunnittelu- ja kehitystyö. Opinnäyte on tehty italialaiselle kangaskutomolle Lodetexille sekä heidän asiakkailleen. Suunnitteluosuuden pohjana on laaja tutkimus aiheesta sekä kattava ideointi- ja konseptuaalinen suunnittelutyö. Suunnittelutyön tarkoituksena on luoda kokoelma erilaisia prototyyppikankaita, joista käy ilmi akustisesti toimivimmat suunnitteluratkaisut. Työn teoreettinen osuus kattaa äänen ja akustiikan perusteet, mikä on olennaista akustoivien verhokankaiden toiminnallisuuden ymmärtämisessä. Ääni toimii työn kokonaiskonseptina, eli se on myös inspiraation lähde sekä luonnostelutyökalu visuaalisessa suunnittelutyössä. Teoreettinen osuus kattaa lisäksi ohuiden akustoivien verhokankaiden tarkemman tarkastelun ja osoittaa muun muassa, mitkä tekijät kankaan rakenteessa vaikuttavat äänen absorbointikykyyn. Teoreettista tietoa heijastellaan opinnäytteen kokeellisessa suunnitteluosuudessa. Työn lopputuloksena toimii practice-based-tutkimuksen tapaan sekä prosessin tarkka kuvaus että esitelty ideakokoelma suunnitelluista prototyyppikankaista. Kankaat on suunniteltu ja valmistettu Italiassa kahden erillisen kehitysjakson aikana. Kehitysjaksot sisältävät protokankaiden valmistuksen, niiden testaamisen, testitulosten analysoinnin sekä mallien jatkokehityksen. Työssä käy ilmi akustoivien verhokankaiden suunnittelun monimutkaisuus. Monet kankaan rakenteelliset tekijät vaikuttavat äänen absorbointikykyyn sekä itsenäisesti että toistensa yhteisvaikutuksesta, mikä vaikeuttaa kankaan suunnittelua huomattavasti. Siksi akustoivien verhokankaiden suunnittelun tulee olla pitkäaikainen prosessi, jotta saadaan selville toimivimmat materiaaliyhdistelmät sekä niitä tukevat rakenteelliset ratkaisut. Opinnäytteessä toteutuu suunnittelutyö, joka yhdistää laajan teknisen tarkastelun sekä luovan kokeilun. Työ tuottaa uutta tietoa funktionaalisen akustoivan kankaan suunnittelusta ja valmistuksesta sekä kutomo Lodetexille että heidän asiakkailleen. Esitelty ideakokoelma tarjoaa kattavan valikoiman verhokankaita, joilla on potentiaalia toimia akustoivina verhokankaina. Opinnäyte toimii lähtökohtana kehitystyölle, joka todennäköisesti jatkuu tulevaisuudessa kutomon asiakkaiden kanssa

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

Solar cells inside woven textiles

Energy harvesting textiles are a relatively new field of research. In the future our clothes, accessories, and other fabrics could generate electricity from the sun and charge our devices on the go. While photovoltaic yarns, and solar cells printed directly on textiles are technologies of the future, there are already suitable solutions on the market for small scale energy harvesting. Some existing products such as energy harvesting backpacks and jackets already make use of these alternatives but mostly the level of integration of solar cells to the textile is low. The technology remains as a separate part instead of merging into the design and construction of textile. The goal of this practice-based research is to create woven textiles that allow integrating photovoltaics to the functional and aesthetic design of the fabric. The background research aims to introduce the relevant terms and concepts about solar cells for textile design purposes, and paint an overall picture of the future of the photovoltaic textiles field. During the practice-based research part, this knowledge is used for woven material prototyping and testing. The thesis work establishes a design strategy which combines creative material experimentation with backing from applied scientific exploration. Traditional textile design practice is used to develop handwoven material drafts which allow inserting solar cells into the structure of multilayered cloth. To find out how the properties of textiles affect the efficiency of the solar cell, the textile prototypes were tested during several rounds. Solar Cells Inside Woven Textiles is a continuation of an interdisciplinary research project with the New Energy Technologies group from Aalto Engineering Physics Department. The thesis builds on the knowledge generated during the previous process. Because of the collaborative nature of the project, the role of a textile designer in an interdisciplinary research project is addressed. The reflections are based on personal experiences during the process and conversations with design and technology professionals about the subject. This thesis work is positioned on the ground in-between design and science. The final outcome is a collection of woven textile prototypes showcasing the learning and possibilities of designing for photovoltaics integration. Visualization of the collected data allows comparison of different materials, colors and weave structures and provides feedback of the design choices. Using textile design as a tool for scientific exploration may offer tangible proposals for future concepts and research questions. This work serves as one example of working as a designer in a hybrid environment

An Extended Review on Fabric Defects and Its Detection Techniques

In Textile Industry, Quality of the Fabric is the main important factor. At the initial stage, it is very essential to identify and avoid the fabrics faults/defects and hence human perception consumes lot of time and cost to reveal the fabrics faults. Now-a-days Automated Inspection Systems are very useful to decrease the fault prediction time and gives best visualizing clarity- based on computer vision and image processing techniques. This paper made an extended review about the quality parameters in the fiber-to-fabric process, fabrics defects detection terminologies applied on major three clusters of fabric defects knitting, woven and sewing fabric defects. And this paper also explains about the statistical performance measures which are used to analyze the defect detection process. Also, comparison among the methods proposed in the field of fabric defect detection

Material relationships: the textile and the garment, the maker and the machine. Developing a composite pattern weaving system

This research brings together the disciplines of woven textile design, zero waste pattern cutting and fashion design to form the Composite Pattern Weaving system; an innovative approach to woven garment design and construction which assimilates textile and garment lay-plan design and construction to produce engineered zero waste and integrally shaped woven garments, containing multiple fabric qualities, from a single length of woven textile. The approach challenges conventional textile and fashion design processes and systems by adopting a holistic and simultaneous approach to the design and production of textile and garment components; facilitating the integration of functional and sustainable design strategies to enhance garment durability and longevity through the implementation of a multi-method lifecycle approach to design. This research adopts the Transitional Design Methodology; an alternative approach of working between traditional and advanced technologies which challenges the constraints of the two modes of production whilst capitalising on their advantages. This cyclical iterative approach emphasises the importance of the relationship between the maker, materials and the machine(s), whilst recognising the potential for a transitional dialogue and knowledge transfer between all aspects of hand and digital production. Employing both modes of production in parallel, the Transitional Design Methodology facilitates a reciprocal relationship whereby concepts, designs and ways of working evolve as the maker moves between modes. Through the production of zero waste woven garment prototypes using hand and digital weaving technologies, the research establishes new integral shaping techniques and woven garment construction methods to minimise material production, consumption and waste, and identifies some of the limitations of fully-fashioned and composite garment weaving. The garment prototypes embody the learning and knowledge derived through the application of the Transitional Design Methodology. They demonstrate the advantages of working iteratively between hand and digital modes of design and construction to produce innovative (and interconnected) design outcomes, to advance skills and processes, and enhance personal practice