A obtenção de resultados de fluência em geossintéticos (isócronas e curva de ruptura por fluência) requer longo tempo de observação e rigoroso controle laboratorial. Dessa forma, muitos produtos disponíveis no mercado brasileiro não foram ensaiados quanto a este fenômeno dificultando sobremaneira a elaboração de projetos mais seguros e econômicos. Há, portanto, a necessidade de estudos não só do fenômeno da fluência em si, mas também de métodos de ensaio que facilitem e acelerem a obtenção das curvas de fluência. Este trabalho apresenta um estudo da fluência de dois geotêxteis não tecidos, um de polipropileno e outro de poliéster, através de ensaios acelerados, utilizando-se o processo denominado Stepped Isothermal Method (SIM). Os valores obtidos pelo método SIM foram comparados aos valores obtidos nos ensaios convencionais, realizados segundo a norma ISO 13431. Os resultados experimentais indicam que os ensaios acelerados, utilizando o método SIM, foram capazes de simular o fenômeno da fluência com boa precisão e, portanto, podem trazer uma grande economia de tempo, além de facilitar e agilizar a caracterização da fluência de geossintéticos. / Creep tests are time consuming and require rigorous laboratory testing control. Because of that many products commercially available in Brazil were not tested regarding this phenomenon. The absence of creep data is an obstacle to the design soil reinforced structures. It is therefore required continuous research effort not only to elucidate creep phenomenon but also to help in the development of test methods that ease and speed up the obtaining of creep curves. This paper presents a creep study carried out on two non-woven geotextiles (PP and PET) using temperature accelerated creep test, namely the Stepped Isothermal Method (SIM). The values obtained using the SIM method were compared to the ones obtained using conventional creep tests following the ISO 13431. The experimental results indicate that the accelerated creep tests, using the SIM method, were capable of simulating the creep phenomenon with good accuracy and, hence, they can bring a great deal of time saving to the characterization of creep in geosynthetics.

Made available in DSpace on 2017-07-25T19:29:56Z (GMT). No. of bitstreams: 1 Jhone Espindola.pdf: 1590754 bytes, checksum: 5b0837eabb44ea5516e71f7193e0ece8 (MD5) Previous issue date: 2012-09-14 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / The vegetables like baby leaf are characterized by the early harvest of cultivated species, and the production and marketing of these are still incipient in Brazil. To assist the production techniques, experiment was conducted between August and October 2011 with the objective of evaluating the productive responses of baby leaf chicory cv. Escarole Lisa in different environmental conditions and spacing between plants. The experimental design was a randomized complete block with 04 replications with treatments arranged in split-split. The primary factor was the growing environment (TP- low plastic tunnel; AG-white non woven; AN-natural environment), the secondary factor was spacing between plants (E1- 2 x 5 cm; E2- 4 x 5 cm; E3- 2 x 10 cm; E4- 5 x 10 cm) and tertiary factor was evaluation periods (14, 21, 28, 35 and 42 days after sowing - DAS). The characteristics evaluated were plant height (AP), leaf area index (IAF), number of leaves per plant (NF), length (CMF) and width (LMF) of the largest leaf, fresh fitomassas (FMF) and dry (FMS) and plant productivity (P). In protect cultivation, the plants reached the harvesting stage (plant height = 10 cm) at 35 days after harvest while (DAS), in the natural environment was at 41 DAS. The NF, at the point of harvest, was higher for plants grown in AN, differentiating the results for AP, CMF, LMF, FMF and IAF. FMF values in TP and AG were higher until it reaches the point of harvest. For growing baby leaf chicory, it was found that the average temperature between 18 and 19ºC was the most suitable for plant growth under protected cultivation in relation to the natural environment. The interaction between different environmental conditions and spacing between plants was significant only for FMF. For cultivation under AG, the spacing between plants E2 and E4 resulted in plants with FMF higher than the spacing between plants E1 and E3. In relation to FMF, Plants grown in AN had lower values than those under TP and AG, except for E3, where plants under GA did not differ from those of AN. For the interaction between evaluation periods and spacing between plants, there was a significant effect for FMF, FMS and IAF. It was found that the FMF and FMS in E1 and E3 were lower than E2, and E4 in 35 DAS. The results of IAF demonstrated that plants grown in smaller spacing between plants (E1) had greater leaf area expansion compared to those in lower density (E4). At harvesting stage, there was a higher productivity when the combination was used spacing between plants E1 and cultivation environment AN. It was verified that is possible to obtain precocity in the cultivation of baby leaf chicory without loss of quality in TP and AG. When all the plants reach the harvesting stage, it is possible to obtain higher productivity using the natural environment (AN) together with the spacing between plants (E1). The use of protect cultivation (non-woven and low tunnel) and spacing E1 are suitable for the cultivation and marketing of whole plant (unit sales) of baby leaf chicory instead of selling by weight. / As hortaliças tipo baby leaf são caracterizadas pela colheita precoce das folhas das espécies cultivadas, sendo que a produção e comercialização das mesmas ainda são incipientes no Brasil. Para auxiliar as técnicas de produção, foi realizado experimento entre agosto e outubro de 2011 com o objetivo de avaliar as respostas produtivas de baby leaf de chicória cv. Escarola Lisa em diferentes ambientes de cultivo e espaçamentos de plantio. O delineamento experimental foi o de blocos casualizados, com 04 repetições, com tratamentos distribuídos em parcelas sub-subdivididas. O fator primário foi ambiente de cultivo (TP- Túnel baixo com plástico; AG- Agrotêxtil branco diretamente sobre as plantas; AN- Ambiente natural); o fator secundário foi espaçamento de plantio (E1- 2 x 5 cm; E2- 4 x 5 cm; E3- 2 x 10 cm; E4- 5 x 10 cm) e o fator terciário foi momentos de avaliação (14; 21; 28; 35 e 42 dias após a semeadura - DAS). As características avaliadas foram altura de plantas (AP), índice de área foliar (IAF), número de folhas por planta (NF), comprimento (CMF) e largura (LMF) da maior folha, fitomassas fresca (FMF) e seca (FMS) das plantas e produtividade (P). Nos ambientes protegidos, as plantas atingiram o ponto de colheita (10 cm de altura) aos 35 DAS enquanto em ambiente natural foi aos 42 DAS. O NF, no ponto de colheita, foi superior para as plantas cultivadas em AN, diferenciando dos resultados encontrados para AP, CMF, LMF, FMF e IAF onde em TP e AG os valores foram superiores ao AN. Para FMS os valores em TP e AG foram superiores até atingir o ponto de colheita para baby leaf. Para o cultivo de chicória baby leaf foi constatado que a temperatura média entre 18 e 19ºC foi adequada para o maior crescimento das plantas em cultivo protegido em relação ao ambiente natural, que teve média de 16ºC. A interação entre ambiente de cultivo e espaçamentos foi significativa somente para FMF. Para o cultivo sob AG, os espaçamentos E2 e E4 resultaram em plantas com FMF superior àquelas espaçadas em E1 e E3. As plantas cultivadas em AN apresentaram menores valores de FMF que aquelas sob TP e AG, exceto para o E3 onde a FMF das plantas sob AG não diferiu daquelas do AN. Em relação à interação entre espaçamento e momentos de avaliação, verificou-se efeito significativo para FMF, FMS e IAF. Foi verificado que a FMF e FMS em E1 e E3 foram menores que em E2 e E4 a partir de 35 DAS. Os resultados de IAF demonstraram que as plantas cultivadas no menor espaçamento (E1) apresentaram maior expansão da área foliar em relação àquelas menos adensadas (E4). No ponto de colheita, houve maior produtividade quando foi utilizada a combinação entre o espaçamento E1 e cultivo em ambiente AN. Concluiu-se que é possível obter precocidade no cultivo de baby leaf de chicória sem perda de qualidade sob TP e AG. Quando todas as plantas atingem o ponto de colheita, é possível obter maior produtividade utilizando o ambiente natural (AN) juntamente com o espaçamento mais adensado (E1). O uso do cultivo protegido (Agrotêxtil e Túnel baixo) e o espaçamento E1 são adequados para o cultivo e comercialização de planta inteira (venda da unidade) de baby leaf de chicória em lugar da venda por peso produto.

A obtenção de resultados de fluência em geossintéticos (isócronas e curva de ruptura por fluência) requer longo tempo de observação e rigoroso controle laboratorial. Dessa forma, muitos produtos disponíveis no mercado brasileiro não foram ensaiados quanto a este fenômeno dificultando sobremaneira a elaboração de projetos mais seguros e econômicos. Há, portanto, a necessidade de estudos não só do fenômeno da fluência em si, mas também de métodos de ensaio que facilitem e acelerem a obtenção das curvas de fluência. Este trabalho apresenta um estudo da fluência de dois geotêxteis não tecidos, um de polipropileno e outro de poliéster, através de ensaios acelerados, utilizando-se o processo denominado Stepped Isothermal Method (SIM). Os valores obtidos pelo método SIM foram comparados aos valores obtidos nos ensaios convencionais, realizados segundo a norma ISO 13431. Os resultados experimentais indicam que os ensaios acelerados, utilizando o método SIM, foram capazes de simular o fenômeno da fluência com boa precisão e, portanto, podem trazer uma grande economia de tempo, além de facilitar e agilizar a caracterização da fluência de geossintéticos. / Creep tests are time consuming and require rigorous laboratory testing control. Because of that many products commercially available in Brazil were not tested regarding this phenomenon. The absence of creep data is an obstacle to the design soil reinforced structures. It is therefore required continuous research effort not only to elucidate creep phenomenon but also to help in the development of test methods that ease and speed up the obtaining of creep curves. This paper presents a creep study carried out on two non-woven geotextiles (PP and PET) using temperature accelerated creep test, namely the Stepped Isothermal Method (SIM). The values obtained using the SIM method were compared to the ones obtained using conventional creep tests following the ISO 13431. The experimental results indicate that the accelerated creep tests, using the SIM method, were capable of simulating the creep phenomenon with good accuracy and, hence, they can bring a great deal of time saving to the characterization of creep in geosynthetics.

Målet med detta arbete är att undersöka smörjsystemet på två utsatta leder på en Boomer E2C. Förfrågan om examensarbetet kommer från Atlas Copco Rock Drills AB i Örebro som också tillverkar maskinen. Atlas Copco Rock Drills AB har idag ett fettsmörjningssystem som upprätthåller funktionerna på lederna. Uppgiften är att sammanfatta och utvärdera dagens system samt att finna nya lösningsförslag som skulle kunna ersätta eller delvis ersätta systemet. Information har hämtats från dokumentation, ritningar och samtal med konstruktörer på företaget. Efter att alla förutsättningarna för lederna specificerats så har lösningsförslag sökts. Genom att träffa lagerleverantörer och söka artiklar så har idéer formats. Brainstorming har använts för att kunna se nya lösningar. Undersökningen har visat att det finns problem med dagens lösning vad gäller slanghaverier och driftstopp i fält. Atlas Copco AB uttrycker även att kunskapen och dokumentationen angående systemet är otillräckligt. Efter artikelsökning så kan konstateras att forskningen och kunskapen på området med tungt belastade, oscillerande och fettsmörjda leder är liten. Dimensionering sker ofta med hjälp av erfarenhet och med tankesättet ”det har fungerat förut”. När lösningsförslagen har jämförts så har detta gjorts genom att använda metoden AHP (Analytic Hierachy Process). Med denna metod så jämför man kriterierna från kravspecifikationen med lösningsförslag så att man matematiskt kan räkna fram ett vinnande lösningsförslag. Resultatet visar att en smörjfri lösning skulle teoretiskt vara att föredra. Denna skulle tillverkas av en modern polymer och kompletteras med en inre tätning och ett yttre skydd. Atlas Copco rekommenderas att testa de olika förslagen för att komma fram till vilken som är bäst lämpad för applikationen. / The goal of this work is to investigate the lubrication system on two exposed joints on a Boomer E2C. The request for the thesis comes from Atlas Copco Rock Drills AB, Örebro, which also manufactures the machine. Today Atlas Copco Rock Drills AB has a grease lubrication system that secures the function of the joints. The task is to summarize and evaluate the current systems and to find new solutions that would be able to replace or partially replace the current system. Information was gathered from documents, construction drawings and conversations with engineers at the company. Solutions and ideas have been formed by meeting stock suppliers and searching for articles. Brainstorming has been used in order to find new solutions. The investigation has shown that there are problems with the current solution in terms of hose failures and downtime in the field. Atlas Copco AB also expresses that there is a lack of documentation and knowledge regarding the lubrication system. After the various article searches it became clear that research and knowledge in the area with heavy duty, oscillating and grease lubricated joints is insufficient. The design is often done with the help of experience and with the mindset "it has worked before." When the solutions and ideas have been compared, this has been done by using AHP (Analytic Hierarchy Process). This method compares the criteria that must be fulfilled by the solutions and then calculates the best one. The results show that a lubrication-free solution would theoretically be preferable. This would be produced by a modern polymer and supplemented with an inner seal and an outer protection. Atlas Copco is recommended to test the various proposals to be able to decide which the best solution for the application is.

Electromagnetic interference (EMI) is one of the most common problems encountered in microwave applications. Interaction of electromagnetic (EM) waves from different sources may result in device malfunction due to misinterpretation of the transferred data or information loss. On the other hand, development of materials with reduced radar detectability is desired in defense applications. Considering the limitations in weight and thickness, development of lightweight structural materials with enhanced electromagnetic absorption potential is needed. In this study, development and characterization of glass fiber-reinforced polymer (GFRP) composite materials to be used in EM wave absorbing or EMI shielding applications was aimed. Incorporation of electromagnetic wave absorption characteristic has been achieved by the application of conductive thin film on fiber glass woven fabric reinforcement layers. Characterization of EM wave absorption potential was conducted using &ldquo / free-space method&rdquo / in 18 &ndash / 27 GHz frequency range. Single and multilayered combinations of surface-modified fiber glass woven fabrics were characterized in terms of their EM wave interaction properties and design principles for efficient broadband EM wave absorbing multilayered GFRP composite material have been presented. A computer aided computation method has also developed in order to predict EM wave transmission, reflection, and hence absorption characteristics of multilayered structures from single layer properties. Estimated results were verified compared to free-space measurement results. In the current study, up to 85% electromagnetic wave absorption has been obtained within 18-27 GHz frequency range (K band). Enhancement of EM wave absorption potential of multilayer structure has also been demonstrated by computer aided computation.

The incorporation of inflatable structures into aerospace systems can produce significant advantages in stowed volume to mechanical effectiveness and overall weight. Many applications of these ultra-lightweight systems are designed to precisely control internal or external surfaces, or both, to achieve desired performance. The modeling of these structures becomes complex due to the material nonlinearities inherent to the majority of construction materials used in inflatable structures. Furthermore, accurately modeling the response and behavior of the interfacing boundaries that are common to many inflatable systems will lead to better understanding of the entire class of structures. The research presented involved using nonlinear finite element simulations correlated with photogrammetry testing to develop a procedure for defining material properties for commercially available polyurethane-coated woven nylon fabric, which is representative of coated materials that have been proven materials for use in many inflatable systems. Further, the new material model was used to design and develop an inflatable pathfinder system which employs only internal pressure to control an assembly of internal membranes. This canonical inflatable system will be used for exploration and development of general understanding of efficient design methodology and analysis of future systems. Canonical structures are incorporated into the design of the phased pathfinder system to allow for more universal insight. Nonlinear finite element simulations were performed to evaluate the effect of various boundary conditions, loading configurations, and material orientations on the geometric precision of geometries representing typical internal/external surfaces commonly incorporated into inflatable pathfinder system. The response of the inflatable system to possible damage was also studied using nonlinear finite element simulations. Development of a correlated material model for analysis of the inflatable pathfinder system has improved the efficiency of design and analysis techniques of future inflatable structures.

Dans ce travail de thèse, une modélisation multi-échelle est mise en place à partir du concept d’homogénéisation périodique pour étudier le comportement cyclique et dépendant du temps des composites tissés à matrice thermoplastique. Avec l’approche proposée, le comportement macroscopique du composite est déterminé à partir d’une simulation éléments finis effectuée sur une cellule unitaire représentative de la microstructure périodique, où les lois de comportement des constituants sont directement intégrées, à savoir: la matrice et les torons. La réponse locale de la matrice est décrite par une loi de comportement phénoménologique multi-mécanismes intégrant viscoélasticité, viscoplasticité et endommagement ductile. Pour les torons, une loi de comportement hybride micromécanique-phénoménologique est considérée. Cette dernière prend en compte l’endommagement anisotrope et l’anélasticité induite par la présence d’un réseau diffus de microfissures à travers une description micromécanique d’un volume élémentaire représentatif contenant des microfissures. Les capacités du modèle multi-échelles sont validées en comparant les prédictions numériques aux essais expérimentaux. Les capacités du modèle sont également illustrées à travers plusieurs exemples où le composite subit des déformations dépendantes du temps lors de chargements monotones, de chargements à amplitude constante ou cyclique et encore lors de chargement multiaxiaux non proportionnels. En outre, le modèle multi-échelle est aussi utilisé pour analyser l’influence des mécanismes de déformation locaux sur la réponse macroscopique du composite. / In this thesis, a multi-scale model established from the concept of periodic homogenization is utilized to study the cyclic and time-dependent response of thermoplastic-based woven composites. With the proposed approach, the macroscopic behaviour of the composite is determined from a finite element simulation of the representative unit cell of the periodic microstructure, where the local constitutive behaviours of the components are directly integrated, namely: the matrix and the yarns. The local response of the thermoplastic matrix is described by a phenomenological multi-mechanisms constitutive model accounting for viscoelasticity, viscoplasticity and ductile damage. For the yarns, a hybrid micromechanical-phenomenological constitutive model is considered. The latter accounts for anisotropic damage and anelasticity induced by the presence of a diffuse micro-crack network through the micromechanical description of a micro-cracked representative volume element. The capabilities of the multi-scale model are validated by comparing the numerical prediction with experimental data. The capabilities of the model are also illustrated through several examples where the composite undergoes time-dependent deformations under monotonic loading, constant or cyclic stress levels and non-proportional multi-axial loading. Furthermore, the multi-scale model is also employed to analyse the influence of the local deformation processes on the macroscopic response of the composite.

Electrospinning, un procédé original de mise en forme de polymère par application d'un champ électrique élevé, est largement utilisé pour la synthèse de membranes non tissées nanofibreuses. Les membranes électrospinnées ont une forte porosité et un rapport surface / volume élevé. En effet, ces matériaux ont suscité beaucoup d'intérêt et d'études au cours des dernières décennies, ce qui ouvre la voie à de nombreuses applications telles que la détection, l'ingénierie tissulaire ou la livraison de médicaments. La recherche actuelle vise à avoir des membranes fibreuses avec une architecture contrôlée utilisant différents types de collecteurs.Le développement de nanofibres à base de biopolymères et une stratégie thérapeutique pour la régénération des tissus mous.Le premier objectif de cette thèse était de développer de nouveaux matériaux biocompatibles et bio résorbables à l'aide de fibres à l'échelle nanométrique obtenues par électrospinning. En outre, cette étude a examiné l'influence de la viscosité, de la concentration et de la tension superficielle des solutions de polymère sur les fibres obtenues. En outre, le débit, la tension appliquée et les paramètres environnementaux (température et humidité) ont également été optimisés au cours de la production de nanofibres.Les fibres ont été obtenues à partir de PEO, polymère biocompatible. C'est un polymère linéaire qui se compose de segments éthylène et éther [-CH2CH2O-]n. L'oxyde d'éther peut être utilisé pour interagir avec des espèces hydrophiles. En raison de sa solubilité dans l'eau, sa non-toxicité et sa capacité à être électrospinné, le PEO a été utilisé comme additif dans des solutions de biopolymères pour permettre la formation d'électrodes fibreuses. La résistance mécanique du PEO dépend de la masse moléculaire, de la conformation des chaînes polymères et de la taille des fibres ainsi que la structure du réseau.Le deuxième effort majeur de cette thèse s'est concentré sur le contrôle des mailles fibreuses. Une telle activité de recherche est justifiée par l'influence attendue de la morphologie du réseau de fibres sur les propriétés mécaniques des membranes et leur caractère biomimétique qui favorise la colonisation et la croissance des cellules du tissu hôte. Le contrôle de cette structure a été réalisé grâce au développement de collecteurs.L'objectif de la thèse est de fabriquer des structures fibreuses non tissées aléatoires et structurées par electrospinning. Ces structures fibreuses sont obtenues à partir de Poly (oxyde d'éthylène), PEO, en solutions à différentes concentrations et masses moléculaires.Le dépôt de fibres est réalisé sur deux types de collecteurs: a) Feuille d'aluminium, b) Collecteur micro-structuré (dimension 3 × 3 cm). Les analyses morphologiques des membranes ont été menées à l'aide d'une microscopie électronique à balayage (MEB) et leurs propriétés mécaniques sous traction ont été réalisées à l'aide du rhéomètre ARESG2.La morphologie des matériaux electrospinnées passe graduellement d'une structure de type perles à des fibres uniformes lorsque la concentration et la masse moléculaire augmentent. Une étude comparative des propriétés morphologiques et mécaniques (essai de traction) des deux structures fibreuses a été réalisée. Cette étude a montré qu'il est possible d'avoir une distribution de fibres formant une cellule primitive très uniforme dans un réseau de dimension 3 × 3 cm. Ce réseau structuré a une contrainte à la rupture plus importante que celle du réseau fibreux aléatoire obtenu conventionnellement avec une feuille d'aluminium. / Electrospinning, an original polymer process under high electric fields to produce a network of thin fiber having a micrometer diameter, is widely used for the synthesis of nanofibrous non-woven membranes. The fabricated electrospun membranes have a high porosity and a high surface to volume ratio. Indeed, they reveal much interest and have been much developed in the last decades, which paves the way for numerous applications such as sensing, tissue engineering or drug delivery. Current research aims to have fibrous membranes with a controlled architecture using various types of collectors.This thesis is part of a global and emerging project that focuses on the production of structured scaffolds nanofibers based on biopolymers and dedicated to the therapeutic strategy for the regeneration of soft tissues.In the present work, the first focus was to develop new biocompatible and bioresorbable materials composed of nanoscale fibers obtained by electrospinning. In addition, this study examined the influence of viscosity, concentration, and surface tension of PEO solutions on the obtained fibers. Further, the flow rate, applied voltage and environmental parameters (temperature and humidity) were also optimized in the course of nanofibers production.Biocompatible fibers have been obtained by using PEO. It is a linear polymer that consists of ethylene and ether segments [-CH2CH2O-]n. The ether oxygen allows this polymer to interact with other hydrophilic species, while the ethylene part participates in hydrophobic interactions. Due to its water solubility, non-toxicity and electrospinn ability, PEO has been used as an additive in biopolymer solutions to enable the formation of electrospun fibers. The mechanical strength of the PEO depended on the molecular weight, the conformation of the polymer chains and the fiber scale, the structure of the network.The second major effort of this thesis focused on the control of the mesh fibers. Such research activity is justified by the expected influence of the morphology of the fiber network on the mechanical properties of scaffolds and their biomimetic character that could favor the colonization and growth of the cells of the host tissue. The control of this structure has been achieved through the development of collectors.The objective of this project is making non-woven fibrous structures in uncontrolled architecture as well as non-woven with controlled architecture by using the electrospinning process. These fibrous structures are obtained from Poly(ethylene oxide), PEO, solutions with different concentration and molecular weight. The deposit of fibers is made on two types of collectors: a) Aluminum foil, b) micro-structured collector (dimension 3×3 cm). The morphological analyses of the membranes were investigated using scanning electron microscopy (SEM) and their mechanical properties were characterized by tensile test using the ARESG2 rheometer. The morphology of the electrospun polymer gradually changes from beads to uniform fibers with increasing polymer concentration and molecular weight. A comparative study of the morphological and mechanical (tensile test) properties, of both fibrous structures is performed. This study showed that it is possible to have a distribution of fiber forming a very uniform primitive cell in a network of dimension 3×3 cm. This structured network has a strain at the break more important than that for the network fibers, which are collected on Aluminum foil.

The task performed in this assignment is to improve the reliability of Norden Machinery ABs product family. This is to be done by examining and replacing the belt used to stop the spreading of tubes from ingoing shipping crate to the infeed of the machine. The way that this was approached was by testing different candidates on a spectrum of their rigidity to find if a flexible or more rigid belt would perform better than the current context of the system. The testing was conducted for a period of 4 weeks and results were gathered by examining damages to the belts by the use of microscope. After the damage had been analyzed the conclusion was drawn that flexible alternatives seems to perform the task better than their rigid counterparts however more work is needed in the fields regarding the fastening and operation of the machine to use the best suited candidates derived from this test, the monolithic belt FMT-02TXCT-U1.

Cette thèse s’inscrit à mi-chemin entre l’étude de la déformabilité des structures tissées et la valorisation de la fibre de lin pour des applications dans le renforcement des matériaux composites. Le premier objectif de l’étude est de caractériser expérimentalement le comportement en flexion des mèches de différentes structures constituées de fibres de lin ainsi que des tissus de différentes armures. Les travaux ont abordé aussi des paramètres tels que l’humidité relative et la composition (des mèches comélées ou en lin pure). Le deuxième objectif des travaux est d’étudier le comportement en flexion des tissus en fonction du comportement en flexion des mèches. Cette partie a commencé par la modélisation géométrique des renforts tissés dans le but de suivre l’évolution de la section du tissu qui varie dans la direction de la flexion. La modélisation mésoscopique a permis de calculer analytiquement les propriétés géométriques du tissu en particulier son moment quadratique. Les résultats obtenus ont été utilisés dans la simulation de la flexion du tissu. L’étude a permis de voir jusqu’à quel point le comportement de la mèche et le moment quadratique du tissu pilotent le comportement en flexion du tissu. D’après ces travaux, le comportement en flexion du tissu semble être approché de façon satisfaisante sur toute la gamme de longueurs envisagées à partir de ces deux grandeurs sauf pour les forts taux d’humidité où d’autres phénomènes doivent être considérés. L’étude a souligné que la différence entre deux renforts testés expérimentalement peut être anticipée numériquement. Ainsi, le concepteur de tissus sera capable d’anticiper la rigidité expérimentale du tissu pour faire des tissages adaptés à la mise en forme du renfort. Une étude paramétrique de la flexion a été également réalisée dans le but de déduire les paramètres les plus influents sur lesquels il peut jouer. / This thesis is halfway between the study of the deformability of woven structures and the use of flax fibre as reinforcement of composite materials. The first aim of the study is the experimental characterization of the bending behaviour of tows with different structures made of flax fibres and fabrics with different weaves. Parameters such as relative humidity and the composition (100% flax and commingled tows) were also considered. The second aim of the study is to link the bending behaviour of the fabric to the bending behaviour of its constituent tows. This part starts with the geometric modelling of woven fabrics in order to follow the variation of its section in the bending direction. Mesoscopic modelling allows the analytical calculation of the geometric properties of the fabric in particular its moment of inertia. The results obtained were used in the simulation of the fabrics bending to see how far the behaviour depends on the tows bending behaviour and the moment of inertia. The bending behaviour of the fabric seems to be approached satisfactorily from these two factors. This is verified within the range of lengths considered except for high humidity (in this case, other phenomena must be considered). The study pointed out that the difference between two reinforcements tested experimentally can be predicted numerically. Thus, the fabrics designer will be able to anticipate the experimental bending stiffness of the fabric in order to adapt the weaving to the shape forming. A parametric study of the bending was also achieved in order to deduce the most influential parameters of the fabric for an appropriate weaving.