Σήμερα, τα σύνθετα υλικά χρησιμοποιούνται ευρέως στην καθημερινότητα μας. Με τον όρο σύνθετα εννοούμε τα υλικά τα οποία µακροσκοπικά αποτελούνται από δύο ή περισσότερα χημικά ευδιάκριτα συστατικά μέρη και εμφανίζουν µια συγκεκριμένη διαχωριστική επιφάνεια μεταξύ τους. Το ένα από τα συστατικά μέρη χαρακτηρίζεται ως συστατικό ενίσχυσης και προσδίδει στο σύνθετο βελτιωμένες μηχανικές ιδιότητες. Το δεύτερο συστατικό καλείται μήτρα, είναι συνήθως χαμηλής πυκνότητας και η συμμετοχή του στο σύνθετο εξασφαλίζει τη μέγιστη δυνατή εκμετάλλευση των ιδιοτήτων της ενίσχυσης. Για τις βέλτιστες ιδιότητες τους όμως πρέπει αρχικά να μελετηθούν οι μηχανικές ιδιότητες μήτρας και ενίσχυσης ξεχωριστά. Στην παρούσα εργασία επικεντρωνόμαστε κυρίως στα πολυμερικά σύνθετα υλικά με ενίσχυση από ίνες άνθρακα. Οι εξαιρετικά καλές μηχανικές ιδιότητες που εμφανίζουν οι ίνες άνθρακα τις καθιστούν ιδανικό ενισχυτικό μέσο για πολυμερικές μήτρες με σκοπό την παραγωγή σύνθετων πολυμερικών υλικών υψηλών ειδικών ιδιοτήτων. Οι ίνες αυτές αποτελούνται από άτομα άνθρακα των οποίων οι δεσμοί είναι περίπου παράλληλοι με τον άξονα της ίνας, γεγονός που προσδίδει στο ανθρακόνημα υψηλή δυσκαμψία, αντοχή σε θραύση και χαμηλό συντελεστή θερμικής διαστολής. Λόγω αυτών των ιδιοτήτων, σε συνδυασμό με το χαμηλό βάρος και την αντοχή σε χημική προσβολή, τα ανθρακονήματα χρησιμοποιούνται όλο και περισσότερο στην αεροναυπηγική, τον κατασκευαστικό τομέα και την αυτοκινητοβιομηχανία. Για την μελέτη των μηχανικών και φασματοσκοπικών ιδιοτήτων των ινών άνθρακα χρησιμοποιήθηκαν η συσκευή μηχανικών δοκιμών MTS, η ηλεκτρονική μικροσκοπία σάρωσης (Scanning Electron Microscope, SEM), o Μηχανικός Δυναμικός Αναλυτής (Dynamic Mechanical Analysis, DMA) και η φασματοσκοπία Raman. Η διπλωματική εργασία αποτελείται από δύο μέρη: Στο θεωρητικό μέρος, γίνεται μια βιβλιογραφική εισαγωγή στις ίνες άνθρακα, την παραγωγή και τις ιδιότητες τους. Επιπλέον, αναλύονται οι πειραματικές τεχνικές που προαναφέρθηκαν. Ως αναφορά το πειραματικό κομμάτι, παρουσιάζονται και συγκρίνονται τα αποτελέσματα των ανωτέρω τεχνικών χαρακτηρισμού. / In our days, composite materials are widely used in our life. Composites is meant materials witch macroscopically consist of two or more chemically distinct components have a specific interface between them. One of the components, characterized as enhancing component in the composite and imparts improved mechanical properties. The second component is called matrix, is usually low density and involvement in complex ensures maximum exploitation of the properties of the aid. So, composites optimal properties should initially be studied the mechanical properties of fiber and matrix separately. In this paper we focus mainly on polymeric composites reinforced by carbon fibers. Carbon fibers exhibit extremely good mechanical properties, which make it an ideal tool for reinforcing polymeric matrices to produce composite polymeric materials of high specific properties. These fibers are composed of carbon atoms that their bonds are approximately parallel to the axis of the fiber, which gives high strength, fracture toughness and low thermal expansion coefficient to carbon fibers. Due to these properties, combined with the low weight and resistance to chemical attack, carbon fibers are increasingly used in aeronautical, construction sector and automotive. To study the mechanical and spectroscopy properties of carbon fiber we used device mechanical testing MTS, Scanning Electron Microscopy (SEM), Dynamic Mechanical Analyzer (DMA) and Raman spectroscopy. The thesis consists of two parts: Theory part, which is a bibliographical introduction to carbon fiber production and properties. Furthermore, analyzing the experimental techniques mentioned above. Experimental part, where presented and compared the results of above characterization techniques.

The goal of this research is to investigate the behavior of polymer concrete confined with a carbon fiber sleeve used as a pile foundation. To evaluate the behavior of a confined polymer concrete pile in this research, four steps was considered. The first step of this investigation considered the mix design of polymer concrete, polymer concrete is a new material which is a combination of epoxy resin and aggregate. Instead of using a traditional mix of cement and water to make concrete, epoxy resin is used. Three dissimilar varieties of aggregate are mixed with different ratios in order to reach the maximum bulk density to obtain the maximum strength. After discovering the optimum ratio which gives the maximum bulk density, several samples of the aggregate are mixed with different ratios of epoxy resin. Next, the samples are investigated in a compression test to observe which ratios have the maximum strength and this ratio is used for a polymer concrete mix design to create a pile foundation. The pile is a built using a cast in place method and confined with a sleeve of carbon fiber. The second part of this investigation determined the structural mechanical properties of confined polymer concrete pile material. The unconfined and confined polymer concrete was tested in compression to determine compressive strength and stress-strain behavior. Similar tests were conducted on unconfined and confined cement concrete for comparison between these materials. Additional tension tests were conducted on unconfined polymer concrete. Then, a carbon fiber sleeve was tested in compression test to determine tensile strength and tension stress-strain behavior. After these tests, the confined polymer concrete is modeled in the computer program MATTCAD which is used to calculate the theoretical bending moment capacity and load-displacement curve. Finally, the confined polymer concrete is tested with the MTS 311 Load Frame in three point load flexure test to determine the experimentally bending moment capacity, load-displacement curve and compare with theoretical results. Confined polymer concrete was tested in one and two way cyclic loading to observe the ductility behavior of this material as laterally loaded piles and compared with cement concrete results in cyclic loading. The third part of this investigation determined the geotechnical mechanical properties of confined polymer concrete pile material. Cyclic Multi Degree of Freedom (CYMDOF) device was used to determine interface reaction and friction angle between confined polymer concrete and soil with interface shear test theory method. Furthermore, the same device was used to determine the friction angle of soil with direct shear test theory, and compare the friction angle results together. The last part of this investigation considered the behavior of different sized confined polymer concrete pile in different types of soil. A confined polymer concrete pile was modeled into PLAXIS and OPENSEES PL computer software to analysis pile in axial load and lateral load respectively. Furthermore, a cement concrete pile was modeled with similar software and conditions to compare these two materials.

The use of fiber reinforced polymers (FRP's) for structural repair or retrofit has increased significantly in the last decade, with adoption for civil infrastructure occurring only in the last 20 years. These products are most often used to increase the capacity of damaged or deteriorated structures. Much research has been performed in the arena of testing of various FRP's bonded to both concrete and masonry substrates, the majority of which focusing on three areas; flexural strengthening, in-plane shear strengthening, and mechanical anchoring. Anchorage is commonly the limiting factor in the application of FRP's, due to the inability of the edge of the polymer matrix to reliably extend beyond a point of zero-interfacial stress. Where interfacial stresses exist and the FRP is terminated localized disbondment often occurs, these localized failures then propagate across the entire bond of the structural system. Various mechanical termination details have been tested to mitigate the potential failure modes near the ends of the fabric. There, however, has been very limited research performed on the behavior of dowels which are installed parallel to the FRP fabric and splayed onto the FRP fabric matrix. In this research the mechanical properties of carbon fiber reinforced polymer (CFRP) dowels with a parallel orientation to uniaxial carbon fabric are experimentally tested to determine the tensile capacity of "dowel to splay" CFRP connections and to discover any dominant failure modes.

Advanced composites have become one of the most popular methods of repairing and/or strengthening civil infrastructure in the past couple of decades. While the use of Fiber Reinforced Polymer laminates and sheets for the repair and strengthening of reinforced concrete structures is well established, research on the application of FRP composites to steel structures has been limited. The use of FRP material for the repair and rehabilitation of steel members has numerous benefits over the traditional methods of bolting or welding of steel plates. Carbon FRPs (CFRPs) have been preferred over other FRP material for strengthening of steel structures since CFRPs tend to posses higher stiffness. The emergence of high modulus CFRP plates, with an elastic modulus higher than that of steel, enables researchers to achieve substantial load transfer in steel beams before the steel yields. This research investigates both analytically and experimentally, the bond characteristics between ultra high modulus CFRP strengthened steel members and the flexural behavior of these members. A series of double strap joint tests with two different CFRP strip widths are carried out to evaluate the development length of the bond. Both ultra high modulus and normal modulus CFRP laminates are used to compare strengthened member performance. Steel plates reinforced with CFRP laminates on both sides are loaded in tension to evaluate the load transfer characteristics. Debonding under flexural loads is also studied for ultra high modulus CFRP strengthened steel girders. Flexural tests are carried out under 4-point bending on several small scale wide flange beams. This study also introduces the novel ultra high modulus CFRP plate strip panels for strengthening of steel bridge girders. The first field application of ultra high modulus CFRP laminates in strengthening steel bridge girders in the United States is also carried out as part of the research. Full scale load tests carried out before and after the strengthening are utilized to measure the degree of strengthening achieved and checked against the expected results. A finite element model is developed and calibrated using data obtained from the field testing of the bridge. The model is then used to evaluate the behavior of the bridge under different conditions before and after the strengthening process.

Σκοπός της παρούσας διπλωματικής εργασίας είναι η μελέτη της συμπεριφοράς συνθέτων υλικών με τροποποιημένη πολυμερή μήτρα σε υγροθερμικές συνθήκες κόπωσης. Συγκεκριμένα τα υλικά που χρησιμοποιήθηκαν είναι CFRP (Carbon Fiber Reinforced Polymers), δηλαδή σύνθετα υλικά πολυμερικής μήτρας, τα οποία είναι ενισχυμένα με ίνες άνθρακα. Πρέπει να σημειωθεί ότι χρησιμοποιήθηκαν δυο τύποι πολυμερικών συστημάτων. Το πρώτο σύστημα αποτελείται από την εποξειδική ρητίνη LY 564 και τον σκληρυντή Aradur 2954, ενώ το δεύτερο σύστημα αποτελείται από την κυανεστερική ρητίνη Primaset και το σκληρυντή DT-4000. Επίσης και στα δυο συστήματα τα υλικά που κατασκευάστηκαν ήταν μονο-διεύθυντα (UD προς μία διεύθυνση 00), με εξαίρεση ότι στο εποξειδικό σύστημα κατασκευάστηκαν και Quasi υλικά, στο οποίο οι ίνες έχουν προσανατολισμό σε τέσσερις διαφορετικές διεθύνσεις [(0/+45/-45/90)2]s. Όλα τα υλικά περιέχουν συνολικά 16 στρώσεις ινών. Ακόμη η μήτρα των υλικών μας είναι τροποποιημένη, καθώς περιέχει CNTs (Carbon Nano Tubes) νανοσωληνίσκους, σε διαφορετικά ποσοστά. Τα ποσοστά που μελετήθηκαν ήταν 0%, 0,1%, 0,5% και 1% CNTs για τα εποξειδικά UD υλικά, 0% CNTs για τα Quasi και τέλος 0%,0,5% και 1% CNTs για το κυανεστερικό σύστημα. Τα συγκεκριμένα υλικά τοποθετήθηκαν σε ειδικό μπάνιο για 60 ημέρες, που ήταν γεμάτο με απιονισμένο νερό και σε θερμοκρασία 800C. Μελετήθηκε συστηματικά η απορρόφηση υγρασίας μέχρι και τον κορεσμό τους, καθώς και η μεταβολή της ηλεκτρικής αντίστασης των υλικών αυτών. Ακόμη μετά από 60 ημέρες και αφού τα υλικά βγήκαν από το μπάνιο τοποθετήθηκαν σε φούρνο θερμοκρασίας 800C. Σκοπός της διαδικασίας αυτής ήταν η ξήρανση τους, καθώς και η μέτρηση του χρόνου που απαιτείται για την διαδικασία αυτή. Έγιναν επίσης πειράματα δυναμικής-μηχανικής ανάλυσης (DMA), για την μέλετη της μεταβολής της θερμοκρασίας υαλώδους μετάβασης (Tg) για όλα τα στάδια. Αρχικά έγιναν πειράματα DMA σε όλα τα δοκίμια πρίν τοποθετηθούν στο μπάνιο, στην συνέχεια μετά το στάδιο του κορεσμού τους (περίπου στις 20 ημέρες παραμονής τους στο μπανιο), στις 60 ημέρες παραμονής των δοκιμίων στο νερό και τελικά μετά την διασικασία της ξήρανσης. Τέλος έγιναν πειράματα διηλεκτρικής φασματοσκοπίας για να καθοριστεί η ηλεκτρική αγωγιμότητα σε δοκίμια πριν τοποθετηθούν στο μπάνιο, κατά την διάρκεια του κορεσμού τους και τέλος μετά την ξήρανσή τους. / --

[pt] O objetivo deste trabalho é o estudo experimental do comportamento e do desempenho de vigas de concreto armado reforçadas à flexão com tecidos de compósitos de fibras de carbono.O programa experimental consiste no ensaio de sete vigas biapoiadas com um vão em balanço. Todas as vigas possuem a mesma seção transversal, armaduras e vãos,dimensionadas de forma que, antes do reforço, o valor do momento positivo máximo seja igual ao do momento negativo máximo. A primeira viga ensaiada não foi reforçada e foi utilizada como viga de referência. As vigas reforçadas foram divididas em dois grupos. No primeiro grupo, três vigas foram igualmente reforçadas nas regiões de momentos máximos positivos e negativos. No segundo grupo, três vigas tiveram sua armadura de reforço duplicada, em relação às vigas do primeiro grupo, na região de momento máximo negativo.As vigas foram concretadas, instrumentadas e ensaiadas no Laboratório de Estruturas e Materiais da PUC-Rio. Para tentar reproduzir a situação real, o carregamento foi aplicado nas vigas reforçadas até atingir cerca de 50% do valor previsto para a ruptura. Neste instante a viga já apresentava diversas fissuras e o ensaio foi interrompido para aplicação do reforço sob carregamento.Os resultados obtidos para as vigas em termos de deflexão, deformação da armadura,fissuração, modo e carga de ruptura são analisados. É possível verificar um aumento significativo de resistência e rigidez das vigas reforçadas, confirmando a eficiência deste tipo de reforço. A ductilidade avaliada em termos de critérios energéticos aparece como um parâmetro adequado para a análise do comportamento estrutural de vigas reforçadas com tecidos de compósitos de fibras de carbono. / [en] This investigation deals with the experimental evaluation of the performance of carbon fiber composites used for flexural strengthening of six reinforced concrete beams. The experimental program consists on the tests of seven simply supported beams with an overhanging portion, each one with the same cross section, steel reinforcement and span.The beams were designed to have the same value of maximum positive and negative moments. The first beam was not strengthened and it was used as a reference beam. The flexural strengthening of two categories of beams was considered. Category I beams were designed with equal flexural strengthening in the maximum negative and positive moments region. Category II beams were designed with double flexural strengthening in the maximum negative moment region.A total of three concrete beams of each category were constructed, instrumented and tested at the PUC-Rios Structures and Materials Laboratory. The average concrete strength was 20 MPa. The reinforcement steel bars have a yield strength of MPa. The flexural strengthening was applied under loading.The responses of the beams in terms of deflections, strains and modes of failure were examined. It was possible to verify a significant increasing in loading-carrying capacity of the beams due to strengthening. The results of this investigation are useful in substantiating the design data and providing design guidelines for this type of strengthening and they show that the energetic criterions are adequate parameters for the analysis of the beams.

Excellent properties of Carbon Fiber Reinforced Polymer (CFRP) composites are usually obtained in the direction at which carbon fibers are embedded in the polymeric matrix material. The outstanding properties of this material such as high strength to weight ratio, high stiffness and high resistance to corrosion can be tailored to meet specific design applications. Despite their excellent mechanical properties, application of CFRPs has been limited to more lucrative sectors such as aerospace and automotive industries. This is mainly due to the high costs involved in manufacturing of this material. Machining, milling and drilling, is a critical part of finishing stage of manufacturing process. Milling and drilling of CFRP is complicated due to the inhomogeneous nature of the material and extreme abrasiveness of carbon fibers. This is why CFRP parts are usually made near net shape. However, no matter how close they are produced to the final shape, there still is an inevitable need for some post machining to obtain dimensional accuracies and tolerances. Problems such as fiber-matrix debonding, subsurface damage, rapid tool wear, matrix cracking, fiber pull-out, and delamination are usually expected to occur in machining CFRPs. These problems can affect the dimensional accuracy and performance of the CFRP part in its future application. To improve the efficiency of the machining processes, i.e. to reduce the costs and increase the surface quality, researchers began studying machining Fiber Reinforced Polymer (FRP) composites. Studies into FRPs can be divided in three realms; analytical, experimental and numerical. Analytical models are only good for a limited range [0° – 75°] of Fiber Orientations , to be found from now on as “FO” in this thesis. Experimental studies are expensive and time consuming. Also, a wide variety of controlling parameters exist in an experimental machining study; including cutting parameters such as depth of cut, cutting speed, FO, spindle speed, feed rate as well as tool geometry parameters such as rake angle, clearance angle, and tool edge/nose radius. Furthermore, the powdery dust created during machining is known to cause serious health hazards for the operator. Numerical models, on the other hand, offer the unique capability of studying the complex interaction between the tool and workpiece as well as chip formation mechanisms during the cut. Large number of contributing parameters can be included in the numerical model without wasting material. Three main objectives of numerical models are to predict principal cutting force, thrust force and post-machining subsurface damage. Knowing these, one can work on optimization of machining process by tool geometry and path design. Previous numerical studies mainly focus on the orthogonal cutting of FRP composites. Thus, the existing models in the literature are two-dimensional (2D) for the most part. The 2D finite element models assume plain stress or strain condition. Accordingly, the reported results cannot be reliable and extendable to real cutting situations such as drilling and milling, where oblique cutting of the material occurs. Most of the numerical studies to date claim to predict the principle cutting forces fairly acceptable, yet not for the whole range of fiber orientations. Predicted thrust forces, on the other hand, are generally not in good agreement with experimental results at all. Subsurface damage is reported by some experimental studies and again only for a limited FO range. To address the lack of reliable force and subsurface damage prediction model for the whole FO range, this thesis aims to develop a 3D finite element model, in hope of capturing out-of-plane displacements during stress formation in different material phases (Fiber, Matrix and the Interface bonding). ABAQUS software was chosen as the most commonly used finite element simulation tool in the literature. In present work a user-defined material subroutine (VUMAT) is developed to simulate behavior of carbon fibers during the cut. Carbon fibers are assumed to behave transversely isotropic with brittle (perfectly elastic) fracture. Epoxy matrix is simulated with elasto-plastic behavior. Ductile and shear damage models are also incorporated for the matrix. Surface-based cohesive zone technique in ABAQUS is used to simulate the behavior of the zero-thickness bonding layer. The tool is modeled as a rigid body. Mechanical properties were extracted from the literature. The obtained numerical results are compared to the experimental and numerical data in literature. The model is capable of capturing principal forces very well. Cutting force increases with FO from zero to 45° and then decreases up to 135°. The simulated thrust forces are still underestimated mainly due to the fiber elastic recovery effect. Also, the developed 3D model is shown to capture the subsurface damage generally by means of a predefined dimensionless state variable called, Contact Damage (CSDMG). This variable varies between zero to one. It is stored at each time step and can be called out at the end of the analysis. It was shown that depth of fiber-matrix debonding increases with increase in FO. / Graduate

The main purpose of this study was to investigate and implement a repair design for corrosion damaged bridge bents in order to resist lateral loading, such as wind loads or ship impact. Using the results from a one-third scale bridge bent constructed and tested for a previous study, non-linear modeling was used to simulate the same corrosion damage and load response. The principle variable considered was damage, represented as a percent of effective area loss of prestressing steel within a designated damage zone along the length of piles. Other influencing variables included: prestress transfer length, localized loss in prestress due to corrosion damage, prestress force, and concrete modulus of elasticity. Upon successful convergence of measured and modeled results, carbon fiber repair schemes were then modeled to restore bents to their full capacity. Suitable repairs were judged on the basis of restoration of capacity of the entire pile bent and the interaction diagrams of the individual piles. Results of the modeled repairs suggested that a single layer of a commercially available unidirectional carbon fiber would be sufficient when aligned longitudinally. No benefit from accompanying transverse fibers were considered although such a repair was suggested by the study findings. Analysis indicated that longitudinally bonded carbon fiber reinforced polymer (CFRP) to bridge piles increases a bent’s ability to resist bending moment due to lateral loading at the cap. However, additional capacity to plastic region of the response curve indicated larger capacity gains than by gains to elastic regions.

L’objectif de ce travail est d’effectuer une campagne d’essais expérimentaux d’impact et de compression après impact sur chant de stratifiés composites afin d’établir les scénarios d’endommagements. Un dispositif d'essai au poids tombant a été utilisé afin de réaliser les impacts sur chant sur stratifiés avec différents drapages. Des coupes microscopiques, des radiographies aux rayons X et des analyses ultrasonores ont ensuite été effectuées afin de visualiser et de déterminer le scénario d’endommagement. Des essais de compression après impact ont également été réalisés. Les résultats des tests expérimentaux sont comparés avec un modèle numérique composé d'éléments d’interface pour décrire les fissures matricielles et d’éléments volumiques. Enfin, la prédiction numérique de la tenue résiduelle après impact permettra de diminuer les masses, d’éviter des essais coûteux, et donc de raccourcir la durée de développement. / Low velocity / low energy edge impact and quasi-static experiments have been carried out on carbon fiberreinforced plastic (CFRP) structures. A drop-weight testing machine was used to impact four different UDlaminates at 10, 20 and 35 J impact energy levels. In parallel, a quasi-static study has been conducted in order to compare its results with the impact ones. The impact results show that the static and dynamic behaviors are different. An analytical approach, to understand the impact damage scenario, is provided in order to explain the difference between static and dynamic edge impacts, regardless the stacking or impact energy. This approach explains well the dynamic and static initial stiffness and a crushing plateau. The fiber properties control the initial impact stiffness, while in the quasi-static indentation case, the properties of the matrix control the initial indentation stiffness. The crushing plateau is also controlled by the matrix properties. The impact scenario could be simulated easily knowing the material properties, the stacking sequence and the impact energy. In addition, that is crucial to model the residual strength. And all these experimental results have been compared with a finite element analysis that consists of interface elements to describe the matrix cracks and volume elements in order to simulate the impact and compression after impact damage and to predict the residual strength after impact. The model is in good agreement with the experiment. That will avoid expensive tests, and thus shorten the development time.

L'évolution du contexte industriel pousse l'industrie du transport, et plus particulièrement le secteur automobile, à réaliser des gains de de masse. Ceci passe, pour partie, par le développement de nouvelles solutions en matériaux composites. Le présent travail de thèse est consacré à la caractérisation mécanique et à la modélisation micromécanique d'un nouveau matériau composite SMC renforcé de mèches de fibres de carbone. L'objectif est de constituer une première base de connaissances sur le comportement de ce SMC en fatigue. Les investigations expérimentales passent notamment par l'analyse de la microstructure, la caractérisation du comportement mécanique sous sollicitation quasi-statique et de fatigue ainsi que par l'analyse des modes de dégradations. L'approche multi-échelle développée prend en compte la microstructure du matériau aux deux échelles mises en évidence à travers deux homogénéisations successives par une méthode Mori-Tanaka. Cette stratégie de modélisation permet de relier le comportement des fibres et le comportement élasto-plastique de la matrice à travers une loi de comportement dédiée à celui du matériau composite, et enfin d'intégrer la distribution d'orientation des mèches induites par le procédé de thermocompression.Le modèle multi-échelle a été identifié par une méthode inverse à partir des bases de données expérimentales constituées lors des travaux. La loi constitutive globale, à l'échelle d'un volume élémentaire représentatif, a été implémentée dans la bibliothèque scientifique SMART+ en langage C++ et a été conçue pour être compatible dans le cadre d'analyse de structures par éléments finis. En régime non-linéaire intégrant l’endommagement. / The evolution of the industrial context is pushing the transport industry, and more specifically the automotive sector, toward better energy efficiency. This objective is partly achieved by the development of new composite material solutions. The current work is devoted to the mechanical characterization and the multiscale modeling of a new SMC composite material reinforced with short carbon fibers bundles. The objective is to build a first knowledge base on the behavior of this SMC under fatigue loading. Experimental investigations include the analysis of the microstructure, the characterization of the mechanical behavior under quasi-static and fatigue loading, as well as the analysis of the damage mechanisms. The proposed multiscale approach takes into account the microstructure of the composite at the two scales highlighted through two successive homogenizations by the means of a Mori-Tanaka based method. Such modelling strategy makes it possible to relate elasto-plastic behavior of the matrix through dedicated local constitutive laws and the behavior of the fibers to that of the composite material, and to integrate the orientation distribution of the bundles induced by the manufacturing process... The multiscale model was identified by the mean of an inverse computation method applied on the experimental results taken from the databases created during the works.The global constitutive law, computed at the scale of a representative elementary volume, has been implemented in the SMART+ scientific library in C++ language in such a manner to be compatible in a finite element analysis (FEA) framework.