In this thesis a constitutive model is developed for the numerical prediction of UD composite material behaviour under impact loading. Impact induced loading usually results in three dimensional stress states which significantly influences the failure behaviour. The heterogeneous nature of composite materials, in particular, results in a complex failure behaviour which manifests itself in various failure modes. Predicting the onset and evolution of these failure modes requires the use of physically based three dimensional theories for the prediction of the onset of damage and subsequent damage evolution. Furthermore, the use of polymeric matrices in continuous fibre reinforced composites results in a distinct directional strain rate dependent material behaviour which needs to be incorporated in constitutive models for the numerical simulation of impact events. The developed constitutive model relies on the prediction of the onset of damage evolution by the use of physically based three dimensional stress based failure criteria. A special feature of the proposed model is the identification of potential fracture planes. Numerically efficient algorithms for finding such planes are developed thus enabling the implementation into an explicit FE environment which was prohibitive so far. Damage evolution is simulated by degrading the tractions which are acting on the failure mode dependent fracture planes. The damage evolution and consequent energy dissipation is thereby driven by physically based dissipation potentials which consider only stresses which contribute to damage growth. The well known mesh dependent energy dissipation in Continuum Damage Mechanics is reduced by the introduction of an element size dependent parameter into the constitutive equations. An experimental program is conducted to investigate the compressive behaviour of composites. The focus of the study is on the rate dependent failure behaviour. The experiments are designed such that the failure mechanisms can be studied at varying strain rates with identical boundary conditions. This allows for direct conclusions about the strain rate dependent material behaviour. Novel optical measurement techniques are applied across all investigated strain rates thus ensuring an improved observation of the failure modes. The proposed constitutive model is finally verified by modelling of three point beam bending experiments which were performed quasi-statically and at impact velocities. The experimental technique for beam bending at impact loading was therefore improved thus yielding significantly more accurate experimental data.

L'utilisation de limiteurs de localisation est nécessaire pour prendre en compte l'apparition de macro-fissures lors de la simulation de l'évolution des dégradations dans les matériaux composites stratifiés en accord avec des expérimentations. Ceux-ci introduisent un paramètre qui peut être relié à une longueur, ou un temps caractéristique, qui peut alors être identifié. L'approche introduite au LMT-Cachan consiste, dans le cadre dynamique, à utiliser un modèle d'endommagement retardé. Elle est basée sur le fait qu'une fissure ne peut pas apparaître instantanément. Ce modèle donne d'excellents résultats en restant dans le cadre de la dynamique et a l'avantage d'être local en espace. Cependant il requiert une discrétisation temporelle de la taille du temps caractéristique introduit (de l'ordre de la microseconde pour les composites), qui le rend inexploitable pour des simulations de chargement en quasi-statique. Les simulations dans ces cas de chargement nécessitent donc l'utilisation d'un temps caractéristique différent de celui identifié qui ne permet plus de maintenir un résultat en accord avec l'expérience. On cherche alors à adapter les paramètres de la loi d'évolution de l'endommagement afin d'obtenir une propagation de la macro-fissure dans la zone localisée qui soit compatible énergétiquement avec la mécanique de la rupture en contrôlant le taux de restitution d'énergie. Ce travail est dédié à maintenir l'objectivité de la solution et à adapter l'énergie dissipé à la mécanique de la rupture afin de pouvoir utiliser un temps caractéristique exploitable lors de simulations d'éprouvettes en composites sous un chargement quasi-statique. / The use of localization limiters is needed to take into account the apparition of macro-cracks during the simulation of the evolution of degradations in laminated composite materials with respect to experiments. Those introduce a parameter which can be related to a characteristic length, or a characteristic time, and therefore be identified. The approach introduced at LMT-Cachan is, in dynamics, to use a delayed damage model. It's based on the fact that a crack can't appear instantaneously. This model gives excellent results in dynamics and has the advantage to be local in space. Unfortunately, it requires a time discretization related to the characteristic time introduced (of the order of a microsecond for composites), which is far too computationally expensive for quasi-static simulations. Simulations in these loading cases need the use of a different characteristic time from the one identified which can't maintain anymore a result in accordance to experiments. We then adapt the parameters of the damage evolution law to obtain a propagation of a macro-crack in the localized zone that is energetically compatible with fracture mechanics by controlling the strain energy release rate. This work is dedicated to maintain the objectivity of the solution and to adapt the dissipated energy to fracture mechanics to be able to use a characteristic time exploitable for the simulation of composite samples under quasi-static loading.

L’étanchéité à l’interface, le retrait de polymérisation, le taux de conversion, la contrainte de polymérisation et l’influence du facteur C, l’absorption d’eau et la solubilité de trois résines composites de restauration photopolymérisables ont été évalués in vitro. Une résine condensable (Filtek P60), une résine fluide (Filtek Flow) et leur adhésif (Scotchbond 1) et un ormocer et son adhésif (Admira & Admira Bond) ont été utilisés, la polymérisation s’est faite à l’aide d’une lampe LED selon deux modes continus de 20s et 40s et selon un mode exponentiel de 20s. L’étanchéité a été évaluée selon la pénétration d’un colorant (ISO 11405) ainsi qu’en MEB, la technique de la déflection de la lame de verre a été utilisée pour déterminer le retrait de polymérisation, la contrainte de polymérisation a été déterminée à l’aide d’une machine de traction, le taux de conversion a été mesuré en spectroscopie infrarouge à transformée de Fourier, l’absorption/ solubilité a été mesurée selon la méthode ISO 4049. L’étanchéité est significativement supérieure pour tous les matériaux à l’interface amélaire par rapport à l’interface cémentaire. Les retraits de polymérisation sont significativement différents pour tous les matériaux. Le mode de polymérisation affecte significativement les cinétiques de contraction. Les taux de conversion et les contraintes de polymérisation sont significativement différents pour tous les matériaux sans influence du mode de polymérisation. La diminution du facteur C entraine une diminution des contraintes et de leurs cinétiques. D’importantes différences d’absorption/ solubilité ont été mises en évidence entre les matériaux. / Interface tightness, polymerization shrinkage, conversion rate, polymerization stress and corresponding C-factor, and water absorption/ solubility of three photo-polymerizable composite resins were evaluated in vitro. They included a condensable resin (Filtek P60), a fluid resin (Filtek Flow), both with their adhesive (Scotchbond 1), and an ormocer with its adhesive (Admira & Admira Bond). Polymerization was performed using a LED lamp in two continuous modes (20s and 40s), and in the exponential mode (20s). Tightness was evaluated using a dye penetration test (ISO 11405) and SEM analysis. The glass slide deflection technique was used to determine polymerization shrinkage. Polymerization stress was determined with a materials testing machine. Conversion rate was measured by Fourier Transform Infrared Spectroscopy, and absorption/ solubility was measured by the ISO 4049 test method. All materials with enamel interfaces were significantly better for tightness than were cement interfaces. Polymerization shrinkage was significantly different for all materials. The polymerization mode had a significant impact on shrinkage kinetics. Conversion rates and polymerization stresses were significantly different for all materials but were not affected by the polymerization mode. The decrease in factor-C reduced stress and stress kinetics. The different materials showed marked differences in absorption/ solubility.

Ce travail de thèse propose un modèle numérique complet pour l'écoulement transitoire des eaux souterraines dans les milieux poreux et fracturés et son application sur l’analyse de la stabilité des pentes sous l’effet d’une diminution du niveau de l’eau dans un réservoir. L’écouement de l’eau dans les milieux fracturés est complexe, en raison de la présence d'un grand nombre de fractures et de fortes variations dans les propriétés géométriques et hydrauliques de ces milieux.La thèse est organisée en six chapitres.Le premier chapitre pésente les problèmes abordés et les objectifs de la thèse. Le 2nd chapitre présente une synthèse des analyses numériques de l'écoulement dans les milieux fracturés et de ses effets sur la stabilité des pentes. Le 3ème chapitre présente le développment d’un modèle numérique d'écoulement transitoire saturé dans des milieux fracturés avec une surface libre en utilisant la méthode des éléments composites (CEM). Le 4ème chapitre présente un modèle numérique d'écoulement transitoire à saturation variable, dans les milieux fracturés à l'aide du CEM.Le 5ème chapitre présente une étude de la stabilité des pentes sous l’effet de variation des paramètres hydrauliques et de résistance des sols, et da géométrie des pentes.Le 6ème chapitre présente une étude paramétrique de l'influence des caractéristiques de fracture sur l'écoulement transitoire et la stabilité d’une pente soumise à des conditions de diminution. / This thesis presents a comprehensive numerical method for analyzing transient groundwater flow in porous and fractured media and its application to the analysis of the stability of soil and rock slopes subjected to transient groundwater flow induced by reservoir drawdown conditions. Compared to that of porous media, the analysis of flow in fractured media is relatively complex, due to the presence of a large number of fractures and strong variations in geometric and hydraulic properties.The thesis is organized in six chapters. Chapter 1 presents the issues to be addressed and the thesis objectives. Chapter 2 discusses basic theories related to the numerical analysis of groundwater flow in fractured media and its effects on slope stability.Chapter 3 develops the numerical model of transient, saturated flow in fractured media with a free surface using the composite element method (CEM). Chapter 4 presents the numerical model of transient, variably-saturated flow in fractured media using the CEM.Chapter 5 includes an investigation of the stability of homogeneous soil slopes under drawdown conditions, depending on the drawdown rate, hydraulic and strength parameters of soils, and slope geometry.The last chapter presents a parametric study on the influence of fracture characteristics on transient flow and stability of layered rock slope subjected to drawdown conditions.

Department of Mechanical, Industrial and Aeronautical Engineering MSc (Mechanical Engineering) / Aramid fibre reinforced epoxy composites were hybridised by the addition of electrospun PAN (polyacrylonitrile) and ECNF (electrospun carbon nanofibre) doped PAN nanomats. One of the major concerns in polymer composites is the effect of the interlaminar properties on the overall mechanical properties of the composite. Electrospun carbon nanofibres were used as doping agents within PAN nanofibres, and coated in between aramid epoxy laminates to improve the interlaminar properties. PAN nanomats and ECNF doped PAN nanomats were created by the use electrospinning on the surface of aramid fibre sheets. Multiscale hybrid aramid reinforced composites were then fabricated. Mechanical characterization was carried out to determine the effect of PAN and CNF doped PAN nanofibre mats on aramid fibre reinforced epoxy. It was found that PAN reinforced nanomats had improved the mechanical properties and more specifically, when doped by ECNFs, the volume fraction of ECNFs played a vital role. An addition of 1% vol. CNF doped 0.1% vol. PAN reinforcement within a 30% vol. aramid fibre composite (control composite), improved the tensile strength and elastic modulus by 17.3% and 730% respectively. The 0.5% vol. PAN reinforced AFC (aramid fibre composite) specimens revealed a major increase in the flexural strength by 9.67% and 12.1%, when doped by both 0.5% vol. ECNFs and 1% vol. ECNFs respectively. The 0.5% vol. CNF doped reinforcement increased the impact energy by over 40%, for both the 0.1% vol. and 0.2 % vol. PAN reinforced aramid hybrid specimens. The 0.5% vol. CNF doped 0.5% vol. PAN had increased by 30% when compared to a non-doped sample. Morphological studies indicated interlaminar shearing between plies was affected by CNF agglomerations. This was discovered when determining the impact properties of the multiscale doped hybrid composites. Electrospun nanofibres however, assisted in improving the interlaminar regions within aramid epoxy by mechanical locking within the epoxy, and creating an adhesive bond using Van der Waals forces and electrostatic charges between nanofibre and macro fibre. Hybridising aramid epoxy with the use of nanofibres assisted in improving various mechanical properties. Impact degradation was one disadvantage of hybridising using CNF doped PAN nanofibre reinforcements. / MT2017

Ph.D., Faculty of Engineering and the Built Environment, University of the Witwatersand, 2012 / This thesis focuses on the boron suboxide B6O, a boron-rich super-hard ceramic material. With hardness values previously reported between 24 GPa and 45 GPa, B6O is one of the hardest known materials. Although first reports on boron suboxides date back as far as 1909 (Weintraub E., Transactions of the American Electrochemical Society, 16 (1909) 165), it is the B6O-based composites that have attracted considerable interest in recent years due to their enormous technological potential, especially as an alternative to polycrystalline diamond and polycrystalline cubic boron nitride for wear and abrasive applications. Investigations into the properties of B6O itself appear to have been neglected in favour of the improvement of densification and fracture toughness of the composites. The B6O samples used for the work reported in this work was hot-pressed was prepared under an argon environment at 1800 C and 50 MPa for 20 minutes followed metallographical preparation. The density of the hot-pressed compacts measured 2.44 g/cm3. The starting B6O powder material was supplied from the Fraunhofer Institute for Ceramic Technologies and Systems, Dresden. This thesis primarily seeks to generate and report as much practical data for polycrystalline B6O materials prepared by uniaxial hot-pressing as possible from a variety of characterization techniques. Firstly, the Raman spectra of hot-pressed B6O, which was until now poorly understood, was investigated using using a 514.5 nm green Ar+ laser excitation source. Secondly, the fundamental nature of some mechanical properties of hot-pressed B6O were investigated by means of Vickers and Berkovich indentation techniques. New approaches for data analysis, especially the investigations of the nanomechanical properties of hot-pressed B6O by Berkovich nanoindentation, were also suggested. Thirdly, the intrinsic hardness of hot-pressed B6O was investigated by means of a comprehensive inter-model comparison study. Fourthly, a combined experimental and simulation approach for determining mechanical properties of hot-pressed B6O by nanoindentation was also carried out, based on the outcomes of the study, the deformation response of the material under dynamic indentation was investigated at di erent stages using a custom developed finite element model. Finally, based on the preliminary ab initio density functional calculations of the structural properties of B6O conducted by Lowther showing that the presence of a high electronegativity interstitial in the B6O structure could enhance the strength of the bonding in B6O, fluorine ion implantation into B6O were conducted. The e ects to the structural and the nanomechanical properties of radiation damage induced by ion implantation was investigated. The possible formation of novel nanostructures in the ion-irradiated B6O matrix near-surface was also investigated. Results obtained from this study provides a vast amount of practical data for hot-pressed B6O materials as well as a number of novel analysis approaches for the extraction useful properties from the measured raw data. Firstly, using an automated background subtraction method, observable first- and second-order Raman spectra of B6O were obtained. A comparative analysis with previously reported spectra of other -rhombohedral boron-rich ceramic materials demonstrate a good agreement. Results also confirm the existence of highly resolved Raman modes measured at ambient conditions using a green Ar+ excitation source which is contrary to the conventional understanding. Secondly, results from the micro-indentation investigations indicate the measured microhardness exhibits indentation load dependence. A model inter-comparison study of indentation size e ects in the microhardness measurements of hot-pressed B6O is comprehensively discussed. Thirdly, the intrinsic hardness value of 30 GPa was deduced. Fourthly, a quantitative analysis approach was developed to simulate multi-cycling loading load-displacement curves from a single measured load-displacement nanoindentation curve. Based on the results, the nature of the indentation size e ect in the nanoindentation hardness as well as the intrinsic nanomechanical properties of hot-pressed B6O were established. Fifthly, a combined experimental and finite element method simulation approach for determining mechanical properties of hot-pressed B6O by nanoindentation was developed. Based on the outcomes of the combined experimental and simulation studies, the deformation response of the material under dynamic indentation was also investigated at di erent stages using a custom developed finite element model. Finally, results from the structural characterization of the ion implanted B6O material demonstrates the formation of novel nanostructures by means of the ion bombardment of B6O. In addition, the study presented here also seeks to investigate the e ects of the fluorine ion implantation on the near-surface nanomechanical properties of hot-pressed B6O. The principal conclusions that the study provide are both comprehensive practical data for B6O materials prepared by uniaxial hot-pressing. A number of properties, including the Raman spectra, the intrinsic hardness, and the radiation resistance and the e ects of radiation damage are reported in the thesis.

Dans cette étude, nous avons préparé deux matériaux composites conducteurs par le procédé d’électropolymérisation. Lebut de la première partie de la thèse était l’élaboration de films composites polyaniline /LiMn2O4 pour leur applicationcomme matériau de cathode dans les batteries lithium-ion. Les analyses par diffraction des rayons X, analyse EDX etspectrométrie IRTF ont confirmé l'incorporation de LiMn2O4 dans les films composites. Les analyses électrochimiquesdes films obtenus ont mis en évidence une conductivité plus élevée des films composites comparée à la conductivité desfilms de PANI. La deuxième partie a été consacrée à la préparation de l’oxyde de graphène (OG) à partir de graphiteselon 2 méthodes de synthèse dérivées de la méthode de Hummers. Les résultats obtenus ont montré que le de gréd’oxydation des feuillets n’était pas le seul critère à prendre en compte pour évaluer la stabilité du OG dans l’eau. Lesfeuillets d’OG obtenus ont été incorporés à la polyaniline par électropolymérisation d’une suspension d’OG et d’anilineen milieu neutre. Le milieu électrolytique neutre conduit à des chaînes oligomères de PANI de faible masse molaire avecune proportion significative d’unités aromatiques mono et 1,2-disubstituées dans la structure finale. Différents substratsmétalliques ont été testés et les films ont été en particulier déposés sur fer afin d’évaluer leur protection anticorrosion. / In this study, we prepared two conductive composite materials based on polyaniline (PANI) byelectrodeposition. First, we investigated the development of new polyaniline/LiMn2O4 composite films forapplication as cathode material in lithium-ion batteries. Analysis by X-ray diffraction, EDS analysis and FTIRspectroscopy confirmed the incorporation of LiMn2O4 in composite films. The electrochemical analysis of thefilms obtained showed a higher conductivity of the composite films compared to the conductivity of the filmsof PANI. The second part was devoted to the preparation of oxidized graphene (GO) from graphite by 2methods of synthesis derived from the method of Hummers. The results showed that the degree of oxidation ofthe graphene sheets was not the only criterion in assessing the stability of GO in water. Electropolymerizationof aniline in a neutral electrolyte containing GO sheets was carried out to prepare PANI-GO composite films.The neutral electrolytic medium leads to PANI oligomer chains of low molecular weight with a significantproportion of aromatic mono units and 1,2-di-substituted units in the final structure. The electrodeposition wasperformed on inert and oxidizable metals. The corrosion protection efficiency of PANI/GO composite filmswas studied in HCl corrosion medium.

Les développements récents des applications d’électronique portable demande de plus en plus l’utilisation de systèmes de récupération d’énergie à partir de sources environnantes de basse énergie. La conversion piézoélectrique à partir de sources vibratoire pourrait être un moyen intéressant pour l’alimentation électrique de petits systèmes. Dans ce travail, nous investiguons les potentialités de films de polymère bio-sourcé à base de polyamide 11 (PA11). Dans un premier temps, les effets de traitements physiques ou chimiques sur le développement des phases cristallines du PA11 ont été longuement étudiés. Dans un deuxième temps, des nano-argiles ont été utilisées comme modificateurs de structure dans la matrice PA11. Des nanocomposites de PA11/argile ont été réalisés en utilisant des argiles en feuillets et en nanotubes par extrusion. L’effet de ces argile n’est pas significatif sur la qualité structurale des composites obtenus. L’ajout d’argile en feuillets (cloisite 20A, cloisite 10A et cloisite Na+)conduit à une amélioration des caractéristiques mécaniques alors que l’ajout de silicates tubulaires (nanotubes d’halloysite) n’a pas d’effet significatif. Parmi tous les nanocomposites préparés, le nanocomposite chargé de Cloisite Na+ a montré la meilleure propriétés piézoélectriques. Il semble que la polarité plus élevée de la Cloisite Na+ puisse être à l’origine de la meilleure réponse à la polarisation de ces composites. Une méthode spécifique de quantification de la récupération d’énergie vibratoire a été développée pour ces composites polymères/argile. Les capacités de récupération d’énergie par vibration ont été étudiées sur l’argile PA11 chargée de Cloisite Na+. / In the last few years it has been an increasing demand for the elaboration of flexible energy conversion sources due to the rapid increase in the usage of portable electronic devices. The piezoelectric conversion from vibration sources could be an interesting way to charge small systems. In this work, we investigate the potential of bio-based polyamide 11 (PA11) polymer films. At first, the effect of physical and chemical treatments on the development of crystalline phases in polyamide 11 has been thoroughly investigated. In a second step, nanoclays have been used as structural modifiers in PA 11 matrix. Nanocomposites were prepared using layered and tubular clays by melt-blending process and it was found that addition of layered silicates (cloisite 20A, cloisite 10A and cloisite Na+) results in an increase in mechanical properties, while the addition of tubular silicates (halloysite nanotube) has no significant effect. Addition of clay is not significant on the structural quality of the obtained nanocomposites. PA11 nanocomposite loaded with Cloisite Na+ have shown the best piezoelectric properties. It appears that the higher value of the polarity of Cloisite Na + may be responsible of the best answer to the polarization of the composites. A specific method for the quantification of energy vibration recovery has been developed for these nanocomposites. The capabilities of vibrational energy recovery were studied on PA11 loaded with Cloisite Na+.

O desenvolvimento de novos materiais com fonte renovável, baixo custo, melhores propriedades físico-mecânicas e biodegradáveis tem se tornado o principal objetivo de muitas empresas e grupos de pesquisa. O objetivo deste trabalho foi preparar e caracterizar física, química e biologicamente um biocompósito à base de membrana de celulose com própolis. Foram preparadas membranas de celulose com própolis nas concentrações de 1,2%, 2,4% e 3,6%, secas e úmidas, realizados testes de caracterização através de Espectroscopia Vibracional na Região Infra-Vermelho, Difratometria de Raios-X, Microscopia Eletrônica de Varredura, Análise Térmica [Calorimetria Exploratória Diferencial e Termogravimetria] e análise microbiológica para S. aureus. A presença de concentrações diferentes de própolis nas membranas foi identificada nos diversos métodos utilizados e através do ensaio antimicrobiano, a concentração mínima de 0,34% de própolis foi ativo à S. aureus. Portanto, os resultados obtidos são promissores para trabalhos futuros in vivo e possíveis aplicações médicas. / The development of new materials with renewable, low cost, better physical and mechanical properties and biodegradable has become the main goal of many companies and research groups. The aim of this work was prepare and characterize physical, chemical and biologically biocomposites based at a cellulose membrane with propolis. Cellulose membranes were prepared with propolis at concentrations of 1.2%, 2.4% and 3.6%, wet and dry tests performed characterization using vibrational spectroscopy Infra-Red, X-ray Diffraction, Microscopy Scanning Electron, thermal analysis [differential scanning calorimetry and thermogravimetric] and microbiological analysis for S. aureus. The presence of different concentrations of propolis in the membranes was identified in various methods used by testing and antimicrobial, the minimum concentration of 0.34% propolis was active at St. aureus. Therefore, the results are promising for future studies in vivo and potential medical applications.

Neste trabalho foram avaliadas as propriedades de um adesivo estrutural uretânico que visavam colagens de peças automotivas compostas por combinações de compósitos, termoplásticos e metais, que requerem do adesivo um elevado desempenho e compatibilidade com esses materiais. Para tanto, foram avaliadas as resistências ao cisalhamento de juntas formadas com estes substratos e o adesivo uretânico em diversas condições de exposição, que visam simular os efeitos deletérios que estas juntas estarão expostas durante sua utilização. Estes métodos permitiram caracterizar o adesivo como estrutural para tais aplicações, pois em todos os ensaios a fratura se deu fora da área de colagem, levando a conclusão de que a junta formada é mais resistente do que o substrato isoladamente. Foram desenvolvidos dois inovadores tratamentos de superfície alternativos ao lixamento, que foram o desengraxe com solventes e tratamento com plasma. Estes tratamentos tem contribuído significativamente om a comunidade e a partir deste estudo tem sido utilizados na indústria. A avaliação do comportamento térmico do adesivo e dos substratos permitiu o desenvolvimento de métodos de análise da composição das frações de massa de matriz polimérica, cargas minerais e fibra de vidro de modo prático, rápido e preciso, por uso da termogravimetria. A calorimetria diferencial exploratória possibilitou avaliar as transições vítreas dos substratos e do adesivo, bem como a energia liberada na reação do adesivo uretânico. Os fenômenos de interação química entre o adesivo e os substratos foram investigados pelo uso da técnica de espectroscopia infravermelho por reflectância atenuada, onde pode-se de forma inédita comprovar a existência de reações covalentes e de hidrogênio entre o adesivo e os substratos, que explicam a elevada aderência deste adesivo.Os resultados de todos os ensaios e análises levam à conclusão final que o adesivo uretânico, embora muitas vezes não considerado como estrutural, é um candidato plenamente capacitado ao trabalho de adesão estrutural, especialmente para uso automotivo nas condições descritas neste trabalho. / In this study there were evaluated the properties of a structural urethane adhesive used for bonding automotive parts made from combinations of composites, thermoplastics and metals, which require a high adhesive performance and compatibility with these materials. Thus, there were evaluated the shear strength of joints formed with these substrates and adhesive urethane different exposure conditions, which aim to simulate the deleterious effects that these joints are exposed during their use. These methods allowed characterization like structural adhesive for these applications, because in all tests the fracture occurred outside the area of bonding, leading to the conclusion that the joint formed is stronger than the substrate alone. There were developed two innovative surface treatments alternative to grinding, which was a degreasing solvent and treatment with plasma. These methods have significantly contributed to the community and from this study has been used in industry. The evaluation of the thermal behavior of the adhesive and the substrates allowed the development of methods for analyzing the composition of mass fractions of polymer matrix, fillers and fiberglass in a practical, fast and accurate, by use of thermogravimetry. The differential scanning calorimetry allowed to evaluate the glass transitions of substrates and adhesive, and the energy released in the reaction of urethane adhesive. The phenomena of chemical interaction between the adhesive and the substrates were investigated by use of infrared spectroscopy by attenuated reflectance, where it can be in an unprecedented way to prove the existence of covalent and hydrogen reactions between the adhesive and the substrates, which explains the high adhesion of this adhesive.The results of all testing and analysis lead to the final conclusion that the adhesive urethane, although often not considered as structural, is a fully qualified candidate for structural work of adhesion, especially for automotive use under the conditions described in this thesis.