Dans cette thèse, nous présentons trois études concernant les interactions entre séismes et la phase de nucléation des forts tremblements de terre. La première partie de ce travail concerne le NO de la Turquie, où deux systèmes tectoniques sont présents : décrochement sur la Faille Nord Anatolienne et extension dans des essaims situés autour de la faille. Nous montrons que ces deux systèmes interagissent, mais répondent différemment à l'excitation du séisme d'Izmit (1999). Les calculs des changements de contraintes de Coulomb induits par le séisme d'Izmit indiquent que les évènements en décrochement répondent aux contraintes dynamiques, alors que les séismes en extension semblent contrôlés par la déformation statique de la croûte. Dans la seconde partie de cette thèse, nous analysons une importante séquence sismique qui s'est produite en 2008 en Grèce. Cette analyse a montré que les séismes en subduction ou en décrochement composant la séquence reflètent le mouvement du SO rigide de la Grèce vers le SSO accompagné du plongement de la plaque Africaine et du retrait vers le sud de la subduction. Cette première étape de déformation est suivie, quelques mois plus tard, de la déformation interne de la plaque Egée qui se manifeste par de l'extension N-S. Cette séquence sismique est le témoin de l'existence d'un couplage dynamique entre la subduction et le prolongement de la Faille Nord Anatolienne dans la région égéenne. Enfin, le but de la dernière partie de cette thèse a été d'apporter des éléments de réponse à la question : existe-t-il un phénomène observable par le biais de la sismicité qui précède de manière systématique les grands tremblements de terre? Pour cela nous avons étudié l'activité sismique précédant des séismes de M$geq 6.5$ dans des régions bien instrumentées (Japon, Cascades et NO des Etats-Unis). Nous montrons que la grande majorité des séismes interplaques est précédée d'une accélération de la sismicité, au contraire des séismes intraplaques. Nous mettons également en évidence une différence entre les séismes en décrochement et les séismes en subduction : les pré-chocs des séismes en subduction sont localisés dans une grande région, rendant un déclenchement en cascade des évènements et du choc principal impossible. / We present three studies about earthquake interactions and the nucleation phase of big earthquakes. The first part of this work deals with the northwestern Turkey, where two tectonic regimes exist, with the transform North Anatolian Fault and extension clusters around it. We show that these two systems interact, but respond differently to Izmit earthquake (1999) stimulation. Computations of the Coulomb stress changes induced by the Izmit earthquake indicate that strike-slip events respond to dynamic stresses, whereas the extension ones seem to be controlled by the static deformation of the crust. In the second part, we analyze a seismic sequence that occurred in 2008 in Greece. This analysis shows that subduction or strike-slip earthquakes of the sequence depict the overall motion of the southwestern Greece to the SSW, accompanied by the plunge and the southward retreat of the slab. This first deformation stage is followed, few months later, by the internal deformation of the Aegean plate, which occurs as N-S extension. This seismic sequence depicts the existence of dynamic coupling between the Hellenic subduction and the prolongation of the North Anatolian Fault. The aim of the last part was to shed some lights on the question: is there a systematic seismic phenomena preceding the occurrence of big earthquakes? To do that, we studied seismic activity preceding M$geq$6.5 earthquakes in some well-instrumented areas of the North Pacific. We show that most of the interplate earthquakes are preceded by an increase of the activity, unlike the intraplate ones. We also highlight a different behavior between strike-slip and subduction events: foreshocks of subduction earthquakes are located in a large area, preventing a cascade triggering.

La caractérisation des distributions spatio-temporelles des déformations transitoires le long de failles actives constitue actuellement l’un des axes privilégiés de recherches visant la compréhension des processus contrôlant le cycle sismique. Dans ce contexte, nous nous intéressons à deux sites d’études aux caractéristiques comportementales distinctes: la lacune sismique de Guerrero, siège de 4 séismes lents depuis 1997 (zone de subduction, d’une longueur de 100 km à l’ouest d’Acapulco au Mexique, dernière rupture en 1911, temps de récurrence ~4 ans) et le segment de Parkfield (segment de 20-30 km le long de la faille de San Andreas, Californie, 7 ruptures successives -Mw6- depuis 1857, temps de récurrence de ~22 ans). Dans le cas du Mexique, nous portons notre attention sur le séisme lent de 2009-2010 survenu au niveau de la lacune sismique et, dans le cas du segment de Parkfield, nous décrivons la déformation post-sismique suite au séisme du 28 septembre 2004, dernière rupture en date de ce segment, sur la période 2005-2010. Nous utilisons l’interférométrie radar différentiel satellitaire (DINSAR), complété de données GPS, pour estimer les faibles déformations (centimétriques) générées en surface par ces types de déformations. À l’issue de ce travail, dans le cas de la lacune sismique de Guerrero, nos mesures semblent montrer que le séisme lent de 2009-2010 affecte la partie sismogène de la lacune tout en affectant une portion de la subduction qui dépasse les limites géographiques de celle-ci. Dans le cas de Parkfield, nous parvenons à mettre en avant une prolongation temporelle jusqu’en 2010 du glissement post-sismique en plus d’une extension spatiale de ce glissement qui dépasse les limites de la rupture de 2004. Ces nouveaux éléments permettent de discuter plus en avant l’impact de ces déformations transitoires sur le comportement de ces systèmes de failles situés tout deux, sur des sites d’intérêts scientifiques majeurs. / Characterizing the spacio-temporal evolution of transient deformations along active faults is, by now, one of the most promising ways to better understand the mechanisms that drive the seismic cycle. In this context, we focused our attention on two areas that exhibit different characteristic behaviour types: the Guerrero seismic gap, a location of 4 consecutive slow slip events since 1997 (subduction zone, 100 km long westward from Acapulco, Mexico, last ruptured in 1911, repeating time ~4 years) and the Parkfield segment (20-30 km long segment, San Andreas fault, California, 7 successive breaks -Mw6- since 1857, repeating time ~22 years). In the case of Mexico, we particularly focused our attention on the 2009-2010 slow slip event that occurred at the gap location. In the case of Parkfield, we described the post-seismic deformation related to the 28th September 2004 Mw6 event (last recorded break) from 2005 to 2010. We used space-based differential radar interferometry (DINSAR) in addition to GPS data, to assess surface displacements at centimeter scale that are in relation with those two phenomena. As an outcome of the work, in the Guerrero seismic gap case, our measurements indicate that the 2009-2010 slow slip event has affected the seismogenic part of the gap and extents outside the spatial limits of it. In the case of Parkfield, our measurements indicate that the Parkfield segment has a post-seismic behaviour that lasts until 2010 at least and spatially extends outside the edge the 2004 coseismic trace along the fault line. These elements allow us to discuss the implication of such transient deformations in the two particular cases of the Guerrero seismic gap and the Parkfield segment, both of first scientific interest.

A Presente dissertação apresenta uma aplicação de Inteligência Computacional na área de Geotecnia, com a utilização da Técnica de Neuro-Fuzzy para indicar a suscetibilidade de escorregamento de taludes no município do Rio de Janeiro, a partir de inspeção visual. Neste trabalho, a suscetibilidade corresponde à possibilidade de ocorrência de escorregamento sem considerar os danos relacionados ao evento. Adotou-se como variável de saída a Previsão de Escorregamento (PE) com três adjetivos que correspondem a Suscetibilidades Alta, Média e Baixa. A metodologia utilizada consistiu em, inicialmente, montar um banco de dados com informações preliminares de análise de estabilidade, com a indicação dos condicionantes de escorregamento relacionados à geomorfologia, pluviosidade, capacidade de drenagem, vegetação e ocupação com seus respectivos graus de suscetibilidades de escorregamento obtidos em um conjunto de Laudos de Vistoria da Geo Rio. O banco de dados foi aplicado em um algoritmo de Neuro-Fuzzy. Diversos testes foram realizados com as alterações dos parâmetros do modelo Neuro-Fuzzy para uma combinação de fatores condicionantes de escorregamento e refinamento do banco de dados. Os testes apresentaram diminuição do erro fornecido pelo programa com o aumento de tipos de condicionantes utilizados no treinamento, o que permite inferir que o escorregamento ocorre por uma complexa relação entre diversos fatores condicionantes. O banco de dados utilizado nos testes apresenta descontinuidades nas relações entre os diversos condicionantes, ou seja, para uma mesma faixa de valores de Altura do talude, não é possível obter uma relação para todas as faixas de outro condicionante e, até mesmo, para todas as faixas da Previsão de Escorregamento. As PEs obtidas na validação do modelo tiveram seus valores próximos aos desejados somente nos conjuntos de variáveis utilizadas para o treinamento. O modelo não foi capaz de apresentar valores de suscetibilidades dentro da faixa de valores utilizados no treinamento para combinação de variáveis com pequenos ruídos, o que indica a necessidade de ampliação do banco de dados tanto quantitativamente quanto qualitativamente de modo a cobrir as descontinuidades apresentadas nas relações entre as variáveis. / This paper is an application of Computational Intelligence in the Geotechnical Engineering, with the use of Neuro-Fuzzy Technique to indicate the susceptibility of landslide slopes in the city of Rio de Janeiro, from visual inspection. In this work, the susceptibility corresponds to the possibility of slipping without considering the damage related to the event. Adopted as the output variable Forecast Slip (PE Previsão de Escorregamento) with three adjectives that correspond to susceptibilities High, Medium and Low. The methodology used was to initially build a database with preliminary information for stability analysis, indicating the slip constraints related to geomorphology, rainfall, drainage capacity, vegetation, and occupation with their respective degrees of susceptibilities slip obtained on a set of the Reports of Condition Geo Rio. The database was implemented in a Neuro-Fuzzy algorithm. Several tests were conducted with the changes of model parameters Neuro-Fuzzy for a combination of conditioning factors of slipping and refinement of the database. The tests showed a decrease of the error provided by the program with increasing types of constraints used in the training, which allows us to infer that the slip occurs by a complex relationship between various conditioning factors. The database used in the tests discontinuities present in relations between the different conditions, ie, for the same range of height values of the slope, it is not possible to obtain a relationship for all the tracks of another condition, and even for all tracks from Forecast Slip. The PEs obtained in the validation of the model values were close to the desired only in sets of variables used for training. The model was not able to present values of susceptibilities in the range of values used in training for the combination of variables with small noise, which presents the need to expand the database so quantitatively and qualitatively in order to cover the discontinuities presented in relations between the variables.

Nos sistemas de freio automotivo, o principal componente que determina seu desempenho é o material de fricção, pois um bom material de fricção deve garantir estabilidade no atrito em diferentes condições de uso, além de possuir resistência à corrosão, longa vida útil, baixa taxa de desgaste, boa relação custo versus desempenho e baixo ruído. Desde que o conforto dos veículos tornou-se um fator importante para indicar sua qualidade, eliminar ou reduzir os ruídos e vibrações de seus componentes passou a ser uma vantagem competitiva no mercado automotivo, e, o problema de ruído nos sistemas de freios vem sendo um dos maiores causadores de reclamações de clientes nos últimos anos. O ruído de freio é na maioria das vezes o resultado de uma vibração auto excitada induzida pela fricção ou uma instabilidade dinâmica do sistema de freio. O processo de stick-slip é um típico exemplo de oscilação induzida por atrito, observada em baixas velocidades de deslizamento e geralmente resulta em vibrações, que geram ruídos graves e rangidos. Com o objetivo de verificar a viabilidade da utilização das medições de vibração durante a ocorrência do fenômeno do stick-slip para a caracterização de materiais de fricção utilizando um tribômetro, foram preparados seis materiais de fricção produzidos pela empresa Fras-le, fabricante de materiais de fricção para freios automotivos. Os ensaios foram realizados no Laboratório de Tribologia (Latrib) da Escola de Engenharia da Universidade Federal do Rio Grande do Sul (UFRGS). No tribômetro utilizado nos ensaios foi instalado um acelerômetro sobre o suporte onde é fixada a pastilha do material de fricção a ser ensaiado. Vários ensaios foram realizados, cada um sob ação de força normal e velocidade de giro do disco constantes. Os resultados dos ensaios demonstraram que o tribômetro apresenta excelente desempenho para caracterização de materiais de fricção, possibilitando o desenvolvimento de novos materiais a partir de ensaios realizados neste equipamento. A avaliação da resposta da aceleração da vibração obtida nos ensaios demonstrou que a resposta da vibração é dependente dos diversos parâmetros medidos, como deslocamento, velocidade e variação de torque, e para melhor prever a propensão de um determinado material em apresentar vibração de stick-slip deve-se levar em consideração, além da variação de torque, o torque máximo de cada ciclo de stick-slip. Além disso, o uso do acelerômetro para avaliação de ensaios de stick-slip mostrou-se viável e seu uso deve ser estimulado em trabalhos futuros. / In automotive brake systems, the main component that determines their performance is the friction material, because good friction material must ensure stability in friction under different conditions of use, as well as corrosion resistance, long life, low wear rate, good relation between cost and performance, and low noise. Since the comfort of vehicles has become important factor to indicate its quality, eliminate or reduce the noise and vibration of its components has become a competitive advantage in the automotive market, and the problem of noise in brake systems has been a cause of customer complaints in recent years. The brake noise is most often the result of a self-excited vibration induced friction or dynamic instability of the brake system. The stick-slip phenomenon is a typical example of oscillation induced by friction observed at low sliding speeds and generally results in vibrations which generate noise. In order to check the feasibility of using vibration measurements during the occurrence of the stick-slip phenomenon in the characterization of friction materials using a tribometer, were prepared six friction materials produced by the company Fras-le, manufacturer of friction materials for automotive brake. The tests were performed in the Laboratory of Tribology (Latrib) of the School of Engineering at Federal University of Rio Grande do Sul (UFRGS). In tribometer used for testing an accelerometer was installed on the support of the pad of friction material to be tested. Several tests were conducted, each under constant normal force and speed of rotation of the disk. The test results showed that the tribometer shows excellent performance for characterization of friction materials, enabling the development of new materials from tests performed on this equipment. The evaluation of the response of vibration acceleration obtained in the tests demonstrated that the response of vibration is dependent on various measured parameters, such as displacement, velocity and torque variation, and to better predict the propensity of a material to present vibration stickslip must take into account both the variation of torque and the maximum torque of each cycle of stick-slip. Furthermore, the use of accelerometer for assessing stick-slip tests was viable and its use should be encouraged in future work.

Si l'amorçage des fissures de fatigue est aujourd'hui bien compris dans le cas de monocristaux de métaux purs, ce phénomène s'avère plus complexe à cerner et à prédire dans le cas d'alliages métalliques polycristallins tels que l'acier AISI 316LN.D'un point de vue expérimental, notre étude s'est concentrée sur la caractérisation du comportement mécanique et l'étude, à différentes échelles, des phénomènes liés à l'amorçage des fissures de fatigue oligocyclique dans l'acier 316LN. Pour des niveaux de déformation appliquée de Δε/2 = 0,3 et 0,5%, l'adoucissement cyclique observé au cours des essais coïncide avec l'organisation des dislocations sous forme de bandes. Ces bandes sont liées à l'activation des systèmes de plus haut facteur de Schmid. Elles portent la majeure partie de la déformation et provoquent en surface des intrusions et extrusions favorisant l'apparition et la coalescence de fissures.D'un point de vue modélisation, nous avons proposé un nouveau modèle de plasticité cristalline intégrant des dislocations géométriquement nécessaires (GND) directement calculées à partir du second gradient de la rotation élastique. Implémenté dans les codes d'éléments finis AbaqusTM et Cast3mTM, ce modèle s'inspire des travaux sur le monocristal en transformations finies de Peirce et al. (1983) et de Teodosiu et al. (1993). Adapté au cas des polycristaux par Hoc (1999) et Erieau (2003), il a été enrichi par l’introduction GND selon la théorie proposée par Acharya et Bassani (2000). Les simulations réalisées sur des différents types d'agrégats (2D extrudé et 3D) montrent que la prise en compte de GND permet :- de reproduire les effets de taille de grains au niveau macroscopique et local,- de décrire plus finement les champs de contraintes calculés.Ces simulations ont permis de mettre en évidence l'influence des matrices d'élasticité et d'écrouissage sur les valeurs et l'évolution des contraintes macroscopique effective et cinématique moyenne et le rôle important des conditions aux limites lors des calculs d'agrégats. / If fatigue crack initiation is currently quite well understood for pure single crystals, its comprehension and prediction in cases of polycrystal alloys such as AISI 316LN stainless steel remain complicated.Experimentally our study focuses on the characterisation of the mechanical behaviour and on the study at different scales of the phenomenon leading to low cycle fatigue crack initiation in 316LN stainless steel. For straining amplitudes of Δε/2 = 0,3 and 0,5%, the cyclic softening observed during testing has been related to the organisation of dislocations in band structures. These bands, formed due to the activation of slip systems having the greatest Schmid's factor, carry the most part of the deformation. Their emergence at free surfaces leads to the formation of intrusions and extrusions which help cracks initiate and spread.Numerically we worked on the mesoscopic scale, proposing a new model of crystalline plasticity. This model integrates geometrically necessary dislocations (GND) directly computed from the lattice curvature. Implemented in the finite element code AbaqusTM and Cast3mTM, it is based on single crystal finite deformations laws proposed by Peirce et al. (1983) and Teodosiu et al. (1993). Extended for polycrystals by Hoc (2001) and Erieau (2003), it has been improved by the introduction of GND (Acharya and Bassani, 2000). The simulations performed on different types of aggregates (2D/3D) have shown that taking GND into account enables:- the prediction of the grain size effect on a macroscopic and on a local scale,- a finer computation of local stress field.The influence of the elasticity and interaction matrices on the values and the evolution of the isotropic and kinematic mean stresses has been shown. The importance of boundary conditions on computed mechanical fields could also be pointed out.

Nous étudions par simulation numérique le transport et le dépôt turbulent d’inclusions d’oxydes métalliques (de l’ordre de 10 µm de diamètre) en suspension dans l’acier liquide. Deux surfaces de dépôt sont envisagées : l’interface acier liquide/paroi solide et l’interface métal liquide/laitier. Dans les deux cas, nous nous focalisons sur la couche limite adjacente à l’interface. Le comportement des inclusions en suspension est examiné à l’aide d’un suivi lagrangien où le poids, la poussée d’Archimède, la force d’accélération en volume, la force de masse ajoutée et la force de traînée sont prises en compte dans l’équation de la dynamique. Dans le cas de la paroi solide, nous nous appuyons sur une représentation schématique de l’écoulement du métal liquide dans la sous-couche visqueuse et dans la zone tampon, où les structures turbulentes qui apportent le liquide à la paroi (sweeps) ou l’éjectent (bursts) sont décrites analytiquement (modèle d’Ahmadi). Les simulations numériques montrent que les mécanismes principaux de dépôt des inclusions sont la sédimentation et dans une moindre mesure l’interception directe. Notons cependant que la contribution de l’interception directe croît avec l’intensité turbulente de l’écoulement et peut devenir prépondérante pour les vitesses de frottement les plus élevées (au-delà de 0,1 m.s-1). Les effets inertiels ont, quant à eux, une contribution négligeable sur le dépôt des inclusions (contrairement au cas des aérosols). Enfin, la prise en compte des interactions hydrodynamiques entre les inclusions et la paroi solide conduit à une diminution significative de la vitesse de dépôt des inclusions. Dans le cas de l’interface acier liquide/laitier, l’écoulement du métal liquide est calculé par simulation numérique directe (DNS) à l’échelle de la couche de surface. La turbulence, générée à distance de l’interface par un forçage aléatoire, diffuse vers l’interface métal liquide/laitier modélisée comme une surface libre indéformable. L’évolution des inclusions en suspension est obtenue par un suivi lagrangien à l’aide d’un couplage one-way. Le nombre de Reynolds de surface des simulations varie de 68 à 235. Le diamètre des inclusions varie de 10-5m à 5.10-5m et le rapport entre la densité des inclusions et la densité du métal varie de 0,5 (inclusions d’alumine) à 1 (inclusions fictives). Il apparaît que le dépôt des inclusions d’alumine est contrôlé par la sédimentation. En l’absence d’effet gravitaire, le dépôt d’inclusions est contrôlé par l’interception directe et dépend fortement du nombre de Reynolds de surface. Dans ce dernier cas, nous montrons que la vitesse de dépôt adimensionnée par la vitesse de Kolmogorov de surface est proportionnelle au diamètre des inclusions adimensionné par la longueur de Kolmogorov de surface. La prise en compte des interactions hydrodynamiques entre les inclusions et la surface libre conduit à une diminution de moitié de la contribution de l’interception directe mais affecte peu la contribution gravitationnelle. En outre, en l’absence d’effet gravitaire, la linéarité entre la vitesse de dépôt adimensionnée et le diamètre des inclusions adimensionné est conservée. / The deposition of metallic oxide inclusions (of about 10 µm in diameter) suspended in liquid steel is studied by numerical simulation. Two types of deposition surface are investigated, i.e., the liquid steel/solid wall interface and the liquid steel/liquid slag interface. In both cases, we focus on the boundary layer adjacent to the interface. The inclusion behavior is examined thanks to Lagrangian particle tracking: Newton’s second law governing inclusion motion includes the buoyancy force, the pressure gradient force, the added mass force and the steady drag force.For the liquid steel/solid wall interface, the inclusion behavior is analyzed in the buffer layer and in the viscous layer. These layers are described according to Ahmadi’s model, which provides a kinematic representation of the turbulent structures responsible for deposition, i.e., the sweeps and the bursts of liquid. The numerical simulations show that the deposition is mainly controlled by sedimentation. However, since the direct interception contribution increases with the turbulence intensity, direct interception becomes dominant for the highest values of the friction velocity (greater than 0.1 m.s-1). When the hydrodynamic interactions between the inclusions and the solid surface are taken into account, the deposition velocity is significantly reduced. Finally, it should be noted that the inertial forces have a negligible effect on the inclusion deposition velocity. For the liquid steel/liquid slag interface, the inclusion turbulent deposition is investigated using direct numerical simulation of the liquid flow combined with Lagrangian particle tracking under conditions of one-way coupling. The interface is modeled as a non-deformable free-slip surface. Unsheared turbulence is generated by random forcing in a finite-height region parallel to the free-slip surface. In between, the turbulence diffuses toward the free surface. The Reynolds number at the interface varies from 68 to 235. The inclusion diameter varies from 10-5m to 5.10-5m and the particle to liquid density ratio from 0.5 (alumina inclusions) to 1 (fictitious inclusions). It appears that the deposition of alumina inclusions is controlled by sedimentation whereas direct interception is the only deposition mechanism for non-buoyant inclusions. In the latter case, the deposition velocity strongly depends on the surface Reynolds number. It is shown that the deposition velocity made dimensionless by the free surface characteristic velocity scales as the inclusion diameter made dimensionless by the Kolmogorov length scale calculated at the free surface. When the hydrodynamic interactions between the inclusions and the free surface are taken into account, the direct interception contribution of the deposition velocity is significantly reduced (about half of the value without hydrodynamic retardation) but the scaling law is conserved.

Trata-se uma análise elastoplástica de tensões planas nos métodos de conformação em forjamentos com matriz aberta ou fechada e trefilação. Emprega-se o método das linhas de fluência, desenvolvido por Hencky e Prager. O estudo visa a determinação das tensões na região plástica e do campo de velocidades na região deformada, utilizando o método de Prager aplicado a um processo analítico. / An elastoplastic analysis of plane strain in axisymmetric flat and closed punch die and wiredrawing was made using the slip lines method, developed by Hencky and Prager. Studies were made to determine the strains in the plastic zone and the velocities in deformed zone using the Prager\'s method applyed in an analytical process.

Nos sistemas de freio automotivo, o principal componente que determina seu desempenho é o material de fricção, pois um bom material de fricção deve garantir estabilidade no atrito em diferentes condições de uso, além de possuir resistência à corrosão, longa vida útil, baixa taxa de desgaste, boa relação custo versus desempenho e baixo ruído. Desde que o conforto dos veículos tornou-se um fator importante para indicar sua qualidade, eliminar ou reduzir os ruídos e vibrações de seus componentes passou a ser uma vantagem competitiva no mercado automotivo, e, o problema de ruído nos sistemas de freios vem sendo um dos maiores causadores de reclamações de clientes nos últimos anos. O ruído de freio é na maioria das vezes o resultado de uma vibração auto excitada induzida pela fricção ou uma instabilidade dinâmica do sistema de freio. O processo de stick-slip é um típico exemplo de oscilação induzida por atrito, observada em baixas velocidades de deslizamento e geralmente resulta em vibrações, que geram ruídos graves e rangidos. Com o objetivo de verificar a viabilidade da utilização das medições de vibração durante a ocorrência do fenômeno do stick-slip para a caracterização de materiais de fricção utilizando um tribômetro, foram preparados seis materiais de fricção produzidos pela empresa Fras-le, fabricante de materiais de fricção para freios automotivos. Os ensaios foram realizados no Laboratório de Tribologia (Latrib) da Escola de Engenharia da Universidade Federal do Rio Grande do Sul (UFRGS). No tribômetro utilizado nos ensaios foi instalado um acelerômetro sobre o suporte onde é fixada a pastilha do material de fricção a ser ensaiado. Vários ensaios foram realizados, cada um sob ação de força normal e velocidade de giro do disco constantes. Os resultados dos ensaios demonstraram que o tribômetro apresenta excelente desempenho para caracterização de materiais de fricção, possibilitando o desenvolvimento de novos materiais a partir de ensaios realizados neste equipamento. A avaliação da resposta da aceleração da vibração obtida nos ensaios demonstrou que a resposta da vibração é dependente dos diversos parâmetros medidos, como deslocamento, velocidade e variação de torque, e para melhor prever a propensão de um determinado material em apresentar vibração de stick-slip deve-se levar em consideração, além da variação de torque, o torque máximo de cada ciclo de stick-slip. Além disso, o uso do acelerômetro para avaliação de ensaios de stick-slip mostrou-se viável e seu uso deve ser estimulado em trabalhos futuros. / In automotive brake systems, the main component that determines their performance is the friction material, because good friction material must ensure stability in friction under different conditions of use, as well as corrosion resistance, long life, low wear rate, good relation between cost and performance, and low noise. Since the comfort of vehicles has become important factor to indicate its quality, eliminate or reduce the noise and vibration of its components has become a competitive advantage in the automotive market, and the problem of noise in brake systems has been a cause of customer complaints in recent years. The brake noise is most often the result of a self-excited vibration induced friction or dynamic instability of the brake system. The stick-slip phenomenon is a typical example of oscillation induced by friction observed at low sliding speeds and generally results in vibrations which generate noise. In order to check the feasibility of using vibration measurements during the occurrence of the stick-slip phenomenon in the characterization of friction materials using a tribometer, were prepared six friction materials produced by the company Fras-le, manufacturer of friction materials for automotive brake. The tests were performed in the Laboratory of Tribology (Latrib) of the School of Engineering at Federal University of Rio Grande do Sul (UFRGS). In tribometer used for testing an accelerometer was installed on the support of the pad of friction material to be tested. Several tests were conducted, each under constant normal force and speed of rotation of the disk. The test results showed that the tribometer shows excellent performance for characterization of friction materials, enabling the development of new materials from tests performed on this equipment. The evaluation of the response of vibration acceleration obtained in the tests demonstrated that the response of vibration is dependent on various measured parameters, such as displacement, velocity and torque variation, and to better predict the propensity of a material to present vibration stickslip must take into account both the variation of torque and the maximum torque of each cycle of stick-slip. Furthermore, the use of accelerometer for assessing stick-slip tests was viable and its use should be encouraged in future work.

Orientador: Maria Fausta Cajahyba Pereira de Castro / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Estudos da Linguagem / Made available in DSpace on 2018-08-21T08:17:00Z (GMT). No. of bitstreams: 1 Vivacqua_MariaVictoriaGuinle_D.pdf: 1330050 bytes, checksum: 29ea2edd8d126a8158ea7c97f5791e27 (MD5) Previous issue date: 2012 / Resumo: O objetivo deste trabalho é discutir as concepções de erro e de lapso de língua, uma vez que a oscilação entre os termos é responsável por dificuldades na distinção entre os fenômenos. Nosso trabalho parte da noção de erro, no século XIX, associada no debate lingüístico às questões de mudança e de variação lingüística para entender de que modo as leis fonéticas e a analogia podem operar como fator de mudança. Meringer (1895) foi o primeiro autor a se tornar referência ao apresentar e classificar um corpus com mais de 8.000 lapsos ou erros de fala, de escrita e de leitura, cuja categorização permanece atual na área de Psicolinguística. O interesse do filólogo era compreender as regras que regem erros e lapsos e verificar a existência de um mecanismo mental que explicaria de que maneira os sons de uma palavra, de uma frase e também das palavras inteiras entre si acham-se ligados e entrelaçados em tais fenômenos. Freud toma o corpus de Meringer para empreender seu estudo sobre os lapsos, tratados como manifestações do inconsciente que se mostram por meio de substituições e contaminações do material lingüístico, e a noção de inconsciente emerge como aquilo que definitivamente rompe a relação entre o trabalho de Freud e Meringer. Nosso objetivo consiste em verificar o estatuto dessas concepções e seus limites, em suas diversas manifestações, tanto na língua materna como em uma língua outra. Abordamos os problemas teóricos da área de aquisição de linguagem, a começar pela desnaturalização da definição de língua materna para discutirmos a questão do erro na fala da criança. Com Pereira de Castro (2006) e Milner ([1978] 1987) discutimos o estatuto singular dessa língua para compreender o modo como a língua materna, que constitui um falante, permite o movimento do falante entre as outras línguas, uma vez que a plasticidade do material linguístico tanto o remete à sua língua quanto a um funcionamento psíquico que o guia na enunciação da língua estrangeira. Apresentamos e discutimos textos da obra freudiana para entender a construção da noção de inconsciente que sustenta a noção de lapso de língua. Encaminhamos nossa discussão através da análise de episódios em que o falante se encontra entre línguas. Concluímos que o conceito de lalangue une os fenômenos de erro e lapso. Partimos desse conceito, que está presente na Linguística (MILNER [1978] 1987), assim como na Psicanálise, para discutir como a noção de inconsciente se vale da complacência que o material linguístico oferece. Os erros da fala infantil e os erros e lapsos do falante entre línguas, revelam as zonas de equívoco da língua, que desempenham um importante papel na trajetória da criança na sua língua materna e na relação do falante com as línguas outras / Abstract: The aim of this paper is to discuss the concepts of error and slips of the tongue, as oscillation in the use of these terms makes it difficult to distinguish between the phenomena they describe. We begin in the 19th century with the notion of error, which was associated with studies of linguistic variation and change that attempted to understand how phonetic laws and the analogy could operate as a factor of change. Meringer (1895), the first author to become an important reference in the area, developed a corpus with more than 8,000 slips of the tongue and errors of speech, reading, and writing, and his categorization remains current in the area of psycholinguistics. His interest was to understand the rules governing errors and slips of the tongue, and to verify the existence of a mental mechanism that would explain how the sounds of a word, a phrase, and whole words, are connected and intertwined in such phenomena. Freud used Meringer's corpus in his study on slips of the tongue, treating them as a manifestation of the unconscious material that appears through substitution and contamination of linguistic material. The notion of the unconscious, however, emerges as a definite break between the work of Freud and Meringer. Our goal is to verify the status of the conceptions of error and slips of the tongue, as well as their limits, in their various manifestations both in the mother tongue and in other languages. In order to examine the issue of error in the speech of the child, we discuss theoretical problems in the area of language acquisition, starting with the denaturalization of the definition of mother tongue. Making reference to Pereira de Castro (2006) and Milner ([1978] 1987), we discuss the singular status of the mother tongue in order to understand the way that this language, which constitutes the speaker, permits him or her to move between languages, given that the plasticity of linguistic material refers both to the language itself as well as to a psychic functioning that guides the speaker in the utterance of a foreign language. We present and discuss certain Freudian texts in order to understand the construction of the concept of the unconscious that sustains the notion of slip of the tongue. We develop our discussion through analysis of episodes in which the speaker finds him or herself between languages, and conclude that the concept of lalangue unites the phenomena of error and slip of the tongue. Starting from this concept, present in linguistics (MILNER [1978] 1987) as well as in psychoanalysis, we discuss how the notion of the unconscious is based on the complacency that the linguistic material offers. Children's speech errors and speakers' errors and slips of the tongue between languages, reveal areas of equivocity in language which play an important role in the development of children in their mother tongue and in a speaker's relationship with other languages / Doutorado / Linguistica / Doutora em Linguística

Orientador: Eni de Lourdes Puccinelli Orlandi / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Estudos da Linguagem / Made available in DSpace on 2018-08-21T19:00:36Z (GMT). No. of bitstreams: 1 Azambuja_ElizeteBeatriz_D.pdf: 5918005 bytes, checksum: 160726167ee1a9371afda7949e4ea570 (MD5) Previous issue date: 2012 / Résumé: Avec ce travail, nous cherchons de comprendre la production de "la hypercorrection". Nous traitons cette notion, qui est traditionnellement étudiée par la sociolinguistique, du point de vue de l'analyse de discours. C'est à cause de cette différence de perspective théorique que nous utilisons des guillemets pour leterme. Compte tenu que la langue et le sujet ne sont pas séparés, nous travaillonsavec le discours sur la langue et la façon dont l'idéologie se matérialise dans La discursivité dominante dans notre société. De cette manière, nous faisons une lecture de certains aspects qui, historiquement, constituent les idées linguistiques. Le corpus que nous organisons est hétérogène en ce qui concerne les conditions de production. Nous le divisons en deux ensembles d' énoncés. Le premier ensemble comprend des énoncés dans lesquels nous analisons le discours sur la langue produit par des sujets dans diverses positions sociales. L'autre groupe d'énoncés nous permet d'observer le fonctionnement des différents faits de "la hypercorrection". Notre proposition de reflection sur ces faits linguistico-discursifs du point de vue discursif nous permet de les penser non pas comme des <<erreurs>>, mais comme équivoque, point où la langue, sujette à la faille, s'inscrit dans l'histoire. En outre, nous considérons ces faits comme des marques Du fonctionnement de l'idéologie, comme un indice d'affectation du sujet par la langue institutionnalisée, affrontement dans lequel la mémoire qui se réfère au discours de l'écriture devient visible. Cette étude nous permet de mettre en rapport la production de "la hypercorrection" et la tension entre la langue imaginaire et le fonctionnement de la langue fluide, le décallage entre la langue nationale et langue maternelle. En outre, cette étude nous aide à comprendre que "la hypercorrection" se construit idéologiquement entre l'inquiétude du sujet face à sa langue maternelle et/ou leur désir de s'inscrire dans une langue considérée comme légitime / Resumo: Com este trabalho, buscamos compreender a produção da "hipercorreção". Tomamos essa noção, tradicionalmente estudada pela Sociolinguística, para tratála pela perspectiva da Análise de Discurso e essa diferença de olhar demarcamos pelo uso das aspas no termo. Considerando que não se separam língua e sujeito, lidamos com o discurso sobre a língua e o modo com que a ideologia se materializa na discursividade que predomina em nossa sociedade, fazendo uma leitura de alguns aspectos que, historicamente, constituem as ideias linguísticas. O corpus que organizamos é heterogêneo em relação às condições de produção e o subdividimos em dois conjuntos de enunciados, sendo que o primeiro é constituído por enunciados em que analisamos o discurso sobre a língua produzido por sujeitos em posições sociais diversificadas. O outro grupo de enunciados possibilita-nos observar o funcionamento de diferentes fatos de "hipercorreção". A nossa proposta de reflexão destes fatos linguístico-discursivos da perspectiva discursiva permite-nos pensá-los não como "erro", mas como equívoco, ponto em que a língua, sujeita à falha, se inscreve na história. Além disso, consideramos tais fatos como marcas do funcionamento da ideologia, enquanto indício do afetamento do sujeito pela língua institucionalizada, embate em que a memória que remete ao discurso da escrita se torna visível. Este estudo nos possibilita relacionar a produção da "hipercorreção" com a tensão entre a língua imaginária e o funcionamento da língua fluida, com o descompasso entre a língua nacional e a língua materna. Além disso, contribuiu para que compreendêssemos que ela se constitui ideologicamente entre o desassossego do sujeito com a sua língua materna e/ou o seu desejo de se inscrever na língua que é considerada legítima / Abstract: With this work, we seek to understand the production of "hypercorrection." We take this notion, traditionally studied by Sociolinguistics, to treat it from the perspective of discourse analysis and the difference in look we established for the use of the term in quotation marks. Whereas not separate language and subject, dealing with the discourse about language and the way that ideology is embodied in the discourse that prevails in our society, doing a reading of some aspects that historically constitute the linguistic ideas. The corpus that we organize is heterogeneous in relations to the conditions of production and we subdivided into two sets of statements, being the first of which consists of statements in which we analyze the discourse on language produced by subjects in diverse social positions. The other group of statements enables us to observe the functioning of different facts "hypercorrection." Our proposal for consideration of these facts the linguistic-discursive discursive perspective allows us to think of them not as "error", but as equivocal, at which point the language, subject to failure, is written falls in the history. Furthermore, we consider such facts as trademarks operation of ideology, as evidence of the subject's tongue being affects of the institutionalized language, in which memory which refers to speech writing becomes visible. This study enables us to relate the production of "hypercorrection" with the tension between the imaginary language and the function of the fluid language, with the mismatch between national language and mother tongue. Furthermore, it contributed to for us to understand that it is constitute ideologically between the subject's restlessness with their mother tongue and/or their desire to enroll in the language that is considered legitimate / Doutorado / Linguistica / Doutora em Linguística