Never before has the car industry been as challenging, interesting, and demanding as it is today. New and advanced techniques are being continuously introduced, which has led to increasing competition in an almost ever-expanding car market. As the pace and complexity heightens in the car market, manufacturing processes must advance at an equal speed. An important manufacturing process within the automotive industry, and the focus of this thesis, is sheet metal forming (SMF). Sheet metal forming is used to create door panels, structural beams, and trunk lids, among other parts, by forming sheets of metal in press lines with stamping dies. The SMF process has been simulated for the past couple of decades with finite element (FE) simulations, whereby one can predict factors such as shape, strains, thickness, springback, risk of failure, and wrinkles. A factor that most SMF simulations do not currently include is the die and press elasticity. This factor is handled manually during the die tryout phase, which is often long and expensive. The importance of accurately representing press and die elasticity in SMF simulations is the focus of this research project. The research objective is to achieve virtual tryout and improved production support through SMF simulations that consider elastic die and press deformations. Loading a die with production forces and including the deformations in SMF simulations achieves a reliable result. It is impossible to achieve accurate simulation results without including the die deformations. This thesis also describes numerical methods for optimizing and compensating tool surfaces against press and die deformations. In order for these compensations to be valid, it is imperative to accurately represent dies and presses. A method of measuring and inverse modeling the elasticity of a press table has been developed and is based on digital image correlation (DIC) measurements and structural optimization with FE software. Optimization, structural analysis, and SMF simulations together with experimental measurements have immense potential to improve simulation results and significantly reduce the lead time of stamping dies. Last but not least, improved production support and die design are other areas that can benefit from these tools. / Aldrig tidigare har bilindustrin varit så utmanande, intressant och spännande som idag. Ny och avancerad teknik introduceras i en allt snabbare takt vilket leder till ständigt ökande konkurrens på en, nästan ständigt, ökande bilmarknad. Den ständigt ökande komplexiteten ställer även krav på tillverkningsprocesserna. En viktig process, som denna licentiatuppsats fokuserar på, är pressning av plåt. Tillverkningstekniken används för att forma plåtar till dörrpaneler, strukturbalkar, motorhuvar, etc. Plåtar formas med hjälp av pressverktyg monterade i plåtformningspressar. Plåtformningsprocessen simuleras sedan ett par decennium tillbaka med Finita Element (FE) simuleringar. Man kan på så sätt prediktera form, töjningar, tjocklek, återfjädring, rynkor, risk för försträckning och sprickor m.m. En faktor som för tillfället inte inkluderas i näst intill alla plåtformningssimuleringar är elastiska press- och verktygsdeformationer. Detta hanteras istället manuellt under, den oftast långa och dyra, inprovningsfasen. Detta projekt har visat på vikten av att representera press och verktygsdeformationer i plåtformningssimuleringar. Detta demonstreras genom en analys av ett verkligt pressverktyg som belastas med produktionskrafter. Det är inte möjligt att uppnå bra simuleringsresultat utan att inkludera verktygsdeformationer i simuleringsmodellen. Uppsatsen beskriver även numeriska metoder för att optimera och kompensera verktygsytor mot press och verktygsdeformationer. För att dessa kompenseringar ska stämma är det viktigt att man representerar både verktyg och press på ett korrekt sätt. Förslag på en metod för att mäta och inversmodellera pressdeformationer har utvecklats, metoden är baserad på mätningar med DIC-systemet ARAMIS och optimering i FE-mjukvaror. Optimering, strukturanalys, och plåtformningsanalys tillsammans med experimentella mätningar har en stor potential att förbättra plåtformningssimuleringar samt reducera ledtiden för pressverktyg. Sist men inte minst, andra positiva effekter är en enklare och smidigare konstruktionsprocess och förbättrad produktionssupport.

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[pt] A análise de fluxo de água sob condição transiente não saturada requer o conhecimento das propriedades hidráulicas do solo. Essas relações constitutivas, denominadas curva característica e função de condutividade hidráulica, são descritas através de modelos empíricos que geralmente possuem vários parâmetros que devem ser calibrados com relação a dados coletados. Muitos dos parâmetros nos modelos constitutivos não podem ser medidos diretamente em campo ou laboratório, mas somente podem ser inferidos de forma significativa a partir de dados coletados e da modelagem inversa. Para obter os parâmetros do solo com a análise inversa, um algoritmo de otimização de busca local ou global pode ser aplicado. As otimizações globais são mais capazes de encontrar parâmetros ótimos, no entanto, a solução direta, por meio da modelagem numérica é computacionalmente custosa. Portanto, soluções analíticas (modelo substituto) podem superar essa falha acelerando o processo de otimização. Nesta dissertação, apresentamos a Regressão Polinomial Evolucionária (EPR) como uma ferramenta para desenvolver modelos substitutos do fluxo não saturado. Um rico conjunto de dados de parâmetros hidráulicos do solo é usado para calibrar o nosso modelo, e dados do mundo real são utilizados para validar nossa metodologia. Nossos resultados demonstram que o modelo da EPR prevê com precisão os dados de carga de pressão. As simulações do modelo se mostram concordantes com as simulações do programa Hydrus. / [en] Water flow analyses under transient soil hydraulic conditions require knowledge of the soil hydraulic properties. These constitutive relationships, named soil-water characteristic curve (SWCC) and hydraulic conductivity function (HCF) are described through empirical models which generally have several parameters that must be calibrated against collected data. Many of the parameters in SWCC and HCF models cannot be directly measured in field or laboratory but can only be meaningfully inferred from collected data and inverse modeling. In order to obtain the soil parameters with the inverse process, a local or global optimization algorithm may be applied. Global optimizations are more capable of fiding optimum parameters, however the direct solution through numerical modeling are time consuming. Therefore, analytical solutions (surrogate models) may overcome this shortcomming by accelerating the optimization process. In this work we introduce Evolutionary Polynomial Regression (EPR) as a tool to develop surrogate models of the physically-based unsaturated flow. A rich dataset of soil hydraulic parameters is used to calibrate our surrogate model, and real-world data are then utilized to validate our methodology. Our results demonstrate that the EPR model predicts accurately the observed pressure head data. The model simulations are shown to be in good agreement with the Hydrus software package.

La gestion et la dépollution de sites contaminés peuvent être complexe et demandent un investissement important pour localiser les sources de contaminations, zones émettant les flux de polluants les plus importants. Les travaux réalisés proposent une stratégie pour localiser les sources de pollution à partir de mesures in situ de flux massiques et de modélisation inverse. Ainsi, dans le cadre de l’étude, un outil innovant a d’abord été développé afin de mesurer la vitesse des eaux souterraines dans un puits. L’outil appelé DVT (Direct Velocity Tool) a permis de répondre aux contraintes imposées par les outils existants et de mesurer des vitesses d’écoulement très lentes. Des essais en laboratoire et des tests en site réels ont été réalisés et comparés à d’autres outils de mesure. Le DVT permet aussi indirectement de définir la portion de source conduisant au flux de polluant maximum, en le combinant avec une mesure locale de concentration. L’étude présente ensuite l’utilisation de la modélisation inverse pour localiser une source de contaminant et d’estimer les paramètres définissant les caractéristiques du domaine. Pour cela, l'étude s'est faite sur deux cas synthétiques. Pour adapter les méthodes à une véritable gestion de sites pollués, une stratégie itérative est développée en imposant un ajout limité de nouvelles observations à chaque phase de modélisation, basée sur l’approche de type Data Worth. Les résultats de la position de la source sur les deux cas synthétiques ont permis d’évaluer la méthode mise en place et de juger son applicabilité à une problématique réelle. Cette stratégie de localisation de source est par la suite testée sur un site réel à partir (i) de mesures in situ de flux massiques avec les vitesses au DVT et les concentrations et (ii) la modélisation. Les essais ont permis de cibler les forages à mettre en place sur site aidant à localiser la source. Néanmoins, en analysant plus précisément les résultats, le champ de conductivité hydraulique estimé par l'optimisation ne correspond pas à la réalité. De plus, les flux massiques de contaminants ainsi que le ratio des polluants du site, mettent en valeur deux panaches distincts. Une phase finale de modélisation a donc été lancée afin d'estimer (i) la présence potentielle de deux sources et (ii) la chimie de la zone étudiée. Les résultats de la stratégie sont comparés aux mesures geoprobe qui a pu confirmer la présence d’une des deux sources identifiées. / Contaminated sites management and remediation can be complex and require a significant investment to locate the contaminant source, which delivers the higher pollutant mass fluxes. The study proposes a strategy for contaminant source localisation using in situ measurement and inverse modelling. First, an innovative tool was developed to measure groundwater velocity in a well. The developed tool called DVT (Direct Velocity Tool) made it possible to measure a low Darcy flux. Laboratory and field tests were performed with the DVT and compared to other velocity measurement tools. By combining the DVT with a local concentration measurement, it is possible to calculate the mass fluxes passing through wells. Then the thesis present the inverse modeling used for source localisation and parameters estimation. The study was done on two synthetics cases using the non-linear optimisation method. To adapt the method to a real management of polluted sites, an iterative strategy is developed by imposing a limited addition of new observations to each modeling phase. This strategy is base on the Data Worth approach. Source localisation results on the two synthetic cases made it possible to judge the method applicability to a real site problem. The source localisation strategy is then applied to a real site with (i) mass flux measurement with velocities (DVT) and concentrations and (ii) inverse modeling. The modeling phases made it possible to locate the new wells and helped the source localisation. Nevertheless, by analysing the results more precisely, the hydraulic conductivity field estimated by the optimisation did not correspond to reality. In addition, contaminant mass fluxes highlightes two distinct zones of flux. By analysing the pollutant ratio of the site, it appears that two plumes are potentially present. Thus, another inverse modeling phase has been tested (i) to locate the two potential sources and (ii) to estimate the chemistry of the site. Results of the strategy were compared to the geoprobe campaign which confirmed the second source location.

Dans cette thèse, plusieurs approches de modélisation de composites renforcés par des fibres sont proposées. Le matériau étudié est le béton fibré, et dans ce modèle, on tient compte de l’influence de trois constituants : le béton, les fibres, et la liaison entre eux. Le comportement du béton est analysé avec un modèle d’endommagement, les fibres d'acier sont considérées comme élastiques linéaires, et le comportement sur l'interface est décrit avec une loi de glissement avec l’extraction complète de la fibre. Une approche multi-échelle pour coupler tous les constituants est proposée, dans laquelle le calcul à l'échelle macro est effectué en utilisant la procédure de solution operator-split. Cette approche partitionnée divise le calcul en deux phases, globale et locale, dans lesquelles différents mécanismes de rupture sont traités séparément, ce qui est conforme au comportement du composite observé expérimentalement. L'identification des paramètres est effectuée en minimisant l'erreur entre les valeurs calculées et mesurées. Les modèles proposés sont validés par des exemples numériques. / In this thesis, several approaches for modeling fiber-reinforced composites are proposed. The material under consideration is fiber-reinforced concrete, which is composed of a few constituents: concrete, short steel fibers, and the interface between them. The behavior of concrete is described by a damage model with localized failure, fibers are taken to be linear elastic, and the behavior of the interface is modeled with a bond-slip pull-out law. A multi-scale approach for coupling all the constituents is proposed, where the macro-scale computation is carried out using the operator-split solution procedure. This partitioned approach divides the computation in two phases, global and local, where different failure mechanisms are treated separately, which is in accordance with the experimentally observed composite behavior. An inverse model for fiber-reinforced concrete is presented, where the stochastic caracterization of the fibers is known from their distribution inside the domain. Parameter identification is performed by minimizing the error between the computed and measured values. The proposed models are validated through numerical examples.