The potential of hydrogen as a clean energy carrier is hotly debated, but it promises to significantly contribute to a sustainable energy future. Hydrogen can replace fossil fuels in carbon-intensive industries, heavy transport and aviation, and support a renewable energysystem by acting as energy storage to balance intermittent supply. With increasing investment, high demand projections and the promise of hydrogen to reduce carbon emissions, it is becoming increasingly important to include hydrogen in energy models. While some studies include hydrogen in their energy models, they don’t comprehensively analyse the effects of uncertainty, which is significant in the hydrogen sector. This thesis addresses this gap by developing a Nordic energy model that includes hydrogen supply and storage using OSeMOSYS, based on the European OSeMBE model. In addition to a scenario analysis, a global sensitivity analysis is performed to identify the most influential uncertainties and key interactions between the hydrogen and electricity sectors. The study identifies hydrogen demand and carbon pricing as key uncertain drivers of change, affecting system costs and emissions levels. Uncertainty about the efficiency of carbon capture and the potential for biomass technology with carbon capture and storage also significantly impact emissions. While the share of renewables is projected to be robust, the technologies used for hydrogen production are susceptible to uncertainties. Steam reforming dominates in the absence of a strong carbon price. Electricity and hydrogen from biomass can provide negative emissions and have the potential to play an important role in decarbonisation. However, biomass availability is limited and policy support like carbon pricing is needed to make these technologies competitive in the market. A key link between the electricity and the hydrogen system is electrolysers. However, while cheaper electricity makes electrolysers more attractive, the cost and performance of hydrogen production technologies, such as steam reforming or biomass gasification, are more relevant in determining which hydrogen technologies will dominate. Hydrogen storage and fuel cells aren’t used in the study, except in small amounts for some of the runs in the sensitivity analysis. However, this may change with a specified time-dependent hydrogen demand or a finer time representation in the model. The thesis shows that uncertainties around hydrogen have a much larger impact on emissions than uncertainties around the electricity system. Hydrogen technologies are in close competition, with steam reforming difficult to displace. While in the Nordic countries, the advance of renewables in electricity generation seems unstoppable, the hydrogen sector needs public policy support to become an ally in decarbonisation rather than a burden. / Vätgasens potential som en ren energibärare är omdiskuterad, men den kan bidra avsevärt till en hållbar energiframtid. Vätgas kan ersätta fossila bränslen i koldioxidintensiva industrier, tunga transporter och luftfart, och stödja ett förnybart energisystem genom att fungera som energilagring för att balansera intermittenta leveranser. Med ökande investeringar, prognoser om hög efterfrågan och löftet om att vätgas kan minska koldioxidutsläppen blir det allt viktigare att inkludera vätgas i energimodeller. Vissa studier inkluderar vätgas i sina energimodeller, men de analyserar inte effekterna av osäkerhet på ett heltäckande sätt, vilket är betydande inom vätgassektorn. Den här avhandlingen adresserar detta gap genom att utveckla en nordisk energimodell som inkluderar vätgasförsörjning och lagring med hjälp av OSeMOSYS, baserat på den europeiska OSeMBE-modellen. Förutom en scenarioanalys utförs en global känslighetsanalys för att identifiera de mest inflytelserika osäkerheterna och viktiga interaktioner mellan vätgas- och elsektorerna. Studien identifierar efterfrågan på vätgas och prissättningen på koldioxid som viktiga osäkra drivkrafter för förändring, vilket påverkar systemkostnader och utsläppsnivåer. Osäkerheten kring koldioxidavskiljningens effektivitet och potentialen för biomassateknik med koldioxidavskiljning och lagring påverkar också utsläppen avsevärt. Även om andelen förnybara energikällor förväntas vara robust, är de tekniker som används för vätgasproduktion känsliga för osäkerheter. Ångreformering dominerar i avsaknad av ett starkt koldioxidpris. Elektricitet och vätgas från biomassa kan ge negativa utsläpp och har potential att spela enviktig roll i utfasningen av fossila bränslen. Tillgången på biomassa är dock begränsad och politiskt stöd i form av t.ex. koldioxidpriser behövs för att göra dessa tekniker konkurrenskraftiga på marknaden. En viktig länk mellan el- och vätgassystemet är elektrolysörer. Men även om billigare el gör elektrolysörer mer attraktiva, är kostnaden och prestandan för vätgasproduktionstekniker såsom ångreformering eller förgasning av biomassa mer relevanta för att avgöra vilka vätgastekniker som kommer att dominera. Vätgaslagring och bränsleceller används inte i studien, förutom i små mängder för några av körningarna i känslighetsanalysen. Detta kan dock förändras med en specificerad tidsberoende vätgasefterfrågan eller en finare tidsrepresentation i modellen. Avhandlingen visar att osäkerheter kring vätgas har en mycket större inverkan på utsläppen än osäkerheter kring elsystemet. Vätgasteknikerna konkurrerar nära varandra, men ångreformering är svår att ersätta. I de nordiska länderna verkar framstegen för förnybara energikällor inom elproduktion vara ostoppbara, men vätgassektorn behöver offentligt politiskt stöd för att bli en allierad i utfasningen av fossila bränslen snarare än en börda.

Exploring the concepts of long range aerial transport of microorganisms is the main motivation of this study. For this purpose we use theories and concepts of dynamical systems in the context of geophysical fluid systems. We apply powerful notions such as finite-time Lyapunov exponent (FTLE) and the associated Lagrangian coherent structures (LCS) and we attempt to provide mathematical explanations and frameworks for some applied questions which are based on realistic concerns of atmospheric transport phenomena. Accordingly, we quantify the accuracy of prediction of FTLE-LCS features and we determine the sensitivity of such predictions to forecasting parameters. In addition, we consider the spatiotemporal resolution of the operational data sets and we propose the concept of probabilistic source and destination regions which leads to the definition of stochastic FTLE fields. Moreover, we put forward the idea of using ensemble forecasting to quantify the uncertainty of the forecast results. Finally, we investigate the statistical properties of localized measurements of atmospheric microbial structure and their connections to the concept of local FTLE time-series. Results of this study would pave the way for more efficient models and management strategies for the spread of infectious diseases affecting plants, domestic animals, and humans. / Ph. D.

Most mature oil reservoirs or fields tend to perform below expectations, owing to high level of associated gas production. This creates a sub-optimal performance of the oil production surface facilities; increasing oil production specific operating cost. In many scenarios oil companies flare/vent this gas. In addition to oil production constraints, associated gas flaring and venting consists an environmental disasters and economic waste. Significant steps are now being devised to utilise associated gas using different exploitation techniques. Most of the technologies requires large associated gas throughput. However, small-scale associated gas resources and non-associated natural gas reserves (commonly referred to as stranded gas or marginal field) remains largely unexploited. Thus, the objective of this thesis is to evaluate techno- economic of gas turbine engines for onsite electric power generation called gas- to-wire (GTW) using the small-scaled associated gas resources. The range of stranded flared associated gas and non-associated gas reserves considered is around 10 billion to 1 trillion standard cubic feet undergoing production decline. The gas turbine engines considered for power plant in this study are based on simple cycle or combustion turbines. Simple cycle choice of power-plant is conceived to meet certain flexibility in power plant capacity factor and availability during production decline. In addition, it represents the basic power plant module cable of being developed into other power plant types in future to meet different local energy requirements. This study developed a novel gas-to-wire techno-economic and risk analysis framework, with capability for probabilistic uncertainty analysis using Monte Carlo simulation (MCS) method. It comprises an iterative calculation of the probabilistic recoverable reserves with decline module and power plant thermodynamic performance module enabled by Turbomatch (an in-house code) and Gas Turb® software coupled with economic risk modules with @Risk® commercial software. This algorithm is a useful tool for simulating the interaction between disrupted gas production profiles induced by production decline and its effect on power plant techno-economic performance over associated gas utilization economic life. Furthermore, a divestment and make- up fuel protocol is proposed for management of gas turbine engine units to mitigate economical underperformance of power plant regime experienced due to production decline. The results show that utilization of associated gas for onsite power generation is a promising technology for converting waste to energy. Though, associated gas composition can be significant to gas turbine performance but a typical Nigerian associated gas considered is as good as a regular natural gas. The majority of capital investment risk is associated with production decline both natural and manmade. Finally, the rate of capital investment returns decreases with smaller reserves.

The work presented in this thesis aims to provide various tools to be used during design process to make maximum use of the increasing availability of accurate engine blade measurement data for high fidelity fluid mechanic simulations at a reasonable computational expense. A new method for uncertainty propagation for geometric error has been proposed for fluid mechanics codes using adjoint error correction. Inexpensive Monte Carlo (IMC) method targets small uncertainties and provides complete probability distribution for the objective function at a significantly reduced computational cost. A brief literature survey of the existing methods is followed by the formulation of IMC. An example algebraic model is used to demonstrate the IMC method. The IMC method is extended to fluid mechanic applications using Principal Component Analysis (PCA) for reduced order modelling. Implementation details for the IMC method are discussed using an example airfoil code. Finally, the IMC method has been implemented and validated for an industrial fluid mechanic code HYDRA. A consistent methodology has been developed for the automatic generation of the linear and adjoint codes by selective use of automatic differentiation (AD) technique. The method has the advantage of keeping the linear and the adjoint codes in-sync with the changes in the underlying nonlinear fluid mechanic solver. The use of various consistency checks have been demonstrated to ease the development and maintenance process of the linear and the adjoint codes. The use of AD has been extended for the calculation of the complete Hessian using forward-on-forward approach. The complete mathematical formulation for Hessian calculation using the linear and the adjoint solutions has been outlined for fluid mechanic solvers. An efficient implementation for the Hessian calculation is demonstrated using the airfoil code. A new application of the Independent Component Analysis (ICA) is proposed for manufacturing uncertainty source identification. The mathematical formulation is outlined followed by an example application of ICA for artificially generated uncertainty for the NACA0012 airfoil.

The purpose with this study is to show how the subjective uncertainty analysis can be applied to the cost estimates and examine how the attitudes towards risk budgeting of construction projects works. Biogas Mellannorrland is based on a case study and focuses on four location options for the biogas plant. For each option, a cost estimate in form of a fixed cost and variable cost elements, where the latter are uncertain. Pearson-Tukey method have been applied as a method to estimating subjective probabilities. An assumption is made so that the uncertain costs are normally distributed, where the parameters’ mean and standard deviation collected from respondents indicating percentiles at 5% and 95% for doubtful cost elements. In order to identify the project managers risk attitude, the risk premium method will be used to calculate where the expected value is produced by Pearson-Tukey method. The expected value is subtracted with certainty equivalent, which consist of the budgeted amount. The study was conducted through interviews in order to obtain the costs and the subjective probabilities. The study results show that it is difficult to determine which option is the best, or the worst, by just looking at the expected value. The risk premium shows that each option is a risk averse choice for the project managers, since the risk premium was greater than zero. / Denna studie syftar till att visa hur subjektiv osäkerhetsanalys kan tillämpas vid kostnadskalkyler samt undersöka riskattityder vid budgetering av byggprojekt. Undersökningen är en fallstudie vid Biogas Mellannorrland och fokuserar på fyra lokaliseringsalternativ för biogasanläggning. För varje alternativ görs en kostnadskalkyl i form av ett antal fasta och rörliga delkostnader, där de senare är osäkra. Som metod för att skatta subjektiva sannolikheter har Pearson-Tukey-metoden tillämpats. Ett antagande görs att osäkra kostnader är normalfördelade, där parametrarna väntevärde och standardavvikelse hämtas från respondenter som anger percentilerna vid 5 % och 95 % för osäkra delkostnader. För att identifiera projektledarnas riskattityd, kommer riskpremium att beräknas, där det förväntade värdet tas fram med Pearson-Tukey- metoden. Det förväntade värdet subtraheras med säkerhetsekvivalensen, vilket utgörs av det budgeterade beloppet. Studien har genomförts med hjälp av intervjuer för att få fram kostnader och subjektiva sannolikheter. Studiens resultat visar att det är svårt att avgöra vilka alternativ som är bäst eller sämst genom att bara titta på väntevärdet. Med riskpremium visar alla alternativ att projektledarna gör ett riskaversivt val, eftersom riskpremium blev större än noll.

A comprehensive assessment of water security incorporates a range of water-related concepts, since water policy issues to specific technical aspects of hydrological conditions and their interactions with societal needs and ecosystem functioning. This doctoral thesis is organized into three chapters that address such range of water security-related topics, aiming to establish a conceptual baseline and propose deterministic and stochastic accounting frameworks for a river basin water security evaluation. Specific assumptions and research questions are defined in each chapter, and are related to the management of \'Cantareira water supply system\' (located in Southeastern Brazil), focusing on different scales and on its political and hydrological aspects as well. The first chapter acts as a conceptual baseline for water security assessment, by examining general aspects of the Brazilian water policy and water allocation system. This study contrasts Brazilian and American water management systems applied to water transfer projects, discussing experiences from the \'Cantareira system\' and Colorado river basin. A deterministic accounting framework is presented in the second chapter, which is based on management of blue and green water kinds (defined in accordance with hydrological processes and storage types), and demonstrates how a quantitative analysis of provisioning and use (abstraction and consumption) of both water kinds can be conducted. An agricultural basin (291 km²) within the Cantareira water supply system (located upstream of the Cachoeira reservoir) was used to illustrate this approach. The impact of blue and green water use on median water resources conditions is accounted by the scarcity indicator, while the vulnerability indicator considers the probability of low availability of water resources. In the third chapter quantifies and discusses the impacts of uncertainties on water security indicators (proposed in the chapter 2), based on a multi-model and resampling framework, that considers several uncertainty sources including those related to: i) observed streamflow data; ii) hydrological model structure; iii) residual analysis; iv) Environmental Flow Requirement methods; v) the definition of critical conditions for water provision; and vi) the critical demand imposed by human activities. Then, the uncertainty is propagated through different methodological arrangements applied to the same study basin of chapter 2. In brief, the first chapter indicates that both Brazilian and American water management system can potentially contribute to each other. In the second chapter, the Blue/Green water-based accounting framework reveal clear spatial and temporal patterns of water scarcity and vulnerability levels within the basin, thereby improving our understanding of how and where water-related threats to human and aquatic ecosystem security can arise (so called hot-spots). The third chapter provide a general method that can form basis for meaningful support to end-users facing water resource challenges by enabling them to incorporate a viable uncertainty analysis into a robust decision making process. Further investigation are proposed in each research step of this doctoral thesis. / A avaliação da segurança hídrica pode incorporar vários conceitos relacionados à água, desde aspectos da política de recursos hídricos até questões hidrológicas específicas e suas interações com a sociedade e ecossistemas. Esta tese de doutorado busca estabelecer uma base conceitual e propor esquemas metodológicos com base determinística e estocástica para avaliação da segurança hídrica de bacias hidrográficas. Objetivos específicos são definidos em cada capítulo e relacionam-se à gestão do \'Sistema Cantareira de abastecimento de água\' (localizado no Sudeste do Brasil), com foco em diferentes escalas, bem como aspectos políticos e hidrológicos. O primeiro capítulo é apresentado como baseline conceitual, examinando aspectos gerais da política de recursos hídricos e sistemas alocação de água. Este estudo compara sistemas de gestão aplicados a projetos de transposição de água inter/intra-bacias no Brasil e Estados Unidos, discutindo experiências do Sistema Cantareira e da bacia do rio Colorado. O segundo capítulo, por sua vez, propõe e analisa um esquema metodológico determinístico baseado na gestão das águas azul e verde (definidas de acordo com processos hidrológicos e unidades de armazenamento). Este estudo demonstra como uma análise quantitativa da provisão e utilização de ambos os tipos de água pode ser conduzida, propondo indicadores de escassez e vulnerabilidade hídrica. Esta abordagem foi aplicada em uma bacia agrícola (291 km²), localizada a montante do reservatório Cachoeira, que é integrante do Sistema Cantareira. O terceiro capítulo quantifica e analisa os impactos das incertezas sobre os indicadores de segurança hídrica propostos no capítulo 2, utilizando um esquema metodológico estocástico baseado em múltiplos modelos e reamostragem, que incorpora variadas fontes de incerteza, tais como: i) dados observados de vazão; ii) estrutura do modelo hidrológico; iii) análise de resíduos do modelo hidrológico; iv) estimativa de vazão ambiental; v) definição de condições críticas de provisão e vi) demanda hídrica. Em seguida, as incertezas são propagadas através de diferentes arranjos metodológicos aplicados na mesma bacia estudo do capítulo 2. Em conclusão, o primeiro capítulo sugere uma potencial troca de contribuições provenientes de ambos os sistemas de gestão brasileiro e americano. O segundo capítulo revela padrões espaciais e temporais dos resultados dos indicadores de escassez e vulnerabilidade, melhorando assim a compreensão de como e onde ameaças à segurança hídrica podem surgir. Por sua vez, a análise de incertezas desenvolvida no terceiro capítulo é capaz de gerar suporte a gestores de recursos hídricos e processo de tomada de decisões robustas. Recomendações específicas são geradas em cada capítulo da presente tese de doutorado.

Dans ce travail, la caractérisation mécanique de l’interphase entre les zones amorphes et cristallines dans le polyéthylène a été abordée. La caractérisation élastique est effectuée en appliquant deux approches micromécaniques à partir des données de la simulation moléculaire pour la zone interlamellaire. Ces approches micromécaniques sont d’une part le modèle étendu d’inclusion composite, et d’autre part la méthode de double inclusion. Les résultats des deux approches s’accordent parfaitement. Il a été mis en évidence que le tenseur de rigidité de l’interphase n’est pas défini positif, l’interphase est donc mécaniquement instable. La comparaison avec les résultats expérimentaux valide la méthodologie proposée. Pour la caractérisation hyperélastique, l’algorithme hybride proposé consiste à appliquer la loi de comportement d’un milieu continu isotrope, compressible et hyperélastique aux résultats de la simulation de la dynamique moléculaire d’un élément unitaire de polyéthylène. La notion d’optimisation d’un ensemble de fonctions coûts non négatives est l’idée clé de cette partie. Les paramètres hyperélastiques identifiés sont en bon accord avec ceux qui ont été estimés expérimentalement. L’évolution des frontières de l’interphase avec la déformation est le second résultat de cette analyse. La fin du travail est dédiée à la simulation numérique de la grande déformation viscoplastique d’un agrégat de polyéthylène. Le modèle de Gent adopté pour la contrainte de rappel, le tenseur de projection proposé pour l’approche modifiée de Taylor, et l’optimisation multiniveau font parties des contributions apportées. / Elastic characterization of the interphase layer in polyethylene is implemented by applying the relationships of two micromechanical approaches, “Extended Composite Inclusion Model” and “Double-Inclusion Method”, to the Monte Carlo molecular simulation data for the interlamellar domain. The results of the two approaches match perfectly. The interphase stiffness lacks the common feature of positive definiteness, which indicates its mechanical instability. Comparison with experimental results endorses the proposed methodology. For the hyperelastic characterization of the interlamellar domain and the interphase layer, the proposed hybrid algorithm consists in applying the constitutive equations of an isotropic, compressible, hyperelastic continuum to the molecular dynamics simulation results of a polyethylene stack. Evolution of the interphase boundaries are introduced as auxiliary variables and the notion of minimizing a set of nonnegative objective functions is employed for parameter identification. The identified hyperelastic parameters for the interlamellar domain arein good agreement with the ones that have been estimated experimentally. Finally, the large, viscoplastic deformation of an aggregate of polyethylene is reexamined. The Gent model adopted for the back stress of the noncrystalline phase, correcting the projection tensor for the modified Taylor approach, and the idea of multilevel optimization are among the contributions made.

O uso de materiais piezelétricos no desenvolvimento de dispositivos para o aproveitamento de energia provinda de vibrações mecânicas, Energy Harvesting, tem sido largamente estudado na última década. Materiais piezelétricos podem ser encontrados na forma de finas camadas ou pastilhas, sendo facilmente integradas a estruturas sem aumento significativo de massa. A conversão de energia mecânica em energia elétrica se dá graças ao acoplamento eletromecânico dos materiais piezelétricos. A maioria das publicações encontradas na literatura exploram o uso de dispositivos eletromecânicos ressonantes, sintonizados na frequência de operação da estrutura, maximizando assim, a energia elétrica de saída dada uma certa condição de operação. O desempenho desses dispositivos ressonantes para coletar e armazenar energia é altamente dependente da adequada sintonização da sua frequência de ressonância com a frequência de operação do sistema/estrutura. Este trabalho apresenta o projeto, otimização e análise de incertezas de um dispositivo coletor/armazenador de energia que consiste em uma placa sob duas condições de contorno, engastada-livre (EL) e deslizante-livre (DL), com massa sísmica e materiais piezelétricos conectados a um circuito shunt. Um modelo em elementos finitos de placa laminada piezelétrica conectada a circuitos R e RL é utilizado combinando as teorias de camada equivalente e deformação de cisalhamento de primeira ordem. A disposição/quantidade de material piezelétrico bem como a massa sísmica acoplados à estrutura foram otimizadas utilizando-se um Algoritmo Genético, levando em conta análises mecânica (modelo mecânico, geometria, peso) e elétrica (modelo elétrico, circuito armazenador). Além disso, o efeito de incertezas dos parâmetros dielétrico e piezelétrico do transdutor, e da indutância elétrica ligada em série ao circuito coletor/armazenador de energia foi estudado. Os resultados indicam que a inclusão de uma indutância sintética ao circuito pode melhorar a coleta de energia em uma banda de frequência e, ainda, que a otimização geométrica pode reduzir a quantidade de material piezelétrico sem no entanto diminuir significativamente a energia gerada. / The use of piezoelectric materials in the development of devices to harvest energy from mechanical vibrations (Energy Harvesting) has been widely studied in the last decade. Piezoelectric materials can be found in the form of thin layers or patches easily integrated into structures without significant mass increase. The conversion of mechanical energy into electric power is provided by the electromechanical coupling of piezoelectric materials. Most publications in the literature explore the use of resonant electromechanical devices, tuned to the operating frequency of the host structure, thus maximizing the power output given a certain operating condition. The performance of these resonant devices to harvest and store energy is highly dependent on the proper tuning of its resonance frequency with the operation frequency of the system/structure. This work presents a design, optimization and uncertainty analysis of energy harvester device consisting of a plate with tip mass and piezoelectric materials connected to shunt circuits. Two boundary conditions are used for the plate, cantilever (EL) and sliding-free (DL). A coupled finite element model with R and RL circuits, combining equivalent single layer and first order shear deformation theories, was used. The distribution and volume of piezoelectric material and the tip mass coupled to the structure were optimized using a Genetic Algorithm, accounting for both mechanical (mechanical model, geometry, weight) and electric (electric model, storer circuit) analyses. Furthermore, the effect of uncertainties of transducer dielectric and piezoelectric constants and electric inductance connected in series with harvesting circuit was studied. The results indicate that the inclusion of a synthetic inductance can improve energy harvesting performance over a frequency range and also that the geometric optimization may reduce the piezoelectric material volume without diminishing significantly the harvested energy.

Esta tese apresenta uma análise numérica do controle de vibrações estruturais através de cerâmicas piezelétricas em extensão conectadas a circuitos ativo-passivos compostos por resistência, indutância e fonte de tensão. Para tal, um modelo de elementos finitos de vigas sanduíche com três camadas elásticas e/ou piezelétricas foi desenvolvido. Realizou-se também uma modelagem dos componentes do circuito elétrico e seu acoplamento à estrutura gerando assim uma equação de movimento acoplada para a estrutura com elementos piezelétricos conectados aos circuitos elétricos. Uma análise harmônica das equações obtidas foi realizada para se obter uma avaliação preliminar dos efeitos causados pelos componentes elétricos do circuito na estrutura. Observou-se que os elementos passivos do circuito, resistência e indutância, tem não somente um efeito de absorvedor dinâmico de vibrações mas, também, promovem uma amplificação da autoridade de controle no caso de se atuar através da fonte de tensão. Usando a metodologia tradicional de projeto de absorvedores dinâmicos de vibrações, derivou-se expressões para os valores de resistência e indutância de modo a maximizar o desempenho passivo do sistema. Uma análise do efeito de incertezas das constantes piezelétricas e dielétricas da cerâmica piezelétrica considerada e dos componentes de resistência e indutância do circuito elétrico no desempenho do controle passivo e ativo-passivo de estrutura tipo viga cantilever foi realizada. O objetivo desta análise foi quantificar robustez e sensibilidade do controle proposto. Em sequida, um estudo de otimização dos valores de resistência e indutância do circuito elétrico em função da tensão elétrica de controle máxima a ser aplicada em uma placa com diversos atuadores piezelétricos foi realizado. Finalmente e também para a estrutura tipo placa, uma análise de incertezas da rigidez da cola na interface entre estrutura e atuadores piezelétricos e seus efeitos no desempenho do controle passivo e ativo-passivo foi realizada. / This work presents a numerical analysis of the structural vibration control using piezoelectric materials in extension mode connected to active-passive electric circuits composed of resistance, inductance and voltage source. For that, a finite element model for sandwich beams with three elastic or piezoelectric layers was developed. A modeling of the electric circuit dynamics and its coupling to the structure with piezoelectric elements was also done. A harmonic analysis of the resulting equations was performed to yield a preliminary evaluation of the effects caused by the electric circuit components on the structure. It was observed that the passive circuit components not only lead to a dynamic vibration absorber effect but also to an amplification of the control authority in case of actuation using the voltage source. Using the standard methodology for the design of dynamic vibration absorbers, expressions were derived for the resistance and inductance values that optimize the passive vibration control performance of the system. An analysis of the effect of uncertainties of piezoelectric and dielectric constants of piezoelectric ceramic and resistance and inductance components of the shunt circuit on the passive and active-passive control performance for a cantilever beam structure was performed. The objective of this analysis was to quantify robustness and sensitivity of the proposed control. Then, an optimization study of the values of resistance and inductance of the shunt circuit as a function of the maximum control voltage to be applied on a plate with several piezoelectric actuators was performed. Finally and also for the plate structure, an analysis of uncertainties in the stiffness of the adhesive interface between structure and piezoelectric actuators and their effects on the performance of passive control and active-passive was performed.

La généralisation planifiée du Bâtiment à Énergie POSitive est un enjeu important de développement durable, notamment dans une vision à long terme. Cependant, concevoir de tels bâtiments à moindre impact environnemental et à des coûts maîtrisés pour le marché constitue une problématique complexe pour les professionnels du secteur. Ces travaux de thèse se sont ainsi intéressés au développement d’une méthodologie permettant de fournir une aide à la décision opérationnelle et robuste pour l’écoconception de maisons à énergie positive (MEPOS). Basée sur l’optimisation multicritère (via un algorithme génétique), la démarche proposée associe au sein d’une plateforme multi-outils, simulation thermique dynamique, analyse de cycle de vie, et fonctions de coût de construction, pour identifier, sur une base multicritère (front de Pareto) et sur le cycle de vie, des concepts de MEPOS performantes et fournir au décideur une description des meilleurs compromis. Également intégrées dans la plateforme, des méthodes d’analyses de sensibilité et d’incertitude offrent la possibilité de sélectionner les variables de conception les plus influentes en amont de l’optimisation, et d’évaluer le risque de non-robustesse d’une décision en aval de l’optimisation, notamment au regard des incertitudes sur le comportement des occupants (avec un modèle stochastique d’occupation), et de l’évolution prévisible du climat jusqu’à la fin du siècle. Via une collaboration avec un constructeur, la méthodologie a été appliquée en temps réel au sein d’un processus de conception intégrée d’une MEPOS. / The planned generalisation of Plus Energy Buildings constitutes an important topic for sustainable development, especially in a long term vision. However, designing such buildings at lower environmental impact and with competitive cost for the market constitutes a complex issue for the sector’s professionals. This thesis focused on the development of a methodology providing an operational and robust decision support to eco-design plus-energy houses. Based on multi-criteria optimisation (via a genetic algorithm), the proposed approach combines in a multi-tools platform, dynamic building energy simulation, life cycle assessment, and cost construction functions, in order to identify, on a multi-criteria (Pareto front) and life cycle basis, efficient plus-energy houses concepts and to provide decision maker a description of the best compromises. Also included in the platform, sensitivity and uncertainty analysis methods offer the possibility to select the most influent design variables before optimisation, and to evaluate the non-robustness risk of a decision after optimisation, especially regarding uncertainties on occupants’ behaviour (with a stochastic model of occupancy) and climate’s predictable evolution up to the end of the century. Via collaboration with a constructor, the methodology was applied in real-time throughout a integrated design process of a plus-energy house.