Modular construction is a relatively new technique where prefabricated units are assembled on-site to produce a complete building. Due to detailing requirements for the assembly of the modules, these systems are prone to undesirable failure mechanisms during large earthquakes. Specifically, for multi-story Modular Steel Buildings (MSBs), inelasticity concentration in vertical connections can be an area of concern. Diaphragm interaction, relative displacements between modules and the forces in the horizontal connections need to be investigated. In this study, two 4-story MSBs with two different structural configurations were chosen to be analyzed. In the first model which was introduced in a study by Annan et al. (2009 a), some of the unrealistic detailing assumptions were challenged. To have a more accurate assessment of the structural capacity, in the second model, a more realistic MSB model was proposed. Using OpenSees, Incremental Dynamic Analyses (IDA) have been performed and conclusions were made.

Modular construction is a relatively new technique where prefabricated units are assembled on-site to produce a complete building. Due to detailing requirements for the assembly of the modules, these systems are prone to undesirable failure mechanisms during large earthquakes. Specifically, for multi-story Modular Steel Buildings (MSBs), inelasticity concentration in vertical connections can be an area of concern. Diaphragm interaction, relative displacements between modules and the forces in the horizontal connections need to be investigated. In this study, two 4-story MSBs with two different structural configurations were chosen to be analyzed. In the first model which was introduced in a study by Annan et al. (2009 a), some of the unrealistic detailing assumptions were challenged. To have a more accurate assessment of the structural capacity, in the second model, a more realistic MSB model was proposed. Using OpenSees, Incremental Dynamic Analyses (IDA) have been performed and conclusions were made.

The seismic response of steel monopole wind turbine towers is investigated and their risk is assessed in the Canadian seismic environment. This topic is of concern as wind turbines are increasingly being installed in seismic areas and design codes do not clearly address this aspect of design. An implicit finite element model of a 1.65MW tower was developed and validated. Incremental dynamic analysis was carried out to evaluate its behaviour under seismic excitation, to define several damage states, and to develop a framework for determining its probability of damage. This framework was implemented in two Canadian locations, where the risk was found to be low for the seismic hazard level prescribed for buildings. However, the design of wind turbine towers is subject to change, as is the design spectrum. Thus, a methodology is outlined to thoroughly investigate the probability of reaching predetermined damage states under seismic loading for future considerations.

The seismic response of steel monopole wind turbine towers is investigated and their risk is assessed in the Canadian seismic environment. This topic is of concern as wind turbines are increasingly being installed in seismic areas and design codes do not clearly address this aspect of design. An implicit finite element model of a 1.65MW tower was developed and validated. Incremental dynamic analysis was carried out to evaluate its behaviour under seismic excitation, to define several damage states, and to develop a framework for determining its probability of damage. This framework was implemented in two Canadian locations, where the risk was found to be low for the seismic hazard level prescribed for buildings. However, the design of wind turbine towers is subject to change, as is the design spectrum. Thus, a methodology is outlined to thoroughly investigate the probability of reaching predetermined damage states under seismic loading for future considerations.

In this study, dynamic response of Akk&ouml / pr&uuml / Dam under earthquake motions is analyzed and the permanent displacements are evaluated. Initially, the critical slip surface of the dam and the corresponding yield acceleration are determined by using the computer program SLOPE. Then, by employing the finite element program SAP2000, static analyses are performed to obtain the mean effective stresses which are used in the determination of dynamic material properties of the dam. Four different scenario earthquakes having a magnitude of 7 are used in the dynamic analyses. Two of those scenarios are taken from European Strong Motion Database and the others are generated by XS artificial earthquake generation program prepared by Erdik (1992). Dynamic analyses of the dam are carried out by the finite element program TELDYN. Permanent displacements of the critical slip surface are calculated by utilizing the Newmark method. Consequently, for an earthquake having a magnitude of M=7 and a peak ground acceleration of 0.20g, the maximum permanent displacement of the dam is found to be 15.90 cm. Furthermore, the permanent displacements of the dam are calculated under base motions having different peak ground acceleration values and it is observed that the rate of increase in the amount of permanent displacements is greater than the increase in the amount of peak ground accelerations.

New 3D multi-scale modeling approaches for the structural analysis of native and prosthetic Aortic Valves (AV) are investigated. Three different nonlinear hyperelastic constitutive material models for the mechanical behavior of the AV tissue are introduced. The first is the well-known Holzapfel hyperelastic, anisotropic and homogeneous model. The second model, termed the Collagen Fiber Network (CFN), is a heterogeneous model that recognizes the hyperelastic collagen and elastin layers using different layered finite elements. The third hyperelastic model is implemented using a new nonlinear micromechanical formulation of the High Fidelity Generalized Method of Cells (HFGMC) originally proposed by Aboudi. The latter two material models are heterogeneous and explicitly recognize the in-situ tissue constituents. Initially, a full scale 3D structural model of a polymeric-based prosthetic AV model is studied. This model is verified using deformation metrics obtained from images taken with high speed cameras during in-vitro experiments. The predictions from the proposed polymeric AV model are in good agreement with the test data. Next, the three tissue material models are examined in their ability to predict the anisotropic material behavior of porcine AV leaflet tissue. The Holzapfel model is calibrated from the overall anisotropic uni- and biaxial stress-strain data while the in-situ elastin and collagen constituents in the CFN and HFGMC models are calibrated to match the overall effective responses. Dynamic structural analysis is performed for the porcine AV with applied transvalvular pressure measured from repeated in-vitro tests conducted in this study. Principal stretches are computed from the experimental measurements and compared with the AV material-structural predictions. The proposed multi-scale modeling approach for the native AV is capable of predicting the structural behavior during the entire cardiac cycle without suffering from numerical convergence problems. Finally, new nonlinear micromechanical formulations based on the HFGMC method are developed and applied for various types of tissue materials including the human arterial wall layers and porcine AV leaflets. The proposed hyperelastic HFGMC model is compared to the CFN model and the Holzapfel models. It is shown that the HFGMC is an effective modeling approach for the arteries especially when the collagen fiber network has a periodic microstructure.

Dans le domaine des cartes à puce, les analyses de vulnérabilité demandent d’être à la pointe de l’art en termes d’attaques et de techniques de protection. Une attaque classique est l’injection de fautes, réalisée au niveau matériel notamment par des techniques laser. Pour anticiper les impacts possibles de ce type d'attaque, certaines analyses sont menées au niveau logiciel. Il est donc fortement d’actualité de pouvoir définir des critères et proposer des outils automatiques permettant d’évaluer la robustesse d’une application à ce type d’attaque, d’autant plus que les techniques d’attaques matérielles permettent maintenant d’enchaîner plusieurs attaques (spatiales ou temporelles) au cours d’une exécution. En effet, des travaux de recherche récents évaluent l'impact des contre-mesures face à ce type d'attaque[1], ou tentent de modéliser les injections de faute au niveau C[2]. Le sujet de thèse proposé s'inscrit dans cette problématique, avec néanmoins la particularité novatrice de s'intéresser au couplage des analyses statique et dynamique dans le cas des injections de fautes effectuées au niveau binaire. Un des objectifs de la thèse est d'offrir un cadre paramétrable permettant de simuler des attaques par faute telles qu'elles peuvent être réalisées par le laboratoire CESTI-LETI au niveau matériel. Il faudra donc proposer un modèle intermédiaire générique permettant de spécifier des contraintes réelles comme par exemple les différents types de mémoires (RAM, EEPROM, ROM), qui peuvent induire des fautes permanentes ou volatiles. Concilier les analyses statiques du code et l'injection de fautes dynamiques devra permettre de maîtriser la combinatoire des exécutions et de guider l'analyse à l'aide de patterns d'attaques. À ce titre, on sera amené à proposer une taxonomie des attaques et de nouvelles modélisations d'attaques. Il faudra également adapter les outils d'analyse statique aux conséquences de l'injection dynamique de fautes, qui peut modifier profondément le code en changeant l'interprétation des instructions, ce qui a un effet similaire à la génération de code à l'exécution. Ce sujet de thèse s'inscrit dans la stratégie d'innovation du CESTI-LETI et pourra aboutir à un vérificateur automatique de code utilisable par les évaluateurs du CESTI-LETI. [1] A. Séré, J-L. Lanet et J. Iguchi-Cartigny. « Evaluation of Countermeasures Against Fault Attacks on Smart Cards ». en. In : International Journal of Security and Its Applications 5.2 (2011). [2] Xavier Kauffmann-Tourkestansky. « Analyses sécuritaires de code de carte à puce sous attaques physiques simulées ». Français. THESE. Université d’Orléans, nov. 2012. url : http://tel.archives-ouvertes.fr/tel-00771273. / Vulnerability detections for smart cards require state of the art methods both to attack and to protect the secure device. A typical type of attack is fault injection, most notably performed by means of laser techniques. To prevent some of the consequences of this kind of attacks, several analyses are conducted at the software level. Being able to define criteria and to propose automated tools that can survey the robustness of an application to fault injection is thus nowadays a hot topic, even more so since the hardware attack techniques allow today an attacker to perform several attacks in a single software execution. Indeed, recent research works evaluate the effectiveness of counter-measures against fault injection[1], or attempt to develop models of fault injection at the C level[2]. This thesis project addresses the issue of multiple faults injection, albeit by adding the distinctive aspect of static and dynamic analysis interaction in a context of binary-level fault injection. An objective of the thesis is to achieve a configurable framework to simulate fault injections in the way they are currently performed by the CESTI-LETI laboratory on the actual hardware. To do so we will develop a generic intermediate model that will allow us to specify hardware constraints, such as the various kinds of memories (RAM, EEPROM, ROM), whose different properties can induce either permanent or volatile faults. Combining the static code analysis with dynamic fault injections should prevent the combinatory explosion of the executiions while attack patterns will guide the analysis. A taxonomy of attacks and new attack modelisations could emerge from this work. An adaption of the tools for static analysis is also required, because dynamic fault injection can deeply change the code by modifying the interpretation of the instructions, in a similar manner to dynamic compilation. This thesis project falls within the CESTI-LETI's innovation strategy, et could lead to an automated code verifier that could be used by the CESTI-LETI evaluation specialists. [1] A. Séré, J-L. Lanet et J. Iguchi-Cartigny. « Evaluation of Countermeasures Against Fault Attacks on Smart Cards ». en. In : International Journal of Security and Its Applications 5.2 (2011). [2] Xavier Kauffmann-Tourkestansky. « Analyses sécuritaires de code de carte à puce sous attaques physiques simulées ». Français. THESE. Université d’Orléans, nov. 2012. url : http://tel.archives-ouvertes.fr/tel-00771273.

This work presents a method to perform formal and dynamic verification of concurrent software. The objective is to provide a method capable of identifying problems in programs whose execution is based on multiple threads, and analyze behavioral properties. The method is able to detect problems in concurrent software, as well as check conformity of the concurrent software with desirable behavior, based on information collected dynamically, i.e. at runtime. The information collected consists of the software execution flow as well as data about the way communicate the software components during this run. The data collected reflect the software's execution, which ensures greater confidence to the information collected. This information is analyzed to identify deadlocks and race conditions in a process called Dynamic Analysis. In addition, this information is also used to automatically generate a model that describes the behavior of a software, which is used for verification of behavioral properties. This process is called Formal Verification. The automatic model generation eliminates the need for manual construction of the model, which requires much effort and knowledge of formal methods, this can increase costs and development time software. However, the dynamic analysis is known to only perform coverage of the current behavior of competing software systems. Current behavior is one that occurs only during an execution of concurrent software systems, without considering all other possible behaviors from the non-determinism. Due to the non-determinism, concurrent software can produce different results for the same input to each execution of software. Therefore reproduce the behavior that leads to competitive software failure is a complex task. This paper proposes a method to perform formal verification and dynamic concurrent software capable of capturing the non-deterministic behavior of these systems and provide reduced development costs by eliminating the need for manual construction of concurrent software system models. The method is validated by a case study consists of three test software systems. / Fundação de Amparo a Pesquisa do Estado de Alagoas / Neste trabalho é apresentado um método para verificação formal e dinâmica de software concorrentes. O objetivo é oferecer um método capaz de identificar problemas inerentes a programas cuja execução baseia-se em múltiplas threads, além de analisar propriedades comportamentais descritas com base nos preceitos da lógica temporal. Propõe-se um método capaz de detectar problemas e verificar formalmente a adequação da execução de sistemas de software concorrentes com relação ao comportamento desejável a tais sistemas, baseando-se em informações coletadas dinamicamente, ou seja, em tempo de execução. As informações coletadas correspondem às sequências de execução de sistemas de software, bem como dados sobre a maneira como se comunicam seus componentes durante sua execução. Os dados colhidos refletem a execução do sistema de software propriamente dito, o que garante maior confiança às informações coletadas. Tais informações são analisadas de modo a identificar impasses e condições de corrida em um processo denominado Análise Dinâmica. Ademais, estas informações também são utilizadas para geração automática de um modelo que descreve o comportamento do sistema de software, o qual é utilizado para verificação de propriedades comportamentais. A este processo de verificação dá-se o nome de Verificação Formal. A geração automática do modelo elimina a necessidade de construção manual do mesmo, que requer muito esforço e conhecimento acerca de métodos formais, isso pode aumentar custos e tempo de desenvolvimento do sistema de software. Entretanto, a análise dinâmica é conhecida por apenas realizar cobertura sobre o comportamento atual de sistemas de software concorrentes, sem considerar a análise de todas as outras possíveis sequências de execuções devido ao não determinismo. Em razão do comportamento não determinístico, sistemas de software concorrentes são capazes de produzir resultados diferentes para a mesma entrada a cada nova execução. Deste modo, reproduzir o comportamento que leva sistemas de software concorrente à falha é uma tarefa complexa. O presente trabalho propõe um método para realizar verificação formal e dinâmica de sistemas de software concorrente capaz de capturar o comportamento não determinístico desses sistemas, além de proporcionar a redução de custos de desenvolvimento através da eliminação da necessidade de construção manual de modelos de sistemas de software concorrente. O método é validado através de um estudo de caso composto por testes em três sistemas de software.

La vérification de logiciels est une activité dont l'importance est cruciale pour les logiciels embarqués critiques. Les différentes approches envisageables peuvent être classées en quatre catégories : les méthodes d'analyse statique non formelles, les méthodes d'analyse statique formelles, les méthodes d'analyse dynamique non formelles et les méthodes d'analyse dynamique formelles. L'objectif de cette thèse est de vérifier des propriétés temporelles dans un cadre industriel, par analyse dynamique formelle.La contribution comporte trois parties. Un langage adapté à l'expression des propriétés à vérifier, tirées du contexte industriel d'Airbus, a été dé ni. Il repose notamment sur la logique temporelle linéaire mais également sur un langage d'expressions régulières.La vérification d'une propriété temporelle s'effectue sur une trace d'exécution d'un logiciel, générée à partir d'un cas de test pré-existant. L'analyse statique est utilisée pour générer la trace en fonction des informations nécessaires à la vérification de la propriété temporelle formalisée.Cette approche de vérification propose une solution pragmatique au problème posé par le caractère ni des traces considérées. Des adaptations et des optimisations ont également été mises en œuvre pour améliorer l'efficacité de l'approche et faciliter son utilisation dans un contexte industriel. Deux prototypes ont été implémentés,des expérimentations ont été menées sur différents logiciels d'Airbus. / Software Verification is decisive for embedded software. The different verification approaches can be classified in four categories : non formal static analysis,formal static analysis, non formal dynamic analysis and formal dynamic analysis.The main goal of this thesis is to verify temporal properties on real industrial applications,with the help of formal dynamic analysis.There are three parts for this contribution. A language, which is well adapted to the properties we want to verify in the Airbus context was defined. This language is grounded on linear temporal logic and also on a regular expression language.Verification of a temporal property is done on an execution trace, generated from an existing test case. Generation also depends on required information to verify the formalized property. Static analysis is used to generate the trace depending on the formalized property.The thesis also proposes a pragmatic solution to the end of trace problem. In addition,specific adaptations and optimisations were defined to improve efficiency and user-friendliness and thus allow an industrial use of this approach. Two applications were implemented. Some experiments were led on different Airbus software.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / A experiência dos engenheiros estruturais e os conhecimentos adquiridos pelo uso de materiais e novas tecnologias, têm ocasionado estruturas de aço e mistas (aço-concreto) de passarelas cada vez mais ousadas. Este fato tem gerado estruturas de passarelas esbeltas, e consequentemente, alterando os seus estados de limite de serviço e último associados ao seu projeto. Uma consequência direta desta tendência de projeto é o aumento considerável das vibrações das estruturas. Portanto, a presente investigação foi realizada com base em um modelo de carregamento mais realista, desenvolvido para incorporar os efeitos dinâmicos induzidos pela caminhada de pessoas. O modelo de carregamento considera a subida e a descida da massa efetiva do corpo em cada passo. A posição da carga dinâmica também foi alterada de acordo com a posição do pedestre sobre a estrutura e a função do tempo gerada, possui uma variação espacial e temporal. O efeito do calcanhar do pedestre também foi incorporado na análise. O modelo estrutural investigado baseia-se em uma passarela tubular (aço-concreto), medindo 82,5m. A estrutura é composta por três vãos (32,5 m, 20,0 m e 17,5 m, respectivamente) e dois balanços (7,5 m e 5,0 m, respectivamente). O sistema estrutural é constituído por perfis de aço tubular e uma laje de concreto, e é atualmente utilizada para travessia de pedestres. Esta investigação é realizada com base em resultados experimentais, relacionando a resposta dinâmica da passarela com as obtidas via modelos de elementos finitos. O modelo computacional proposto adota as técnicas de refinamento de malha, usualmente presente em simulações pelo método de elementos finitos. O modelo de elementos finitos foi desenvolvido e validado com resultados experimentais. Este modelo de passarela tubular permitiu uma avaliação dinâmica completa, investigando especialmente ao conforto humano e seus limites de utilização associados à vibração. A resposta dinâmica do sistema, em termos de acelerações de pico, foi obtida e comparada com os valores limites propostos por diversos autores e padrões de projeto. As acelerações de pico encontradas na presente análise indicou que a passarela tubular investigada apresentou problemas relacionados com o conforto humano. Por isso, foi detectado que este tipo de estrutura pode atingir níveis de vibrações excessivas que podem comprometer o conforto do usuário na passarela e especialmente a sua segurança. / The structural engineers experience and knowledge allied by the use newly developed materials and technologies have produced steel and composite (steel-concrete) footbridges with daring structures. This fact have generated very slender structural footbridges and consequently changed the serviceability and ultimate limit states associated to their design. A direct consequence of this design trend is a considerable increase of structural vibrations. Therefore, the present investigation was carried out based on a more realistic load model developed to incorporate the dynamic effects induced by people walking. The load model considered the ascent and descending movement of the human body effective mass at each step. The position of the dynamic load was also changed according to the individual position and the generated time function, having a space and time description. The effect of the human heel was also incorporated in the analysis. The investigated structural model was based on a tubular composite (steel-concrete) footbridge, spanning 82.5 m. The structure is composed by three spans (32.5 m, 17.5 m and 20.0 m, respectively) and two overhangs (7.5 m and 5.0 m, respectively). The structural system is constituted by tubular steel sections and a concrete slab and is currently used for pedestrian crossing. This investigation is carried out based on correlations between the experimental results related to the footbridge dynamic response and those obtained with finite element models. The proposed computational model adopted the usual mesh refinement techniques present in finite element method simulations. The finite element model has been developed and validated with the experimental results. This model enabled a complete dynamic evaluation of the investigated tubular footbridge especially in terms of human comfort and its associated vibration serviceability limit states. The system dynamic response, in terms of peak accelerations, was obtained and compared to the limiting values proposed by several authors and design standards. The peak accelerations found in the present analysis indicated that the investigated tubular footbridge presented problems related with human comfort. Hence it was detected that this type of structure can reach high vibration levels that can compromise the footbridge users comfort and especially its safety.