5th IFAC Symposium on Mechatronic Systems, Marriott Boston Cambridge, Cambridge, MA, USA, Sept 13-15, 2010

Le Sous-comité de la conception et de la construction navale de l'Organisation maritime internationale (OMI) a entrepris l'élaboration de critères de stabilité intacts de deuxième génération (SGISC). Le SGISC est une règle supplémentaire qui complète les règles actuelles.En outre, ces critères sont structurés en trois niveaux, à savoir le premier niveau, le deuxième niveau et l'évaluation directe. Les procédures d'évaluation directe pour chaque échec de stabilité sont développées avec la technologie de pointe la plus avancée disponible soit par analyse numérique, soit par travail expérimental pour une analyse quantitative. Dans cette thèse, on présente une implémentation des niveaux 1 et 2 du SGISC dans le solveur hydrostatique, une approche expérimentale pour le navire en détresse dans une tempête et des simulations RANS du même critère. En conclusion, il est possible de mettre en oeuvre les critères de stabilité du navire intact de deuxième génération dans le code de stabilité GHS ©, un code couramment utilisé par les industriels dans le domaine. Cinq navires ont été considérés pour vérifier cette mise en oeuvre. Une méthode expérimentale utilisant une grande soufflerie et une méthode de calcul CFD simplifiée ont été appliquées sur deux modèles. Dans les deux cas, les résultats montrent que l'angle de roulis maximal atteint par les deux navires étudiés est inférieur à celui donné par le calcul réglementaire. La méthode expérimentale est certainement plus proche de la réalité et le calcul CFD reste conservateur sans être aussi contraignant que la réglementation. En conclusion les méthodes expérimentale et numérique développées et utilisées dans ce travail de thèse peuvent être proposées pour l’évaluation directe du critère. / The Sub-Committee of Ship Design and Construction of International Maritime Organisation (IMO) has undertaken the development of Second Generation Intact Stability Criteria (SGISC). The GISC is an additional rule that complement present rules. Five failure modes will be address in SGISC are excessive roll in dead ship condition, pure loss of stability, broaching, parametric roll, and excessive acceleration. Moreover, these criteria are structured in three levels namely, first level, second level and direct assessment. Direct assessment procedures for every stability failure are developed with the most advanced state-of-the art technology available either by numerical analysis or experimental work for quantitative analysis. In this thesis, implementations of Level 1 and Level 2 of the SGISC in the hydrostatic solver, experimental approached for dead ship condition and RANS simulation are presented.In conclusion, it was possible to implement the stability criteria of the intact second-generation vessel in the GHS © code of stability, a code commonly used by industrialists in the field. Five vessels were considered to verify this implementation. An experimental wind tunnel method and a simplified CFD calculation method were used on two different models. In both cases, the results show that the maximum roll angle reached by the two vessels studied is lower than the one given by the regulatory calculation. The experimental method is certainly closer to reality and the calculation CFD remains conservative without being as binding as the regulation.Therefore, the two approaches, numerical and experimental can be proposed to be used for Direct Assessment of the criterion.

$aL’objectif de cette thèse est de comprendre le phénomène de suffusion (érosion interne) dans ses processus et ses conséquences sur le comportement mécanique des sols à faible cohésion par l’établissement d’une relation directe ou indirecte entre la stabilité interne de ces matériaux et leur critère de rupture. L’érosion interne vue essentiellement sous l’angle de la suffusion a été analysée par des modélisations numériques et des essais expérimentaux. Les principaux essais utilisés sont : - Ecoulements d’eau à travers un matériau granulaire dans une colonne. - Essais de cisaillement triaxial non drainés. Pour la modélisation numérique, PFC3D a été utilisé pour les simulations d’essais triaxiaux et la prise en charge du couplage fluide solide a été possible grâce à une option de type CFD (Coupling Fluid Dynamique). Ce code DEM a permis le développement d’une nouvelle méthode de génération d’échantillon granulaire à partir de sa courbe granulométrique et de sa porosité cibles. L’évolution des porosités, celle des courbes granulométriques et de l’état de stabilité interne avant et après écoulement ont été identifiées comme indicateur du niveau de suffusion. Les critères de stabilité de Kenney & Lau et de Kezdi ont permis d’apprécier la stabilité interne des échantillons. Les conséquences de la suffusion se sont manifestées par : Une diminution de l’angle de frottement interne dans le cas d’une suffusion interne; une augmentation de l’angle de frottement dans le cas d’une suffusion externe. Les comparaisons des résultats expérimentaux et numériques tant pour les écoulements que pour les essais triaxiaux ont présenté de bonnes concordances. Enfin, une proposition d’un nouveau critère de stabilité interne est établie, elle est déduite de l’analyse des relations entre le comportement mécanique et la stabilité interne, notamment la contractance du matériau. / The objective of this thesis is to understand the phenomenon of suffusion (internal erosion) in its process and its effects on the mechanical behavior of loose soil by establishing a direct or indirect relationship between the internal stability of these materials and failure criterion. Numerical modeling and experimental tests analyzed the internal erosion in terms of the suffusion. The main tests used are : - Water flows through a granular material in a column. - Undrained shear triaxial tests. For numerical modeling, PFC3D was used for simulations of triaxial tests and the treatment of solid fluid coupling was possible through a CFD type of option (Coupling Fluid Dynamics). This DEM code has allowed the development of a new method of generating granular sample from its grading curve and its target porosity. The evolutions of porosity, grading curves and the state of internal stability before and after discharge were identified as indicator of suffusion. Kenney & Lau and Kezdi stability criteria were used to assess the internal stability of samples. The consequences of suffusion were expressed by: A reduction of the internal friction angle in the case of an internal suffusion; an increase of the friction angle in the case of an external suffusion. Comparisons of experimental and numerical results for both flows and triaxial tests have shown good agreements. Finally, a proposal of a new criterion of internal stability is established, it is deducted from the analysis of the relationship between the mechanical behavior and internal stability, including the material contractance.

Continues field monitoring and searching sensor data remains an imminent element emphasizes the influence of the Internet of Things (IoT). Most of the existing systems are concede spatial coordinates or semantic keywords to retrieve the entail data, which are not comprehensive constraints because of sensor cohesion, unique localization haphazardness. To address this issue, we propose deep learning inspired sensor-rank consolidation (DLi-SRC) system that enables 3-set of algorithms. First, sensor cohesion algorithm based on Lyapunov approach to accelerate sensor stability. Second, sensor unique localization algorithm based on rank-inferior measurement index to avoid redundancy data and data loss. Third, a heuristic directive algorithm to improve entail data search efficiency, which returns appropriate ranked sensor results as per searching specifications. We examined thorough simulations to describe the DLi-SRC effectiveness. The outcomes reveal that our approach has significant performance gain, such as search efficiency, service quality, sensor existence rate enhancement by 91%, and sensor energy gain by 49% than benchmark standard approaches.

The aim of this thesis is to describe behavior of cracks in layered polymer materials. Quasi-brittle fracture (through the initiation and subsequent crack propagation mechanism) under low stresses is the most common mode of failure of polymer materials. In this case plastic deformations are localized in the vinicity of the crack tip and linear elastic fracture mechanics description of the crack behavior can be used. The knowledge of fracture parameters change during the crack propagation in multilayer body is a key point for establishing of the maximum load and consequently for the assessment of the residua lifetime. In contrast to homogeneous bodies the estimation of stress intensity factors for multilayer (composite) structure is numerically more elaborated and the fracture mechanics approach is complicated by the existence of interfaces between single layers, where material parameters are changed by a step. Special attention is paid to the configuration of a crack growing close to the material interface and along the interface. For the crack with tip on the material interface the effective values of stress intensity factor based on the crack stability criteria are estimated. It is shown that under special conditions (depending mainly on the elastic mismatch of materials) the existence of material interface has positive influence on the lifetime of the multilayered structure.

The main objective of this project is to investigate the applicability of the IMO second-generation intact stability criteria in enhancing the process of designing fishing vessels, which often face stability challenges due to their narrow hulls and harsh operating environments. The study involves analyzing the impact of these criteria, specifically focusing on dead ship conditions and Level 1 and Level 2 excessive acceleration criteria, on the design of three fishing vessels. Through thorough theoretical examination and practical assessment, the research seeks to provide naval architects with valuable insights into designing safer and more stable fishing vessels. The investigation also explores the potential benefits of incorporating bilge keels to mitigate lateral acceleration effects, aiming to enhance crew safety. Finally, a discussion of the computation results is held, followed by a conclusion. / Huvudsyftet med detta projekt är att undersöka tillämpbarheten av IMO:s andra generationens kriterier för intaktstabilitet för att förbättra processen med att designa fiskefartyg. Denna typ av fartyg har ofta flera stabilitetsutmaningar på grund av deras smala skrov och krävande driftsmiljöer. Studien innefattar att analysera effekterna av dessa kriterier, med särskild fokus på "dead ship" villkor samt nivå 1- och nivå 2-kriterierna för kraftiga acceleration, på designen av tre fiskefartyg. Genom teoretisk granskning och praktisk bedömning ämnar forskningen ge fartygskonstruktörer insikter för att designa säkrare och mer stabila fiskefartyg. Undersökningen utforskar också de potentiella fördelarna med att inkludera slingerkölar för att mildra effekterna av lateral acceleration och därmed öka besättningens säkerhet. Rapporten avslutas med en diskussion kring beräkningsresultaten, följt av en slutsats.

This thesis is devoted to the theory and phenomenology of neutrino physics. While the standard model of particle physics has been extremely successful, it fails to account for massive neutrinos, which are necessary to describe the observations of neutrino oscillations made by several different experiments. Thus, neutrino physics is a possible window for exploring the physics beyond the standard model, making it both interesting and important for our fundamental understanding of Nature. Throughout this thesis, we will discuss different aspects of neutrino physics, ranging from taking all three types of neutrinos into account in neutrino oscillation experiments to exploring the possibilities of neutrino mass models to produce a viable source of the baryon asymmetry of the Universe. The emphasis of the thesis is on neutrino oscillations which, given their implication of neutrino masses, is a phenomenon where other results that are not describable in the standard model could be found, such as new interactions between neutrinos and fermions. / QC 20100630

This paper deals with the consensus problem under communication network inducing delays. It is well-known that introducing a delay leads in general to a reduction of the performance or to instability due to the fact that timedelay systems are infinite dimensional. For instance, the set of initial conditions of a time-delay system is not a vector but a function taken in an interval. Therefore, investigating the effect of time-delays in the consensus problem is an important issue. In the present paper, we assume that each agent receives instantaneously its own state information but receives the state information from its neighbors after a constant delay. Two stability criteria are provided based on the frequency approach and on Lyapunov-Krasovskii techniques given in terms of LMI. An analytic expression of the consensus equilibrium which depends on the delay and on the initial conditions taken in an interval is derived. The efficiency of the method is tested for different network communication schemes. / <p>QC 20110120</p>

This Ph.D. thesis was written under the supervision of Assoc. Prof. Luboš Náhlík, Ph.D. and Assoc. Prof. Pavel Hutař, Ph.D. Thesis is focused mainly on application of generalized linear elastic fracture mechanics, which allows description of crack behaviour propagating from general singular stress concentrators, such as material interfaces or sharp V-notches, and verification of validity of used fracture criteria. The obtained results were used in the next part of the thesis, which deals with the issue of crack propagating in ceramic composites, where the stress distribution field is strongly influenced by the existence of material interface and presence of residual stresses, that arise during manufacturing process of composite.