The structural behaviour of pavement structures is known to be affected by the traffic-related loading and by the ambient factors to which the structure is subjected. A new mechanistic-empirical (M-E) pavement design method is under development in Sweden with the main purpose to adequately predict pavement structural response and performance. An M-E design method for a flexible pavement means application of the principles of engineering mechanics to evaluate the response of pavement structure to traffic loading and much improved design methods to carry out distress prediction or how performance changes with time. This would ensure a fundamental understanding of how the pavement structure responds to a certain action or loading conditions.  The mechanistic-empirical approach is more flexible as it is able to adapt to new situations such as new pavement materials and loading situations. It is important to take into account the real loading and climatic conditions and predict the resulting changes in material properties and structural behaviour at the time of loading as well as in the long-term. New models are therefore required for the further development of pavement design method, and it needs to be validated through reliable data obtained through realistic measurements. In this licentiate thesis, the effects of the environmental factors and loading by heavy vehicles in pavements are investigated. The results of the study are based on environmental data from multiple locations in Sweden and on measurements from two instrumented road sections located near the village of Långträsk in the northern part of Sweden. Both roads consist of thin flexible pavements, the behaviour of which is highly dependent on the variation of the temperature of the asphalt layer, the moisture content in the unbound granular layers, and frost depth conditions. The licentiate report consists of three scientific publications.  Paper 1 presents a country-specific case study in which the frost penetration depth in various Swedish roads is predicted by a statistically derived empirical model that uses the air freezing index calculated from the air temperature as an input. The model correlation is based on meteorological data from 44 meteorological stations and pavement cross-sectional temperature distribution data from 49 road weather information system (RWIS) stations over all five climatic zones throughout all of Sweden. Paper 2 focuses on the response of an instrumented test section subjected to loading by falling weight deflectometer (FWD) and heavy vehicles. The mechanical response instrumentation consisted of asphalt strain gauges (ASG), strain measuring units (εMU), and soil pressure cells (SPC) installed at different locations in the structure. The layer stiffness values were obtained via backcalculation based on the FWD surface deflections bowls. The recorded values of the mechanical response were compared against calculated values by multilayer elastic theory (MLET) based software. Three different heavy vehicles weighing from ~64 tons to ~74 tons were compared in terms of damage caused to the pavement structure. It was found that if the number of axles was increased and dual tyres were used, longer heavier vehicles were not more destructive to the pavement structure than shorter vehicles with fewer axles and higher axial load and tyre pressure. In paper 3, the effect of the seasonal variation of the environmental factors on the behaviour of an instrumented road test section was investigated. The same loading configuration described in paper 2 was used on four different measurement campaigns in different seasons over the span of 1 year. The environmental variables were monitored throughout the year by asphalt thermocouples, a frost rod, and time-domain reflectometer (TDR) probes. The mechanical response sensors and the environmental sensors were found to be a reliable data collection method throughout the entire year. By comparing the recorded response values to the MLET calculated values, it was shown that it is possible to model the mechanical behaviour of pavement structures using linear-elastic MLET if the temperature variations in the asphalt layer and the moisture variations in the granular layers are taken into account. / Utvecklingen av det strukturella tillståndet av vägbyggnader är beroende av trafikmängd samt vägkonstruktionens omgivningsfaktorer. En mekanistisk-empiriskdimensioneringsmetod för vägkonstruktioner är under utveckling i Sverige med huvudsyftet att på realistiskt sätt kunna förutsäga vägens respons och tillståndsutveckling. En M-E dimensionering betyder att man applicerar mekanistiska grundprinciper för att bestämma vägkonstruktionens respons under trafikbelastning och tillämpar sedan överföringsfunktioner för att förutsäga nedbrytningsförloppet. Att använda en mekanistiskt baserad metod innebär att man får en grundläggande förståelse av hur vägkonstruktionen svarar på en specifik påverkan eller belastning. Detta mera realistiska tillvägagångsätt ger dessutom ökad flexibilitet och gör att metoden kan appliceras vid nya belastningsfall eller under nya klimatförhållanden. Det blir därför möjligt att ta hänsyn till det riktiga belastningsfallet under de rätta klimatförhållandena. Detta gör att nyamodeller för vägkonstruktionens respons behövs och att dessa måste valideras för realistiska trafikbelastningsfall. I denna licentiatavhandling undersöks hur omgivningsvariabler och trafikbelastning från tunga lastbilar påverkar vägkonstruktioner. Resultat från denna studie bygger på omgivningsdata från ett stort antal mätstationer i Sverige och från mätningar från två instrumenterade vägsträckor nära byn Långträski Norrland. Båda vägkonstruktionerna består av tunna vägöverbyggnader och därför är responsen starkt beroende av beläggningstemperaturen och fuktinnehållet i vägbyggnadens obundna lager samt frostdjupet.Rapporten bygger på tre publikationer.Första artikeln presenterar hur frostdjup i svenska vägar kan förutsägas utifrån en statistisk modell som använder ett frostindex beräknat från lufttemperaturen. Modellen bygger på en anpassning av data från 44 meteorologiska väderstationer och 49 av Trafikverkets väderinformationsstationer distribuerade över alla fem klimatzoner i Sverige. Den andra artikeln fokuserar på responsmätningar från en instrumenterad vägtestplats där både fallvikt samt tunga lastbilar har använts för lastgenerering. Den vägtekniska instrumenteringen bestod av asfalttöjningsgivare (ASG), trycktöjningsgivare (MU), och jordtyckceller (SPC) installerade på olika djup. Styvhet av de olika lagren bakberäknades baserat på data från fallviktsmätningarna. De registrerade värdena från de vägtekniska givarna jämfördes med desom beräknades med hjälp av beräkningsverktyget ERAPave. Tre lastbilar med den totala tyngden mellan ~64 –~74 ton användes sedan för att jämföra deras relativa nedbrytningseffekt. Slutsatsen är att om antal axlar ökas med ökad tyngdoch om parmonterade däck användes är nedbrytningseffekten från 74 ton lastbil inte större än från en lättare lastbil med färre axlar. I artikel tre fokuseras det på effekten av hur klimatfaktorer påverkar vägkonstruktionens respons. Samma lastbilar som iden andra artikeln användes under fyra mätkampanjer vid olika tidpunkter på året. Omgivningsparametrarna registrerades i form av beläggningstemperatur och fukt i de obundna lagren samt frostdjupet. Vägens mekaniska respons beräknades genom att uppdatera styvhetsmodulerna utifrån beläggningens temperatur och de obundna lagrens med fuktkvoter och jämföra med de uppmätta responsvärdena. Beräkningsmetodiken visar sig ge bra överensstämmelse med det om uppmättes. / <p>QC 210303</p>

No description available.

Modulare Prozessanlagen bestehen aus einfach austauschbaren Prozess- und Funktionseinheiten, deren Konfiguration (Aufbau) und Rekonfiguration (Umbau) neue Möglichkeiten der flexiblen Prozessrealisierung eröffnen. Die Wandelbarkeit der Anlagen stellt aus Perspektive der funktionalen Sicherheit eine Herausforderung dar, da bestehende Methoden und Vorgehensweisen auf den verhältnismäßig statischen Betrieb von konventionellen Anlagen optimiert sind. Um den Zielkonflikt zwischen Flexibilität und Sicherheit abzumildern wurde ein Konzept zur Orchestrierung von verteilten Sicherheitssystemen entwickelt und in einer Demonstrationsanlage erfolgreich erprobt. Der Konzeptentwurf integriert sowohl technische als auch menschliche Anforderungen, mit dem Ziel, Operateure durch eine geschickte Systemgestaltung zur Beherrschung der Re-Konfiguration zu befähigen. / Modular process plants consist of easily exchangeable process and functional units whose configuration (assembly) and reconfiguration (modification) open up new possibilities for flexible process implementation. The changeability of the plants poses a challenge from the perspective of functional safety, since existing methods and procedures are optimized for the relatively static operation of conventional plants. To mitigate the trade-off between flexibility and safety, a concept for orchestrating distributed safety systems was developed and successfully tested in a demonstration plant. The concept design integrates both technical and human requirements, with the goal of enabling operators to master reconfiguration through smart system design.

At present, structural health monitoring efforts focus primarily on the sensors and sensing systems for detecting instances and locations of damage through techniques such as X-ray, micro CT, acoustic emission, infrared thermography, lamb wave etc., which only detect cracks at relatively large length scales and rely heavily on sensors and sensing systems which are external to the material system. As an alternative to conventional commercially available SHM techniques, the current work explores processing-structure-property relationships starting from carbon nanotube (CNT) based nanocomposites to particulate composites with nanocomposite binder/matrix materials, i.e. hybrid particulate composites to investigate deformation and damage sensing capabilities of inherently sensing materials and structures through their piezoresistive (coupled electro-mechanical) response. Initial efforts focused on controlling the dispersion of CNTs and orientation of CNT filaments within nanocomposites under dielectrophoresis to guide design and fabrication process of nanocomposites by tuning CNT concentration, applied AC electric field intensity, frequency and exposure time. It is observed that a combination of exposure time to AC electric field and the AC field frequency are the key drivers of filament width and spacing and that the network for filament formation is much more efficient for pristine CNTs than for acid treated functionalized CNTs. With the knowledge obtained from controlling the morphological features, AC field-induced long range alignment of CNTs within bulk nanocomposites was scaled up to form structural test coupons. The morphology, electrical and mechanical properties of the coupons were investigated. The anisotropic piezoresistive response both for parallel and transverse to CNT alignment direction within bulk composite coupons under various loading conditions was obtained. It is observed that control of the CNT network allows for the establishment of percolation paths and piezoresistive response well below the nominal percolation threshold observed for random, so called well-dispersed CNT network distributions. The potential for use of such bulk nanocomposites in SHM applications to detect strain and microdamage accumulation is further demonstrated, underscoring the importance of microscale CNT distribution/orientation and network formation/disruption in governing the piezoresistive sensitivities. Finally, what may be the first experimental study in the literature is conducted for real-time embedded microscale strain and damage sensing in energetic materials by distributing the CNT sensing network throughout the binder phase of inert and mock energetic composites through piezoresistive response for SHM in energetic materials. The incorporation of CNTs into inert and mock energetic composites revealed promising self-diagnostic functionalities for in situ real-time SHM applications under quasi-static and low velocity impact loading for solid rocket propellants, detonators and munitions to reduce the stochastic nature of safety characterization and help in designing insult tolerant energetic materials. / Ph. D. / At present, structural health monitoring (SHM) efforts focus primarily on the sensors and sensing systems for detecting instances and locations of damage, which only detect cracks at relatively large length scales and rely heavily on sensors and sensing systems which are external to the material system. As an alternative to conventional commercially available SHM techniques, the current work explores the incorporation of carbon nanotubes (CNTs) into nanocomposites and particulate composites to investigate deformation and damage sensing capabilities of inherently sensing materials and structures through their coupled electromechanical response. Initial efforts focused on controlling the dispersion of CNTs and orientation of CNT filaments within nanocomposites to guide design and fabrication process of nanocomposites. With the knowledge obtained from controlling the morphological features, long range alignment of CNTs within bulk nanocomposites was scaled up to form structural test coupons. The potential for use of such bulk nanocomposites in SHM applications to detect strain and microdamage accumulation is further demonstrated. Finally, what may be the first experimental study in the literature is conducted for real-time embedded deformation and damage sensing in inert and mock energetic composites to reduce the stochastic nature of safety characterization and help in designing insult tolerant solid rocket propellants, detonators and munitions.

Non-destructive testing (NDT) of glass-fibre reinforced polyester (GRP) composite materials has been becoming increasingly important due to their wide applications in engineering components and structures. Electronic Speckle Pattern Interferometry (ESPI) has promising potential in this context because it is a non-contact, whole-field and real-time measurement system. This potential has never been fully exploited and there is only limited knowledge and understanding available in this area. This reality constrains the wide popularity and acceptance of ESPI as a novel NDT technique. Therefore it is of considerable importance to develop an understanding of the capability of ESPI with respect to damage evaluation in GRP composite materials. The research described in this thesis is concerned with an investigation into the applicability of ESPI in the NDT of GRP composite materials. Firstly, a study was carried out to determine excitation techniques in terms of practicality and effectiveness in the ESPI system. Three categories of defects were artificially introduced in GRP composite materials, namely holes, cracks and delaminations each with different geometrical features. ESPI was then employed to evaluate the three kinds of defects individually. It has been found that cracks and holes on back surfaces can be defined when the technique is used in conjunction with thermal excitation. Internal Temperature Differential (ITD) induced fringe patterns were more efficient than External Thermal Source (ETS) induced fringe patterns with regard to detecting the presence of holes and cracks. In the case of delamination, ESPI was found to be capable of detecting the damage when used in combination with mechanical excitation originating from a force transducer hammer. The geometrical features and magnitudes of delaminations were also established as being quantifiable. The validation of ESPI as an NDT technique was carried out in an attempt to establish a better understanding of its suitability and have more confidence in its applications. Four damaged specimens were Subjected to ESPI examination in conjunction with visual inspection, ultrasonic C-scan and sectioning techniques. The geometrical features and magnitudes of damage evaluated using ESPI showed a good correlation with those evaluated by conventional techniques. Poor visibility and readability is an inherent problem associated with ESP! due to an overlapping between the noise and signal frequencies. An improvement of image quality is expected in an attempt to achieve a wide acceptance of ESPI as a novel NDT technique. It has also been demonstrated that this problem can be tackled using optical phase stepping techniques in which optical phase data can be extracted from the intensity fringes. A three-frame optical phase stepping technique was employed to produce the "wrapped" and "unwrapped" phase maps which are capable of indicating internal damage with high visibility and clarity. Finally ESPI was practically employed to evaluate damage in GRP composites introduced by quasi-static and dynamic mechanical loading. It was found that ESP! was capable of monitoring the progressive damage development of specimens subjected to incremental flexural loading. The initial elastic response, damage initiation, propagation and ultimate failure of specimens were clearly characterised by the abnormal fringe pattern variations. In a similar manner, ESPI was employed to evaluate the low velocity falling weight impact induced damage. A correlation was established between the magnitude of damage and the impact event parameters as well as the residual flexural properties.

Qu’ils soient voyageurs occasionnels ou réguliers, les piétons se déplaçant en environnement urbain et en transport en commun ont à faire face à la complexité du réseau de transport des grandes villes. Les aides au déplacement sont nombreuses et variées. Elles peuvent être fixes (par exemple, panneaux de signalisation) ou mobiles (par exemple, applications sur smartphone). Ces aides utilisent principalement la modalité sensorielle visuelle, déjà fortement sollicitée lors d’un déplacement urbain. Une alternative intéressante serait d’utiliser l’haptique (sens du toucher). En effet, cette modalité permet de transmettre au porteur d’un dispositif haptique des informations de déplacement et de navigation, en attirant discrètement son attention par des messages délivrés tactilement.S’inscrivant dans une démarche d’ergonomie prospective, cette thèse vise à étudier l’apport de la modalité haptique comme soutien à l’activité de déplacement piéton urbain. L’objectif appliqué est la conception d’un dispositif haptique d’aide au déplacement innovant, efficace et accepté par les utilisateurs futurs. Ce projet de conception s’est déroulé dans le cadre du projet ANR Tictact, mené par le CEA-LIST de 2011 à 2014. L’utilisation de la modalité haptique étant posée comme un parti pris initial, l’objectif du projet était de déterminer la forme que devrait prendre l’assistance aux usagers et la technologie de l’outil d’aide.Pour répondre à ce défi, nous avons mis en œuvre trois études successives. La première visait à comprendre les activités cognitives élémentaires mobilisées pour consulter les supports d’informations nécessaires à la navigation piétonne. Pour cela, nous avons analysé le comportement d’un piéton effectuant un trajet urbain (en métro et à pied). Les résultats nous ont permis de spécifier les fonctions d’aide que devrait remplir un futur dispositif d’aide au déplacement. Complétées par une revue de la littérature sur les interfaces haptiques et leur utilisation pour l’aide au déplacement, ces résultats nous ont conduits à déterminer les fonctions éligibles à la modalité haptique. La seconde étude visait à concevoir l’interaction haptique avec le dispositif d’aide, en deux étapes : élaborer le concept d’interface et concevoir le langage d’interaction. Une démarche de conception participative a été mise en œuvre, étayée par l’utilisation d’un prototype et de méthodes créatives. Cette démarche a abouti à : (i) identifier un message informationnel approprié à chaque fonction de déplacement ; (ii) traduire ce message (par analogie) en métaphore ; (iii) transformer chaque métaphore en motifs vibratoires délivrés par un bracelet haptique. La troisième étude visait à évaluer le dispositif haptique (bracelet couplé à un Smartphone) en environnement réel. Une analyse d’activité de déplacement urbain a été menée, comparant un groupe disposant de notre prototype haptique d’aide à un groupe sans prototype. Les résultats confirment la potentialité de la modalité haptique pour améliorer les performances de déplacement et notamment une allure de déplacement plus fluide et une diminution du temps de consultation d’un support d’information. Notre étude ouvre des perspectives pour l’utilisation de la modalité haptique dans diverses interfaces mobiles (par exemple une smartwatch). / Whether they are occasional or regular travellers, the pedestrians travelling in an urban environment and using public transportation have to face the complexity of the transportation network of large cities. The travelling aids are numerous and varied. They can be stationary or mobile (for example, applications on smartphones). These aids rely mainly on the visual sensory modality, already heavily requested during urban travel. An interesting alternative would be to use haptics (sense of touch). Indeed, this modality enables to convey travel and navigational information to the owner of a haptic device, by drawing discreetly his attention with tactile messages. Joining an approach of prospective ergonomics, this thesis aims to study the contribution of the haptic modality as a support for the activity of urban pedestrian travel. The applied objective is the design of a haptic device as an innovative travel aid, effective and accepted by the future users. This design project took place within the framework of the ANR project Tictact, led by the CEA-LIST from 2011 till 2014. The use of the haptic modality being put as an initial bias, the objective of the project was to determine the form that the assistance and the technology of the travel aid should take.To tackle this challenge, we conducted three successive studies. The first one, aimed at understanding the elementary cognitive activities mobilized when consulting information necessary to the pedestrian navigation. For that purpose, we analysed the behaviour of a pedestrian undertaking an urban travel (in the subway and on foot). The results allowed us to specify the functions that a future device assisting in the travel should include. Completed by a review of the literature on haptic interfaces and their use for assisting travel, these results led us to determine the eligible functions of the haptic modality.The second study aimed at designing the haptic interaction with the haptic interface, in two stages: first develop the concept of the interface and second design the interaction language. An approach of participative design was implemented, supported by the use of a device prototype and creative methods. This approach succeeded in: i) identifying an informative message suitable for each function of the travel; ii) translating this message (using an analogy) into a metaphor; and iii) transforming every metaphor into vibrotactile patterns delivered by a haptic wristband.The third study aimed at evaluating the haptic device (a wristband coupled with a Smartphone) in a real environment. An analysis of the activity of urban travel was conducted, comparing a group having a prototype of our haptic assistant to a group without such prototype. The results confirm the potentiality of the haptic modality to improve the travel performance in particular to enable a more fluid speed of travel and a decrease in the consultation time of an information medium. Our study opens up perspectives for the use of the haptic modality in diverse mobile interfaces (for example a smartwatch).

Após o aumento de potência do reator IEA-R1 de 2 MW para 5 MW observou-se um aumento da taxa de corrosão nas placas laterais de alguns elementos combustíveis e algumas dúvidas surgiram com relação ao valor de vazão utilizada nas análises termo-hidráulicas. A fim de esclarecer e medir a distribuição de vazão real pelos elementos combustíveis que compõe o núcleo do reator IEA-R1, um elemento combustível protótipo, sem material nuclear, chamado DMPV-01 (Dispositivo para Medida de Pressão e Vazão), em escala real, foi projetado e construído em alumínio. A vazão no canal entre dois elementos combustíveis é muito difícil de estimar ou ser medida. Esta vazão é muito importante no processo de resfriamento das placas laterais. Este trabalho apresenta a concepção e construção de um elemento combustível instrumentado para medir a temperatura real nestas placas laterais para melhor avaliar as condições de resfriamento do combustível. Quatorze termopares foram instalados neste elemento combustível instrumentado. Quatro termopares em cada canal lateral e quatro no canal central, além de um termopar no bocal de entrada e outro no bocal de saída do elemento. Existem três termopares para medida de temperatura do revestimento e um para a temperatura do fluido em cada canal. Três séries de experimentos, para três configurações distintas, foram realizadas com o elemento combustível instrumentado. Em dois experimentos uma caixa de alumínio foi instalada ao redor do núcleo para reduzir o escoamento transverso entre os elementos combustíveis e medir o impacto na temperatura das placas externas. Dada a tamanha quantidade de informações obtidas e sua utilidade no projeto, melhoria e capacitação na construção, montagem e fabricação de elementos combustíveis instrumentados, este projeto constitui um importante marco no estudo de núcleos de reatores de pesquisa. As soluções propostas podem ser amplamente utilizadas para outros reatores de pesquisa. / After the IEA-R1 upgrade from 2 MW to 5 MW it was observed that the corrosion rate increased in a lateral plate of one fuel element and some issues appeared concerning the flow values used in the thermal-hydraulic analysis. In order to clear it up and measure the actual flow distribution among the fuel elements composing the IEA-R1 active core, a dummy element without nuclear fuel material, called DMPV-01 (Pressure and Flow Measurement Device), full scale, was designed and manufactured in aluminum. The flow rate in the channel between two fuel assemblies is very difficult to estimate or measure. This flow rate is very important to the cooling process of the external plates. This work presents the design and construction of an instrumented fuel assembly in order to measure the actual temperature in these lateral plates. Fourteen thermocouples were installed in this instrumented fuel assembly. Four in each lateral channel, one in the inlet nozzle and one in the outlet nozzle. There are three thermocouples in each channel to measure the clad temperature and one thermocouple to measure the fluid temperature. Three series of experiments, for three different core configuration were carried out with the instrumented fuel assembly. In two experiments a box was installed around the core to reduce the cross flow between the fuel assembly and measure the impact in the temperatures of external plates. Given the amount of information generated and its utility in the design, improvement and qualification in construction, assembly and manufacturing of instrumented fuel, this project turned out to be an important landmark on the thermal-hydraulic study of research reactor cores. The proposed solutions could be useful for other research reactors.

L'introduction de systèmes instrumentés dédiés aux applications de sécurité impose l'évaluation de leur sûreté de fonctionnement. On utilise généralement pour cela les bases de données de fiabilité génériques. Cependant, le retour d'expérience pour ces systèmes qui présentent en général des défaillances rares est insuffisant pour valider les résultats obtenus. En outre, la collecte de données de fiabilité et leur extrapolation à d'autres composants introduisent des incertitudes. Les travaux de cette thèse portent sur la problématique de la prise en compte des incertitudes relatives aux données de fiabilité des composants pour l'évaluation de la sûreté de fonctionnement des systèmes par le formalisme des sous ensembles flous. La méthodologie proposée est appliquée à l'évaluation des probabilités de défaillance des Systèmes Instrumentés de Sécurité (SIS) en présence de données de fiabilité imprécises. Nous introduisons deux nouveaux facteurs d'importance pour aider le concepteur. En outre, nous proposons une méthodologie d'aide à la conception des SIS basée sur la modélisation par réseaux de fiabilité et l'optimisation par des algorithmes génétiques de la structure des SIS pour le respect des niveaux d'intégrité de sécurité (SIL) exigés / The use of safety related systems imposes to evaluate their dependability. Laboratory data and generic data are often used to provide failure data of safety components to evaluate their dependability parameters. However, due to the lower solicitation of safety systems in plant, safety components have not been operating long enough to provide statistical valid failure data. Furthermore, measuring and collecting failure data have uncertainty associated with them, and borrowing data from laboratory and generic data sources involve uncertainty as well. Our contribution is to propose a fuzzy approach to evaluate dependability parameters of safety systems when there is an uncertainty about dependability parameters of systems components. This approach is applied to determine the failure probability on demand of Safety Instrumented Systems (SIS) in presence of uncertainty. Furthermore, we present an optimal design of SIS by using reliability graphs and genetic algorithms to identify the choice of components and design configuration in a SIS to meet the required SIL

L’incorporation des instruments intelligents dans les boucles de sécurité nous mène vers une sécurité intelligente et les systèmes deviennent des « systèmes instrumentés de sécurité à intelligence distribuée (SISID) ». La justification de l’usage de ces instruments dans les applications de sécurité n’est pas complètement avérée. L’évaluation de la sûreté de fonctionnement de ce type de systèmes n’est pas triviale. Dans ce travail, la modélisation et l'évaluation des performances relatives à la sûreté de fonctionnement des systèmes instrumentés de sécurité (SIS) sont traitées pour des structures intégrant de l’intelligence dans les instruments de terrain. La méthodologie que nous utilisons consiste en la modélisation de l’aspect fonctionnel et dysfonctionnel de ces systèmes en adoptant le formalisme basé sur les réseaux de Petri stochastiques qui assurent la représentation du comportement dynamique de ce type de systèmes. La modélisation est traitée sous la forme d’une approche stochastique utilisant les réseaux d’activité stochastiques SAN (Stochastic Activity Network). L’introduction d’indicateurs de performances permet de mettre en évidence l’effet de l’intégration des niveaux d’intelligence dans les applications de sécurité. La méthode de Monte Carlo est utilisée pour évaluer les paramètres de sûreté de fonctionnement des SIS en conformité avec les normes de sécurité relatives aux systèmes instrumentés de sécurité (CEI 61508 et CEI 61511). Nous avons proposé une méthode et les outils associés pour approcher cette évaluation par simulation et ainsi apporter une aide à la conception des systèmes instrumentés de sécurité (SIS) intégrant quelques fonctionnalités des instruments intelligents / The incorporation of intelligent instruments in safety loops leads towards the concept of intelligent safety and the systems become “Intelligent Distributed Safety Instrumented Systems (IDSIS)”. The justification for using these instruments in safety applications is not fully proven and the dependability evaluation of such systems is a difficult task. Achieved work in this thesis deals with modelling and thus the performance evaluation relating to the dependability for structures which have intelligence in the instruments constituting the Safety Instrumented Systems (SIS). In the modelling of the system, the functional and dysfunctional aspects coexist and the dynamic approach using the Stochastic Activity Network (SAN) is proposed to overcome the difficulties mentioned above. The introduction of performance indicators highlight the effect of the integration of intelligence levels in safety applications. Monte-Carlo method is used to assess the dependability parameters in compliance with safety standards related to SIS (IEC 61508 & IEC 61511). We have proposed a method and associated tools to approach this evaluation by simulation and thus provide assistance in designing Safety Instrumented Systems (SIS) integrating some features of intelligent tools

O presente trabalho visou determinar a tenacidade à fratura dinâmica, KID, primeiramente pelos conceitos da Mecânica da Fratura Elástica Linear (MFEL) e posteriormente pela Mecânica da Fratura Elasto-Plástica (MFEP), JID, em materiais que em operação podem estar sujeitos a impactos em diferentes temperaturas. Os materiais estudados, de uso na indústria aeronáutica, foram uma liga de titânio Ti6Al4V (norma SAE AMS 4911), na condição recozida e uma liga de aço inoxidável PH 15-5 (norma SAE AMS 5659), na condição H1000. Os corpos de prova pré-trincados e entalhados foram retirados nas orientações L-T e L-S, a fim de que fossem determinadas e comparadas a relação tenacidade/densidade ou tenacidade específica dos materiais estudados. Em seguida os corpos de prova foram ensaiados sob condições de carga dinâmica em uma máquina de ensaio Charpy instrumentado, marca Instron-Wolpert PW30, conforme a norma ASTM-E23, com velocidade de carregamento de 5,52 m/s e nas temperaturas de 23 e 400ºC. Os valores das tenacidades, posteriormente comparados e correlacionados, foram obtidos de acordo com as expressões matemáticas mencionadas na literatura. A razão entre as energias estimadas de iniciação (Ei) e de propagação (Ep), (Ei/Ep), foi obtida a partir dos gráficos de carga-deslocamento x tempo. A determinação e caracterização dos aspectos macro e microscópicos da fratura foram realizadas através de microscopia ótica e de varredura. Em seguida, confrontaram-se os valores e os aspectos preponderantes dos mecanismos de fratura apresentados por cada material. / The present work aimed to evaluate the dynamic fracture toughness, KID, firstly using the Linear Elastic Fracture Mechanics parameter, (LEFM), and secondly using the Elasto-Plastic Fracture Mechanics (EPFM), JID. The materials used in this work are from aeronautic grade and are subjected to in service impact loads and temperature variation. The materials are a titanium alloy Ti6Al4V (standard SAE AMS 4911), in the annealed condition and a PH 15-5 stainless steel (standard SAE AMS 5659), H1000 condition. Both precracked and notched specimens were taken in the L-T and L-S directions, for the evaluation and comparison of the toughness/density ratio, i. e., the specific dynamic fracture toughness of the materials studied. Therefore, the specimens were tested under dynamic load using an Instron-Wolpert PW30 Instrumented Charpy Equipment, following the ASTM-E23 standard, with load speed of 5,52 m/s at 23 and 400ºC. The fracture toughness values were compared using mathematical expression from literature. The ration between the initiation (Ei) and propagation (Ep) energies, (Ei/Ep), was obtained from the load-displacement x time. The characterization of the macro and microscopic aspects of the fracture mechanisms were carried out using optical microscope and scan electronic microscope. The fracture toughness values and the fractographic observations were correlated and compared for the two materials studied.