Ce travail de thèse porte sur les mécanismes d’amorçage en détonation par choc des explosifs solides de type coulé-fondu. Les explosifs solides sont des matériaux hétérogènes constitués de grains de matière énergétique dans un liant pouvant être lui-même énergétique. Si l’existence des points chauds, sites préférentiels d’initiation des réactions chimiques à l’échelle locale, est largement reconnue, la topologie de la croissance des réactions, et l’influence de la microstructure sur cette dernière n’est que peu étudiée dans les explosifs coulés-fondus. Deux familles d’explosifs ont été retenues pour cette étude : les hexolites, mélanges de grains d’hexogène (RDX) et d’un liant trinitrotoluène (TNT) et les ontalites, composées d’oxynitrotriazole (ONTA) et de TNT. Les recherches se sont orientées autour du triptyque : caractérisation – expérimentations – modélisation.Un important travail de compilation et de ré-exploitation de données issues de la littérature, associé à une modélisation des équations d’état des explosifs purs, ont permis de définir des lois permettant de calculer le comportement de ces derniers sous choc. Ces lois ont ensuite été validées par une méthode de mélange sur différentes compositions coulées-fondues et composites. Parallèlement, la microstructure des compositions d’étude a également été caractérisée via des mesures de granulométrie et de microtomographie, inédites sur ce type d’explosif.Des expérimentations d’impact plan soutenu ont été réalisées afin d’établir les diagrammes de marche des ondes de choc réactives, permettant de relier la profondeur de transition à la détonation à la pression de sollicitation. Elles ont permis de mettre en lumière l’influence de la microstructure sur la sensibilité au choc de deux hexolites et d’acquérir des données sur deux ontalites. L’utilisation de deux métrologies innovantes, la radio-interférométrie à 94 GHz et les fibres optiques à réseau de Bragg, a permis de mesurer la transition choc – détonation (TCD) de façon continue avec une résolution inédite. Enfin des essais d’impact plan non soutenu ont été réalisés à des fins de validation.Un modèle de TCD est proposé. Ce dernier, basé sur une approche de germination-croissance des fronts de déflagration à l’échelle locale, permet de prendre en compte la microstructure des explosifs. Ces travaux semblent mettre en évidence l’influence de la fracturation des grains d’explosif sous choc, qu’il conviendra d’étudier dans le futur. Enfin, une étape de terminaison des réactions lors de la TCD, associée à des calculs thermocinétiques détaillés, a été étudiée. / This study deals with the detonation initiation by shock of condensed melt-cast high explosives. Solid explosives are heterogeneous materials, made of energetic material grains in a binder, which can be energetic itself. If the existence of hot-spots, preferred initiation sites for chemical reaction at the local scale, is widely recognized, the reaction growth topology, and the microstructure influence, are poorly known for melt-cast explosives. We study here two melt-cast explosive families: hexolites, a mix of hexogen (RDX) grains and trinitrotoluene (TNT) binder, and ontalites made of nitrotriazolone (NTO) and TNT. This study has been focused on the triptyque: characterization - experimentations - modeling.An important work of compilation and re-exploitation of literature data, combined with pure explosives’ equation of state modeling, allowed us to define laws to calculate the explosives’ comportment under a shock solicitation. These ones have been validated, thanks to a mixing method, on different melt-cast and cast-curd plastic bonded explosives. At the same time, the compositions’ microstructure has been also characterized via granulometry measurements and microtomographies, never published for this type of explosive.Plate impact tests have been performed in order to establish the reactive shock trajectory of these compositions, allowing us to determine the relation between the run-distance of detonation and the input pressure. It brought the microstructure influence on hexolite shock sensitivity to light, and gave us some first results for ontalites. The use of continuous and innovative measurements, as microwave interferometry and chirped fiber Bragg gratings, allowed us to study the shock to detonation transition (SDT) with a resolution never seen before. Finally, non-sustained plate impact test have been performed for a validation purpose.A SDT model is proposed. Based on a germination-growth approach of deflagration fronts at the local scale, it takes into account the explosive’s microstructure. This work seems to show the grain fragmentation under shock influence, point we will have to study in the future. Finally, a completion step of reactions, associated with chemical kinetics calculations, has been studied.

The purpose of this project is to explore the FBG (Fiber Bragg Grating) technology and create a force sensor. The result can be used as a basis for further projects.The project starts with force and strain measurements. The project then evolves to incorporate multiple FBG sensors. An uncommon method of writing the FBG withcoating is tested, which results in a FBG with most of the coating left.The result is a multi-FBG sensor. And even though the individual FBG is not linear the sum shows fantastic linearity with R-square of 0.99999. The change in wavelength is 1328pm/N. A common issue in the strain measurement is discussed and proof is provided. This shows that the reference value of the FBG is 1.12pm/μstrain instead of 1.21pm/μstrain. This is important if the FBG is mounted in a structure, because then the material proprieties will be dominating. Another result is that the peaks of Fabry Perot grating pair are linear but with different coecients.

L’objectif principal de cette thèse était d’examiner dans quelle mesure il est possible d’étendre l’approche de la courbe maîtresse à des composants complexes afin de déterminer des conditions de déverminage et de réaliser une prédiction de durée de vie en fonction de ces conditions de déverminage. Nous avons considéré la stabilité d’un réseau dit élémentaire (réseau carré, à pas constant et droit) puis le problème de la stabilité (selon des critères spécifiques) des composants complexes: les CDC et les monofiltres GFF. Cette thèse a permis de décrire de façon rigoureuse, puis d'utiliser le cadre de travail VAREPA pour résoudre des problèmes issus de l'industrie de télécoms. A cet effet, des séries d’études de vieillissement accéléré sur des réseaux simples et complexes ont été menées. Un protocole de mesure permettant de déterminer les incertitudes de mesure a été mis au point afin de déterminer de façon fiable des intervalles de confiance sur les prédictions de durée de vie.Nous avons étudié les cinétiques de croissance des réseaux inscrits dans une fibre dédiée à l’inscription des CDC (Coreactive). Cette étude nous a permis de montrer que la réaction prédominante à l’origine des changements d’indice de réfraction est activée par une absorption à 1 photon. D’autre part, nous avons étendu le cadre de travail utilisé pour prédire l’effacement des réseaux (VAREPA) afin de rendre compte de leurs cinétiques d’inscription. Puis nous avons cherché à déterminer les conditions de passivation et à prédire la durée de vie des réseaux déverminés en présence d’hydrogène résiduelle (procédé industriel actuel). Pour cela, nous avons établi la courbe maîtresse de réseaux photoinscrits non déverminés puis nous avons validé les conditions de déverminage et les prédictions de durée de vie en construisant une nouvelle courbe maîtresse sur des réseaux déverminés.Nous avons étudié la stabilité thermique des réseaux inscrits dans une fibre hydrogénée dédiée aux futurs monofiltres GFF dans des conditions d’inscription similaires à celles de ces composants. Nous avons utilisé les courbes maîtresses établies à partir des réseaux élémentaires (mais apodisés) simplement dégazés « à froid » (ici 2jours à 50°C puis 2 jours à 110°C). Puis, nous avons fait vieillir le profil d’indice (cœur et gaine) d’un monofiltre GFF. Puis, nous avons recalculé la réponse spectrale de ce filtre vieilli (e.g. 30jours à 200°C) et nous l’avons comparé à des mesures expérimentales. Cette approche reste générale et permet de changer les conditions de déverminage au besoin. Cette étude nous a permis de mettre en évidence que la stabilité des variations d’indice photo-induites dans le cœur dépend peu de l’amplitude initiale de la modulation pour des valeurs comprises entre quelques 10-5 et 10-3. Du fait de la présence d’une gaine optique fortement photosensible (car fortement dopée en Ge), nous avons établi les courbes maîtresses des variations d’indice photo-inscrites dans le cœur et la gaine optique pour des valeurs allant jusque 10-3 dans le cœur et 3.10-3 dans la gaine. Nous avons ainsi obtenu des courbes maîtresses présentant le même k0 (fréquence d'essai, i.e facteur pré exponentiel) mais dont la forme est légèrement différente. La stabilité des variations d’indice est meilleure dans le cœur (moins dopé en Ge) que dans la gaine photosensible. Dans un second temps, nous avons cherché à déterminer les conditions de passivation et à prédire la durée de vie des réseaux déverminés à partir des réseaux de Bragg qualifiés d’élémentaires. Pour la première fois à notre connaissance, nous avons validé de façon fiable les conditions de passivation et les prédictions de durée de vie en construisant une nouvelle courbe maîtresse sur des monofiltres GFF préalablement déverminés. Conformément à la théorie, cette courbe maîtresse présente le même k0 et une forme similaire à celle établie au moyen de réseaux non déverminés, ce qui valide la fiabilité de nos prédictions. / The main objective of this thesis was to investigate how it is possible to extend the master curveapproach to complex components, in order to calculate annealing conditions and giving a life timeprediction according those annealing conditions. We studied the stability of a simple Bragg grating (noapodisation, constant pitch, no tilt). Then, we have been able to study the problem of the stability(according to specific criteria) of complex components: CDC and GFF monofilters. This thesis allowed toshow precisely what is the VAREPA framework and how to apply it to optical telecommunicationsproblems. To give an answer to the question of the possibility of extending the master curve approach tocomplex components, series of accelerate aging studies have been carried out. For this purpose, ameasurement protocol including the determination of the measurement uncertainty was developed. Thisprotocol allow, to determine confidence intervals on the life time prediction.We studied the kinetics of photo induced index growth in the optical fiber dedicated forfabrication of CDC (Coreactive). This study allowed us to demonstrate that the predominant reaction atthe origin of changes in refractive index is activated by a one photon absorption. On the other hand wehave extended the VEREPA framework used to predict the Bragg gratings erasure to take into account thegrowing kinetics. In a second step we tried to calculate annealing conditions in the presence of residualmolecular hydrogen and associated Bragg grating life time prediction. For that purpose we established themaster curve of photo-induced Bragg gratings without annealing, then we validated the annealingconditions and lifetime predictions by building a new master curve from aging of annealed Bragg gratings(in presence of residual hydrogen).We studied the thermal stability of hydrogenated fiber Bragg gratings dedicated to futuremonofiltres GFF in similar conditions to those components. We used master curves from basic Bragggratings (ie no apodisation, constant pitch, no tilt) simply out-gazed at "cold" temperature (here 2 days at50 ° C and 2 days at 110 ° C). Then the aging of the index profile of a GFF monofilter have beensimulated (index profile of the core and of the cladding, each of them having a different master curve).For that purpose the profile have been separated into 35 "basic" filters. Then the spectral response of thisaged monofilter (e.g. 30 days at 200°C) have been calculated and compared with experimentalmeasurements. The advantage of this approach is that it is general and allow to change the annealingconditions if needed. Firstly, this study allowed to highlight that the stability of photo-induced indexchanges in the core depend little on the initial amplitude modulation for values between several 10-5 and10-3. Secondly, due to the presence of a highly sensitive optical cladding (and therefore highly Ge doped),Master curves, of photo-induced index change in the core and the cladding have been established forvalues ranging up to 10-3 in the core and 3.10-3 in the cladding. Master Curves with the same k0 havebeen obtained but the elbow and the slopes are different. Stability of index variations in the core is better(less Ge doped) than in the photosensitive cladding. In a second step, from the basic Bragg gratings, theannealing conditions and the lifetime have been determined. For the first time to our knowledge, thereliably of the annealing conditions and the life time predictions have been validated by building a newmaster curve on annealed GFF monofilters. According to the theory, this master curve show the same k0as the one determined using non-annealed gratings. More beyond the elbow, the two curves are same,which validates the reliability of our predictions.

Made available in DSpace on 2016-12-12T20:27:37Z (GMT). No. of bitstreams: 1 Yujuan Wang.pdf: 1608760 bytes, checksum: 9cb82304a2c95c2b0e357dc7f8449815 (MD5) Previous issue date: 2012-12-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents the development of an FPGA-based optical interrogation system of multiplexed FBG sensors. The Fabry-Perot filter is used to implement the tunable filter method, as a demodulator for FBG sensors. The tuning signal generation for Fabry-Perot filter and the data aquisition are implemented and syncronized em FPGA. Peak-detection algorithms, based on centroid and FIR filter, are implemented em FPGA. The peak displacement detected of FBG reflected spectrum is used to refer sensed elements, such as variation of temperature and refractive index. Besides, other auxiliary digital circuits are implemented for the system configuration, visulization of the detected peak information and the serial communication to monitor entire spectra in computer. All these digital circuits are working on their own duty at the same time, synchronised by the crystal clock of FPGA. The system was used to monitor the fabrication process of an refractive index sensor. The fabricated sensor was tested by measuring the refractive index of water and sucrose. In another experiment, the system was tested by measuring the temperature of a water sample. In addition, a method to calibrate the tuning signal generator is proposed, which can also be employed in other applications that uses DA converters. Finally, the developed system was packaged to facilitate its transportation. / Este trabalho descreve a implementação de um sistema de interrogação óptico para FBGs multiplexadas, com o controle dos processos implementado em FPGA. A interrogação das FBGs é realizada por meio do método de filtro sintonizável, com o uso de filtro Fabry-Perot. Um FPGA é utilizado para gerar sinal de sintonia para o filtro Fabry-Perot e realizar a leitura do sinal espectral refletido pelas FBGs. Algoritmos de detecção de pico (centroide e filtro FIR) foram implementados no FPGA para processar os sinais refletidos por cada FBG, com o objetivo de inferir as propriedades sensoreadas, como variação de temperatura ou índice de refração. Além destes circuitos digitais, são implementados outros circuitos digitais para a configuração do sistema, para a visualização do pico detectado do sinal espectral e para o monitoramento do espectro inteiro via comunicação serial. Todos circuitos cumprem a própria função paralelamente em virtude do paralelismo do FPGA, sincronizado pelo clock do oscilador cristal do FPGA. O sistema desenvolvido foi utilizado no monitoramento do processo de fabricação de sensor de índice de refração e então na leitura do índice de refração de amostras de sacarose e água. O sistema também foi utilizado para a leitura da temperatura de amostras de água, onde foi estimada a sensibilidade e a resolução do sistema. Também foi proposto um método para a calibração do sistema, que pode ser utilizado também em outros trabalhos. O sistema final foi colocado em uma maleta para facilitar o seu transporte para o local de uso.

The aim of master's thesis is to get familiarized with the problems of measurement and analysis of seismic waves. Theoretical part deals with the description of seismic waves, especially their types, sources and properties. Attention was afterwards focused on the measurement systems of these waves, emphasis was placed on their principles and advantages. The practical part discusses methods of noise reduction and highlighting of significant events in measured data. At the end, individual methods are implemented into user-friendly graphical interface.

The master theses deals with a detailed analysis of optical fiber sensors. Specifically, there are discussed optical fibers, various types of sensors and realization optical fiber senzor and senzor system that has been optimized and processed data in real time. In master theses also describes the LabView programming enviroment and uses components, including the entire sensor systém of a sensors system that sends measured data

[pt] O presente trabalho aborda o desenvolvimento de sistemas de detecção de gases na região do infravermelho. Conceitos fundamentais sobre a teoria eletromagnética da luz e como o sinal luminoso pode ser absorvido por gases é apresentado na etapa inicial. Em seguida, são apresentados novos métodos de detecção utilizando fibras ópticas através de simulações eletromagnéticas destas fibras e por observações de medições em laboratório. O software utilizado é o Optiwave. Um sistema de interrogação baseado em um laser em anel é desenvolvido para o comprimento de onda em 2000 nm. São aplicados dispositivos ópticos, fibras padrão, fibras micro estruturadas como elementos constituintes de sistemas de detecção de gases. Adicionalmente, um método de detecção coerente homodina e um subsistema capaz de detectar variações do índice de refração até pelo menos a sexta casa decimal são introduzidos, discutidos e propostos como novas técnicas a serem utilizadas na detecção e medição de gases. O desenvolvimento das técnicas aqui propostas tem ainda por finalidade segurança industrial e ambiental, avaliação de riscos de explosões, e no controle de vazamentos, emissões e poluição atmosférica. / [en] This thesis discusses the development of gas detection systems in the infrared region. Fundamental concepts on the electromagnetic theory of light and how the light signal can be absorbed by gases is shown in the initial stage. Then, the possibility of new optical fiber detection methods is presented using electromagnetic simulations and laboratory observations activities. The software used is the Optiwave. A scanning system based on laser ring is designed for the wavelength of 2000 nm. In this step, the study of Bragg gratings is explored. Other systems using optical devices, Micro structured optical fibers, coherent homodyne systems are presented and realized. Besides, a subsystem able to detect at least 10- 6 variations of the refraction index is introduced and evaluated as a gas detection application. All procedures presented can also be activated in industrial security, environment and atmospheric pollution evaluation, gas leakage, and gas blasts risks.