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The master thesis is focused to design and realization of experimental equipment for researching of residual stress determination for specimen with non-uniform distribution stress along the depth. Literature search study of problematic was performed and it was used for elaboration of chapters about origin of residual stress, their classification and chapters about methods, which are used for measuring of residual stress and their determination. The following part explains the design of experimental equipment and stress-strain analysis of selected parts of this equipment. Then the final design of equipment is presented, including complete production drawings, and it’s explained final assembling of experimental equipment. Final chapter is devoted to examinable loading of specimen.

Residual state of stress in structural materials affect positively or negatively behaviour of component parts. The goal of this scope is not to deal with possible process of creating residual stresses neither about elimination of residual stress, but is focused how to determine magnitude of residual stress by hole-drilling method. We need to know magnitude and direction (angular orientation) of principal stresses to determine how residual state of stress affects behaviour of specimen. The most widely used modern technique for measuring residual stresses is hole-drilling strain-gage method. Hole-drilling method is in scope of this paper and is restricted only for measuring uniform residual stresses of steel specimens with finite dimensions. Structural, linear, elastic and isotropic material model is used with material properties =0,3 and E=2,1[10]^5 MPa. For correct application of this method we need to determine calibration coefficients “a“ and “b“ first. These coefficients are used to determine magnitude and direction of residual stresses in specific depth and diameter of drilled hole for materials with finite dimensions. Geometry and shape of model is simply represented by block with planar faces. Note that numerical determination of calibration coefficients is useful only for one type of strain gauge rosette RY 61 S. Main goals of this thesis are motivation and request to clearly report effectiveness, accuracy and applicability of calibration coefficients in relation to thickness of specimen, dimensions of drilled hole, condition of “through” or “blind” hole and number of drilled increments. High quality and accuracy of created numerical model is necessary too. Numerical simulation of residual stresses by MKP needs to be done to obtain requested results. All results are presented by 3D, 2D graphs and tables and compared with analytical results or results from other authors. Although is this publication focused on numerical modeling using FEM, hole-drilling method has many significant restrictions. The most substantial of them is influence of eccentricity of drilled hole, creation of stress concentration near drilled area and subsequent plastification, influence of geometrical inaccuracy of hole, etc. All these aspects have significant influence of determining calibration coefficients and can not be included into numerical simulation. These problems are closely discussed in background research. All obtained results should be helpful for practical use of calculated calibration coefficients to determine uniform residual stresses of specimens with various thickness and drilled hole. All these results are also applicable only for one type of strain gauge rosette, which is RY 61 S.

Ce travail de thèse est consacré au développement de sources lasers femtosecondes à haute cadence, de forte puissancemoyenne (>10 W) avec des énergies supérieures à 100 μJ. Ce type de sources est primordial pour le développementd’applications industrielles variées (micro-usinage athermique, chirurgie oculaire, …) ainsi qu’en recherchefondamentale pour l’étude de l’interaction laser matière.Après un chapitre d’introduction sur l’état de l’art des chaînes lasers de forte puissance moyenne à base de matériauxdopés ytterbium, la réalisation d’une chaîne laser de forte puissance moyenne compacte à base de fibre photoniquemicrostructurée à large aire modale sera présentée. Il sera notamment démontré les principales limitations en termed’énergie et de puissance moyenne. D’une part, le fort confinement de l’impulsion lumineuse dans le coeur de la fibrefavorise l’accumulation d’effets non-linéaires lors de l’amplification et détériore la qualité de l’impulsion. D’autrepart, en raison du diamètre de coeur important (> 70 μm) choisit pour lutter contre l’effet précèdent, le guidage dumode fondamental TEM00 de ces fibres est très critique et devient sensible à la charge thermique interne à la fibre.Cette source laser a été utilisée dans le cas de deux applications bien spécifiques : le perçage de plaques d’acierépaisses pour une finalité de déminage (relatif au cadre du financement de cette thèse par la Direction Générale del’Armement) et à la génération d’harmoniques d’ordres élevées à très haute cadence (relatif au domaine d’expertisedu CELIA). Ces deux applications sont traitées au cours du troisième chapitre.A la vue des limitations observées et afin de disposer de chaînes lasers plus énergétiques et offrant des duréesd’impulsions encore plus courtes, une nouvelles architecture d’amplification a été proposée : le pompage fortebrillance de matériaux dopés Ytterbium. Ce concept présenté dans le dernier chapitre utilise le développement desources fibrées monomodes continues émettant à 976 nm. Cette architecture d’amplification a été utilisée afin deréaliser d’une part un oscillateur sub-70 fs et de forte puissance moyenne (>2,3 W) à une cadence de 73 MHz etd’autre part : un amplificateur type « booster » à fort gain. Deux expériences qui ont été réalisées avec des cristauxd’Yb:CaF2. Ce matériaux présente en effet l’avantage d’avoir un très large spectre d’émission (>60 nm) propice à lagénération et amplification d’impulsions femtosecondes mais aussi d’être « compatible » avec les chaînes de trèsforte puissance grâce à sa très bonne conductivité thermique. / This work concerns the development of high repetition rate femtosecond lasers with high average power (>10 W)and energies in excess of 100 μJ. Such lasers are paramount for the development of new industrial applications(athermal micro-drilling, eye surgery, ...) and for fundamental research on high repetition rate laser matter interactionstudies.After a brief introduction and the state of the art summary on high-average power femtosecond laser with ytterbiumdoped materials, a compact high-average power femtosecond laser with a large mode area microstructured rod typeamplifier will be presented. It will browse the main limitations in terms of energy and average power. Limitationsare mainly due to the strong confinement of the electric field propagating in the fibre core leading to non-linear effectsaccumulated during the amplification. On the other hand, for larger core diameter (> 70 μm), the fundamental modeguiding (TEM00) is very weak and thus very sensitive to the internal thermal load of the fibre.This laser source has been used in two specific applications: athermal drilling of thick stainless steel plate for mineclearing(an application of interest for the Direction Générale de l’Armement) and High order Harmonics Generationat high repetition rate (related to CELIA activities). These two applications are presented in the third chapter.In order to stretch the limits and generate more energetic and a shorter pulse, a new amplification scheme has beenproposed, namely high brightness optical pumping of ytterbium doped materials. This concept presented in the lastchapter benefits from the development of high average power single-mode fibre lasers source emitting at 976 nm.This amplification scheme allowed us to realize a high average power Kerr-lens oscillator delivering pulses with apulse duration below than 70 fs and an average power of 2.3W at a repetition rate of 73 MHz. In a second phase, wealso developed a « booster » amplifier with a high single- pass-gain. These two results have been obtained by usingYb-doped CaF2 crystals. This material presents the advantage to have a very broad emission bandwidth (> 60nm)suitable to generate and amplify femtosecond pulses and to be compatible with high average power laser due to hisvery good thermal conductivity.

Comprehensive analysis of the ringcore method used for the determination of the residual stresses in mechanical components is presented in this thesis. Principles, advantages, disadvantages and applicability of this semidestructive experimental method are discussed too. At the same time the ringcore method is compared with the hole drilling method, which is used more frequently. All aspects of the ringcore method are analyzed by the finite element method. FE simulations, performed on the universal numerical model, verified principles of the integral method and the incremental strain method. FE simulations also provided basic information for the uncertainty analysis, which significantly affects the accuracy of the residual stress measurement. The main goal, which the present work deals with, is to create a global overview of all ringcore methods´ aspects elaborated in a clear and complex form.

La conservación del patrimonio cultural esta considerado como un principio fundamental en la vida cultural de las sociedades modernas. En los últimos años, se han realizado extensas investigaciones en torno a esta área, conduciendo a desarrollos en la inspección, ensayos no destructivos, monitorización y análisis estructural de monumentos.Por otra parte, el análisis de construcciones antiguas formula importantes desafíos dada la complejidad de su geometría, la variabilidad de las propiedades de los materiales tradicionales, las diferentes técnicas de construcción, la ausencia de conocimiento sobre los daños existentes, y de cómo afectan determinadas acciones a las construcciones a lo largo de su vida.Dichos desafíos suponen que las construcciones del patrimonio arquitectónico estén sometidas a una serie de dificultades de diagnóstico y restauración, que limitan la aplicación de las disposiciones normativas y las pautas vigentes en el ámbito general de la construcción. Y es por todo ello que la comprensión, el análisis y la reparación de construcciones históricas se establece como uno de los desafíos más importantes de los técnicos modernos.¿Sería razonable operar a un enfermo sin tener constancia objetiva del mal que adolece?, en ese caso ¿porqué intervenimos en nuestra herencia cultural sin tener conocimiento contrastado de las causas desencadenantes de sus procesos patológicos?Respondiendo a la cuestión formulada, las intervenciones en las construcciones antiguas, dada su fragilidad, requieren precisión, detalle y formación especial en el desarrollo de un estudio previo riguroso de diagnóstico que de soporte a las decisiones sobre las técnicas de intervención que deben adoptarse.En este proceso es fundamental la fase de reconocimiento - análisis, dado que es en esta etapa en la que se plantean hipótesis y se comprueban, de forma objetiva, a través de cálculos y ensayos. Dentro de la fase referida, debe prestarse especial atención al reconocimiento experimental, dado que dicha inspección además de contribuir a la obtención de parámetros de entrada de los modelos de análisis, tiene como misión el contribuir a calibrarlos mediante la comprobación experimental de los resultados obtenidos analíticamente en determinados puntos de control.Por su parte, es deseable que dicho reconocimiento experimental se realice de la forma menos intrusiva posible para con la construcción, sobremanera en el caso de bienes de carácter monumental.En línea con lo argumentado, la investigación que se presenta incide, dentro del proceso metodológico general de intervención en una construcción antigua, en la fase del reconocimiento experimental, in situ, ligeramente destructivo, y a su vez, dentro de éste, en las técnicas orientadas a obtener información útil desde un punto de vista de la caracterización mecánica de elementos estructurales de fábrica.En este sentido, se pretende contribuir a la puesta a punto, en España, de métodos para la evaluación in situ de la fiabilidad de los elementos estructurales existentes en construcciones históricas de obra de fábrica. Para ello, se van a focalizar los esfuerzos en el calibrado, en laboratorio, de las técnicas de gatos planos, hole drilling y mini-presurometría de fábricas, y posteriormente se aplicarán a casos reales in situ. / Cultural heritage conservation is considered as a fundamental principle of modern societies' cultural life. In recent years, extensive research has been done on this area, leading developments on inspection, non-destructive testing, monitoring and monument structural analysis.In other hand, old buildings analysis implies significant challenges due to the complexity of its geometry, variability of traditional materials properties, different construction techniques, lack of knowledge about existing damage, and how certain actions affect throughout their life to buildings.These challenges mean that architectural heritage buildings are subject to diagnosis and refurbishment difficulties, which limit the application of standards and construction guidelines. That is why the understanding, the analysis and the historic buildings' repair, are considered as one of the most important challenges of modern technicians.Would it be reasonable to operate a patient without objective evidence of the illness that suffers? In that case, why do we intervene in our cultural heritage without knowing the causes that have initiated its pathological processes?Answering to this question, interventions in old buildings, because of its fragility, require accuracy, detail and a special education in the development of a previous diagnostic study, in order to give support to decisions to be adopted on intervention techniques.In this process, it is essential the phase survey - analysis, because it is at this stage where the hypothesis are set out and verified with calculations and tests. Within this phase, it should pay special attention to experimental survey, since such inspection contributes to both obtaining input parameters of the model analysis, and contributes to calibrate it using the experimental verification of the results obtained analytically at certain checkpoints.Moreover, it is desirable that such experimental survey is performed of the least intrusive way as possible for the construction, greatly in the case of monumental constructions.Within the general process of intervention on old constructions, the research presented insists on the on-site experimental survey stage, slightly destructive, and within it, on the techniques aimed to obtain useful information for the mechanical characterization of masonry structural elements.In this sense, it aims to contribute to the development in Spain of methods for on-site evaluation of the structural elements' reliability in masonry historical buildings. For this, efforts will focus on the calibration, in laboratory, of the techniques of flat jacks, hole drilling and masonry mini-pressurometer, and then its application to real on-site cases.

Cette thèse s’inscrit dans le domaine de la modélisation des circuits analogiques et mixtes.Le travail part d’une problématique industrielle concernant les circuits électroniques utilisés dansles systèmes de forage pétrolier pour des besoins d’instrumentation et mesures. Ce travail de recherche concerne les circuits du front-end analogique que nous trouvons dans cette application industrielle. Nous examinons et nous essayons de trouver des modèles pour décrire l’effet des hautes températures sur les circuits électroniques dans un forage pétrolier. Ces circuits font partie des circuits industriels conventionnels. Ils ont généralement une température maximale de fonctionnement qui ne dépasse pas 125°C. Même si la température modifie le comportement de ces circuits, il existe des techniques d’adaptation qui permettent de compenser l’effet de la température sur ces circuits. Cependant, pour bien réussir la phase de la conception, il faut d’abord bien caractériser le comportement des différents circuits industriels utilisés en haute température. Il faut également trouver des modèles exacts qui décrivent le comportement de ces circuits en haute température. Or nous savons que la majorité des circuits industriels analogiques et mixtes sont décrits par des modèles de type SPICE. Par un choix de l’entreprise Schlumberger, notre partenaire industriel qui a financé ce travail, nous nous sommes intéressés dans notre étude à un composantspécifique présent dans la majorité des circuits analogiques et mixtes d’instrumentation :l’amplificateur opérationnel (l’AOP).Le travail commence par une étude des spécifications du circuit ainsi que le modèle SPICE.Une étude de la structure de ce modèle et sa simulation ont montré la non-précision du modèle audelàde 125°C. L’étude de validité du modèle a concerné le paramètre de la tension de décalage etle paramètre taux de rejection du mode commun. Nous avons interprété la différence des résultatsentre les mesures et la simulation de la tension de décalage. Nous avons constaté la limitation quereprésente l’approche structurelle par modélisation SPICE. Pour cette raison, nous avonssélectionné l’approche de modélisation comportementale pour les différents avantages qu’elleprésente. Ces avantages répondent à nos besoins et conviennent les mesures qui ont été effectuées.Nous avons sélectionné le langage VHDL-AMS et l’environnement Cadence ADVanceMS. Pourdéveloppé les modèles, nous avons alors énuméré les différents paramètres de performance d’unAOP. Nous avons validé la représentation de chaque paramètre par un circuit de test approprié.Dans un deuxième temps, nous avons approximé la variation de ces paramètres en température pardes équations polynomiales et exponentielles pour développer le modèle précis en HT. Le modèlea été validé par un circuit de test similaire au circuit expérimental. De bons résultats ont ététrouvés. L’erreur moyenne entre simulation VHDL-AMS et mesures n’a pas dépassé 3,11%. Dansle denier chapitre, nous avons simulé des circuits d’une chaine d’instrumentation. Nous avonssimulé l’effet de la température sur un capteur piézo-résistif (pont de Wheatstone). Trois architectures d’un amplificateur d’instrumentation ont été également modélisées e en se basant surle modèle VHD-AMS de l’AOP. / This work is dealing with the modelling of analogue and mixed signal circuits. Moreprecisely, we focus on modelling the circuits of an analogue front-end which is used in down-holedrilling industry for instrumentation and measurement purposes. This research had as a goal tomodel the temperature increasing effect in the behaviour of each circuit of the considered frontend.The studied circuits belong to the family of “conventional” circuits. Most of these circuitsoperate in a temperature which does not exceed 125°C. Even if the behaviour of the circuit changesdue to an increasing of the temperature, there are some well-know techniques that enable thecompensation of such effects. However, in order to obtain a precise simulation in the design phase,it is very important to have accurate models that describe the temperature increasing effect. Asmost of the commercial circuits models are written in SPICE, it is necessary first to review theaccuracy of SPICE models in high temperature (HT). This work focus on a specific circuit: theoperational amplifier (opamp). This device is present in many instrumentation circuits. Obtainingan accurate op-amp model in HT will help us develop accurate models of these circuits byconsidering their architectural description which is based on the opamp model.The work starts with the study of the structure of the SPICE model of the considered opamp.This study enables us to confirm the non-validity of the SPICE model in HT. The validity studyconsists in comparing the SPCE simulation results of two parameters (the voltage offset and thecommon mode rejection ratio) to measurement results. Moreover, we present an interpretation tothe difference that was observed in this comparison. After comparing different modellingapproaches, we select the behavioural modelling one. The VHDL-AMS was used to develop thenew precise opamp model in HT. The simulation is performance in Cadence/ADVanceMSenvironment. The representation of each opamp parameter is validated by a specific circuit. Thismodel is developed in two steps. In the first step, we develop an opamp model in which there is noconsideration of the temperature effect. In the second step, dependence of each parameter to thetemperature is described by a polynomial or exponential function. This function is the result of thefitting process of the measurement results. These equations are inserted in the VHDL-AMS model.All parameters are again validated in each temperature. The test-circuit is the same circuit used inthe experimental test of the opamp parameters. The average error between measurement andsimulation does not exceed 3.11%. In the last chapter, we simulate some circuits of the theanalogue front-end of an acquisition system. We simulate for example the effect of the temperatureeffect on the accuracy of a Wheatstone bridge. Three architecture of an instrumentation amplifierwere also modelled and simulated in different temperature of [20°C, 220°C] in the basis of thedeveloped opamp model.

Comprehensive analysis of the ringcore method used for the determination of the residual stresses in mechanical components is presented in this thesis. Principles, advantages, disadvantages and applicability of this semidestructive experimental method are discussed too. At the same time the ringcore method is compared with the hole drilling method, which is used more frequently. All aspects of the ringcore method are analyzed by the finite element method. FE simulations, performed on the universal numerical model, verified principles of the integral method and the incremental strain method. FE simulations also provided basic information for the uncertainty analysis, which significantly affects the accuracy of the residual stress measurement. The main goal, which the present work deals with, is to create a global overview of all ringcore methods´ aspects elaborated in a clear and complex form.