Portail HAL IMT Mines Albi
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Modélisation de la phase de fusion/imprégnation dans le procédé de fabrication de tape composite thermoplastique
No full textThe aim of this thesis is to develop the modelling and simulation of heating operations in the manufacturing process of prepregs using slurry impregnation. In the first part of the manuscript, the study of the IR oven is carried out. An experimental campaign was conducted in order to understand the operation of the IR oven and the influence of process parameters on its functioning. Then the ovens radiation source: IR lamps equipped with a ceramic reflector was studied and modelled using an inverse identification approach. Using these results, a more complete modelling of the IR oven could be established and the numerical results compared with the experimental tests carried out in the first chapter. In the second part of the manuscript, the study of the prepreg during heating was carried out. An experimental campaign was used to obtain experimental data concerning the manufacturing process parameters and the temperature of the product during heating. The characterization of the optical properties of the material, the calculation of the heating rate and the observation of the microstructure were carried out. Then the thermo-physical properties were modelled from the experimental observations. Finally, all of the information obtained made it possible to establish a preliminary model of the heating of the prepreg.Cette thèse a pour but de développer la modélisation et la simulation des opérations de chauffage dans le procédé de fabrication de pré-imprégnés en voie aqueuse. Dans la première partie du manuscrit, l’étude du four IR est menée. Une campagne expérimentale a été menée afin de comprendre le fonctionnement du four IR et l’influence des paramètres procédé sur son fonctionnement. Ensuite, la source de rayonnement du four : des lampes IR dotées d’un réflecteur céramique, a été étudiée et modélisée en utilisant une approche d’identification inverse. A l’aide de ces résultats une modélisation plus complète du four IR a pu être établie et les résultats numériques confrontés aux essais expérimentaux effectués dans le premier chapitre. Dans la seconde partie du manuscrit, l’étude du pré-imprégné au cours du chauffage a été menée. Une campagne expérimentale a permis d’obtenir des données expérimentales concernant les paramètres procédés de fabrication et la température du produit au cours du chauffage. La caractérisation des propriétés optiques des matériaux, le calcul de la vitesse de chauffage et l’observation de la microstructure ont été réalisés. Ensuite les propriétés thermo-physiques ont été modélisées à partir des observations expérimentales. Enfin, l’ensemble des informations obtenues ont permis d’établir un modèle préliminaire du chauffage du pré-imprégné
HospiT'Win : conception d’un double numérique basé sur la simulation à événements discrets pour le suivi en temps réel et la prédiction à court terme des parcours des patients à l’hôpital
No full textHospitals are demanding workplaces that have real-time services and require extensive human interaction at the resource level (doctors, nurses, etc.), the location level (exam rooms, operating rooms, etc.), the process level (pathways), and the user level (patients). Designing and managing such a health care facility can be inherently challenging due to the critical nature of the services and their wide variety and variability, as well as the difficult adjustment to a partially unforeseeable demand of care. To increase the efficiency and the quality of care while curbing healthcare costs, a hospital requires decision-making support tools. These can be based on organizational engineering methods and tools for monitoring the current state of the organization in real time, for predicting its behavior in the near-future, and for improving its processes. Among the tools, discrete event simulation (DES) is able to model the operational process behavior and to assess performance by simulating a chain of events that occur over time. However, despite important features provided by DES software tools, they are often limited to building “offline” simulation models that are not connected to the real world in real time. These simulation models may not be suitable for retrieving the current state of the organization, and they cannot be considered a "Digital Twin". Furthermore, these simulations start with an “empty” and “idle” state, which can be different from the real-world state and imply a bias in the statistics reports at the end of the simulation run. This research work deals with a DES-based Digital Twin (DT) approach. It is based on DES models which are used (1) for real-time and online monitoring of patient pathways, and (2) for near-future offline prediction when facing unexpected behavior or unpredictable situations. The major goal of this research is to provide a framework for building a Digital Twin of patient pathways that health care practitioners and decision makers can use as a decision support tool. Some specific issues are also addressed: initialization of the DES models, real-time synchronization with the real world, and the connection between monitoring and prediction models. As a proof of concept, experiments are carried out using an emulator of a hospital service that is connected to a Digital Twin that follows our approach.L'hôpital est un lieu de travail exigeant qui nécessite une prise en charge en temps réel du patient et une interaction humaine élevée au niveau des ressources (médecin, infirmières, etc.), de l'emplacement (salle d'examen, salle d'opération, etc.), des processus (parcours de soins et de santé) et au niveau des usagers (patients). Concevoir et manager un établissement de santé peut être difficile. D’une part, parce que les services peuvent être des ressources critiques, et présenter une grande variété et une grande variabilité. D’autre part, l’adaptation à une demande de soins partiellement imprévisible peut se révéler très complexe. Pour augmenter l'efficacité et la qualité des soins tout en limitant les coûts, un hôpital a donc besoin d’outils d’aide à la décision. Ils peuvent être basés sur des méthodes et des outils d'ingénierie organisationnelle afin de suivre l’état des services en temps réel, de prédire leur comportement dans un futur proche, et d'améliorer les processus. Parmi les méthodes et outils disponibles, la simulation à événements discrets (SED) permet de mieux comprendre le comportement des processus opérationnels et d'évaluer leur performance en simulant une chaîne d'événements qui se produisent dans le temps. Cependant, bien que les logiciels de SED disposent de multiples fonctionnalités, ils se limitent principalement à la construction de modèles de simulation « hors ligne » qui ne sont donc pas connectés au monde réel en temps réel. Par conséquent, les modèles ne sont pas adaptés pour récupérer l'état courant d’une organisation à un instant précis, ils ne peuvent donc pas être considérés comme des doubles numériques (DN). De plus, les simulations démarrent dans un état « vide » et « inactif », qui peut être différent de l'état réel, ce qui peut entrainer un biais dans les rapports statistiques à la fin de la simulation. Notre travail de recherche propose une approche de double numérique à base d'un simulateur à événement discret. Notre double numérique fournit une représentation virtuelle et en temps réel qui est synchronisée avec les ressources physiques et/ou les activités des processus. Il est basé sur des modèles de SED qui sont utilisés pour (1) le suivi en temps réel et en ligne des parcours des patients, et (2) la prédiction hors ligne du futur proche face à un comportement inattendu ou à des situations imprévisibles. L'objectif principal de cette thèse est de fournir un cadre pour la construction d’un double numérique du parcours des patients que des professionnels de santé et des décideurs pourraient utiliser comme outil d'aide à la décision. Plusieurs problématiques spécifiques sont également abordées : l'initialisation des modèles de SED sur l'état courant, la synchronisation en temps réel avec le monde réel, et la connexion entre le modèle de suivi et le modèle de prédiction. Comme preuve de concept, nous proposons des expérimentations basées sur un émulateur d'un service hospitalier connecté à un double numérique développé suivant notre approche
PARTICLE FILTER-MODEL PREDICTIVE CONTROL FOR OIL RESERVOIR MANAGEMENT
No full textInternational audienceIn this work, the application of a Nonlinear Model Predictive Control (NMPC) with state estimation in the waterflooding process as supervisory control was studied. The methodology employed the Particle Filter (PF) in step of the model-based optimization of the NMPC with Particle Filter Optimization (PFO) and step of the filtering through the Auxiliary Particle Filter (APF). This way, it is presented a new Bayesian approach to NMPC for reservoir management. The proposed methodology aimed at being robust to overwhelm nonlinearities and non-Gaussian uncertainties inherent in oil reservoir systems. The results showed the potential of APF in the estimation step not presenting degeneration or impoverishment of the sample, in view of that the dimension of the problem is considerably high, and, in the model-based optimization step with PFO which handled well the nonlinearity of the model and maintained control of production. The results also supported the contribution of this work with advances in the application of PF as a tool in the context of reservoir management and especially in its use as an optimization tool
ISIEM: a methodology to deploy a knowledge-based system to support bidding process
No full textInternational audienceWhen responding to calls for tenders, companies must elaborate on relevant bids relative to the needs and expectations of customers (for example, in terms of price and delay). We built and deployed a knowledge-based system (KBS) to aid companies when developing bids. Based on a pre-defined generic bid model, a methodology to support companies when deploying the KBS is proposed in this paper. To capture, formalize, and reuse knowledge relevant to bids, a combination of several approaches, such as taxonomy, constraint satisfaction problem, and case-based reasoning, is proposed. The methodology is composed of five steps: Initialization, Specialization, Implementation, Exploitation, and Maintenance. A case study from a company building electrical parts of harbor lifting devices illustrates our proposal and allows validating the proposed methodology
Expert system dedicated to condition-based maintenance based on a knowledge graph approach: Application to an aeronautic system
No full textInternational audienceCondition Based Maintenance (CBM) has become the focus of many research topics over the past decades. This is mostly related to the development of new machine learning algorithms and the ever increasing capacity to collect data allowing failures to be detected and the system’s remaining lifetime to be estimated while requiring few or no expert knowledge. However, current machine learning based CBM solutions have limitations. They require an extensive and relevant data set to train on and are performed at the component level, not system-wide. Conversely, Expert Systems (ES) do not have these restrictions but should be used on systems with available expert knowledge and are currently suffering from efficiency, scalability and applicability limits. In this paper, an ES solution for CBM based on an heterogeneous information network will be presented to address the efficiency, scalability and applicability issues of modern ES. An application to an aircraft system will be used as case study to illustrate the process and performance of this solution for anomaly detection and diagnostics
Influence of Austenitization Parameters on the Precipitation Sequence and the Chemical Homogenization of Austenite in a High-Performance Fe–Ni–Cr–Al–Ti–Mo Stainless Maraging Steel
No full textInternational audienceMLX19 stainless maraging steel grade exhibits a mechanical strength/fracture toughness balance within the required range for landing gear applications. However, the microstructure after the heat treatment still needs to be precisely controlled to obtain a better repeatability of the mechanical properties. This work shows that austenitizing is a critical stage. The influence of austenitization treatment parameters on the microstructure obtained after quenching was thus precisely quantified. It was first revealed that, after a standard austenitization at 850 °C and for specific heating rates and holding times, undissolved β-NiAl precipitates, reaching sizes up to 500 nm, still remain in the as-quenched state, in addition to a high retained austenite fraction. It was also found that large amounts of retained austenite are the result of local heterogeneities in the chemical composition of the austenitic phase prior to quenching, while the undissolved precipitates change the overall chemical composition of the austenitic matrix. New austenitization conditions were thus proposed, leading to a better homogeneity of the chemical composition of the martensitic matrix after quenching
Conception d’un modèle de simulation pour l’évaluation de la pertinence de l’Internet Physique pour les chaînes d’approvisionnement humanitaires
No full textInternational audienceIn the aftermath of a disaster, supplying relief items to affected people is a real challenge for humanitarian organizations. Showing a lack of effectiveness in the response, their practices are put into question. The Physical Internet approach, aiming at reorganizing logistics in a way for improved resource management and better coordination of actors while meeting the stakeholders and environment growing expectations, seems relevant for the humanitarian sector reinvention. However, this assumption needs to be proved through a rigorous scientific process. In this perspective, the paper offers to frame the design of an experiment based on a flow simulation model to evaluate the relevance of the Physical Internet concepts application in a humanitarian context. The steps defined, inspired by the system engineering field, ensure that the simulation meets the objective while ensuring the experiment reliability.La livraison de produits de première nécessité aux victimes des catastrophes naturelles représente un véritable défi pour les organisations humanitaires. Critiquées pour un manque d'efficacité, elles doivent aujourd'hui chercher à se réinventer. L'approche Internet Physique, qui propose une réorganisation de la logistique pour une meilleure gestion des ressources et coordination des acteurs tout en répondant aux exigences croissantes des parties prenantes et environnementales, pourrait s'avérer pertinente pour le secteur humanitaire. Cependant, cette hypothèse demande à être vérifiée au travers d'une démarche scientifique rigoureuse. Dans cette perspective, l'article propose la structuration d'une expérience basée sur un modèle de simulation de flux afin d'évaluer la pertinence de l'application de concepts de l'Internet Physique à un contexte humanitaire. Les étapes définies, inspirées des concepts de l'ingénierie des systèmes, permettent de garantir à la simulation son adéquation avec l'objectif de l'expérience et sa fiabilité
Review on the catalytic tri-reforming of methane - Part II: Catalyst development
No full textInternational audienceMethane reforming allows the production of synthesis gas (syngas) which is an important gas mixture feedstock for the production of chemicals and energy carriers. Steam reforming of methane (SRM) and partial oxidation of methane (POM) have been deployed at large industrial scale, while dry reforming of methane (DRM) and more recently tri-reforming of methane (TRM) are intensively studied. TRM simultaneously combines SRM, POM and DRM in a unique process and allows overcoming several weaknesses of each individual methane reforming process: e.g. regulation of the molar ratio of H2/CO by controlling feed composition; adaptation to the variation in biogas composition as renewable resource. TRM process strongly requires a solid catalyst. To date, the design of efficient TRM catalysts remains a challenge. This work reviews recent achievements on the development of catalysts for TRM, and provides a guideline for future work related to TRM catalysts
Continuuous assessment of the resilience of critical infrastructure: the Nantes ring road flood experimental scenario
No full textInternational audienceFlooding is frequent on the Nantes ring road and disrupts users dependent on this mode of transport directly or indirectly. To deal with them, the road operator has defined preventive and curative measures based essentially on the flow of the river involved in the submergence of the roadway. The RESIIST (Resilience of Interconnected Infrastructures and Systems) research project aims to develop a methodology and tools to assess the resilience of Critical Infrastructures (within the meaning of European Directive 2008/114/EC), of which we find the ring road. In order to test them, a scenario will be used to simulate the events likely to cause flooding, characterise the disturbances caused by these events and the interactions with adjacent road infrastructures and present a decision aidingbased on the road operator's criteria. RESIIST can contribute to improving the resilience of critical infrastructures by enabling stakeholders to continuously monitor data from the context, to interpret them and deduce the disruption’s risks on infrastructure and territory and finally to benefit from proposals for solutions adapted and corresponding to their decision criteria. More modestly, this scenario could serve as a support in discussions on possible work concerning the ring road and the crisis management protocols
