Analytical models of avian flight have previously been used to predict mechanical and metabolic power consumption during cruise. These models are limited, in that they neglect details of wing kinematics, and model power by assuming a fixed or rotary wing (actuator disk) weight support mechanism. Theoretical methods that incorporate wing kinematics potentially offer more accurate predictions of power consumption by calculating instantaneous aerodynamic loads on the wing. However, the success of these models inherently depends on the availability and accuracy of experimental kinematic data. The predictive simulation approach offers an alternative strategy, whereby kinematics are neither neglected nor measured experimentally, but calculated as part of the solution procedure. This thesis describes the development of a predictive tool for simulating avian wingbeat kinematics and wakes. The tool is designed in a modular format, in order to be extensible for future research in the biomechanics community. The primary simulation module is an inverse dynamic avian wing model that predicts aerodynamic forces and mechanical power consumption for given wing kinematics. The model is constructed from previous experimental studies of avian wing biomechanics. Wing motion is defined through joint kinematic time histories, and aerodynamic forces are predicted using blade element momentum theory. Mechanical power consumption at the shoulder joint is derived from both aerodynamic and inertial torque components associated with the shoulder joint rotation rate. An optimisation module is developed to determine wing kinematics that generate aerodynamic loads for propulsion and weight support in given flight conditions, while minimising mechanical power consumption. For minimum power cruise, optimisation reveals numerous local minima solutions that exhibit large variations in wing kinematics. Validation of the model against wind tunnel data shows that optimised solutions capture qualitative trends in wing kinematics with varying cruise speed. Sensitivity analyses show that the model outputs are most affected by the defined maximum lift coefficient and wing length, whereby perturbations in these parameters lead to significant changes in the predicted amount of upstroke wing retraction. Optimised solutions for allometrically scaled bird models show only small differences in predicted advance ratio, which is consistent with field study observations. Accelerating and climbing flight solutions also show similar qualitative trends in wing kinematics to experimental measurements, including a reduction in stroke plane inclination for increasing acceleration or climb angle. The model predicts that both climb angle and climb speed should be greater for birds with more available instantaneous mechanical power. Simulations of the wake using a discrete vortex model capture fundamental features of the wake geometry that have been observed experimentally. Reconstruction of the velocity field shows that this method overpredicts induced velocity in retracting-wing wakes, and should therefore only be applied to extended-wing phases of an avian wingbeat.

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The industrial company Scania CV AB is a world leader in the manufacturing of commercial vehicles. They offer a modular systems that include heavy trucks and buses that can be configured to a range of different needs. However, this adaptability leads to a problem where each order can have a large variance of assemblers that are re-quired during the manufacturing process. In other words, variant assemblers have a workflow that can shift from high workload to low workload and vice versa in a short period of time. To solve this problem a prototype will be developed. This prototype will be used to check if it’s possible to optimize the work schedule for variant assem-blers with the help of predictive simulations. The result of the study became an implementation in form of a prototype. This prototype is built up in two layers; a data layer and a simulation layer. The data layer provides the simulation layer with two different datasets. The first dataset is based on historical data and is derived from Scania’s production in Zwolle. The second dataset is based on synthetic data which is formed with a high utilization rate in order to mimic a better production situation with less product variants to assemble. The simulation layer consists of a DES-model that is modelled after a station in the final assembly of Zwolle. After a simulation has been executed, this layer generates a simulation result in form of a graph that presents the utilization rate for a group of variant assemblers. This will happened for each dataset in the data layer, in this case two times. The simulation result that got produced shows that it’s possible to create a simulation with predictive characteristics. A long term solution for Scania’s problem statement requires more research within the possibility of combining different technologies such as DES with predictive methods such as ML and GAs. / Industriföretaget Scania CV AB är världsledande inom tillverkning av kommersiella fordon. De tillhandahåller ett modulärt system som inkluderar tunga lastbilar och bussar som kan konfigureras till en rad olika behov. Den här anpassningsförmågan leder dock till ett problem där varje order som tillverkas kan ha en stor varians av hur många montörer som krävs under produktion. I andra ord så har variantmontö-rer ett arbetsflöde som kan skifta från hög arbetsbelastning till låg arbetsbelastning och vice versa under en kort period. För att lösa dessa typer av problem så ska en prototyp med prediktiva egenskaper så som Diskrete Event Simulering (DES). Denna prototyp ska undersöka om det är möjlighet att optimera arbetsscheman för variantmontörer med hjälpa av prediktiva simuleringar. Resultatet av studien blev en implementation i form av en prototyp. Denna prototyp är uppbyggd i två lager; ett datalager samt ett simuleringslager. Datalagret tillhandahåller simuleringslagret med två dataset. Det första datasetet är baserad på historisk data och är härledd från Scania’s produktion i Zwolle. Det andra datasetet är baserat på syntetisk data som är framtagen med en högre utnyttjandegrad för att efterlikna ett bättre produktionssitation med färre produkt varianter att montera. Simuleringslagret består av en DES-model som är modulerad efter en station i slutmontering i Zwolle. Efter att en simulering har exekverats så genererar detta lager ett simuleringsresultat i form av en graf som presenterar utnyttjandegraden för en grupp med variant montörer. Detta sker för varje dataset i datalagret, i detta fall två gånger. Simuleringsresultatet som togs fram visar att det är möjligt att ha skapa simuleringar med prediktiva egenskaper. En långsiktig lösning för Scania’s problem-beskrivningen kräver mer forskning inom möjligheten att kombinera tekniker som DES med prediktiva metoder som ML och GAs.

Cette thèse s'articule autour de l'optimisation électro-optique des OLEDs (Organic Light Emitting Device) via le développement de méthodes et d'outils de simulation. La modélisation électrique des OLEDs est complexe et sujette à recherche. Au début de la thèse, aucune simulation électrique des OLEDs de l'état de l'art n'avait été présentée jusqu'alors. Le développement d'une simulation, fondée sur des données expérimentales, contribuerait à l'établissement d'une modélisation prédictive, pour une meilleure compréhension et une R&D plus efficace. Dans un premier temps, une méthode d'extraction des paramètres de transport des matériaux utilisés est développée par fit (reconstitution des résultats expérimentaux par simulation) via la fabrication de dispositifs spécifiques. Lesdites valeurs, extraites et comparées selon deux modèles de mobilité, ont assurées la constitution d'une base de données. L'emploi de celle-ci a permis la réalisation de la simulation, complète et à plusieurs températures, du comportement électrique d'une OLED entière. L'étude minutieuse des profils intrinsèques simulés a servi à relever une accumulation de charges à l'interface de recombinaison, néfaste à l'évolution dans le temps des performances du dispositif. Dans un second temps, nous nous sommes proposé de solutionner le problème par la création d'un mélange bipolaire, afin d'élargir le profil de recombinaison. Après optimisation du mélange au sein de l'OLED, une augmentation de durée de vie à mi luminance de ca. +30% a été mise en évidence, de même qu'une stabilisation en tension du point de couleur. Pour approfondir la compréhension des mécanismes en jeu, la caractérisation TOF-SIMS d'empilements organiques a fait l'objet d'études. Les premiers résultats, très encourageants, ont permis la reconstitution entière du profil chimique de l'empilement OLED. Une deuxième série de résultats a démontré la possibilité de détecter les molécules organiques telles qu'évaporées, qui donnera accès à des informations plus poussées sur la dégradation des matériaux. Enfin, une cathode alternative en WO3/Ag/WO3 (WAW) a été optimisée par simulation dans le but de démontrer l'importance de l'augmentation du coefficient d'extraction de lumière. La réalisation des dispositifs a permis de démontrer une hausse de la luminance et de l'efficacité de 40% due à la cathode, en accord avec la simulation. Le transfert du point de procédé sur une machine de catégorie industrielle a résulté en la fabrication de dispositifs OLED avec cathode WAW présentant une augmentation de la durée de vie à mi luminance de +75% par rapport à la référence. / The work presented here revolves around electrical and optical optimization of OLEDs (Organic Light Emitting Device) through the development of simulation methods and tools. The electrical modeling of OLED is a complex field, belonging to R&D. At the beginning of this work, no state of the art OLED electrical simulation has been presented yet. The development of simulation, based on experimental data, would contribute to the establishment of predictive simulation, allowing a better understanding and faster R&D cycles. Firstly, an extraction method for organic semiconductors' transport parameters has been developed by fit procedure (reconstitution of experimental results with simulation). The extracted values, compared between the two mobility models, were used to compile a database. These sets allowed the realization of the simulation at various temperatures of the electrical behavior of a complete OLED stack. The careful analysis of the simulated intrinsic profiles gave an insight on charge accumulation at the recombination interface, harmful for the lifetime performance of the device. Secondly, we proposed to solve the problem with a bipolar blend to enlarge the recombination profile. After optimization of the blend inside the OLED, an increase of the lifetime of ca. +30% has been highlighted, as well as the stabilization of the color point dependency to voltage. To further understand the mechanisms related to the insertion of this layer, TOF-SIMS characterization of organic layers was studied. Very promising early results allowed the profiling of a full OLED stack, and determination of each layer. A second wave of results, bound to Ar beam analysis, demonstrated the possibility to detect undamaged molecule signatures, giving access to far more degradation related information than before. Finally, an alternative cathode made of WO3/Ag/WO3 (WAW) has been optimized for white OLED microdisplays to enhance the light outcoupling coefficient. The fabrication of the devices demonstrated a +40% increase in luminance and current efficiency, in perfect agreement with simulation. The transfer of the process onto an industrial class deposition cluster tool resulted in the fabrication of OLEDs with WAW cathodes demonstrating a +75% increase of the lifetime at half luminance.