Afin d’améliorer la qualité des solutions proposées par l’optimisation dans les processus de conception, il est important de se donner des outils permettant à l’optimiseur de parcourir l’espace de conception le plus largement possible. L’objet de cette Thèse est d’analyser différentes méthodes de paramétrage de formes surfaciques d’une automobile en vue de proposer à Renault un processus d’optimisation efficace. Trois méthodes sont analysées dans cette Thèse. Les deux premières sont issues de l’existant, et proposent de mélanger des formes, afin de créer de la diversité. Ainsi, on maximise l’exploration de l’espace de conception, tout en limitant l’effort de paramétrage des CAO. On montre qu’elles ont un fort potentiel, mais impliquent l’utilisation de méthodes d’optimisation difficiles à mettre en œuvre aujourd’hui. La troisième méthode étudiée consiste à exploiter la formulation de Koiter des équations de coques, qui intègre paramètres de forme et mécanique, et de l’utiliser pour faire de l’optimisation de forme sur critères mécaniques. Cette méthode a par ailleurs pour avantage de permettre le calcul des gradients. D’autre part, nous montrons qu’il est possible d’utiliser les points de contrôles de carreaux de Bézier comme paramètres d’optimisation, et ainsi, de limiter au strict nécessaire le nombre de variables du problème d’optimisation, tout en permettant une large exploration de l’espace de conception. Cependant, cette méthode est non-standard dans l’industrie et implique des développements spécifiques, qui ont été réalisés dans le cadre de cette Thèse. Enfin, nous mettons en place dans cette Thèse les éléments d’un processus d’optimisation de forme surfacique. / To improve optimized solutions quality in the design process, it is important to provide the optimizer tools to navigate the design space as much as possible. The purpose of this thesis is to analyze different parametrization methods for automotive surface shapes, in order to offer Renault an efficient optimization process. Three methods are analyzed in this thesis. The first two are closed to the existing ones, and propose to blend shapes to create diversity. Thus, we are able to maximize the exploration of the design space, while minimizing the effort for CAD setting. We show their high potential, but they involve the use of optimization methods difficult to implement today. The third method is designed to exploit the formulation of Koiter shell equations, which integrates mechanical and shape parameters, and to use it to perform shape optimization with respect to different mechanical criteria. This method also has the advantage of allowing the gradients calculation. On the other hand, we show that it is possible to use the Bezier’s control points as optimization parameters, and thus control the minimum number of variables necessary for the optimization problem, while allowing a broad exploration of the design space. However, this method is non-standard in the industry and involves specific developments that have been made in the context of this thesis. Finally, we implement in this thesis essentials elements of an optimization process for surface shapes.

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The objective of this study is to identify the optimal designs of converging-diverging supersonic and hypersonic nozzles that perform at maximum uniformity of thermodynamic and flow-field properties with respect to their average values at the nozzle exit. Since this is a multi-objective design optimization problem, the design variables used are parameters defining the shape of the nozzle. This work presents how variation of such parameters can influence the nozzle exit flow non-uniformities. A Computational Fluid Dynamics (CFD) software package, ANSYS FLUENT, was used to simulate the compressible, viscous gas flow-field in forty nozzle shapes, including the heat transfer analysis. The results of two turbulence models, k-e and k-ω, were computed and compared. With the analysis results obtained, the Response Surface Methodology (RSM) was applied for the purpose of performing a multi-objective optimization. The optimization was performed with ModeFrontier software package using Kriging and Radial Basis Functions (RBF) response surfaces. Final Pareto optimal nozzle shapes were then analyzed with ANSYS FLUENT to confirm the accuracy of the optimization process.

The ability to withstand a short circuit is the most essential feature of a power transformer. The most important reason to design short-circuits proof transformers is to ensure the reliability of the power grid (avoiding black outs etc.) and safety (fire and explosion in case of failure). During short circuit, the most effected winding is the LV winding due to the flow high currents even during the normal working condition. So during a short circuit large forces are generated which act on the winding and these forces can reach hundreds of tons in fraction of a second, so the transformer must be properly designed in order to withstand these forces or the transformer can fail in different ways. One of the possible failure modes called “Spiraling” is discussed and analyzed in this thesis. Spiraling Occurs when the LV winding twists tangentially in the opposite direction at the ends due to radial short circuit forces. From literature study the transient forces acting on the winding during a 3-phase short circuit was determined and these transient forces were used to perform simulations on the model. The axial and radial forces applied on the model were such that it has a uniform magnitude per each turn. Various analysis was performed on the model which includes the Static, Modal and Transient Structural analysis in Ansys Workbench and each analysis involved parametric analysis where the deformations and the torsional mode shapes were determined

This master’s thesis deals with the analysis of geometric shapes fuselage amfibie SEAGLE and propose optimal shapes for the improvement of hydrodynamic and aerodynamic properties.

This thesis deals with the cutting of flat shapes of polystyrene by industrial robot using Robotmaster. There are some variants of the shaped components that can create by using Robotmaster. The task of the work is also a demonstration task in the realization of use a resistance wire as a tool and polystyrene boards as a workpiece material.

In order to achieve good apparel fit, it is necessary to identify, define and classify the size and shape of a population based on a combination of key body measurements (Petrova & Ashdown, 2008). Unrepresentative sizing systems ultimately lead to apparel fit problems which are further compounded by an unstandardised and ambiguous communication of sizing and fit within the apparel manufacturing sector (Chun-Yoon & Jasper, 1996; Winks, 1997; Simmons & Istook, 2004). According to Magagula and Zwane (2006), the sizing system used by the apparel industry in Swaziland is based on British anthropometric measurements taken in the 1940s; yet there is a significant variance in the body proportions and dimensions of different ethnic groups and within ethnic groups (Yu, 2004c:183). It is therefore predictable that young Swazi women would experience apparel fit problems with ready-to-wear apparel. Body forms are manufactured using body dimensions of the apparel manufacturer’s target market in order to yield satisfactory levels of fit. This is however not the case for the Swazi market, as very little current anthropometric data exists on Swazi women. As a result, small-scale apparel manufacturers encounter problems with regard to body forms that are not manufactured according to the shape of Swazi women. The aim of this research was therefore to identify and describe the most prevalent body shapes of young Swazi women using body dimensions, to identify and describe the body shapes of the currently used body forms through body dimensions, to describe and compare the most prevalent body measurements and proportions of young Swazi women and those of currently used body forms, and finally to test and evaluate the fit of the test garment which represents the most prevalent size and shape of the Swazi women, on the body forms. This study is explorative in nature as it helped to clarify a largely undefined area of body shape analysis in respect of young Swazi women. Under the quantitative research strategy, a survey research methodology was used. Anthropometric techniques and traditional tailor’s measurements were used to obtain body measurements for various dimensions of young Swazi women, and training in anthropometry was undertaken to ensure that the measurements were taken reliably and accurately. It emerges from the results of this study that the most prevalent body shape of young Swazi women is the triangular body shape, followed by the hourglass body shape, while the inverted triangle is the least common body shape. The two body form brands employed in this study on the other hand are found to bear different body shapes from each other. Though one brand appears to have the same shape as that of the most prevalent body shape of young Swazi women, it is apparent that there are notable differences regarding the degree of the body contours, i.e. the Swazi women are conspicuously heavier and more rounded at the hip area – as the measurement differences show. The expectation that this body form will offer a better fit to Swazi women as they have similar body shapes in principle, is not realised when the fit of the test garment is evaluated, due to the vast differences in the drop values. The fit problems that are predicted to be experienced by young Swazi women when using the body forms for pattern generation, based on the significant measurement differences, are indeed observed during the evaluation of the fit of the test garment on the body forms. The fit problems exhibited during the testing of the fit of the test garment based on the most prevalent body shape of young Swazi women on the body forms, are mainly due to a wider lower hip girth and shorter length proportions at the upper torso of the young Swazi women. The results of this study contribute to a better understanding of the body shapes that exist among young Swazi women and the fit problems that young Swazi women experience as a consequence of unrepresentative body forms being used in terms of size and shape. Furthermore, the need for all stakeholders in the apparel manufacturing industry to reach consensus on the standardisation and communication of sizing emerges as a step toward affording better fitting apparel to the Swazi women. / Dissertation (MConsumer Science)--University of Pretoria, 2012. / gm2014 / Consumer Science / unrestricted

In South Africa, a representative anthropometric study of South African women has never been undertaken, as such little is known about the body shapes of South African women. Nevertheless, research on the body shapes of South African women is ongoing (Makhanya, 2012). According to the preliminary findings of Makhanya’s (2012) research, 59.26% of South African female students of African descent have a triangular body shape. The triangular body shape differs from the ideal body shape that ready-to-wear apparel sizing is presently based on, and is a contributing factor to the problems experienced with the quality of fit of ready-to-wear apparel by South African women of African descent. Therefore, the aim of this exploratory study was to develop experimental size specifications for the body measurements required for a basic sheath dress for South African female students of African descent with a triangular body shape. The students were of medium height, aged between 18 and 25 years, in the size 6/30 to size 14/38 size range, and enrolled at the University of Pretoria. The experimental size specifications were developed by statistically analysing an anthropometric database of female students of the University of Pretoria using regression analysis. Thereafter, the quality of fit attained from the experimental size specifications and the traditional (i.e. current) size specifications was evaluated to determine whether the experimental size specifications offer the unit of analysis with improved overall quality of fit. A panel of professionals with experience in apparel fit evaluation evaluated the quality of fit of the test garments. The test garments developed from the experimental size specifications were considered by the panel of professionals to offer the unit of analysis with improved overall quality of fit. The findings of the study suggest that South African ready-to-wear apparel sizing needs to accommodate the different body shapes found in South Africa. / Dissertation (MConsumer Science)--University of Pretoria, 2012. / gm2014 / Consumer Science / unrestricted

Ces travaux de thèse portent sur la proposition de stratégies de segmentation des tumeurs cancéreuses dans un contexte multimodal et multitemporel. La multimodalité fait référence au couplage de données TEP/TDM pour exploiter conjointement les deux sources d’information pour améliorer les performances de la segmentation. La multitemporalité fait référence à la disposition des images acquises à différents dates, ce qui limite une correspondance spatiale possible entre elles.Dans une première méthode, une structure arborescente est utilisée pour traiter et pour extraire des informations afin d’alimenter une segmentation par marche aléatoire. Un ensemble d'attributs est utilisé pour caractériser les nœuds de l'arbre, puis le filtrer et projeter des informations afin de créer une image vectorielle. Un marcheur aléatoire guidé par les données vectorielles provenant de l'arbre est utilisé pour étiqueter les voxels à des fins de segmentation.La deuxième méthode traite le problème de la multitemporalité en modifiant le paradigme de voxel à voxel par celui de nœud à nœud. Deux arbres sont alors modélisés à partir de la TEP et de la TDM avec injection de contraste pour comparer leurs nœuds par une différence entre leurs attributs et ainsi correspondre à ceux considérés comme similaires en supprimant ceux qui ne le sont pas.Dans une troisième méthode, qui est une extension de la première, l'arbre calculé à partir de l'image est directement utilisé pour mettre en œuvre l'algorithme développé. Une structure arborescente est construite sur la TEP, puis les données TDM sont projetées sur l’arbre en tant qu’informations contextuelles. Un algorithme de stabilité de nœud est appliqué afin de détecter et d'élaguer les nœuds instables. Des graines, extraites de la TEP, sont projetées dans l'arbre pour fournir des étiquettes (pour la tumeur et le fond) à ses nœuds correspondants et les propager au sein de la hiérarchie. Les régions évaluées comme incertaines sont soumises à une méthode de marche aléatoire vectorielle pour compléter l'étiquetage de l'arbre et finaliser la segmentation. / This work focuses on the proposition of cancerous tumor segmentation strategies in a multimodal and multitemporal context. Multimodal scope refers to coupling PET/CT data in order to jointly exploit both information sources with the purpose of improving segmentation performance. Multitemporal scope refers to the use of images acquired at different dates, which limits a possible spatial correspondence between them.In a first method, a tree is used to process and extract information dedicated to feed a random walker segmentation. A set of region-based attributes is used to characterize tree nodes, filter the tree and then project data into the image space for building a vectorial image. A random walker guided by vectorial tree data on image lattice is used to label voxels for segmentation.The second method is geared toward multitemporality problem by changing voxel-to-voxel for node-to-node paradigm. A tree structure is thus applied to model two hierarchical graphs from PET and contrast-enhanced CT, respectively, and compare attribute distances between their nodes to match those assumed similar whereas discarding the others.In a third method, namely an extension of the first one, the tree is directly involved as the data-structure for algorithm application. A tree structure is built on the PET image, and CT data is then projected onto the tree as contextual information. A node stability algorithm is applied to detect and prune unstable attribute nodes. PET-based seeds are projected into the tree to assign node seed labels (tumor and background) and propagate them by hierarchy. The uncertain nodes, with region-based attributes as descriptors, are involved in a vectorial random walker method to complete tree labeling and build the segmentation.

The Wind Turbine industry continues to drive towards high market penetrationand profitability. In order to keep Wind Turbines in field for as long as possiblecomputational analysis tools are required. The open source tool QBlade[38] softwarewas extended to now contain routines to analyse the structural properties of WindTurbine blades. This was achieved using 2D integration methods and a Tapered Euler-Bernoulli beam element in order to find the mode shapes and 2D sectional properties.This was a key step towards integrating the National Renewable Energy LaboratoriesFAST package[32] which has the ability to analyse Aeroelastic Responses. The QFEMmodule performed well for the test cases including: hollow isotropic blade, rotatingbeam and tapered beam. Some improvements can be made to the torsion estimationof the 2D sections but this has no effect on the mode shapes required for the FASTsimulations.