One obstacle preventing more engineers from using finite element analysis (FEA) is the difficulty of transferring data between steps in the modeling process. A Fortran computer program, Rosetta.BYU, has been developed to open data paths between finite element preprocessors (mesh generators) and finite element analysis programs, using a custom data structure. It accepts neutral data files, Version 2.0 IGES data files, and Movie.BYU files for input/output. An application of Rosetta is described. A general workstation manager program, Davinci.BYU, is reviewed that provides a support layer between the engineer and the operating system, organizes software and data files, and facilitates on-line documentation and demonstrations. Requirements of a good user interface are discussed and supporting software, Squire.BYU, is described. An application of this software in an industrial setting is described.

Directive-based programming of graphics processing units (GPUs) has recently appeared as a viable alternative to using specialized low-level languages such as CUDA C and OpenCL for general-purpose GPU programming. This technique, which uses directive or pragma statements to annotate source codes written in traditional high-level languages, is designed to permit a unified code base to serve multiple computational platforms and to simplify the transition of legacy codes to new architectures. This work analyzes the popular OpenACC programming standard, as implemented by the PGI compiler suite, in order to evaluate its utility and performance potential in computational fluid dynamics (CFD) applications. Of particular interest is the handling of stencil algorithms, which are an important component of finite-difference and finite-volume numerical methods. To this end, the process of applying the OpenACC Fortran API to a preexisting finite-difference CFD code is examined in detail, and all modifications that must be made to the original source in order to run efficiently on the GPU are noted. Optimization techniques for OpenACC are also explored, and it is demonstrated that tuning the code for a particular accelerator architecture can result in performance increases of over 30%. There are also some limitations and programming restrictions imposed by the API: it is observed that certain useful features of modern Fortran (2003/8) are effectively disabled within OpenACC regions. Finally, a combination of OpenACC and OpenMP directives is used to create a truly cross-platform Fortran code that can be compiled for either CPU or GPU hardware. The performance of the OpenACC code is measured on several contemporary NVIDIA GPU architectures, and a comparison is made between double and single precision arithmetic showing that if reduced precision can be tolerated, it can lead to significant speedups. To assess the performance gains relative to a typical CPU implementation, the execution time for a standard benchmark case (lid-driven cavity) is used as a reference. The OpenACC version is compared against the identical Fortran code recompiled to use OpenMP on multicore CPUs, as well as a highly-optimized C++ version of the code that utilizes hardware aware programming techniques to attain higher performance on the Intel Xeon platforms being tested. Low-level optimizations specific to these architectures are analyzed and it is observed that the stencil access pattern required by the structured-grid CFD code sometimes leads to performance degrading conflict misses in the hardware managed CPU caches. The GPU code, which primarily uses software managed caching, is found to be free from these issues. Overall, it is observed that the OpenACC GPU code compares favorably against even the best optimized CPU version: using a single NVIDIA K20x GPU, the Fortran+OpenACC code is seen to outperform the optimized C++ version by 20% and the Fortran+OpenMP version by more than 100% with both CPU codes running on a 16-core Xeon workstation. / Master of Science

<p>Advanced computer simulations will play a more and more important role in future aircraft development and aeronautic research. Hardware-in-the-loop simulations enable examination of single components without the need of a full-scale model of the system. This project investigates the possibility of conducting hardware-in-the-loop simulations using a hydraulic test rig utilizing modern computer equipment. Controllers and models have been built in Simulink and Hopsan. Most hydraulic and mechanical components used in Hopsan have also been translated from Fortran to C and compiled into shared libraries (.dll). This provides an easy way of importing Hopsan models in LabVIEW, which is used to control the test rig. The results have been compared between Hopsan and LabVIEW, and no major differences in the results could be found. Importing Hopsan components to LabVIEW can potentially enable powerful features not available in Hopsan, such as hardware-in-the-loop simulations, multi-core processing and advanced plotting tools. It does however require fast computer systems to achieve real-time speed. The results of this project can provide interesting starting points in the development of the next generation of Hopsan.</p>

Advanced computer simulations will play a more and more important role in future aircraft development and aeronautic research. Hardware-in-the-loop simulations enable examination of single components without the need of a full-scale model of the system. This project investigates the possibility of conducting hardware-in-the-loop simulations using a hydraulic test rig utilizing modern computer equipment. Controllers and models have been built in Simulink and Hopsan. Most hydraulic and mechanical components used in Hopsan have also been translated from Fortran to C and compiled into shared libraries (.dll). This provides an easy way of importing Hopsan models in LabVIEW, which is used to control the test rig. The results have been compared between Hopsan and LabVIEW, and no major differences in the results could be found. Importing Hopsan components to LabVIEW can potentially enable powerful features not available in Hopsan, such as hardware-in-the-loop simulations, multi-core processing and advanced plotting tools. It does however require fast computer systems to achieve real-time speed. The results of this project can provide interesting starting points in the development of the next generation of Hopsan.

Orientadores: Rubens Maciel Filho, Liliane Maria Ferrareso Lona / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-04T02:31:19Z (GMT). No. of bitstreams: 1 MendozaMarin_FlorentinoLazaro_D.pdf: 8929110 bytes, checksum: 9041b9e7f02f9a324fa10cde9a962f54 (MD5) Previous issue date: 2004 / Resumo: O modelo determinístico e processo homopolimerização na emulsão do estireno são aplicados em reator tubular contínuo sem e com deflectores angulares internos sob condição isotérmica e não isotérmica. Os resultados de modelagem e simulação foram realizados a estado estacionário, modelo unidimensional, coordenada cilíndrica, fluxo pistão laminar completamente desenvolvido, modelo Smith-Ewart para estimar a conversão do monômero, cinética química de Arrhenius corno modelo de velocidade finita laminar para computar a geração química. O objetivo é modelar, simular e analisar o comportamento do reator de homopolimerização na emulsão do estireno com deflectores angulares inclinados internos, e comparar com reator tubular. Os métodos experimental e matemático-dedutivo foram aplicados para obter resultados, por meio de programação computacional, usando Dinâmica de Fluido Computacional através do método de volumes finitos. As seguintes variáveis como temperatura de reação constante e variável, reator tubular sem e com deflectores, temperatura de alimentação, diâmetro de reator, processo adiabático e exotérmico, calor de reação constante e velocidade axial completamente desenvolvida foram investigados. Os efeitos de conversão de monômero, área transversal interna, temperatura axial, concentração do polímero, radicais e iniciador, outros corno densidade de polímero e monômero, perda de carga e queda de pressão foram determinados e simulados. Os produtos foram caracterizados com Número de Partículas (nucleação homogênea e heterogênea), distribuição de peso molecular, tamanho de partículas de polímero e distribuição de viscosidade. Estes resultados foram validados com resultados da literatura sob condição igualou aproximada. Os resultados sob condições não isotérmicas foram melhores que os resultados isotérmicos em termos de caracterização do polímero. Isso mostra que o desenho alternativo proposto (com deflectores) permite obter o polímero com propriedades melhores em termos de número de partículas, distribuição de peso molecular, distribuição do tamanho de partículas e viscosidade / Abstract: Deterministic model and emulsion homopolymerization process of styrene are applied in continuous tubular reactor without and with internal angular baffles under isothermic and no isothermic conditions. The modeling and simulation results were approximate to steady state, one-dimensional model, cylindrical coordinate, fully developed laminar plug flow, Smith-Ewart model to estimate the monomer conversion, Arrhenius chemical kinetics as laminar finite-rate model to compute chemical source. The objective is to model, simulate and to analyze the emulsion homopolymerization reactor performance of styrene with internal-inc1ined angular baffles, and to compare with continuous tubular reactor. The experimental and mathematical-deductive methods were applied to obtain results, by means of computational programming, using Computational Fluid Dynamics (program code), finite volume method. The following variables such as constant and variable reaction temperature, tubular reactor without and with baffles, feed temperature, reactor diameter, adiabatic and exothermic process, constant reaction heat and fully developed axial velocity were investigated. The monomer conversion, internal transversal are a, axial temperature, concentration of polymer, radicals and initiator, others as density of polymer and monomer, head loss and pressure drop effects were determined and simulated. The products were characterized by partic1es number (homogeneous and heterogeneous nuc1eation), molecular weight distribution, polymer partic1es size and polymer viscosity distribution. These results were validated with literature results under same or approximate condition. The results under no isothermic conditions were better than isothermic results in terms of polymer characterization. It is shown that the proposed alternative design (with baffles) allow to obtain the polymer with better properties in terms of number of partic1es, molecular weight distribution, particle size distribution and viscosity / Doutorado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Die Dissertation beschäftigt sich mit der gekoppelten Simulation von Klimaanlage, Regelung und Gebäude mit Hilfe des Simulationssystems TRNSYS. Während für das Gebäude ein vorhandenes TRNSYS Modul verwendet wird, wurden für Klimaanlage und Regelung neue Simulationsmodule entwickelt. Der Klimaanlagensimulator ist seinerseits modular aufgebaut enthält sowohl geometrisch physikalische und empirische als auch kombinierte Modelle für die Simulation von Ventilatoren, Lufterhitzern, Feuchtluftkühlern, Befeuchtern, Regeneratoren, Plattenwärmeüberträgern, Kreislaufwärmerückgewinnern, Ventilen, hydraulischen Schaltungen usw., die für die Simulation sehr variabel miteinander verschaltet werden können. Es wurden optimierte Regelstrategien für konventionelle und DEC-Anlagen entwickelt und entsprechende TRNSYS-Module zur Umsetzung in die Simulation programmiert. Für die Sequenzregelung mehrerer Größen (z.B. Temperatur, Feuchte) wurde ein frei programmierbarer Mehrsequenzregler entwickelt, der den scheinbaren Reglerstillstand über Verknüpfungen blockierter Stellglieder einer Regelsequenz verhindert. Die Qualität der Regelsequenzen wurde mit Hilfe eines über das Rosenbrockverfahren und der dynamischen Optimierung ermittelten optimalen Vergleichsprozesses bewertet.

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I. Presentation du traducteur PIAFTRAD : le système PIAF, adaptation du système PIAF à la traduction, fonctionnement du traducteur.<br />II. Description des problèmes de traduction : définitions et notations de base. Problèmes liés à la structure de la machine. Problèmes liés au langage. <br />III. Evaluation : résultats, perspectives d'optimisation

Dans le domaine du calcul de haute performance, les architectures d'exécution sont en continuelle évolution. L'augmentation du nombre de nœuds de calcul, ou le choix d'une topologie réseau plus rapide représentent un investissement important tant en temps qu'en moyen financier. Les méthodes de prédiction de performances permettent de guider ce choix. En parallèle à ce développement, les systèmes HPC pair-à-pair (P2P) se sont également développés ces dernières années. Ce type d'architecture hétérogène permettrait la résolution des problèmes scientifiques pour un coût très faible par rapport au coût d'une architecture dédiée.Ce manuscrit présente une méthode nouvelle de prédiction de performances pour les applications réelles de calcul distribué, exécutées dans des conditions réelles. La prédiction prend en compte l'optimisation du compilateur. Les résultats sont extrapolables et ils sont obtenus pour un ralentissement réduit. Ce travail de recherche est implémenté dans un logiciel nouveau nommé dPerf. dPerf est capable de prédire les performances des applications C, C++ ou Fortran qui communiquent en utilisant les normes MPI ou P2P-SAP et qui s'exécutent sur une architecture cible pair à pair, hétérogène et décentralisée. La précision de cette contribution a été étudiée sur (i) la transformée Laplace, pour l'aspect séquentiel, (ii) le benchmark IS de NAS, pour l'aspect MPI, (iii) et le code de l'obstacle pour l'aspect calcul P2P décentralisé et l'extrapolation du nombre de nœuds.

In our age in which the use of electronic devices is expanding all over the world, their reliability and miniaturization have become very crucial. The thesis is based on the study of one of the most frequent failure mechanisms in semiconductor packages, the delamination of interface or the separation of two bonded materials, in order to improve their adhesion and a fortiori the reliability of microelectronic devices. It focuses on the metal (-oxide) / polymer interfaces because they cover 95% of all existing interfaces. Since several years, research activities at mesoscopic scale (1-10µm) have proved that the more roughened the surface of the interface, i.e., presenting sharp asperities, the better the adhesion between these two materials. Because roughness exhibits extremely complex shapes, it is difficult to find a description that can be used for reliability analysis of interfaces. In order to investigate quantitatively the effect of roughness variation on adhesion properties, studies have been carried out involving analytical fracture mechanics; then numerical studies were conducted with Finite Element Analysis. Both were done in a deterministic way by assuming an ideal profile which is repeated periodically. With the development of statistical and stochastic roughness representation on the one hand, and with the emergence of probabilistic fracture mechanics on the other, the present work adds a stochastic framework to the previous studies. In fact, one of the Stochastic Finite Element Methods, the Perturbation method is chosen for implementation, because it can investigate the effect of the geometric variations on the mechanical response such as displacement field. In addition, it can carry out at once what traditional Finite Element Analysis does with numerous simulations which require changing geometric parameters each time. This method is developed analytically, then numerically by implementing a module in a Finite Element package MSc. Marc/Mentat. In order to get acquainted and to validate the implementation, the Perturbation method is applied analytically and numerically to the 3 point bending test on a beam problem, because the input of the Perturbation method in terms of roughness parameters is still being studied. The capabilities and limitations of the implementation are outlined. Finally, recommendations for using the implementation and for furture work on roughness representation are discussed.