Thesis (MScEng) -- Stellenbosch University, 1976. / pt. A. Theory and computer program -- pt. B. Experimental. / INTRODUCTION: The advent of the high speed computer has revolutionized structural design in all spheres of Engineering. Up till then structural stress analysis was limited to over-simplification of the structure in question to comply with derived classical mathematical solutions. In practice however the picture is very different, the structure usually being complex and highly redundant in nature. The techniques involving Energy Methods to solve such structures have been known for a long time. However they required weeks of hand calculations to solve only a small number of redundancies in a structure. Neville Shute mentions this in his book Slide Rule. The development of Matrix algebra and the finite element method has made it possible to analyse, say, a complete aircraft structure in a matter of days. using a large capacity high speed computer~ Experimental results have shown that finite element stress analysis comes much closer to reality than the dated classical methods.

Nous nous opposons dans cette thèse à la tentative de Maurice Merleau-Ponty pour réduire toute forme de "qualia" à des prédicats structuraux, tentative par laquelle nous comprenons l'ontologie de la « chair » qu'il nous semble mettre en place dès ses premiers travaux sur « l'expression ». Nous visons cependant à travers lui plus généralement toute théorie « structurale» de la sensation, désignant par là toute théorie qui soutient qu'on ne peut pas déterminer relationnellement un contenu de sensation sans le modifier intrinsèquement. La tâche est cependant rendue difficile par le grand nombre de faits empiriques que Merleau-Ponty convoque à l'appui de sa théorie structurale. En particulier, il s'appuie sur l'interprétation structurale de ces faits qui avait déjà été réalisée avant lui par Kurt Koffka au sein de la psychologie de la forme. Nous commençons donc par examiner cette interprétation et les faits sur lesquels elle repose, en montrant qu'ils ne peuvent paraître corroborer une théorie structurale que si l'on confond « abstraire » et « séparer réellement » une qualité de son contexte. Nous convoquons alors William James à l'appui de ces conclusions, en rappelant qu'il avait déjà montré contre les théories néo-hégéliennes de son époque l'illégitimité de leur prétention à se réclamer de faits psychologiques similaires, et qu'il avait soutenu contre eux une théorie de la connaissance par accointance que nous cherchons à reprendre à notre compte, pour esquisser une défense de l'introspection pure et simple. / We are trying here to object to Maurice Merleau-Ponty's attempt to reduce qua/ia to structural predicates, which is the way we understand his ontology of the "flesh", as he seems to us to develop it already in his first works on "expression". We are more generally objecting through him to any kind of "structural" theory concerning sensation, meaning by this any theory which claims that one cannot attribute a relation to a sensorial content without intrinsically altering it. Our task is complicated by the great number of empirical facts that Merleau-Ponty calls for to prove his structural theory. He notably finds great help in the structural interpretation Kurt Koffka had already laid down for these facts as a Gestalt psychologist. Consequently, we begin with the examination of this theory and of the facts that support it, showing that they cannot seem to corroborate a structural theory unless one confuses "abstraction" and "real separation" of a qua/e from its context. We then call for William James to support these conclusions, reminding that he had already showed the illegitimacy of the claim by the neo-Hegelian writers of his time to find empirical proof for their own structural theories in similar psychological data. He had also suggested a "knowledge by acquaintance" theory against those writers that we are trying to use in defense for introspection pure and simple.

A análise da continuidade espacial inclui uma série de ferramentas para estimar e modelar a continuidade de variáveis aleatórias regionalizadas. Ela é a base para muitas das avaliações de depósitos minerais baseadas na geoestatísitca. O modelo ajustado é de grande importância e influencia nos resultados em vários algoritmos de krigagem e simulações subsequentes. Tanto os softwares acadêmicos e comerciais podem melhorar no desenvolvimento dos gráficos, na interatividade com o usuário e no uso de formas automáticas de modelagem. O SGeMS (Stanford Geoestatistical Modeling Software) é um programa gratuito usado entre a comunidade de geoestatísticos ao qual tem um grande potencial de desenvolvimento, mas que, no entanto, ainda não possui todas as ferramentas de análise da continuidade espacial incorporadas. Diferentemente do SGeMS, o GSLIB é uma boa biblioteca gratuita para análise geoestatística e é mais completa, mas as estradas do programa são modificadas pela edição de arquivos .txt e usando linhas de comando o que torna a utilização do software pouco amigável com o usuário, apesar da robustez e qualidade dos programas da biblioteca. Dada as limitações dos mais usados e completos softwares gratuitos de geoestatística, essa dissertação objetiva a transcrição e adaptação do algoritmo do GSLIB (GamV .f) para o software SGeMS, modificando a lógica de programação para criar diferentes ferramentas auxiliares como h-scatterplots e mapas de variograma e covariograma. Os resultados demonstraram que a adaptação de algoritmos antigos leva a uma solução gratuita. Além disso, um algoritmo para a otimização da modelagem de variogramas pelo método dos mínimos quadrados foi desenvolvido. As rotinas foram desenvolvidas ambas em C++ e em Python. Os algoritmos foram validados com os valores obtidos pelo software GSLIB. Todos os desenvolvimentos dos plug-ins foram testados e validados usando dois casos ilustrativos: um depósito de ferro e um caso polimetálico. Os resultados provaram ser consistentes e similares com aqueles obtidos com softwares comerciais e renomados. / The spatial continuity analysis includes a serie of tools to estimate and model the continuity of regionalized random variables. It is the basics for many mineral deposit evaluation methods based on geostatistics. The model adjusted is of paramount importance and influences the results in many subsequent kriging and simulation algorithms. Both commercial and academic softwares can be improved in graphics, users interactivity with and automated tools for modeling spatial continuity. SGeMS (Stanford Geoestatistical Modeling Software) is a freeware program used among the geostatistical community which has an extremely potential for development however it does not have enough variographic or graphical tools. Unlike SGeMS, GSLIB is a good and more complete free library for geostatistical analysis, however the program inputs are modified by editing of .txt files and uses DOS command lines. This makes the software less user friendly, despite its robustness and quality. Given the limitation on both most used and complete freeware geostatistical softwares, this dissertation aims at transcripting and adpating an algorithm from GSLIB(GamV.f) into SGeMS software, handling the programming logic to create different auxiliary tools as h-scatterplot and variomaps. The results demonstrated that the adaptation of the old and stable algortihms lead to an inexpensive solution. Futhermore, an algorithm was developed for optimizing variogram modeling based on weigthed least squares method. The routines were developed in both C++ and Phyton. The algorithms were validated against actual values generated by GSLIB. All developed of plug-ins were tested and validated using two illustration studies: an iron ore deposit and a polymetallic one. The results proved to be consistent and similar to the ones obtained by commercial well known sofwares.

This thesis was conducted in the design office of “Blackwing SwedenAB”, a Swedish aircraft manufacturer. The mission is to study air loadson a mechanical retractable landing gear. This study is realised to verifyif the structure is resistant enough for a landing and find the retractionspeed of the system. To accomplish those goals, the thesis was realisedon site with a state of-the-art, research on technical solutions, handcalculations, ANSYS analysis and tests with validation by a companyexpert. Testing is part of the certification and results show the structureis strong enough to resist air loads but present also an unexpected result.All this work assures the stability of the structure for a safe landing butalso a need to redesign the leg for a stronger support at impact.

Na área de simulação de processos, existe uma visível tendência da migração das ferramentas seqüenciais modulares, que hoje são as mais amplamente utilizadas, para as baseadas em equações. Uma das principais vantagens do paradigma baseado em equações ou simultâneo é que este se mostra eficiente na solução de problemas de simulação, otimização, estimação de parâmetros e reconciliação de dados, todos baseados em um mesmo conjunto de modelos, evitando retrabalho de modelagem. Porém, a tecnologia simultânea também apresenta algumas deficiências, onde destacam-se os problemas de robustez tanto na modelagem quanto na obtenção de resultados numéricos. Este trabalho tem como objetivo reunir e desenvolver técnicas que permitam reduzir estas deficiências. Para tanto, as técnicas conhecidas para depuração de sistemas de equações que representam problemas estacionários e dinâmicos foram estudadas em detalhe. Pôde-se observar que para o caso estático os métodos disponíveis para depuração de modelos, já se apresentam em um nível bem desenvolvido. Já para o caso dinâmico, onde há uma maior complexidade, as técnicas conhecidas encontram-se em um nível de desenvolvimento muito menor. Neste ponto encontram-se as principais contribuições deste trabalho. / In the field of process simulation the movement from the sequential modular tools, which are currently the most widely used, to the equation based approach is clear. One of the key advantages of the equation based or simulatneous approach is that using a single model one can solve simulation, optimization, parameter estimation, and optimization problems. This fact avoids modeling rework for each application. However, the simultaneous technology has problems regarding modeling and solving robustness. This work aims to group and develop methods capable of minimize these deficiencies. In order to achieve this goal, available debugging approaches for both steady-state and dynamic system of equations were studied in detail. For the steady-state case well stablished debugging techniques are known. For dynamic models, where the complexity is higher, the analysis and debugging methods are much less mature. This was the source for the major contributions of this work.

The analysis of social reasoning is at the core of understanding how to manage social networks. Since interpersonal relations are composed of multiple factors with different nature (i.e., structural and social factors), we explore their influence on the strategizing processes in social networks. The research is based on the consideration of social networks in terms of network games. Therefore, we formalize interpersonal relations using the methods of structural and social analysis combined with game theoretic approach. Specifically, we formalize social power of an agent and use it to quantify payoffs. Based on reasoning over values of power we show how individuals reach stability and Nash equilibrium with their peers in network games.

A análise da continuidade espacial inclui uma série de ferramentas para estimar e modelar a continuidade de variáveis aleatórias regionalizadas. Ela é a base para muitas das avaliações de depósitos minerais baseadas na geoestatísitca. O modelo ajustado é de grande importância e influencia nos resultados em vários algoritmos de krigagem e simulações subsequentes. Tanto os softwares acadêmicos e comerciais podem melhorar no desenvolvimento dos gráficos, na interatividade com o usuário e no uso de formas automáticas de modelagem. O SGeMS (Stanford Geoestatistical Modeling Software) é um programa gratuito usado entre a comunidade de geoestatísticos ao qual tem um grande potencial de desenvolvimento, mas que, no entanto, ainda não possui todas as ferramentas de análise da continuidade espacial incorporadas. Diferentemente do SGeMS, o GSLIB é uma boa biblioteca gratuita para análise geoestatística e é mais completa, mas as estradas do programa são modificadas pela edição de arquivos .txt e usando linhas de comando o que torna a utilização do software pouco amigável com o usuário, apesar da robustez e qualidade dos programas da biblioteca. Dada as limitações dos mais usados e completos softwares gratuitos de geoestatística, essa dissertação objetiva a transcrição e adaptação do algoritmo do GSLIB (GamV .f) para o software SGeMS, modificando a lógica de programação para criar diferentes ferramentas auxiliares como h-scatterplots e mapas de variograma e covariograma. Os resultados demonstraram que a adaptação de algoritmos antigos leva a uma solução gratuita. Além disso, um algoritmo para a otimização da modelagem de variogramas pelo método dos mínimos quadrados foi desenvolvido. As rotinas foram desenvolvidas ambas em C++ e em Python. Os algoritmos foram validados com os valores obtidos pelo software GSLIB. Todos os desenvolvimentos dos plug-ins foram testados e validados usando dois casos ilustrativos: um depósito de ferro e um caso polimetálico. Os resultados provaram ser consistentes e similares com aqueles obtidos com softwares comerciais e renomados. / The spatial continuity analysis includes a serie of tools to estimate and model the continuity of regionalized random variables. It is the basics for many mineral deposit evaluation methods based on geostatistics. The model adjusted is of paramount importance and influences the results in many subsequent kriging and simulation algorithms. Both commercial and academic softwares can be improved in graphics, users interactivity with and automated tools for modeling spatial continuity. SGeMS (Stanford Geoestatistical Modeling Software) is a freeware program used among the geostatistical community which has an extremely potential for development however it does not have enough variographic or graphical tools. Unlike SGeMS, GSLIB is a good and more complete free library for geostatistical analysis, however the program inputs are modified by editing of .txt files and uses DOS command lines. This makes the software less user friendly, despite its robustness and quality. Given the limitation on both most used and complete freeware geostatistical softwares, this dissertation aims at transcripting and adpating an algorithm from GSLIB(GamV.f) into SGeMS software, handling the programming logic to create different auxiliary tools as h-scatterplot and variomaps. The results demonstrated that the adaptation of the old and stable algortihms lead to an inexpensive solution. Futhermore, an algorithm was developed for optimizing variogram modeling based on weigthed least squares method. The routines were developed in both C++ and Phyton. The algorithms were validated against actual values generated by GSLIB. All developed of plug-ins were tested and validated using two illustration studies: an iron ore deposit and a polymetallic one. The results proved to be consistent and similar to the ones obtained by commercial well known sofwares.

Made available in DSpace on 2016-06-02T20:09:23Z (GMT). No. of bitstreams: 1 6717.pdf: 4234806 bytes, checksum: 7f07b52b026f378a97637a2bfdeef7a9 (MD5) Previous issue date: 2015-03-30 / Financiadora de Estudos e Projetos / In face of the needs to improve tools that increase productivity in project design, coupled with technical reliability, it was developed a free computer application that performs the equations and details the longitudinal reinforcement of pre-tensioned simply supported prestreessed beams, so it can assist professionals of the área. The program was developed in the graphical environment of Lazarus, which uses Pascal s programming language, in order to use object-oriented programming (OOP), facilitating the user who wishes to have access to the constituent objects. Initially, the user enters with the geometric cross-section s data, as well as the loading characteristics over the beam. In this way, the software will be able to pre-size its longitudinal reinforcement. According to NBR 6118:2014 is necesary to check tensions in both edges of the beam for the serviceability state combination (SLS) and ultimate limit state (ULS) in an empty-load stage, crack control requierments, as well as checks of deflections. The checking for ULS in full-load stage is made by checking the collapse section. Prestressing losses will be properly calculated according to criteria established in NBR 6118:2014, in order to obtain values closer to reality. Finally, the software checks the transverse reinforcement to see if it can resist the efforts of the shear force. This paper also presents the assumptions and normative precepts used in the program. Several examples of validation were made and it is shown how it can turn into an analysis tool. Also presents the listings and it is also given the different possibilities of expansion. / Frente às necessidades em se aprimorar ferramentas que aumentem a produtividade na elaboração de projetos, aliada à confiabilidade técnica, optou-se por desenvolver um aplicativo computacional livre que realiza o cálculo e o detalhamento da armadura longitudinal, ativa e passiva, de vigas com pré-tração e biapoiadas, de forma a auxiliar profissionais da área da engenharia civil no cálculo estrutural de vigas protendidas. O programa está desenvolvido no ambiente gráfico do Lazarus, que utiliza a linguagem Pascal, de forma a utilizar programação orientada ao objeto (POO), facilitando ao usuário que deseje ter acesso aos objetos constituintes. A princípio, o usuário entra com os dados geométricos da seção transversal, assim como os carregamentos solicitantes da viga. Desta forma, o programa esta apto a pré-dimensionar sua armadura longitudinal. São realizadas verificações de tensões, em ambas as bordas, para as combinações no estado limite de serviço (ELS) e no estado limite último (ELU) em vazio, a análise de abertura de fissuras e as verificações de flechas no elemento. A verificação no estado limite último no tempo infinito é feita verificando a ruptura da seção. As perdas de protensão são devidamente calculadas segundo critérios estabelecidos na NBR6118:2014, de forma a obter valores próximos com a realidade. Por fim, verifica-se a armadura transversal para resistir à força cortante. Neste trabalho são, ainda, apresentadas as hipóteses e preceitos normativos usados no programa. São feitos diversos exemplos de validação e mostra-se como o mesmo pode se transformar em ferramenta de análise. São ainda apresentadas as listagens e indicadas, também, as diversas possibilidades de expansão do mesmo.

Made available in DSpace on 2015-08-20T17:09:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-27. Added 1 bitstream(s) on 2015-08-20T17:26:46Z : No. of bitstreams: 1 000844363.pdf: 3753876 bytes, checksum: ebef28833b55a325c9ee6116b386f497 (MD5) / No presente trabalho foi desenvolvida a formulação linear do método dos elementos de contorno para a análise estrutural de chapas com carregamento normais e tangenciais a sua superfície. A equação integral do deslocamento é deduzida a partir do Teorema de Reciprocidade de Betti, considerando espessura constante na chapa. Posteriormente foi detalhada a teoria para a análise não linear de chapas através do MEC (método dos elementos de contorno) introduzindo ao sistema de equações campos de esforços iniciais (ou plásticos) em células definidas no domínio. A solução não linear se obtém por uma formulação implícita, na qual as correções das deformações são feitas através do operador tangente consistente que se atualiza a cada nova iteração, levando a convergência quadrática do processo iterativo. Utilizou-se como critério de ruptura o de Von Misses. Exemplos foram analisados a fim de mostrar a convergência quadrática no processo iterativo e também a convergência dos resultados numéricos à medida que se refinava a discretização do contorno em elementos e do domínio em células / In this paper the linear formulation of the boundary element method (BEM) for analyzing the stretching plate problem written in terms of displacements and tractions in the normal and tangential directions to the boundary has been developed. The integral equation of displacement is derived from Betti's reciprocity theorem, considering constant thickness on the plate. Then the BEM nonlinear formulation has been obtained by considering an initial (or inelastic) force field over the plate domain, requiring therefore the plate domain discretization into cells. The nonlinear solution is obtained by an implicit formulation, where the strains correction to be computed for each iteration is obtained by considering the consistent tangent operator, leading to a quadratic convergence rate in the iterative procedure required to achieve the plate equilibrium. In the numerical examples, the Von Mises criterion has been adopted to model the material behavior, showing the quadratic convergence rate. Besides different discratizations have been analyzed in order to show as well the results convergence

This thesis addresses the issues surrounding the application of the finite element method to analyse composite structure repairs with an emphasis on aircraft applications. A comprehensive literature survey has been carried out for this purpose and the results are presented. A preliminary study and a comparative study of different modelling approaches have been completed. These studies aim to explore and identify the problems in modelling repairso n simplec ompositep anelsw ith speciala ttention given to adhesivem odelling. Three modelling approaches have been considered: Siener's model which is an extension of the traditional plane strain 2D model used for adhesively bonded joints, Bait's model which is a promising new approach and a full 3D model. These studies have shown that these methods are complementary providing a different insight into bonded repairs. They have also highlighted the need for a new modelling approach which will provide an overall view of bonded repairs. Improved modelling approachesh ave been developedf or externallyb onded patch and flush repairs. These models enable the study of adhesive failure as well as composite adherendf ailures.T hesea pproachesh aveb eena ppliedt o real repairs and the predicted results compared to experimental data. Four case studies have been conducted: external bonded patch repairs to composite plates, a scarf joint for bonded repairs, a flat panel repaired with a scarfed patch and a repaired curved panel. These case studies have shown that bonded repairs to composite structures can be analyseds uccessfullyu sing PC-basedc ommercialf inite elementc odes.