<p>Betrakta en analytisk funktion f som beror av en komplex variabel z och ett ändligt antal reella parametrar param1, param2, ..., paramk, där k är ett positivt heltal. Rötterna till funktionen, med avseende på variabeln z, erhålls genom att lösa ekvationen f(z, param1, param2, ..., paramk)=0. Således kommer dessa rötter att vara beroende av parametrarna. Låt en av parametrarna paramj, där j är ett positivt heltal mindre än eller lika med k, vara monotont ökande eller avtagande på ett reellt intervall. Även funktionens rötter kommer att variera, till följd av de olika värdena på parametern paramj.</p><p>Ett datorprogram, som beräknar och undersöker rörelsen hos rötterna till en funktion då en parameter varierar, har utvecklats och implementerats i MatLab. Underprogram som använder numerisk analys i form av sekantmetoden för att beräkna approximationer av rötter och linear algebra för att kunna identifiera de rötter som är felaktiga, har också skrivits. Det vill säga, programmets huvudsakliga åtgärder ligger i att kontrollera om de beräknade värdena är korrekta och att rätta till de som är felaktiga.</p><p>Examensuppgiften och det implementerade programmet har främst varit inriktade på ljuddämpare, vilket innebär en problemställning, där rötterna till en funktion undersöks för att analysera hur akustiska vågor fortplantas vid olika villkor. Således har den huvudsakliga målsättningen varit att förenkla tillvägagångssättet för att beräkna rötter.</p> / <p>Consider an analytic function f of a complex variable z and of a finite number of real parameters param1, param1, ..., paramk, for a positive integer k. The roots of the function, with respect to the variable z, are obtained by solving the equation f(z, param1, param2, ..., paramk)=0. Consequently those roots will depend on the parameters. Let one of the parameters paramj, where j is a positive integer less or equal to k, be monotonically increasing or decreasing on an interval of the real line. As a consequence of those different values of paramj, also the roots of the function f will vary.</p><p>A computer program that calculates and examines the behavior of the roots of a function as one parameter varies, has been developed and implemented in MatLab. Subroutines have been written, which use numerical analysis by using the secant method to calculate approximations of roots and linear algebra to identify the false roots. That is, the main measures of this program is to make sure that the calculated values are correct and to adjust the false ones.</p><p>The paper and the implemented program are principally concentrated on silencers, that is, on modal analysis. Modal analysis is the examination of how the shape and the behaviour of acoustic waves are affected by different conditions, which is done by studying the roots of a function. Consequently, the main purpose has been to facilitate the procedure of finding roots.</p>

Term of remote-lab is certain types of laboratories which practical experiments are directedfrom a separate area by remote controller devices. This study is part of developing andupgrading advanced vibration remote laboratory. In the new remote lab, users have theability to measure the dynamic characteristics of the test object similar to the current existingremote lab. But in addition to current existing remote lab, they are capable to modifydynamic properties of the test object remotely by attaching vibration test instruments; such asa block of mass, spring-mass or non-linear spring. Doing several accurate experimental testsremotely on the test object are the toughest issues we faced as designers. In creating anddeveloping of this remote-lab, number of different approaches was adopted for producingwell-defined tests. Also, instead of implementing routine devices and techniques for regularvibration laboratories, the new prototypes were designed by finite elements method (FEM)and LABVIEW. For instance, the desirable test object, the attachment mechanism, usefulapplications, and proper software for managing via internet were prepared.

No description available.

Thesis (Ph.D.)--University of Melbourne, Dept. of Civil and Environmental Engineering, 2007. / Typescript. Includes bibliographical references (leaves 344-361).

Thesis (M.App.Sc.) - Carleton University, 2002. / Includes bibliographical references (p. 123-127). Also available in electronic format on the Internet.

Thesis (M. App. Sc.)--Carleton University, 2005. / Includes bibliographical references (p. 181-186). Also available in electronic format on the Internet.

Made available in DSpace on 2016-12-12T20:25:12Z (GMT). No. of bitstreams: 1 Gilberto Paulo Wappler.pdf: 3228907 bytes, checksum: b89445d7a190e66455c34f9382fb8d2f (MD5) Previous issue date: 2014-12-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work has the objective of implementing a structural optimization procedure in order to adjust the natural frequency of electric motors. This is accomplished by modifying some flange dimensions, which is the part connecting the motor to the system being driven. The implemented optimization algorithm is the PSO (Particle Swarm Optimization), which proved to be appropriate for the type of problem considered (non convex and with few design variables). The optimization formulation aims to get a motor/flange whose first natural frequency is equal to a specified value while observing the criterion of Rankine for brittle materials. Both the modal analysis and evaluation of the principal stresses are performed by a commercial finite element code. Due to the large computational cost associated to the combined use of PSO with an external finite element program, it is studied an approximation by least squares of the natural frequency and of the principal stresses. This procedure is effective and extremely efficient. Examples of flange designs obtained using the proposed formulation are presented and discussed, showing the validity of the procedure adopted. / Este trabalho tem como objetivo implementar um procedimento de otimização estrutural aplicado ao ajuste da frequência natural de motores elétricos. Isto é realizado pela modificação de algumas dimensões do flange, elemento de ligação entre o motor e o sistema que está sendo acionado. O algoritmo de otimização implementado é o PSO (Otimização por enxame de partículas), que se mostrou adequado ao tipo de problema considerado (não convexo e com poucas variáveis de projeto). A formulação de otimização tem como objetivo obter um conjunto motor/flange cuja primeira frequência natural seja igual a um valor estipulado, respeitando o critério de Rankine para materiais frágeis. A análise modal e de tensões é realizada por um programa comercial de elementos finitos. Devido ao grande custo computacional associado ao uso conjunto do PSO com um programa externo de elementos finitos, é estudada uma aproximação por mínimos quadrados da frequência natural e das tensões principais. Este procedimento se mostrou eficaz e extremamente eficiente. Exemplos de projetos de flange obtidos com o uso da formulação proposta são apresentados e discutidos, mostrando a validade do procedimento adotado.

Les éboulements rocheux sont difficilement prévisibles en raison de leur soudaineté et du peu d'informations disponibles sur la structure interne du massif rocheux. L'analyse en retour d'éboulements dans des falaises calcaires a montré qu'ils étaient initiés par la fracturation de ponts rocheux et que leur persistance était le principal paramètre à prendre en compte pour des calculs de stabilité. En 1er lieu, nous avons utilisé l'information contenue dans le bruit sismique afin d'évaluer le degré d'instabilité d'une écaille rocheuse. Les données viennent de la falaise calcaire de Chamousset (Vercors) où un réseau sismique a fonctionné 4 mois jusqu'à 2 semaines avant la chute d'une écaille de 21000 m3. Le calcul des spectres de bruit sismique a permis d'identifier la 1ère fréquence propre de l'écaille qui diminue significativement avant l'éboulement. Ce même réseau a enregistré des milliers d'événements dont les plus énergétiques ont été classés. Certains de ces signaux ont des arrivées d'ondes P et S distinctes, permettant d'analyser leur mécanisme de rupture et de calculer leur magnitude et distance hypocentrale. Des simulations favorisent l'hypothèse de ruptures en traction pour expliquer les polarisations. D'autres simulations confirment que les événements situés à l'interface écaille-massif entraînent la résonance de l'écaille, expliquant l'observation de codas mono-fréquentielle avec une amplitude sismique plus forte sur l'écaille. Enfin, l'étude de la réponse thermomécanique d'une 2nde écaille sur un an montre l'influence des paramètres météorologiques sur ses fréquences propres. Les effets réversibles et irréversibles sur ces fréquences ont été identifiés. / Rockfalls are difficult to predict events, owing to the suddenness of the phenomenon and to the little information available about the mass internal structure. Back analysis of collapses in steep limestone showed that rockfalls were initiated by intact rock bridge failures and that the persistence of joints was the main factor controlling the failure probability. First, we used the seismic noise recorded by autonomous monitoring systems to evaluate the degree of coupling of a prone-to-fall column to the rock massif. Seismic data were acquired on top of a limestone cliff in Chamousset (Vercors) during 4 months until 2 week prior the collapse of a 21,000 m3 column. The column 1st natural frequency was easily identified from ambient noise processing and exhibited a significant drop prior the column failure. Thanks to the monitoring system, thousands of seismic events were detected, out of which, the most energetic ones were classified. Some of these events exhibit clear P and S waves, making possible an analysis of the rupture mechanism as well as the calculation of their magnitude and hypocentral distance. Numerical simulations of rock bridge rupture allowed favouring traction rupture to explain the observed polarizations. Other numerical simulations showed that rupture events can trigger the column resonance, explaining the recurrent presence of specific frequencies in the late coda as well as the higher seismic motions on the column. Finally, we studied the thermomechanical response of another column. The influence of meteorological parameters on the column natural frequencies was shown. Both reversible and irreversible effects on the 1st natural frequency were identified.

Detecção de dano em estruturas de engenharia de grandes dimensões através da análise de suas características dinâmicas envolve diversos campos de estudo. O primeiro deles trata da identificação dos parâmetros modais da estrutura, uma vez que executar testes de vibração livre em tais estruturas não é uma tarefa simples, necessita-se de um método robusto que seja capaz de identificar os parâmetros modais dessa estrutura a ações ambientais, campo esse chamado de análise modal operacional. Este trabalho trata do problema de detecção de dano em estruturas que possam ser representadas através de modelos em pórticos planos e vigas e que estejam submetidos à ação de vibrações ambientais. A localização do dano é determinada através de um algoritmo de otimização conhecido como Backtracking Search Algorithm (BSA) fazendo uso de uma função objetivo que utiliza as frequências naturais e modos de vibração identificados da estrutura. Simulações e testes são feitos a fim de verificar a concordância da metodologia para ambos os casos. Para as simulações, são utilizados casos mais gerais de carregamentos dinâmicos, e dois níveis de ruído (3% e 5%) são adicionados ao sinal de respostas para que esses ensaios se assemelhem aos ensaios experimentais, onde o ruído é inerente do processo. Já nos ensaios experimentais, apenas testes de vibração livre são executados. Diversos cenários de dano são propostos para as estruturas analisadas a fim de se verificar a robustez da rotina de detecção de dano. Os resultados mostram que a etapa de identificação modal estocástica através do método de identificação estocástica de subespaço (SSI) teve ótimos resultados, possibilitando, assim, a localização da região danificada da estrutura em todos os casos analisados. / Damage detection in large dimensions engineering structures through the analysis of their dynamic characteristics involves several fields. The first one deals with the structure modal identification parameter, since running free vibration tests in such structures is not a simple task, robust methods are needed in order to identify the modal parameters of this structure under ambient vibrations, this field is known as operational modal analysis. This work deals with the problem of damage detection in structures under ambient vibrations that can be represented by FEM using frame and beam elements. The damage location is determined through an optimization algorithm know as Backtracking Search Algorithm (BSA). It uses as objective function the identified natural frequencies and modes of vibration of the structure. Numerical and experimental tests are performed to assess the agreement of the methodology for both cases. For the numerical tests, more general cases of dynamic loads are used, and two noise levels (3% and 5%) are added to the response signal to assessing the robustness of the methodology close to the field conditions, in which noise is inherent of the process. In the experimental tests, only free vibration tests are performed. Several damage scenarios are proposed for the analyzed structures to check the robustness of the damage detection routine. The results show that the stochastic modal identification using the stochastic subspace identification (SSI) method had excellent results, thus allowing the location of the damaged region of the structure in all analyzed cases.

L'objectif de cette thèse est d'analyser et de caractériser le lien entre les mouvements du sol et la réponse des bâtiments. En particulier, on s'intéresse à réduire les incertitudes qui entrent en jeu dans les méthodes de vulnérabilité, afin d'estimer plus précisément la vulnérabilité des structures au risque sismique. Pour ce faire, cette thèse est basée sur l'utilisation de données enregistrées au sein de bâtiments. Les enregistrements de vibrations ambiantes et de séismes de faibles amplitudes au sein de bâtiments permettent de caractériser le comportement élastique de ces structures. Des modèles peuvent ensuite être définis afin d'étudier les différentes composantes de la variabilité présente au sein des courbes de fragilité. On s'intéresse dans un premier temps au premier niveau de dommage, au-delà duquel les caractéristiques élastiques des bâtiments sont modifiées et les modèles définis ne sont plus valables. Des enregistrements de séismes ayant eu lieu depuis le début des années 1970 dans des bâtiments californiens sont ensuite utilisés. A partir de ces données, on a pu mettre en évidence des relations entre le déplacement au sein des structures et des paramètres décrivant la nocivité des signaux sismiques. Suivant l'indicateur utilisé pour représenter la nocivité des séismes, la réponse des bâtiments peut être estimée plus ou moins précisément. Notamment, les indicateurs faisant intervenir les paramètres dynamiques des bâtiments sont davantage liés avec la réponse des structures, représentée par son déplacement inter-étage moyen. La variabilité de la réponse des bâtiments peut être améliorée en regroupant les bâtiments par typologies (définies suivant leur matériau principal de construction et leur hauteur). En apportant davantage d'informations sur les structures, on peut ainsi diminuer la composante épistémique de la variabilité. De plus, en combinant des indicateurs de nocivité, on peut améliorer la précision pour la prédiction de la réponse de la structure. Une forme fonctionnelle est ainsi proposée afin d'estimer le déplacement inter-étage moyen au sein des structures, pour plusieurs typologies de bâtiments, à partir de quatre indicateurs de nocivité. Cette forme fonctionnelle est utilisée pour établir des courbes de fragilité et peut également être utilisée afin de donner une première estimation des dommages à la suite d'un séisme, en comparant les valeurs de déformations inter-étages avec des valeurs de référence (FEMA, 2003). Enfin, une méthode hybride est proposée pour la construction de courbes de fragilité, faisant intervenir un modèle de comportement non linéaire. Les paramètres de ce modèle sont définis de telle sorte que la réponse du modèle s'ajuste aux enregistrements de séismes effectués dans les bâtiments. Ce modèle est ensuite utilisé pour évaluer les composantes d'incertitudes et pour construire des courbes de fragilité pour tous les niveaux de dommages. / This PhD thesis is focused on the correlation between ground motion and the buildings response. In particular, we interested in reducing the uncertainties that occur in vulnerability methods in order to assess more precisely the seismic vulnerability of existing structures. In order to do this, this thesis is based on the use of data recorded within buildings. Records of ambient vibrations and low amplitude earthquakes within buildings are used to characterize the elastic behaviour of these structures. Linear models can then be defined in order to study the various components of the variability of the fragility curves, for the first damage level. Earthquake that have occurred since the 1970s have been recorded within Californian buildings. From these data, we focused on the relationship between the building response and parameters describing the noxiousness of ground motion. Depending on the indicator used to represent the noxiousness of earthquakes, the building response can be estimated more or less accurately. In particular, indicators involving the dynamic parameters of the buildings are more related with the response of structures, which is represented by its averaged inter-story drift. Grouping buildings by typologies (defined according to their main material of construction and their height) can improve the variability in the response of buildings. Indeed, by providing more information on the structure, we can reduce the epistemic component of variability. In addition, by combining noxiousness parameters, the accuracy in the prediction of the building response can be improved. A functional form is thus proposed to estimate the averaged inter-story drift within the structures, for several typologies of buildings. This functional form is then used to assess fragility curves and can also be used to get an estimate of damage after an earthquake, by comparing the values of inter-story drift from given by the functional form with reference values (FEMA, 2003). Finally, a hybrid method is proposed for the construction of fragility curves, involving a nonlinear model. The parameters of this model are defined so that the response of the model fits the earthquake recordings, which were made within buildings. This model is then used to evaluate the components of variability and to build fragility curves for all damage levels.