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Výpočetní analýza čtyř-koulového testu pro určování pevnosti keramických laminátů se zbytkovou napjatostí / Computational analysis of the ball-on-three-balls test for determination of strength of ceramic laminates with residual stressesVenský, Jiří January 2021 (has links)
Tato diplomová práce se zabývá numerickou simulací B3B zkoušky. Byla provedena rešerše v souvisejících oblastech. Poté byly provedeny numerické simulace této zkoušky pro mnoho různých konfigurací (rovný, zakřivený a zakřivený vrstvený vzorek) pro disk a desku. Byla zjištěna hyperbolická závislost mezi tloušťkou a f faktorem. Závislost f faktoru na křivosti byla lineární. Byla provedena demonstrace možnosti prasknutí na rozhraní vrstev. Poslední část ukázala, jak by zanedbání vlivu zbytkového napětí mohlo vést ke špatnému vyhodnocování experimentů
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Klasifikace zubů na 3D polygonálním modelu čelisti / Tooth Clasification on Jaw 3D Polygonal ModelHulík, Rostislav January 2010 (has links)
This document discusses a solution for tooth classification on 3D jaw polygonal model. Sequentially, I describe techniques for representation and browsing of polygonal model saved in computer memory, techniques for dental curve detection and finally, creation of surface representing approximated tooth plane. After it, I analyze possibilities of height map creation from jaw model which helps in tooth classification in the scope of entire dental curve context and, as a last step, final detection of these teeth in two dimensions. In the same time, I discuss 3D polygonal model segmentation for border extraction, which separates teeth from the rest of the model. In the end of proposed algorithm, I join these two runs into one final detection and classification process of separate teeth, so presented application can automatically indentify and classify teeth to corresponding names and positions with a minimum user interaction. In a second half of this document, I describe implemented solution. According to primary goal, I propose these techniques forcefully to multiplatform approach and maximal user comfort.
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Monitored Neural Networks for Autonomous Articulated Machines / Monitored Neural Network for Curvature Steering of Autonomous Articulated MachinesBeckman, Erik, Harenius, Linus January 2020 (has links)
Being able to safely control autonomous heavy machinery is of uttermost importance for the conversion of traditional machines to autonomous machines. With the continuous growth of autonomous vehicles around the globe, an increasing effort has been put into certifying autonomous vehicles in terms of reliability and safety. In this thesis, we will investigate the problem with a deviation from the planned path for an autonomous hauler from Volvo Construction Equipment. The autonomous hauler has an error within the kinematic model, the feed-forward curvature-steering controller, due to a slip-effect that comes with the third wheel-axle. The deviation can especially be seen in sharp curves, where the deviation needs to be decreased in order to make the autonomous hauler more dependable and achieve an increased accuracy when following any given path. The aim of the thesis is to develop a fully functional Artificial Neural Network that has a new steering angle as output. The hypothesis for this thesis is to use an ANN to mimic the steering of a human driver, since a real driver compensates for the slipping behavior; both because the operator knows where on the road the machine is and also in the way that a human thinks many steps ahead whilst driving. This proposed ANN will have a monitor function which ensures that the steering angle command operates within its boundaries. Hence this thesis implies that it is indeed possible to ensure that the ANN performs reliably with the help of a monitor function in a simulated environment and can thus be used in dependable systems.
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Elektronski sistem za merenje deformacija pri savijanju pomoću polimernog optičkog vlakna sa osetljivom zonom / Electronic system for measurement of deformations under bending by usingpolymer optical fiber with sensitive zoneStupar Dragan 21 April 2016 (has links)
<p>U ovoj doktorskoj disertaciji je razvijen elektronski senzorski sistem za merenje deformacija pri savijanju pomoću polimernog optičkog vlakna sa osetljivom zonom. Opisana je metoda izrade fiber-optičkog senzora zakrivljenosti pomoću polimernog optičkog vlakna. Izvršena je simulacija ponašanja senzora i urađena je karakterizacija senzora. Ispitana je mogućnost primene elektronskog senzorskog sistema za detekciju savijanja i loma građevinskih struktura. Pomoću istog senzora je realizovan fiber-optički goniometar za merenje ugla savijanja ljudskog kolena koji karakterišu linearni odziv u opsegu uglova od -45° do 25°, rezolucija od 1° i osetljivost od 20 mV/°. U tezi je takođe data metoda eliminacije grešaka koje mogu nastati usled savijanja delova vlakna koji vode do i od osetljive zone.</p> / <p>In this thesis, an electronic system for measurement of bend-induced<br />deformations by using polymer optical fiber with sensitive zone is developed.<br />A method for fabrication of the fiber-optic curvature sensor by using polymer<br />optical fiber is described. The simulation and characterization of the sensor<br />behavior have been conducted. The possibility of application of the proposed<br />electronic system in structural health monitoring for bending and crack<br />detection of civil engineering structures is investigated. Also, a fiber-optic<br />goniometer for human joint movement monitoring characterized by a linear<br />response in the range from -45° to 25°, resolution of 1°, and the sensitivity of<br />20 mV/° is implemented. A method for the elimination of errors which may be<br />caused due to bending of lead-in and lead-out sections of the fiber (leading<br />to and from the sensitive zone) is also described.</p>
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Determination of water body structures for small rivers using remote sensing dataKarrasch, Pierre, Henzen, Daniel, Hunger, Sebastian, Hörold, Max 29 August 2019 (has links)
The diversity of habitats in water bodies like rivers is characterised by the status of morphological and hydrological conditions. The good ecological status of water bodies is claimed in the EuropeanWater Framework Directive. For the assessment of this status the hydro-morphology is one of the most important supporting components for the classification of the ecological status of water bodies. Therefore the periodical monitoring is a mandatory measure in the scope of the European Water Framework Directive. Regarding the so called overview-method of the LAWA (German Working Group on water issues of the Federal States and the Federal Government represented by the Federal Environment Ministry) the use of remote sensing data and remote sensing methodologies becomes more important. Therefore remote sensing data on different scales (satellite, aerial photographs) as well as other topographic information (ATKIS) and a high resolution DTM are merged into an integrative process of analysis using remote sensing and GIS methodology. The analyses ared focused on two parameters. First, a detailed landuse classification based on LANDSAT satellite data is performed for whole catchment of a small river. The results show significant increase of urban areas close to the river. The second analyses deals with the determination of river curvature and introduces the use of a quasi-continously representation of the river. An additional challenge is the chosen study area of a low mountain range river. While large rivers are clear visible in remote sensing data, the usability and transformation of the well-established algorithms and work ows to small rivers need a further substantial research.
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Půdorysně zakřivená oblouková lávka pro pěší / Plan curved arch footbridgeTrenz, Jan January 2012 (has links)
The scope of thesis is to design a curved arch footbridge. The main structure consists of composite deck supported by steel arch. The focus is on finding optimal shape of arch and proper cross-sections of elements. Bridge is analysed according to limit states.
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Computergestützte Entwurfsmethoden auf gekrümmten OberflächenKühnert, Tom 04 March 2015 (has links)
Im Fokus dieser Arbeit steht die Entwicklung und Realisierung einer Nutzerschnittstelle für die computergestützte Bearbeitung von Oberflächen dreidimensionaler Designobjekte, die durch herkömmliche CAD-Systeme nur unzureichend unterstützt werden können. Es werden Methoden und Algorithmen erarbeitet, um die Interaktion des Benutzers direkt auf Basis der für das Design relevanten 3D Objektoberflächen zu ermöglichen.
Den Ausgangspunkt bildet das Proxy-Konzept des Forschungsfeldes zur Mensch-Maschine-Interaktion, in welchem physische Stellvertreterobjekte zur Manipulation virtueller Objekte genutzt werden. Im ersten Teil der Arbeit wird dieses Konzept um eine auf die Oberfläche des bearbeiteten Objektes bezogene Interaktion und Designfunktionalität erweitert. Dazu wird das Konzept eines CAD-Proxys entwickelt und verschiedene Umsetzungen und Anwendungen erläutert. Dabei werden die CAD-Proxys in drei Typen unterschieden. Der exakte CAD-Proxy ermöglicht es, ein virtuelles Objekt mit einem formgleichen, physischen Gegenstück zu bearbeiten. Beim abstrakten CAD-Proxy wird gezeigt, wie auch ein anders geformtes Gegenstück zum Einsatz kommen kann. Der augmentierte CAD-Proxy erlaubt die Anzeige des Designs direkt auf dem physischen Gegenstück. Nutzerstudien belegen, dass die CAD-Proxys zur Erstellung eines Designs auf einer Oberfläche deutlich besser geeignet sind als eine klassische Nutzerschnittstelle. Dies gilt insbesondere für anspruchsvolle Designaufgaben, etwa im künstlerischen Design.
Im zweiten Teil der Arbeit wird die Verarbeitung von Linienzügen im Gestaltungsprozess eingeführt, welche das Konzept der aktiven Konturen auf Oberflächen erweitern. Diese Linienzüge werden auf die Form der Oberfläche bezogen verarbeitet und beachten gleichzeitig wichtige Merkmale, wie bspw. die Kanten des Objektes. Es wird ein neues Verfahren vorgestellt, mit dem aktive Konturen auch auf schlecht vernetzten Oberflächen eingesetzt werden können und gleichzeitig Formen flexibler repräsentieren können als bisherige Ansätze. Für den Bezug der Designlinien zur Oberfläche wird eine neue Datenstruktur eingeführt, die ein geometrisches Nachbarschaftsproblem löst. Es wird gezeigt, dass diese Struktur auf den getesteten Objekten mindestens um Faktor 14 schneller ist als alternative Ansätze und auch direkt auf andere Problemstellungen anwendbar ist.
Der dritte Teil enthält die Betrachtungen zum Formverständnis der Designobjekte, welche für die Designlinien und die Modellierung der Designobjekte benötigt werden. Dabei kommt die Krümmungsberechnung als etabliertes Werkzeug derartiger Analysen zum Einsatz. Hier wird eine neue Betrachtung erarbeitet, die den Einfluss unterschiedlicher Faktoren auf die Genauigkeit der Krümmungsschätzung und auf die Eignung verschiedener Schätzungsverfahren erstmals umfassend untersucht. Durch die Kombination existierender Verfahren kann das Verfahren der Shape Operator Approximation entwickelt werden, welches Eigenschaften wie Schätzungsgenauigkeit, Performanz und eine einfache Formulierung bekannter Verfahren vereint.
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[pt] AVALIAÇÃO DE ÍNDICES MODAIS PARA IDENTIFICAÇÃO DE DANOS EM PASSARELAS METÁLICAS / [en] EVALUATION OF MODAL INDICES FOR DAMAGE IDENTIFICATION ON STEEL FOOTBRIDGESAUGUSTO CESAR MIRANDA FEIJAO 27 June 2023 (has links)
[pt] Dentre as diversas metodologias de detecção de danos, destacam-se os
métodos de identificação de danos baseados na resposta da vibração (Vibration-based damage identification - VBDI), uma vez que a deterioração presente em
elementos estruturais influencia diretamente na resposta dinâmica global e local
da estrutura ocasionando alterações nos parâmetros dinâmicos. As diferentes
abordagens encontradas na revisão de literatura para detecção dinâmica de danos
focam principalmente em estruturas unidimensionais ou retas, que, por sua vez,
podem não representar o comportamento dinâmico real de estruturas arrojadas
como pontes e passarelas com geometria diferenciada. Alguns índices modais,
nomeadamente curvatura modal, flexibilidade modal e energia de deformação
modal, foram avaliados para uma passarela de aço com geometria curva. Para isso
utilizou-se um modelo de elementos finitos da mesma, de onde foram extraídos
os modos de vibração tridimensionais. Além disso, um índice recentemente
proposto, denominado vetor resultante, que incorpora coordenadas modais
tridimensionais, também é avaliado e comparado aos índices mencionados
anteriormente. Os resultados mostram que a precisão dos índices na localização
de danos está correlacionada com a região da estrutura onde o dano se encontra.
Conclui-se então que para detecção de dano em uma estrutura real, é necessário
que se utilize mais de um índice de dano. O impacto da magnitude do dano na
acurácia dos índices é também estudado. A influência do dano nas vigas
adjacentes e como isso se reflete nos índices também é investigada, a fim de evitar
ambiguidade na localização de danos, e para direcionar corretamente programas
de inspeção e monitoramento da integridade estrutural. / [en] Among the various damage detection methodologies, the Vibration-based
damage identification (VBDI) methods stand out, since the deterioration present
in structural elements directly influences the global and local dynamic response
of the structure, causing changes in the dynamic parameters. The different
approaches found in the literature review for dynamic damage detection focus
mainly on one-dimensional or straight structures, which in turn may not represent
the actual dynamic behavior of bold structures such as bridges and footbridges
with different geometry. Some modal indices, namely modal curvature, modal
flexibility, and modal strain energy were evaluated for a steel footbridge with
curved geometry. For this purpose, a finite element model of it was used, from
which the three-dimensional mode shapes were extracted. In addition, a recently
proposed index, called resultant vector, which incorporates three-dimensional
modal coordinates, is also evaluated and compared to the aforementioned ones.
The results show that the accuracy of the indices for damage localization is
correlated with the region of the structure where the damage is located. It is then
concluded that for damage detection in a real structure, it is necessary to use more
than one damage index. The impact of the damage magnitude on the accuracy of
the indices is also studied. The influence of damage in adjacent beams and how
this is reflected in the indices is also investigated in order to avoid ambiguity in
damage location, and to correctly direct inspections and structural integrity
monitoring programs.
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Self-assembly of Fatty Acids of Hair at the water-air interfaceBatista, Marine January 2020 (has links)
18-methyl eicosanoic acid (18-MEA), which is a branched fatty acid, is found at the outermost surface of mammalian hair with other straight-chain fatty acids such as palmitic acid and stearic acid. However, the precise role of 18-MEA is not yet completely understood. 18-MEA on Cadmium chloride subphase forms curvature at the water/air interface, leading to the formation of 3D-domains that can be easily transferred into solid support allowing to create complex and multi-functional structures. This project investigates if a non-toxic subphase would also lead to the formation of 3D-domains or if it is an intrinsic property of Cadmium chloride; and to investigate if the domain properties were tuneable. A combination of the Langmuir trough and the Atomic Force Microscopy is used. It is shown that a toxic subphase is not necessary and a more benign sodium subphase can be used to obtain 3D-domains. It is also shown that different chains length interact dissimilarly with the branched fatty acid. This results in the formation of very various structures. It is also shown that the subphase, the surface pressure of deposition and the composition of the fatty acid in the monolayer affect the properties of the domain, leading to different size of domain but also different morphology in the domain. Circular domains, elongated domains, continuous labyrinthine structures, dendritic centipede-like structures and no domains are obtained. / På den yttersta ytan av däggdjurshår återfinns den grenade fettsyran 18-methyleikosansyra tillsammans en mindre mängd av de raka fettsyrornapalmitinsyra och stearinsyra. Den exakta rollen av 18-MEA är dock ännu inte heltklarlagd. Ett monoskikt av 18-MEA på en subfas innehållande kadmiumklorid påtvingar en krökning av vatten–luftgränsytan. Det leder till bildandet av 3D-domäner som lätt kan överföras från vattenytan till fasta ytor vilket möjliggör att dekorera dessa ytor med komplexa och multifunktionella strukturer. Detta projekt undersöker om andra, miljövänliga motjoner i subfasen också skulle leda till bildandet av 3D-domäner eller om det är en inneboende egenskap hos kadmiumklorid. Det här ger även insikt om hur motjoner kan användas för att påverka och kontrollera domänbildningen. En kombination av Langmuirtråg och atomkraftsmikroskopi används för att karakterisera monoskikten. Det visas att en subfas innehållande kadmium inte är nödvändig och att en mer miljövänlig natriumsubfas kan användas för att bilda 3D-domäner. Det visas också att olika kedjors längd interagerar olika med den grenade fettsyran 18-MEA, vilket resulterar i bildandet av olika strukturer i deponerade monoskikt. Det visas också att yttrycket vid deponering och sammansättningen av fettsyror i mono skiktet påverkar egenskaperna hos monoskiktet, vilket leder till varierande storlek och struktur på de bildade domänerna, där cirkulära och långsträckta domäner, kontinuerliga labyrintstrukturer och dendritiska tusenfotingsliknande strukturer observeras.
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Higher Forms and Dimensional Hierarchy in Topological Condensed Matter / Högre former och dimensionshierarki inom topologisk kondenserad materiaHonarmandi, Yashar January 2022 (has links)
This report discusses higher differential forms with applications in the study of topological phenomena. The integer quantum Hall effect is first discussed, demonstrating a connection between models on a lattice and quantum field theories bridged by a topological invariant, namely the Chern number. Next, for parametrized models on a lattice, the higher Berry curvature is described. This is a rank-(d + 2) differential form on a (d + 2)-dimensional parameter manifold which provides a relation between models in a bulk and on a lower-dimensional interface. Finally, a family of quantum field theories connected to a (d + 1)-dimensional manifold, termed a target space, is constructed. This connection is realized through the incorporation of a set of classical fields, and the effective action of the full field theories all contain a Wess-Zumino-Witten term given by the pullback of a rank-(d + 1) differential form from the target space to spacetime. By performing an extension of spacetime, a (d + 2)-form on a (d + 2)-dimensional target space is constructed in a similar way. Extending a theory in d dimensions thus yields a form on a target space of the same dimension as that of a (d + 1)-dimensional theory without extension, defining a dimensional hierarchy. The dimensional relations inherent in the two higher forms studied indicate the possibility of a relation between them. / Denna rapport beskriver högre ordningens differentialformer med tillämpningar inom topologiska fenomen. Den heltaliga kvantmekaniska Halleffekten beskrivs först, som ett exempel på ett samband mellan modeller på ett gitter och kvantfältteorier som förbindas av topologiska invarianter, specifikt Chern-talet. För parametriserade modeller på ett gitter beskrivs därefter den högre Berrykrökningen. Detta är en differentialform av ordning (d + 2) definierad på en (d + 2)-dimensionell parametermångfald som ger en koppling mellan modeller i en kropps inre och på dens gränsskikt, som är i en lägre dimension. Slutligen konstrueras en familj av kvantfältteorier som är kopplade till en (d + 1)-dimensionell mångfald kallad modellens målrum. Denna koppling realiseras genom introduktionen av ett antal klassiska fält, och den effektiva verkan för den fullständiga teorin innehåller en Wess-Zumino-Witten-term som ges av en tillbakadragen (d + 1)-form från målrummet till rumtiden. Genom att utvidga rumtiden kan även en (d + 2)-form på en (d + 2)-dimensionellt målrum konstrueras på ett motsvarande sätt. Utvidgningen av en teori i d dimensioner ger därmed en differentialform på ett målrum med samma dimension som målrummet för en (d + 1)-dimensionell teori utan utvidning, vilket definierar en dimensionell hierarki. Dimensionsrelationerna inbyggda i dessa två differentialformer indikerar den möjliga existensen av en relation mellan dem.
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