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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Modelování směrovacího protokolu Babel / Modelling of Babel Routing Protocol

Rek, Vít January 2015 (has links)
This thesis deals with the simulation of a Babel routing protocol. The goal is to create implementation of simulation model for OMNeT++ simulator. The text includes a description of the protocol and basic principles of computer network simulation in OMNeT++ environment using an INET library. Furthermore, the text discussed existing implementations and submits a proposal of a simulation model, followed by description of its implementation. Finally, the correctness of created model is verified.
12

Modelování směrovacího protokolu EIGRP / Modelling of EIGRP Routing Protocol

Bloudíček, Jan January 2014 (has links)
The network simulation allows analysis of the computer networks behavior and configured protocols. This thesis focuses on the EIGRP routing protocol and its integration into the OMNeT++ simulation enviroment. The text includes a detailed description of the protocol and its configuration on Cisco devices. Furthermore, the text focuses on design of extension that supports routing protocol. The following describes implementation of the protocol according to design. Finally, the implemented solution is compared with the output of real devices.
13

Study of Gear design Concept to Reduce Root Bending- & Contact Stresses for Automotive Transmission / Studie av kugghjulskoncept för att reducera rotböjs- & kontaktspänningar förväxel lådor

Li, Felicia January 2019 (has links)
Advanced technologies for the automotive industry require improved designed precision in different areas. Research is needed in order to meet customer demand and satisfaction to increase durability, efficiency, and reliability. That is why continuous development in transmission system has been an exciting topic for many years. The gears in the transmission system demand high resistance against repeated loads acting on the teeth and the ability to engage without energy loss. The intention is to support that effort by investigating seven design cases of a parallel helical gear pair. This master thesis aims to study a gear design concept of adding a supporting ring to reduce the root bending- and contact stresses. To implement this study, seven different design cases were modelled to study the effect of changing the design. One or two support ring structures were added, or the thickness was increased of the gear considered exposed to high stresses. The purpose is to gain a comparative advantage in the automotive industry. M1 is a reference standard design, while the other models (M2-M5/P1-P3) are modified designs with additional rings or changed in thickness. Simulation is an effective and an useful tool to understand and visualize how the complex interaction of the transmission component appears to be. A finite element method (FEM) program was used to investigate these models. The gear pairs were imported into the pre-processor ANSA, the FEM program Abaqus 2017 was used as a solver, and the results were extracted from the post-processor META. To support the aim of this thesis, two of the seven FEM models were validated against a specialized gear calculated program, WindowsLDP, in order to determine the robustness of the simulation models. The transmission error (TE) measurements, root bending- and contact stresses were observed for the validation. Introducing the different models M3-M5 and P1-P3, the root and contact stresses were reduced by 1.2-4.4 and 0.07-4.3 %, respectively, compared to M1. The transmission error TE could differ as much as 85% in M2-M3 as compared to M1. Systematic errors were generated in model M2, therefore the low root stresses obtained in M2 should be considered carefully. Implementing the so-called misalignment measurement, tilting parameter, microgeometry, and profile modification related to crowning and tip relief is discussed and believed to reduce TE measurements, root- and contact stresses. These modifications have not been studied in this thesis. The LDP results showed a trend of higher values compared to the FEM results, which was suggested to be further investigated in the future. / Dagens avancerade teknik inom fordonsindustrin kräver förbättrad precision hos konstruktioner inom olika områden. Forskning behövs för att möta kundernas efterfrågan och för att öka hållbarhet, effektivitet och tillförlitlighet. Detta är varför kontinuerlig utvecklingen av växellådssystem har varit ett hett ämne i många år. Kugghjulstransmission skall ha högt motstånd mot upprepande belastning som förekommer på tänderna och skall även ha en minimal energiförlust. Detta examensarbete siktar mot att stödja den fortsatta utvecklingen inom området genom en fallstudie, mer specifikt för att studera sju olika kugghjulsmodeller som behandlar ett parallellt spiralformade kugghjul. Målet med detta examensarbete är att studera ett kugghjulskoncept där en ring appliceras för att reducera rot- och kontaktspänningar. Utförandet sker genom att studera sju olika modeller, för att veta hur stor påverkan designen utgör. En eller två stödringstrukturer appliceras, eller att öka kuggbredden på det kugghjul som anses vara det mest kritiska för höga spänningar. Denna studie görs för att kugghjulstillverkaren ska vara i utvecklingens framkant och kunna konkurrera inom fordonsindustrin. M1 ären referens och standard designmodell, medan de andra modellerna (M2-M5/ P1-P3) är modifierade design där med ytterligare ringar eller ändrad kuggbredd. Simulering är en effektiv metod för att förstå och visualisera komplexiteten av komponenter inom växellådan. Ett finita elementmetodens program användes för att undersöka dessa modeller, genom att importera geometrierna till pre-processorn ANSA, där Abaqus 2017 användes som en lösare, där sedan resultaten extraheras från post-processorn META. För att stödja denna studien användes två av de sju FEM-modellerna till att valideras mot ett annat specialiserat kugghjulsprogram inom kuggberäkning som heter WindowsLDP. Detta med avsikt att fastställa simuleringsmodellernas robusthet. Det så kallade överföringsfelet, rotböjnings- och kontaktspänningarna var ingående parametrar som behandlades under valideringen. Modellerna M3-M5/P1-P3 introducerades, där rotböjsspänningen och kontaktspänningen reducerades med 1.2-4.4 och 0.07-4.3% när de jämfördes med M1. Överföringsfelet (TE) kunde skilja upp mot 85% mellan M2-M3 jämfört med M1. Ett systematiskt fel uppstod i modell M2, modellens robusthet kunde därmed ej fastställas, då modellens resultat bör övervägas noggrant. Införande av så kallade växelförskjutning, lutning/vippning parametrar, mikrogeometrier och profilmodifieringen relaterat till kronning och tipavlastning, kommer att genera minskade TE-mätningar samt rot- och kontaktspänningar för de spiralformade kugghjulen. Dessa ämne har ej studerats under detta examensarbete. LDP-resultaten visade högre värden relativt jämfört med de FEM resultat, där en trend kunde observeras. Slutsatsen föreslog att detta bör undersökas ytterligare i framtiden.
14

A Study of a Volvo CE Articulated Hauler’s Hydraulic Tank : Validation of a Finite-Element Model Taking the Fluid-Structure Interaction into Account

Janousek, Miroslav, Burnotte, Thibault January 2018 (has links)
This scientific work is dedicated to the study of the impact of vibrations on the Volvo A60 articulated hauler’s hydraulic tank taking fluid-structure interaction into account. In this work, a theoretical background is presented in order to give the reader a basic awareness of the given problem together with a detailed description of the methods used during the examination of the above mentioned hydraulic tank. To perform an analysis of the finite-element model, ANSYS software was used while ANSA and META were used as the pre- and post-processor. Matlab was used in order to compare the obtained data. As a result of the analysis, this work provides a simplified and yet accurate model and a description of some of the minor problems present in the original Volvo CE model. In order to solve those issues, solutions are proposed.
15

Electrochemiluminescence of novel polyanilino-rutheniumbipyridyl-imidazo phenanthroline and carboxy-difluoroboradiazaindacene luminophores

Molapo, Kerileng Mildred January 2015 (has links)
Philosophiae Doctor - PhD / Electrochemiluminiscence, (ECL), is an electrochemically-induced process that leads to the generation of measurable luminescent signals at the electrode surface. The luminescent signals occur when electrochemically generated intermediates undergo a highly exergonic reaction to produce an electronically excited state that then emits light. Immobilization of the ECL luminophore on an electrode surface provides enhancement of ECL intensity. This work presents results of the feasibility study focused on the application of novel luminophores for electrochemiluminescence (ECL) sensors. The thesis mainly focuses on studying the ECL of polyanilinorutheniumbipyridyl- imidazo phenanthroline and carboxydifluoroboradiazaindancence luminophores. The influence of the synthetic methods on the electrochemical, structural and photophysical properties of poly(8-anilino-lnaphthalene sulphonic acid) (P ANSA) synthesized by electropolymerization (PANSA) and chemical polymerization (PANSA) were studied. Cyclic voltammetry (CV) data revealed that the electrogenerated PANSA contains species of mixed redox states; with evidence of the presence of penigraniline, emeraldine and leucoemeraldine forms of PANSA. In contrast, the CV of PANSA indicated that it is predominantly in the emeraldine form with a reduction potential at approximately + 0.2 V. The presence of emeraldine moiety in PANSA was confirmed from UV-Vis spectroscopy data. A band gap energy value of 2.5 eV was calculated for the emeraldine in PANSA from the UV data. Comparative study of the charge transfer coefficient, DCT, of the two types of PANSA indicated moderate charge propagation in PANSA (DCT = 1.68 ± 0.1 x 10-8 cm2 s-') which was order of magnitude lower than for PANSA (DCT = 1.68 ± 0.3 x 10-7 cm2 s-'). The differences in the structural properties of the two polymers were reflected in their IR spectra, with evidence of C=C and C=N stretching vibrations observed at 2030, 2158 and 2486 cm-I in PANSA, which are absent in PANSA. The mode of synthesis had a modest impact on the photophysics of the polymers, for example PANSA exhibited a luminescent lifetime of9.00 ± 0.05 ns compared with 11.5 ± 0.07 ns for PANSA. However, time resolved emission anisotropy studies gave a rotational correlation time, p, of 13.8 ± 2.47 ns for PANSA compared to 0.633 ± 0.03 ns for its chemically generated analogue. This suggests a much shorter chain length in the PANSA molecule and higher cross-linking or aggregation in PANSA that can limit incorporation of ruthenium complex on the polymer backbone. As a result, electrochemiluminescent films have been formed by electrodepositing polyaniline, PANI, films in the presence of [Ru(bpY)2PIC]2+; bpy is 2,2'-bipyridyl and PIC is (2,2'-bipyridyl)-2( 4- carboxylphenyl) imidazo [4,5 ][ 1,10] phenanthroline in this work. The homogeneous charge transport diffusion coefficient, DCT, for the Ru2+/3+couple within the PANI film is 2.6 ± 0.9 x 10-10 cm2s-l. The large DCT facilitates a fast regeneration of Ru3+and, coupled to a relatively rigid microenvironment, results in a high ECL intensity in the presence oftripropylamine as co-reactant compared to [Ru(bpY)3f+. Significantly, despite the conducting nature of the polymer backbone, the [Ru(bpy)2PICH2]2+ loaded PANI has the highest efficiency, 1.00%, yet reported for a surface confined ruthenium complex. PANI-Ru complex showed to have many properties that make it an ideal luminophore for sensitive and selective analytical methods; however, it would be useful to have other ECL labels that can span a wide range of wavelengths so that simultaneous determination of several analytes in a single sample can be investigated. In this case, the photophysics, electrochemical and electrochemiluminescent properties of a novel 1,3,5,7 -tetramethyl-8-[ (2-fluorophenyl)-6-methoxy-l ,5-naphthyridine-3-carboxy ]-4,4'difluoroboradiazaindace-ne BODIPY -COOH, dye were demonstrated in this work. The photophysics studies revealed that BODIPY -COOH is highly luminescent: exhibiting sharp absorbance bands, intense emission bands and high emission quantum yield. The quantum yield proved to be solvent dependent and was determined to be 0.88 ± 0.02 and 0.60 ± 0.04 in dimethylsulphoxide (DMSO) and acetonitrile (MeCN), respectively. Electrochemiluminescence (ECL) of BODIPYCOOH in solution was generated in the presence of either benzoyl peroxide (BPO) or hydrogen peroxide. The ECL turn-on potential in the presence of BPO was observed at potentials that are greater than - 1.5 V, and when H202 was used the ECL turn-on potential was significantly fine-tuned to less negative potential of - 0.4 V. Electrochemiluminescent thin films of BODIPY -COOH on Pt electrodes exhibited luminescence properties similar to those of the free dye in solution. However, the solution based approach ECL has its own limitations such as loss of signal due to the diffusion of the ECL reagent out of the detection zone. To overcome loss of signal effects, the introduction of cysteamine and cysteine linkers to the BODIPY dye were employed. It was seen that self-quenching was not sufficient to interfere significantly with the film ECL emission properties and thus the BODIPY thin film can be used in ECL applications. Interestingly, the BODIPY film exhibited the strongest luminescence in water and this is potentially useful in ECL application in biological media.
16

Modelování protokolů IS-IS a TRILL / Modelling IS-IS and TRILL

Marek, Marcel January 2013 (has links)
In this thesis, we describe the principles of IS-IS routing protocol. We introduce the current state of implementation of this protocol within the simulation framework OMNeT++. We present the implementation of the IS-IS protocol created within the ANSA project. Moreover, we employ its variant called TRILL that is nowadays deployed as replacement of STP in data-center environment. The aim is to enable the modelling of the protocols without the need having to build physical architecture.
17

FE based method for simulation of rock-loading on a truck

Kohestani, Tamim, Zeaiter, Ali January 2019 (has links)
Volvos trucks are used to carry boulders of varying sizes from different mining sites or construction sites. These boulders are loaded onto the dumper of the truck by a wheel-loader which drops the boulders from various heights causing an impulse like force which distributes throughout the frame and to the rest of the truck. Depending on the size and what height the boulders are being dropped from, the distributed forces can cause damage to important parts of the truck. An experiment done by Volvo has shown that a two-ton weight dropped from 3.5 meters caused some truck components to crack, such as flywheel housing. Since this is alerting and it is costly to do the experiment on all trucks that Volvo manufactures it is our objective to come up with a method based on Finite Element which would evaluate the rock loading case. By using ANSA as the pre-processor which helps set up the model before running a simulation, and Nastran and LS-DYNA as the FEM solvers, a result was obtained that is somewhat comparable with the measurements. In the Nastran model, no non-linearities such as contact were considered, while in LS-DYNA nonlinear contact between the weight and the dumper body was defined, which improved the results considerably. The key conclusion from the two results was that the contact definition used in LS-DYNA is necessary if accurate results are important. Since LS-DYNA uses an explicit numerical method the model can be made more complicated by including more nonlinearities in the model and it would not affect the computation to much or at all. Hence the method would be future proof.
18

Behavioral Analysis of Volvo Cars Instrument Panel During Airbag Deployment

Nazari, Amir, Nourozi, Behrouz January 2016 (has links)
Airbags are a passive safety technology, required to function with zero failure rate. Advances in Computer Aided Engineering have allowed vehicle manufacturers to predict material and system behavior in the event of a crash. The sudden and rapid nature of a vehicle frontal crash, together with strict requirements put on safety make this a sensitive task. This thesis focuses on the front passenger airbag deployment and the instrument panel’s response. Various airbag modelling techniques are studied and presented in this document. This work is part of a larger-scale attempt to model a generic-sled that is physically representative of a real vehicle. Various component tests are to be performed in the sled environment, as opposed to a real vehicle, to save costs. Various modules are added to the sled once their behavior is verified by testing and in simulations. Software are advanced enough to identify location and magnitude of stress concentrations that develop during crash. LS-DYNA is used for explicit finite element simulations of the instrument panel (IP) in question with different airbag models. Verification has been achieved by design of experiment (DOE); with tests conducted to capture both the movements of the airbag housing and IP movements in response. These movements are broken down in various phases, facilitating implementation in the sled environment. Simplifications are made both to the computer models as well as the physical testing environment. The effects of these simplifications are quantified and discussed. Theoretical background is provided where fit while assumptions are justified wherever made. DYNAmore recommendations regarding costeffective calculations as well as result verification are followed. The obtained results show that the FE models replicate the real event with acceptable precision. The findings in this work can, by minor tweaks, be implemented on other IP models in the Volvo Cars range, leading to cost-saving solutions. This thesis provides the necessary information for sled implementations as well as future improvement suggestions. / Krockkudde är en s.k. passiv säkerhetsteknik som krävs att fungera felfritt. Framsteg inom Computer Aided Engineering har tillåtit biltillverkare att förutsäga material och systembeteende i samband med krock. Den plötsliga karaktären av krock, tillsammans med höga säkerhetskrav, gör detta till en känslig uppgift. Denna avhandling fokuserar på passagerarsidans krockkudde och instrumentbrädans (IP) respons under uppblåsning. Olika metoder för modellering av krockkuddar har studerats och presenteras i detta dokument. Arbetet är en del av en större skala försök att modellera en generisk-släde som är fysiskt representativ av en riktig bil; där olika komponent-tester skall utföras för att minska kostnader. När olika modulers beteende verifieras läggs de till släden. Denna verifiering sker genom finita element (FE) simuleringar så väl som fysiska tester. FE mjukvara är idag tillräckligt avancerad för att identifiera samt visualisera spänningskoncentrationer som uppstår i en konstruktion vid krock. LS-DYNA används i detta arbete för explicita FE simuleringar av en Volvo XC90 IP, lastad med olika krockkudde-modeller. Modell verifiering har uppnåtts genom försöksplanering (DOE); med tester utförda för att fånga rörelser av IP så väl som krockkudde-behållaren. Dessa rörelser är sedan uppdelade i olika faser för enklare genomförande i släde miljön. Förenklingar och antaganden görs både till FE modeller och fysiska testmiljön. Effekter av dessa har kvantifierats och relevant teoretisk bakgrund har inkluderats. Dokumentet innehåller även diskussion kring val av mätutrustning samt förbättringsförslag för fortsatt arbete. DYNAmore rekommendationer gällande kostnadseffektiva beräkningar och verifiering av simulerings-resultat har följts. Under arbetet visade sig att FE modellerna kan återskapa händelsen med hög noggrannhet; dessa trotts svårigheter i modellering av plast material. Möjligtvis kan man, genom mindre modifieringar, relatera slutsatserna i detta arbete till olika IP modeller i företagets produktkatalog vilket förmodligen leder till ytterligare kostnadsbesparingar. Denna avhandling ger den information som behövs för genomföranden i den generiska miljön.
19

Indenyl-Metallkomplexe mit Metallen der Gruppe 4

Weiß, Thomas 21 June 2001 (has links) (PDF)
Die vorliegende Arbeit beschreibt die Synthese, das Reaktionsverhalten und die Charakterisierung von neuartigen in Position 2 silylsubstituierten Indenylkomplexen mit Metallen der Gruppe 4 des Periodensystems der Elemente. Insbesondere konnten silylenverbrückte Komplexe synthetisiert werden, in welchen bislang unbekannte indenylhaltige ansa-Zirconocendichloride und Halbsandwichmetalldichlorid-Komplexe mit rigidem Ligandengerüst verwirklicht sind. Diese zeigen besondere Eigenschaften als Katalysatoren in der homogenen Ziegler-Natta-(Co)Polymerisation von Ethen und Propen. Die einfache Zugänglichkeit von 2-Indenylsilanen konnte durch eine Eintopfsynthese erreicht werden, bei welcher ausgehend von 2-Bromindenen sehr gute Ausbeuten erreichbar sind. Zur Synthese der 2-Bromindene wurden verschieden substituierte Indene verwendet. Durch Variation des Substituentenmusters ist es möglich die Eigenschaften des Katalysators gezielt zu beeinflussen. Die positionsabhängige Aufklärung der Substituenteneigenschaften von Me und/oder SiMe3 im Indengerüst nimmt daher einen bedeutenden Anteil dieser Arbeit ein. Zu diesem Zweck wurden neuartige substituierte Indenyltitantrichloride präparativ zugänglich gemacht und in Kombination mit bekannten Indenyltitantrichloriden mittels UV/VIS-Spektroskopie und Cyclovoltammetrie untersucht. Auf der Basis des gewonnenen Datenmaterials gelang es die Wirkung der Substituenten auf die Grenzorbitale von Indenyltitantrichlorid zu modellieren. Unterstützt wurde das Arbeitsmodell durch Extended-Hückel-Rechnungen, wobei die Koeffizientenverteilung im p-System des Indenylliganden als eigenschaftsbestimmend erkannt wurde. Indenyltitantrichloride ermöglichen zudem den Zugang zu Verbindungen des Typs (h5-Ind)TiCl2-OR mit R = Aryl, (h5-Ind)TiCl2 [(Ind) = C9H7, (1-SiMe3C9H6)]. Diese Komplexe zeigen auffällige strukturelle Übereinstimmungen und Ähnlichkeiten mit verbrückten ansa-Amidohalbsandwichtitandichloriden.
20

Řešení kinematických veličin mechanismu a deformačně-napěťová analýza jeho členů při zablokování / Finding kinematic quantities of a mechanism and a structural analysis of its members after blockage

Zvozil, Ondrej January 2018 (has links)
Diplomová práca, ktorá vznikla v spolupráci so spoločnosťou AUFEER DESIGN (AFD), sa zaoberá analýzou konkrétneho stieračového mechanizmu automobilu. Najprv je uvedená stručná história stieračov. Stieracie sústavy sú potom rozdelené podľa ich usporiadania a spôsobu pohonu. V nasledujúcej kapitole je formulovaná problémová situácia, problém a systém podstatných veličín. Kinematické veličiny kľúčových bodov mechanizmu sú určené analytickým aj numerickým prístupom. Výpočtový model pre kinematickú analýzu je vyvinutý v Matlabe a SimMechanics. Ďalšia časť je venovaná vytváraniu konečno-prvkového modelu v programe ANSA. Všetky deformačne-napäťové analýzy sú vykonané v programe Abaqus. Prvá z nich je parametrická štúdia, ktorá odhaľuje kritické polohy mechanizmu z hľadiska tlakového namáhania určitých súčastí. Mechanizmus v kritických polohách je potom zaťažovaný so zablokovanými ramenami stieračov. Nakoniec sú urobené lineárne analýzy straty vzpernej stability súčastí, u ktorých môže nastať, nasledované nelineárnymi analýzami so zahrnutými imperfekciami.

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