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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.
21

Experimental and numerical analysis of nonlinear properties of rail fastening systems / Étude numérique et expérimentale des propriétés non linéaires des systèmes d’attache de rail

Liu, Yan 20 March 2015 (has links)
Le besoin en isolation vibratoire des voies ferrées conduit de plus en plus souvent au recours à des systèmes d'attache de rail souples avec des designs sophistiqués. Par contre, les produits deviennent diversifiés mais leur conception se fait de manière empirique dans la pratique. Dans ce travail de thèse, deux systèmes d'attache de rail sont étudiés expérimentalement et numériquement: un système qui travaille principalement en cisaillement et l'autre en compression. Des essais quasi-statiques et dynamiques sont menés puis les résultats sont analysés à l'aide de différents modèles mécaniques. En plus, une série de tests sur les élastomères utilisés dans les deux systèmes sont réalisés. Ces tests permettent de choisir des modèles hyperélastiques et viscoélastique appropriés, et de déterminer les paramètres de propriétés mécaniques des élastomères dans ces modèles par des simulations Abaqus. En utilisant également Abaqus, des analyses par élément fini des deux systèmes d'attache sont effectués et les résultats sont comparés aux ceux des essais. Des non-linéarités d'origine matérielle et géométrique sont ainsi analysées et expliquées. Enfin, des études de sensibilité des paramètres sont effectuées, suivies d'études d'optimisation structurale. Cet étude devrait être utile pour une meilleure compréhension du comportement mécanique des systèmes d'attache de rail sous chargement statique et dynamique, et au final pour une meilleure pratique dans la conception et l'optimisation des produits / Higher demand on vibration isolation of track structure in modern railway track leads to a trend of lower stiffness of rail fastening systems, places an increasing need for better design approach as well. However the current development status of rail fastening industry is dramatically diversified but mainly empirical. In this work, a shear type and a bonded compressed type of rail fastening systems are investigated experimentally and numerically. Quasi-static and dynamic experiments are carried out and the results are analysed with different mechanical models. Besides, a series of fundamental rubber material tests is performed to accurately describe the rubber material used in the two fastening systems. The most appropriate hyperelastic and hysteresis models are chosen with the help of simulations by Abaqus. Also by using Abaqus, finite element analyses are conducted for the two fastening systems and the numerical results are compared with those of experiments. Material and geometrical nonlinear features observed in the measured displacement-force curves are analysed and explained. Finally, parameter sensitivity of the two fastening specimens are studied, followed by an optimization process to meet practical optimization objectives. The present work is believed to be helpful for understanding the mechanical behavior of rail fastening systems, while enlightening the engineering practice, and eventually improving product designing and optimizing measures
22

Experimentální analýza vybraných systémů kolejnicových upevnění / Experimental Analysis of Chosen Railway Fastening Systems

Tomandl, Vladimír Unknown Date (has links)
Theoretical analysis (i.e. simulation) promoted by the laboratory tests of final product is the important aspect for determination relating to choice and using the new infrastructural constituent. However, the laboratory analysis does not need to make conclusive results in some cases. At that time, it is necessary to complete the process of validation by the measurement in-situ (directly in the track section). The European legislation requires the long-term monitoring of the test constructions in this case. During this time, both the periodic monitoring of the chosen parameters and the following comparison with reference construction are recommended. The reference construction shall be inserted to the same track section and in the same time period as well as the test construction. The track gauge, the longitudinal shifts of rails vis-a-vis the sleepers, the clamping force of fastening, the rail head profile, the sleepers and the state of rail fastenings are possible to classify like the long-term monitored parameters. All these characteristics are so-called static. They are checked in time when no carriages pass through the monitored track section. However, the analysis and determination of the test construction behaviour (dynamic characteristic) are the most accurate by the moving load. Dissertation thesis is focused on measurement and analysis of the dynamic effects at the plain line. The aim of the thesis is the completion of recent system of the new track structures verification for the dynamic parameters observe. Methodology of the measurement and convenient mathematical apparatus for analysing the dynamic effects is proposed.
23

Analýza akustických a vibračních parametrů od železniční dopravy / Analysis of acoustic and vibration parameters from rail transport

Turčíková, Hana January 2014 (has links)
This diploma thesis is focused on operational testing of selected railway lines with different structures of superstructure. For the measurement purposes suitable measuring sections in directional curves on the rail corridors were chosen and suitable measuring methodology was designed. Based on all the tests the dynamic and acoustic parameters of tested structures were determined. For the test evaluations suitable mathematic methods in both time and frequency zone was chosen. Part of my work is also to compare the parameters of the tested structures and to make recommendations for practise.
24

Experimentální analýza dynamických parametrů kolejového roštu / L'analyse expérimentale des paramtres dynamiques du rail grille

Podolník, Adam January 2014 (has links)
In terms of deciding on the appropriate use of the railway superstructure assemblies in both the recommendations arising from the theoretical analysis (modeling), as well as recommendations obtained under static and dynamic testing of the finished product play an important role. Such tests can then be applied in the laboratory or in the field. The thesis will be devoted to operational testing of selected track grid structures in situ. For measurement purposes an appropriate measuring point will be chosen and the methodology of measurement will be proposed. In terms of track geometry sections in curves will be selected. On the basis of tests carried out dynamic parameters of structures will be determined. To their evaluation suitable mathematical system will be chosen. It assumes the use of mathematical methods in time and frequency areas. In the thesis there will also be a comparison of the parameters of the tested structures. Based on the measurements it will be a source of recommendations for the practice.
25

Adheze spojů asfaltových pásů mechanicky kotvených / Adhesion connections asphalt strips mechanically fastened

Petříček, Tomáš Unknown Date (has links)
One-layer mechanical fastening waterproofing systems are often used within the compositions of flat roofs. Although in case of plastic based systems it is a common solution, for asphalt felts it handles about a relatively new approach, since the application of asphalt has a long history in the building industry. There are some key factors which all of the one-layer mechanically fastening systems should meet, especially water-resistance and resistance against the suction of wind. The application of dynamic loads on the joints may damage the bonds, which may lead to leakage of water. In particular the most delicate locations are the anchoring points at places where the waterproofing sheets are not connected mutually and the wind is captured. The characteristics of mechanically fastening waterproofing membranes may be verified by a specific test which is able to simulate the winds suction force, nonetheless it is quite expensive. Throughout the solution of the presented work an equipment was designed to observe the behaviour of roof compositions on smaller segments while taking into account the fastening elements, thus bringing the results closer to reality. In the first phase the presented dissertation aims to look at the possibilities of comparison of mechanically fastening bitumen reinforced sheets in a way, that they would show the extent to which the joints depend on the parameters of bitumen sheet - like the quality of the bitumen mass, the type bearing linen, the thickness of the layer or just the width of strip overlap. In the next phase the research was focused on the extent at which the strength of the resulting mechanically fastened joints is affected by the placement of fastenings elements within the strip overlap, including the possibilities when the distances from the edges of the bitumen strip cannot be maintained or because of improper geometry of fastening elements. The measurements were performed on both variants of flat roofs, thermally insulated
26

Effektivisering av fönstermontering hos ett trähustillverkande företag : En fallstudie på LB-Hus / Improving efficiency on window installation at a wooden house manufacturing company : Case study at LB-Hus

Molin, Felix, Olofsson, Stina January 2023 (has links)
Studiens syfte är att skapa en förståelse kring hur effektiviteten i ett producerande företag kan öka genom förändringar i förtillverkningen. Studien har utförts på fallföretaget LB-Hus i Bromölla som tillverkar prefabricerade trähus. Genom att använda förtillverkning, där komponenter byggs utanför den huvudsakliga produktionen, kan monteringsprocessen påskyndas, minska avfall och omarbetning samt öka kvalitetskontrollen. Förtillverkning kan således resultera i mer avancerade och specialiserade produkter av högre kvalitet samtidigt som risken för felaktiga monteringar eller fel i produktionsprocessen minskar. Studien fokuserar på montering av fönstermoduler och jämför två olika infästningssystem: Adjufix och Click-In. I tidigare studier har det visat sig att det nya infästningssystemet, Click- In, har fördelar när det gäller att direkt installera fönster i monteringslinan, och därför är det också värt att undersöka hur en jämförelse mellan dessa infästningssystem vid förtillverkning av fönstermoduler skulle falla ut. I denna studie har observationer och mätningar gjorts som visade att det nya infästningssystemet är fördelaktigt gentemot det nuvarande med hänsyn till tid och antal arbetsmoment. I en jämförelse med de båda metoderna konstaterades att det nya infästningssystemet minskar monteringstiden med i genomsnitt 2 minuter och 47 sekunder samt att det kräver sju färre arbetsmoment än det gamla infästningssystemet. Implementeringen av det nya systemet skulle därmed minska cykeltiden i förtillverkningen av fönstermoduler. Genom att använda den nya metoden och dra nytta av dess fördelar kan företag öka sin produktions- och monteringseffektivitet, öka kvalitén, minska arbetsmoment, slöseri och risken för felaktiga monteringar. Ändringarna leder då till minskade produktionskostnader och ökad konkurrenskraft på marknaden. / The purpose of the study is to create an understanding of how the efficiency of a manufacturing company can increase through changes in pre-production. The study was carried out at the case company LB-Hus in Bromölla, which manufactures prefabricated wooden houses. Using pre-fabrication, where components are built outside of main production, can speed up the assembly process, reduce waste and rework, and increase quality control. This can result in more advanced and specialized products of a higher quality while reducing the risk of incorrect assemblies or errors in the production process. The study focuses on the installation of window modules and compares two different fastening systems: Adjufix and Click-In. In previous studies, it has been shown that the new fastening system, Click-In, has advantages when it comes to directly installing windows in the assembly line, and therefore it is also worth investigating how a comparison between these fastening systems in the pre-production of window modules would turn out. In this study, observations and measurements have been made which showed that the new attachment system is advantageous compared to the current one with regard to time and number of work steps. In a comparison of the two methods, it is found that the new fastening system reduces the assembly time by an average of 2 minutes and 47 seconds and that it requires seven fewer work steps compared to the old fastening system. The implementation of the new system would thus reduce the cycle time in the pre-production of window modules. By using the new method and taking advantage of its advantages, companies can increase their production and assembly efficiency, increase quality, reduce work steps, waste and the risk of incorrect assemblies. This, in turn, can lead to reduced production costs and increased competitiveness in the market.
27

Analýza spojů proudovodiče při měření proudu ve VN aplikacích / Analysis of current lead joints inside HV current transformers

Pálka, Marek January 2016 (has links)
The main focus of the dissertation thesis is determine the size of the fastening screw connection and fastening torque of the connection, which will be applied during assembly of the instrument current transformers and sensors. The large part of thesis is an experimental measurement of the proposed configurations of connections and modelling (simulating) certain model of connections in Ansys and SolidWorks analysis programs. The result of the dissertation will be design of tightening of the connection according to transient resistance and thermal losses.
28

Optimización y análisis de comportamiento de sistemas de sujeción para vías de ferrocarril de alta velocidad española

Carrascal Vaquero, Isidro Alfonso 06 October 2006 (has links)
Los nuevos ferrocarriles de Alta Velocidad Española (AVE) suponen, respecto a su predecesor, la línea Madrid-Sevilla, un incremento en la velocidad máxima, pasando de los 280-300 km/h de la línea original a los 350 km/h que se pretende alcanzar en los nuevos trazados. Este incremento de velocidad origina mayores solicitaciones que afectan a la superestructura de la vía y, por ello, se hace necesario un redimensionado de todos los parámetros de diseño del trazado. Entre los componentes de la superestructura se encuentra el sistema de sujeción. Este sistema está constituido por un conjunto de pequeños elementos de vía que fijan el carril a la traviesa dando continuidad estructural a la vía. El sistema de sujeción cobra mayor importancia debido a este incremento de los esfuerzos originado por el aumento de las velocidades, convirtiéndose en un elemento clave de la superestructura de vía. Esta Tesis, pretende, en primer lugar, encontrar el sistema óptimo de sujeción que se adapte a las exigencias establecidas por la administración en el "Pliego de bases para el suministro de sujeciones" para ferrocarriles de alta velocidad. En segundo lugar, una vez definido el sistema, analizar el comportamiento de la sujeción, tanto desde el punto de vista individual de cada componente, como desde el punto de vista global. Este análisis incluye la totalidad de propiedades importantes del sistema, desde las mecánicas, ya sean estáticas o dinámicas, hasta las eléctricas, pasando, entre otras, por las de durabilidad y deterioro. También, se estudiarán las posibles variaciones sufridas por estas propiedades en función de parámetros externos, como pueden ser los de carácter ambiental, e internos propios del sistema de sujeción. / The new Spanish High Speed Railways (AVE) involve, regarding its predecessor, Madrid-Seville line, an increase in the maximum speed, going from 280-300 km / h of the original line to 350 km / h that expects in the new routes. This speedup produces greater efforts that affect the superstructure of the track and, therefore, resizing of all design parameters of the track is required. The fastening system is among the components of the superstructure. This system is made up of a set of small track pieces that fasten the rail to the sleeper giving structural continuity to the track. The fastening system is becoming more important because of this greater efforts caused by the increased speeds, becoming a key element of the track superstructure. The aim of this thesis is, first, to find the optimum fastening system that well suits the requirements set by the administration in the "Terms for the supply of fasteners" for high speed railways. Secondly, this thesis, once the system has defined; analyzes the behaviour of the fastening, both from the point of view of individual component, and from a global perspective. This analysis includes all the important properties of the system, from the mechanical properties, whether static or dynamic, to the electrical properties, besides the hardness and deterioration. Also, the possible changes undergone for these properties depending of external parameters, such as the environmental measure, and own internal parameters of the fastening system were studied.
29

Rekonstrukce železniční stanice Milevsko / Upgrading of Milevsko Railway Station

Křemen, Tomáš January 2015 (has links)
The aim of the diploma thesis is the reconstruction of Milevsko railway station. The platforms with access persons with reduced mobility are designed in this station. The rail substructure and station drainage system design was necessary to do within the reconstruction. New assembly of a switches and crossing is the part of reconstruction design as well.
30

Tillämpning av lastskenor för standardiserat montage på skott för kompositfartyg

Phan, Van Trung Nghia January 2023 (has links)
Saab Kockums har på länge tillämpat kompositmaterial i uppbyggande av deras nya fartyg. Detta medför många fördelar kopplat till stealth teknik men samtidigt utgör vissa andra utmaningar gällande installationer ombord. Arbetet utfördes därför med syfte att undersöka möjligheten för användning av lastskenor för standardiserat montage på dessa fartyg. Vidare skulle det utvecklas en standardlösning för montaget där användarvänlighet står som fokus.   Arbetet inleds med en undersökning av produkter från marknaden där också utvecklingspotential identifierades. Fokus med undersökningen var att hitta den optimala utseende för montaget. Dessa punkter användes därefter för att generera idéer för samtliga delar. Den bästa idéen filtreras fram genom poängsättning kopplat till utsatta kravställningen. För infästning av konstruktion bestämdes det med hjälp av olika litteraturstudier tillsammans med dragprovsdata som tillhandahålls av Kockums. Litteraturstudien omfattades studie på egenskaper hos sandwichkonstruktioner samt dragproven på olika lastfallen som utfördes på andra rapporter. Sist verifierades konceptet utifrån olika aspekter baserat på olika sätt. Hållfasthetmässigt är baserade på FEM/manuella beräkningar, tillverkning är baserade på intervju och monteringen baserad på 3D-utskrift.   En konstruktion på montaget erhölls som resultatet av arbetet där den klarade samtliga krav som ställdes. Konstruktionen består av förmonterade skena som har ett homogen utseende tillsammans med vinkelbeslag för montering av eventuella bäddar eller dämpare. Konstruktionen fästs på skottet med M8 blindnitsmuttrar för områden utan stötkrav och M10 muttrar tillsammans med laminatsförstärkning för områden med stötkrav. Som bevisat är det möjligt att tillverka dessa med några enkla steg av standardprofiler från marknaden. Det är även enkelt att montera ombord på fartygen. / Saab Kockums has long time used composite materials in the construction of their new ships. This brings many advantages linked to stealth technology, but at the same time poses some other challenges regarding installations on board. This thesis was therefore performed with the aim of investigating the possibility of using cargo rails for standardized assembly on these ships. Furthermore, a developed standard solution for assembly where ease of use is the focus for this study.  The work begins with an analysis of products from the market and potential development is identified. The focus of the investigation was to find the optimal design for the montage. These potentials were then used to generate ideas for parts in the design. The best idea is filtered through scoring linked to the set of requirements. For attachment of the construction, it was determined with the help of various literature studies along with tensile test data provided by Kockums. The literature study included studies on properties of sandwich constructions as well as tensile tests on different load cases that were carried out on other reports. Finally, the concept is verified based on different aspects. The durability is based on FEM/manual calculations, the manufacturing is based on interview and finally the assembly is based on 3D printing.  A construction of the assembly was obtained as the result of the work and met all the requirements that were set. The construction consists of pre-assembled cargo rails that have a homogeneous appearance together with angle fittings for mounting any foundations or dampers. The structure shall be attached to the bulkhead with M8 blind rivet nuts for areas without impact requirements and M10 nuts together with laminate reinforcement for areas with impact requirements. As proven, it is possible to manufacture these in a few simple steps from standard profiles from the market and easily fit on board the ships.

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