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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.
201

Návrh testovacího stavu pro dlouhodobé testování spojek určených pro kolejová vozidla / Design of test rig for long-term testing of couplings intended for railroad applications

Machálek, Ondřej January 2019 (has links)
The master thesis deals with design of test rig for long-term testing of coupling appointed to railway vehicles. At first, there is made a brief research which is related to railway coupling used for transmitting a torque. This is followed by an analysis of the most used power devices to derive real loads conditions of tested couplings. There is chosen the most appropriate conception based on made analysis and it is followed by the description of designed components. There is made a verification of modal properties non-purchased components which is necessary part of the thesis. Numerical modal analysis was performed in ANSYS Workbench software. In the end of the thesis there are included stress-strain analysis of the chosen designed components.
202

Testování vozidla na čtyřkanálovém vertikálním simulátoru vozovky / Vehicle Testing on Four Post Test Rig

Egorov, Artemii January 2020 (has links)
The object of this master thesis is testing of vehicle using four post rig. The main goal is to make a research about testing and tuning vehicle characteristics on four post rig in order to implement them for testing of TU Brno Racing’s Formula Student racecar. The main method of testing, input signals and measurement description are presented in this thesis. The different methods of analysis of testing data to find best tuning of damper and spring stiffness for different race disciplines are described. In the last part of this work, quarter car model and multibody model in MSC Adams Car is created. Input parameters of model are based on measurements from real car/ component testing, including damper characteristics and static tire radial stiffness for best fit with the characteristics of real vehicle. The measurements themselves were also described in separate chapter of this thesis. The last but not the least goal was to compare these simulations with measurements, made od real four post rig in order to decide whether car model is suitable for racecar development.
203

Konstrukce zkušebního zařízení pro testování adheze a hluku v kontaktu kola a kolejnice / Design of test rig for measurement of adhesion and noise in wheel-rail contact

Gabriel, Tomáš January 2020 (has links)
This master’s thesis is dedicated to the design of an experimental rig that allows investigation of causes for noise during tram’s passing of a track curve and the developement of means to mitigate this noise. The opening section of this thesis contains theoretical background for the tribological mechanics of wheel-rail contact with emphasis on the process of noise generation, followed by an overview of laboratory tst rigs with similar purpose. Design itself is centered around the implementation of the dynamic model of wheel-rail contact using real tram wheel. Resulting test rig allows measurement of the adhesion characteristic in tangential and lateral directions and recording of the generated noise while an angle of attack is set.
204

Konstrukce 1/4 modelu vozidla pro testy tlumičů / Design of 1/4 car model for damper testing

Jaroš, Petr January 2021 (has links)
This thesis deals by the design of 1/4 car model for testing vehicle dampers, which can be used to simulate the real suspension of a vehicle wheel (up to a maximum car weight of 1,970 kg) and the so-called linear wheel suspension. A linear mathematical 1/4 car model with 2 DOF (Degrees Of Freedom) and data from literature search are used to design and derive the basic parameters of the device. The thesis contains a description of the linear mathematical model and its outputs (acceleration of the sprung mass and forces acting on the sprung mass), description of designed device, descriptions of created simulations (static, modal and harmonic analysis in ANSYS Workbench 2020 R2) and conceptual design of the modifications this device for another possible use for testing of bicycles.
205

Automatizace trati pro měření vodních ventilů / Automation of track for measurement of water valves characteristics

Lekeš, Pavel January 2014 (has links)
My diploma thesis describes upgrade of flowbench serving as test rig for regulation valves characteristic measurement. At the beggining, there is an introduction to the water regulation valves theory followed by current machine condition description. Next chapter defines needed improvements and at the end follows proposition of improvements and necessary component definition and final realization. Final chapter summarizes complete project.
206

Automatizace trati pro měření vodních ventilů / Automation of track for measurement of water valves characteristics

Lekeš, Pavel January 2014 (has links)
My diploma thesis describes upgrade of flowbench serving as test rig for regulation valves characteristic measurement. At the beggining, there is an introduction to the water regulation valves theory followed by current machine condition description. Next chapter defines needed improvements and at the end follows proposition of improvements and necessary component definition and final realization. Final chapter summarizes complete project.
207

Jacking and Equalizing Cylinders for NASA- Crawler Transporter

Rühlicke, Ingo January 2016 (has links)
For the transport of their spacecraft from the vehicle assembly building to the launch pads at Kennedy Space Centre, Florida, the National Aeronautics and Space Administration (NASA) is using two special crawler transporters since 1965. First developed for the Saturn V rocket the crawler transporters have been sufficient for all following generations of space ships so far. But for the new generation of Orionspacecraft which is under development now, a load capacity increase for the crawler transporter of plus 50% was necessary. For this task Hunger Hydraulik did develop new jacking, equalizing and levelling (JEL) cylinders with sufficient load capacity but also with some new features to improve the availability, reliability and safety of this system. After design approval and manufacture of the cylinders they have been tested in a special developed one-to-one scale dynamic test rig and after passing this the cylinders had to prove their performance in the crawler transporter itself. This article describes the general application and introduces the technical requirements of this project as well as the realized solution.
208

Utveckling av segmentbytesrigg : En konceptframtagning av segmentbytesrigg för koniska segmenthållare / Development of a segment changing rig - A concept development of a segment change rig for conical segment holders

Gustavsson, Lovisa, Sundberg, Malin January 2022 (has links)
En segmentbytesrigg kan ofta användas vid segmentbyte för raffinörer. Raffinörer har stora hållare som det sitter segment i för att mala ned träflis till pappersmassa. Eftersom dessa nöts ut med tiden är det viktigt att de byts ut, och där är segmentbytesriggen ett viktigt användarverktyg. På uppdrag av Valmet i Sundsvall undersöker detta kandidatarbete möjligheten att förenkla en av Valmets nuvarande segmentbytesriggar. Detta för att göra den mindre dyr och komplex, och därmed mer lättillverkad och mer kostnadseffektiv. Arbetet har följt designprocessens tillvägagångssätt, vilket har bestått av tre stycken faser; analytisk, kreativ och en presentationsfas. Detta resulterade slutligen i ett nytt koncept för en segmentbytesrigg, som är mer simplifierad, billigare att tillverka, men fortfarande bibehåller samma huvud- och bifunktioner. Konceptet har fått kompromissa med viss praktisk bekvämlighet för att kunna nå målet om att göra riggen mer kostnadseffektiv och lättillverkad. / Adjunkt
209

Påldrivning: Jämförelse mellan luft- och vattendriven borrning : En utredning av jämförelser avseende slitage, logistik och driftkostnader

Bengtsson, Andreas, Bodin, Pierre January 2022 (has links)
Skanska Grundläggning in Region Special wishes to gain an increased understanding of the extent to which it differs in the wear of percussion hammers and pilot drill crowns, depending on which driving medium is used in down-the-hole drilling, as well as logistical and economic aspects depending on the chosen method. Down-the-hole drilling means that the hammer works down in the borehole and forms one of the components at the far end of the drill string together with a drill bit. The blow of the hammer is created by air or water at high pressure. The piling method that is examined is drilled steel pipe piles, which means that a steel pipe pile is driven into the ground in step with the hammer and the drill bit's advancement. Once the desired depth has been reached, the drill string with the drill bit is pulled out of the casing and then the steel pipe pile is filled with concrete. The study aims to examine the products' lifespans and repair intervals from several different perspectives and set them against reality, as well as what the different methods have for differences regarding logistics and establishment. This is to create a basis for future decisions on the most suitable method of down-the-hole drilling. The beginning of the study consisted of qualitative preliminary interviews to identify and create a problem formulation that was dealt with via a literature study, five semi-structured interviews, eleven questionnaires, internal data from drilling protocols and purchasing. The result shows that there is some difference in wear in the hammer depending on whether it is an air or water powered system, the wear appears in different places and can have an impact on the life of the hammer. The wear that occurs most frequently on drill bit is grinding on the buttons. Geotechnical differences for various projects are a significant factor in the service life of the equipment. An air hammer requires that the air constantly being mixed with lubricating oil and that an air compressor consumes more diesel compared to a high-pressure pump for the equivalent water hammer. The handling of water that is flushed out of the borehole is considered a concern. To reduce wear on water hammers and thus fewer replacements and more repairs, a drill bit intended for water powered down-the-hole hammer should be used. DTH-drilling with an air hammer is considered an industry standard and a certain skepticism towards a water powered system may indicate inexperience. / Skanska Grundläggning inom Region Special önskar att få en ökad förståelse hur vida det skiljer sig vid slitage av hammare och pilotborrkrona beroende på vilket drivande medium som nyttjas vid sänkhammarborrning, samt logistiska och ekonomiska aspekter beroende på vald metod. Sänkhammarborrning innebär att hammaren arbetar nere i borrhålet och utgör en av komponenterna längst ut på borrsträngen tillsammans med en borrkrona. Hammarens slag skapas av luft eller vatten i högt tryck. Pålningsmetoden som undersöks är borrade stålrörspålar, det betyder att ett foderrör drivs ned i marken i takt med hammaren och borrkronans framfart. Väl när önskat djup uppnåtts lyfts borrsträngen med hammaren och piloten upp ur foderröret för att sedan fyllas upp med betong. Studien syftar till att undersöka produkternas livslängder och reparationsintervall från flera olika perspektiv och ställa dem emot verkligheten, samt vad dem olika metoderna har för olikheter kring logistik och etablering. Detta är för att skapa underlag för framtida beslut om mest lämplig metod av sänkhammarborrning. Studiens begynnelse bestod av kvalitativa förintervjuer för att identifiera och skapa en problemformulering som avhandlades via en litteraturstudie, fem semistrukturerade intervjuer, elva frågeformulär, interna data från borrningsprotokoll och inköp. Resultatet visar att det förekommer viss skillnad i slitage i hammaren beroende på om det är en luft- eller vattenanläggning, slitaget visar sig på olika ställen och kan ha betydelse för hammarens livslängd. Det slitage som uppträder mest frekvent på piloter är nedslipning av stift. Geotekniska egenskaper för olika projekt utgör en betydande faktor för utrustningens livslängd. En lufthammare är i behov av att luften konstant beblandas smörjolja och att en luftkompressor förbrukar mer diesel jämfört med en högtryckspump för motsvarande vattenhammare. Efterhanteringen av vatten som spolas upp anses vara ett bekymmer. För att minska slitage på vattenhammare och därmed färre byten och mer reparationer bör en pilotborrkrona avsedd för vattendriven sänkhammarborrning nyttjas. Sänkhammarborrning med lufthammare anses som branschstandard och en viss skepticism mot en vattendriven anläggning kan tyda på oerfarenhet.
210

Methodology for Obtaining S-N Curves using Fatigue Testing and Static FEA

Anderfelt, Filip, Äse, David January 2022 (has links)
The use of recommended S-N curves, presented in current literature, to analyse and determine the fatigue life of a part is common practice in, inter alia, the construction industry.However, the recommended S-N curves are generally created for larger components used in mainly the construction industry. Hence, the use of S-N curves for the evaluation of smaller parts, may result in over-dimensioning of such parts. For this reason, evaluation and designing of smaller parts could benefit from the development of an in house S-N curve specific for the part. The purpose of this thesis is to generate and validate an in-house method for creating a S-N curve, for a specific part to be compared with recommended S-N curves in the literature. The specific part used for the generating of the method is a welded steel joint with the geometry of two steel pipes, welded together in a t-formation and which has been provided by Thule AB for the purpose of the thesis. The method presented uses the results from 1) physical fatigue tests using a fatigue testing machine and 2) static FEA to derive a S-N curve for the specific part using the least squares method. A fatigue testing rig enables the gathering of data of the number of cycles to failure when the part is subject to a given cyclic load. The rig uses pneumatics to control the forces applied onto the part with the use of a cylinder. Furthermore, the fatigue testing rig was designed to be controlled by the applied force, meaning, that the rig ensured a homogeneous load cycle by measuring the force from a load cell and alternating the direction of the cylinder with an electrically controlled pressure valve. The performance of static FEA evaluations aim at locating stresses in the part. For this thesis the stresses were evaluated using the hot spot method due to the part's welded geometry. The data gathered from the physical fatigue tests and the static FEA evaluations are subsequently combined deriving S-N curves applicable to the part. From the fatigue tests and FEA evaluations for the t-shaped welded steel part, four S-N curves were derived of which two curves showed the results of a linear fitted curve whereas the other curves used the recommended slope of $-1/3$. The results showed that the S-N curves derived, using a set slope, resulted in similar curves to the recommended S-N curve provided by the literature. However, the linear fitted S-N curve showed that the part, according to the S-N curve, had a higher fatigue resistance than recommended.  Due to limitations in the thesis work, the S-N curves derived within the framework of this thesis should be regarded as theoretical and have been strictly used to identify whether the method generated is applicable for deriving of S-N curves.

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