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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.
1

Bestämning av statiska friktionskoefficienter mellan trä och stål / Determination of static friction coefficients between wood and steel

Petersson, Robin, Gajos, Kristian January 2019 (has links)
Med teknikens framfart finns ett ökat behov av numeriska simuleringar avträförband. För att erhålla ett mer tillförlitligt resultat finns ett behov av noggrannarefriktionskoefficienter vid olika förhållanden som påverkar lastöverföring.I den här studien undersöks friktionen mellan materialen LVL (laminated veneerlumber; fanerträ) och stål. Målet är att studien ska resultera i friktionskoefficienterför olika varierande förhållanden som sedan kan användas vid t.ex. olika numeriskasimuleringar.Friktionstesterna utfördes genom att succesivt öka vinkeln på glidytan i form av enstålplatta där en provkropp var placerad. Vinkeln ökades tills det att provkroppenhamnade i rörelse, den uppnådda vinkeln registrerades och räknades sedan om till enfriktionskoefficient.Totalt utfördes 1 800 friktionstester för att ge god statistisk grund åt de slutgiltigamedelvärdena för friktionskoefficienterna. Undersökningen resulterade i enfriktionskoefficient i form av ett medelvärde för respektive varierande förhållande.
2

Static Friction in Slip Critical Bolt Joints : Coefficient of Friction in Steel, Aluminium and ED Coated Steel

Lång, Marcus January 2017 (has links)
This project was performed together with ÅF Industry AB in Trollhättan, Sweden. ÅF’s expertise in Trollhättan is oriented towards the automotive industry. It was conducted within the section of CAE and safety where they, for instance, dimension bolt joints in the cars. Bolt joints play an important role in the automotive industry. Slip critical bolt joints are used widely throughout the vehicles. With lack of good test data, the bolt joints need to be dimensioned conservatively. This may lead to that bolt joints are over-dimensioned, adding more mass to the car. On the contrary, the availability of reliable test data enables designers to optimize joint dimensions to achieve a safe design with minimized mass. A mechanical testing configuration has been designed as well as a testing procedure for a test to determine the static friction value between mating surfaces in bolt joints. The testing configuration has been used to perform tests to find the static friction coefficient in different materials. The study contains varied combinations of steel, aluminium and ED-Coated steel. The study resulted in tables with levels of probability. The developed test configuration is robust and relatively simple to use and is recommended for further use. For improved statistical significance, it was noted that more samples should be used than was used in this study. The aluminium has a smoother surface finish and that could be the reason why its coefficient of friction is lower than steel. It is therefore considered important to also include surface roughness when presenting coefficient of friction results.

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