Sökning: "wheel"

Visar resultat 21 - 25 av 339 avhandlingar innehållade ordet wheel.

1. 21. Adhesion in the wheel-rail contact under contaminated conditions

   Författare :Yi Zhu; Ulf Olofsson; Ines Lopez Arteaga; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; adhesion; wheel-rail contact; contaminants; rough surfaces;

   Sammanfattning : Railway vehicles require a certain level of adhesion between wheel and rail to operate efficiently, reliably, and economically. Different levels of adhesion are needed depending on the vehicle running conditions. LÄS MER

3. 22. Wheel Housing Aerodynamics of Heavy Trucks

   Författare :David Söderblom; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : For trucks in long-haul operation the aerodynamic drag constitutes more than half of the total driving resistance, and by optimising the aerodynamics of thevehicle it is possible to reduce the fuel consumption significantly. The drag of the underbody, including wheels, wheel housings and engine compartment, accounts for a large part of that aerodynamic drag, and very little aerodynamic optimisation has been carried out in this specific area on heavy trucks. LÄS MER

4. 23. Railway Wheel Flats. Martensite Formation, Residual Stresses, and Crack Propagation

   Författare :Johan Jergeus; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sliding contact; metallographic investigation; crack propagation; thermal shock; constitutive modelling; phase transformations; railway wheel flats; full-scale field experiments; transformation plasticity; tread damage; residual stresses; spalling; martensite formation;

   Sammanfattning : A railway wheel flat is a flat spot on the rolling surface of a wheel caused by its unintentional sliding on the rail. The reason for the sliding may be poorly adjusted, frozen or defect brakes, or too high braking forces in relation to the available wheel/rail adhesion. LÄS MER

5. 24. Mechanistic-Empirical Modelling of Flexible Pavement Performance : Verifications Using APT Measurements

   Författare :Abubeker W. Ahmed; Sigurdur Erlingsson; Hervè Di Benedetto; Statens väg- och transportforskningsinstitut; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Performance; Deformation; Model not math ; Rutting wheel ; Viscoelasticity; Elasticity; Axle load; Flexible pavement; Laboratory not an organization ; Test; Thesis; Heavy vehicle simulator; Wheel tracking test; 32 Road: Pavement design; 32 Road: Pavement design; Transportvetenskap; Civil and Architectural Engineering;

   Sammanfattning : Mechanistic-Empirical  (M-E)  pavement  design  procedures  are  composed  of  a  reliable  response model to estimate the state of stress in the pavement and distress models in order to predict the different types of pavement distresses due to the prevailing traffic and environmental conditions. One of the main objectives of this study was to develop a response model based on multilayer elastic  theory   (MLET)  with  improved  computational  performance  by   optimizing  the   time consuming parts of the MLET processes. LÄS MER

7. 25. The Finland-Swedish Wheel of Migration : Identity, Networks and Integration 1976-2000

   Författare :Charlotta Hedberg; Göran Hoppe; Solveig Mårtensson; Uppsala universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Social and economic geography; Cultural migration; Integration and assimilation; Ethnic identity construction; Networks; Spatial identities; Finland Swedes; Kulturgeografi; Human geography; Kulturgeografi;

   Sammanfattning : This dissertation examines the role in the migration process between Sweden and Finland of the Swedish-speaking minority group, the Finland Swedes. The causes underlying migration, as well as the integration of the group in Sweden, constitute the main focuses of the study. LÄS MER