Sökning: "track stiffness"

Visar resultat 21 - 25 av 32 avhandlingar innehållade orden track stiffness.

1. 21. On cyclic accumulation models for degradation of railway foundations

   Författare :Hossein Tahershamsi; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Natural soft clay; Global Sensitivity Analysis; Sobol method; Experimental design; Rate-dependent models; Cyclic accumulation models; Cyclic degradation; Uncertainty analysis;

   Sammanfattning : The degradation of railway foundations due to the repeated loading of traffic induces maintenance and safety obligations for the track operator. One major contributor to track degradation is the accelerated settlement rates in soft soils below the track that lead to alignment issues, especially at stiffness transitions. LÄS MER

3. 22. Towards Optimization of Railway Turnouts

   Författare :Björn Pålsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dynamic vehicle–track interaction; turnout; switch crossing; wheel and rail wear;

   Sammanfattning : The turnout (Switch & Crossing) is a vital component in railway networks as it provides flexibility to traffic operation by allowing trains to switch between tracks. The flexibility comes at a cost as the common lack of a transition curve in the diverging route together with the variation and discontinuities in rail profiles result in higher rail degradation rates than in regular track. LÄS MER

4. 23. Structural Behaviour of Concrete Railway Sleepers

   Författare :Rikard Gustavson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; concrete; finite element analysis; three-wire strand; sleeper; bond; strand; pull-through tests; steel encased; push-in tests; bond mechanism; numerical bond model; dynamic loads;

   Sammanfattning : The railway concrete sleeper is an important part of the railway track structure. The sleeper member requires substantial engineering skills during the design and manufacturing process in order to fulfil the requirements set by modern train traffic. LÄS MER

5. 24. An Investigation of the Iron-Ore Wheel Damages using Vehicle Dynamics Simulation

   Författare :Saeed Hossein Nia; Sebastian Stichel; Matti Rantatalo; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; three-piece bogie; wear; RCF; prediction; traction; braking; heavy haul; simulation; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : Maintenance cost is one of the important issues in railway heavy haul operations. For the iron-ore company LKAB, these costs are mainly associated with the reprofiling and changing of the wheels of the locomotives and wagons. The main reason for the wheel damages is usually surface initiated rolling contact fatigue (RCF) on the wheels. LÄS MER

7. 25. Optimisation of Railway Switches and Crossings

   Författare :Björn Pålsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wheel and rail wear; railway turnout; optimisation; switch crossing; dynamic vehicle-turnout interaction;

   Sammanfattning : Methods for simulation-based optimisation of the design of railway turnouts (switches & crossings, S&C) are developed and demonstrated. Building on knowledge of dynamic wheel–rail interaction in turnouts, it is investigated how rail profile degradation can be reduced by the optimisation of geometry and component stiffness of the track superstructure. LÄS MER