Sökning: "railway traction"

Visar resultat 1 - 5 av 28 avhandlingar innehållade orden railway traction.

1. 1. On the Directivity of Railway Noise Sources

   Författare :Xuetao Zhang; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; railway traction noise; railway rolling noise; line source; railway aerodynamic noise; moving source; equivalent source line; De-Dopplerization; sound emission time; sound immission time; directivity; the Doppler factor;

   Sammanfattning : This dissertation deals with the directivity of railway noise. The directivity of railway noise is of particular importance when we have high-rise buildings close to the track, tunnel openings, partial barriers, or when we calculate the maximum sound pressure level during a pass-by based on the sound power level of the different sub-sources of a train. LÄS MER

3. 2. High Frequency Model of Electrified Railway Propulsion System for EMC Analysis

   Författare :Kelin Jia; Rajeev Thottappillil; Hans Bängtsson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electromagnetic compatibility; railway; propulsion system; multitransmission line; ac motor modeling; vector fitting; fast transient;

   Sammanfattning : A model of the electrified railway propulsion system working in a wide frequency range is studied in this thesis. The high frequency modeling is the first stage to study and predict the Electromagnetic compatibility (EMC) problems in the electrified railway propulsion system, which are safety and reliability issues of high concern. LÄS MER

4. 3. Temperature Stability of Railway Wheel Steels - Influence on Microstructure and Mechanical Properties

   Författare :Krste Cvetkovski; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Railway; Diffusion; Low cycle fatigue; Fe‐Mn‐Si; Spheroidisation;

   Sammanfattning : Being the single component transferring load and traction from the vehicle to the rail, the selection of materials and structural properties of railway wheels are critical. Carbon steel with a pearlitic microstructure is the most commonly used material due to its high strength, low cost and good wear properties. LÄS MER

5. 4. Harmonic Mitigation in Traction Drives

   Författare :Hans Bängtsson; Industriell elektroteknik och automation; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; hydraulics; Mechanical engineering; converter; line interference; track circuit; Railway signalling system; vacuum technology; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik;

   Sammanfattning : In railway traffic the low friction between wheel and rail causes long braking distances, normally much longer than the sight distance of the driver, i.e. if the driver starts the braking when a problem on the track is discovered, it might be too late to brake the train. Therefore, safe railway traffic can not only rely on the driver. LÄS MER

7. 5. On Heavy-Haul Wheel Damages using Vehicle Dynamics Simulation

   Författare :Saeed Hossein Nia; Sebastian Stichel; Carlos Casanueva; Per-Anders Jönsson; Ernesto Garcia Vadillo; KTH; []
   Nyckelord :wear; RCF; rolling contact; traction; braking; heavy-haul; FASTSIM; FaStrip; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : Maintenance cost is one of the important issues in railway heavy-haul operations. In most of the cases, these costs are majorly referring to reprofiling and changing the wheels of the locomotives and the wagons. The main reason of the wheel damages is usually severe wear and/or surface initiated rolling contact fatigue (RCF). LÄS MER