Sökning: "railway rails"

Visar resultat 16 - 20 av 52 avhandlingar innehållade orden railway rails.

  1. 16. Wheels, Rails and Insulated Joints - Damage and Failure Probability at High Speed and Axle Load

    Författare :Johan Sandström; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rail breaks; probability; railway mechanics; contact mechanics; insulated joints; defects; fatigue;

    Sammanfattning : The thesis deals with some fatigue related problems in railway mechanics related to increased axle loads and speeds. The focus is on defects and discontinuities in the wheel--rail system that affect the risk of fatigue and fracture of railway components such as wheels, rails and insulated joints. LÄS MER

  3. 17. 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

  4. 18. Modelling of cyclic and viscous behaviour of thermomechanically loaded pearlitic steels; Application to tread braked railway wheels

    Författare :Ali Esmaeili; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rolling contact fatigue; plasticity; tread braking; full-scale brake rig testing; Railway wheels; finite element analyses; pearlitic steel; viscoplasticity; ratchetting; phase transformations;

    Sammanfattning : In service, railway wheel and rail materials are subjected to high stresses and, in some cases, elevated temperatures. The high stresses are caused by the rolling contact between wheel and rail. Furthermore, heat generated from tread braking and/or sliding between wheel and rail gives additional stress due to constrained thermal expansion. LÄS MER

  5. 19. Simulation of track settlement in railway turnouts-An iterative approach

    Författare :Xin Li; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; track settlement; Railway switch and crossing; cyclic loading; visco-plasticity; vehicle‒track interaction; 3D finite element analysis; granular material; ballast;

    Sammanfattning : In this thesis, a methodology for simulation of track settlement in railway turnouts (switches andcrossings, S&C) is presented. The methodology predicts the accumulated settlement for a given setof traffic loads using an iterative and cross-disciplinary procedure. LÄS MER

  7. 20. Cost-effective maintenance of railway track geometry : a shift from safety limits to maintenance limits

    Författare :Iman Arasteh Khouy; Peter Veit; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Drift och underhållsteknik; Operation and Maintenance Engineering;

    Sammanfattning : Railway infrastructure is a complex system which comprises different subsystems. Long life span is one of the important aspects of this prime mode of transport. However, the useful life of its assets is highly dependent on the maintenance and renewal strategy used during the assets’ life cycle. LÄS MER