Sökning: "railway mechanics"

Visar resultat 11 - 15 av 67 avhandlingar innehållade orden railway mechanics.

1. 11. 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

3. 12. 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

4. 13. Interpretation of Railway Track Alignment Measurements in a Geodynamic Perspective

   Författare :Jonas Majala; Jan Laue; Thorkild Maack Rasmussen; Kenneth Viking; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dynamic load; Railway; Frequency; Track measurement; Geoteknik; Soil Mechanics;

   Sammanfattning : The development in society means that infrastructure like ballasted railway systems are facing challenges due to request for increased number of high-speed trains and heavier freight trains. This implies that ballasted railways get an increased impact from larger dynamic loads. LÄS MER

5. 14. Applicable directivity description of railway noise sources

   Författare :Xuetao Zhang; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; directivity; the Doppler factor; scattered fluid sound; railway noise; perpendicular dipole pair;

   Sammanfattning : For a sound source, directivity is an important parameter to specify. This parameter also reflects the physical feature of the sound generation mechanism. For example, turbulence sound is of quadrupole directivity whilst fluid-structure interaction often induces a sound of dipole characteristic. LÄS MER

7. 15. Wheel–Rail Impact Loads and Track Settlement in Railway Crossings

   Författare :Xin Li; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vehicle--track dynamics; wheel--rail contact; track settlement; material modelling of ballast; Switches and crossings; turnout; cyclic loading; Green s functions;

   Sammanfattning : Turnouts (Switches & Crossings, S&C) are critical components of a railway track requiring regular maintenance and generating high life cycle costs. A main driver for the high maintenance costs is the need to repair and replace switch rails and crossings as these components are subjected to a severe load environment. LÄS MER