Fletcher, D., Scott, D. and Cardwell, B.J. (2012) Simulation study of thermally initiated rail defects. Proceedings of the Institution of Mechanical Engineers. Part F: Journal of Rail and Rapid Transit, 228 (2). pp. 113-127. ISSN 0954-4097
Abstract
Ultrasonically detected ‘squat type’ rail defects are becoming increasingly common on railways throughout the world. On the London Underground (LU) these defects are found on three lines. Focussing on the difference between these lines and others on the LU network has identified vehicles with modern AC traction characteristics as a common theme found only on problem lines. Metallurgical analysis of the defects found that the mechanisms for generation and growth are not consistent with conventional rolling contact fatigue, with evidence of significant thermal input. The defects are only found on open sections. The most susceptible areas to the defects are those where low-speed running is more common. A mathematical model of the traction package has been used to examine the forces and thermal input generated at the wheel–rail interface with modern wheel-spin control systems under wheel slip and adhesion recovery conditions. The outputs have been analysed to assess whether sufficient forces and temperatures are generated to explain the observed rail damage. The results suggest that under certain circumstances wheel-spin recovery generates sufficient rail surface energy for martensitic transformation. Additional modelling suggests that thermal input from wheel- spin aids crack propagation and that regions of slightly degraded (wet as opposed to leaf or oil contaminated) rail adhesion are sufficient to initiate these flaws.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © IMechE 2012. This is an author produced version of a paper subsequently published in Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Mechanical Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 02 Jun 2015 14:35 |
Last Modified: | 21 Mar 2018 14:52 |
Published Version: | http://dx.doi.org/10.1177/0954409712465697 |
Status: | Published |
Publisher: | SAGE Publications |
Refereed: | Yes |
Identification Number: | 10.1177/0954409712465697 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:86303 |