Prediction of Thermal Damage in Rails

Connell, Michael (2013). Prediction of Thermal Damage in Rails B.Sc Thesis, School of Engineering, The University of Queensland.

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Author Connell, Michael
Thesis Title Prediction of Thermal Damage in Rails
School, Centre or Institute School of Engineering
Institution The University of Queensland
Publication date 2013
Thesis type B.Sc Thesis
Supervisor Bill Daniel
Total pages 107
Language eng
Subjects 0913 Mechanical Engineering
0901 Aerospace Engineering
Formatted abstract
Since their initial discovery in the 1950's, squats have caused significant damage to rails. A layer of martensite on the surface of the rail due to thermal damage a hard layer in which the crack is able to seed and a brittle medium which promotes propagation. The aim of this thesis is to predict the thermal damage to the rail due to the several dynamic excitations. A Matlab model simulating multi body dynamics is used to predict the temperature rise in rail head for a track joint and a transition to wet track. The track response and initial speed were varied and the contact forces were calculated with Fastsim and using Polach creep force models to investigate the effects.

It was found that for all gap widths tested the heating was not sufficient to reach high enough temperatures for damage. For a transition to wet track it was found that a livelier track did not result in higher temperatures and heating rates. Lower initial speeds result in higher temperatures because there is more time for conduction.

It was shown that the initial slope of the Polach contact model provided an obstacle to the uncontrolled increase in sliding at Beenleigh. The creep values moved towards the peak of the curve but did not have the required energy to transition to full sliding, hence limiting the heating. This was not the case using on the Airport track with the peak being overcome and the transition to full sliding happening faster than predicted by Fastsim with the lower coefficient of friction resulting in more heating as predicted.
Keyword Thermal damage

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
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Created: Tue, 06 Jan 2015, 11:07:04 EST by Ahmed Taha Siddiqui on behalf of Scholarly Communication and Digitisation Service