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M. Naeimi¹, Z. Li¹, R. Dollevoet¹, J. Wu², R.H. Petrov^2,3 and J. Sietsma^2,3

¹Section of Railway Engineering, Faculty of Civil Engineering and Geoscience, Delft University of Technology, The Netherlands
²Department of Materials Science and Engineering, Delft University of Technology, The Netherlands
³Department of Materials Science and Engineering, Ghent University, Belgium

Keywords: thermo-mechanical effect, finite element, plastic strain, temperature, white etching layer, squats, thermal stress.

Summary

A three-dimensional elasto-plastic finite element (FE) tool has been developed to study the thermo-mechanical originations of squats in rails. The initiation process of rail squats is in principle related to the response of materials against cyclic loading. The thermo-mechanical issues in this process are not yet clear, due to the complicated wheel-rail interaction and the variability of the loads, parameters and material properties. This paper examines the role of thermo-mechanical-related causes on the formation mechanism of squats using numerical modelling. Assuming a range of material behaviour, thermal softening and temperature dependencies, the sliding wheel-rail contact problem is investigated using a three-dimensional FE tool. The temperature rise and thermal stress due to the frictional heat, generated at the contact surface of the wheel and rail, are taken into account. The magnitudes and distributions of thermo-mechanical stresses on rail surface are calculated for realistic loading conditions. Particular attentions are paid to the temperature rise, residual stress and plastic strain with thermal effects under high tractive forces.

The outputs are used to scrutinise if the so-called white etching layer is formed as a result of the temperature rise, needed for structural phase change and to consider the role of plastic deformations.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 110 PROCEEDINGS OF THE THIRD INTERNATIONAL CONFERENCE ON RAILWAY TECHNOLOGY: RESEARCH, DEVELOPMENT AND MAINTENANCE Edited by: J. Pombo Paper 252 Thermo-Mechanical Effects in the Formation Mechanism of Rail Squats M. Naeimi¹, Z. Li¹, R. Dollevoet¹, J. Wu², R.H. Petrov^2,3 and J. Sietsma^2,3 ¹Section of Railway Engineering, Faculty of Civil Engineering and Geoscience, Delft University of Technology, The Netherlands ²Department of Materials Science and Engineering, Delft University of Technology, The Netherlands ³Department of Materials Science and Engineering, Ghent University, Belgium doi:10.4203/ccp.110.252 purchase the full-text of this paper Full Bibliographic Reference for this paper M. Naeimi, Z. Li, R. Dollevoet, J. Wu, R.H. Petrov, J. Sietsma, "Thermo-Mechanical Effects in the Formation Mechanism of Rail Squats", in J. Pombo, (Editor), "Proceedings of the Third International Conference on Railway Technology: Research, Development and Maintenance", Civil-Comp Press, Stirlingshire, UK, Paper 252, 2016. doi:10.4203/ccp.110.252 Keywords: thermo-mechanical effect, finite element, plastic strain, temperature, white etching layer, squats, thermal stress. Summary A three-dimensional elasto-plastic finite element (FE) tool has been developed to study the thermo-mechanical originations of squats in rails. The initiation process of rail squats is in principle related to the response of materials against cyclic loading. The thermo-mechanical issues in this process are not yet clear, due to the complicated wheel-rail interaction and the variability of the loads, parameters and material properties. This paper examines the role of thermo-mechanical-related causes on the formation mechanism of squats using numerical modelling. Assuming a range of material behaviour, thermal softening and temperature dependencies, the sliding wheel-rail contact problem is investigated using a three-dimensional FE tool. The temperature rise and thermal stress due to the frictional heat, generated at the contact surface of the wheel and rail, are taken into account. The magnitudes and distributions of thermo-mechanical stresses on rail surface are calculated for realistic loading conditions. Particular attentions are paid to the temperature rise, residual stress and plastic strain with thermal effects under high tractive forces. The outputs are used to scrutinise if the so-called white etching layer is formed as a result of the temperature rise, needed for structural phase change and to consider the role of plastic deformations. purchase the full-text of this paper (price £22) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £85 +P&P)
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