A comparison of analytical and numerical methods for the calculation of temperatures in wheel/rail contact
TL;DR: In this paper, the maximum surface temperature during rolling contact of railway wheels with sliding friction can be estimated using Blok's flash temperature formula, and an efficient approach is proposed for Hertzian contact.
About: This article is published in Wear.The article was published on 2002-08-01. It has received 128 citations till now. The article focuses on the topics: Bulk temperature & Contact mechanics.
••01 Jun 2004
TL;DR: In this paper, twin-disc wear testing has been carried out to study the wear characteristics of R8T railway wheel steel and three wear regimes were identified; mild, severe, and catastrophic.
Abstract: The need to improve safety and reduce costs means that new specifications are being imposed on railway wheel wear. These mean that more durable wheel steels are required. In order to develop such materials, a greater understanding is needed of the wear mechanisms and transitions occurring in wheel steels. In this work, twin-disc wear testing has been carried out to study the wear characteristics of R8T railway wheel steel. The results have indicated that, compared with previous wheel steels, R8T offers greater wear resistance. Three wear regimes were identified; mild, severe, and catastrophic. Wear rates were seen to increase steadily initially and then to level off, before increasing rapidly as the severity of the contact conditions increased. This paper is concerned with the form of the data and the reasons for the transitions. Analysis of the contact conditions indicated that the first transition in the wear rate was caused by the change from partial slip to full slip conditions at the disc interface. Temperature calculations for the contact showed that the large increase in wear rates seen at the second wear transition may result from a thermally induced reduction in yield strength and other material properties. This improved understanding will help in progressing towards the aim of eventually attaining a wear modelling methodology reliant on material properties rather than wear constants derived from testing.
TL;DR: In this paper, the Amsler twin-roller tester was used to simulate wheel/rail contact in railroad use, and the effect of high pressure as well as micro-slip motion in the contact zone on the decomposition pathways of MoS 2 and WS 2 was investigated.
TL;DR: In this article, a detailed characterization of the WEL and the BEL in a pearlitic rail steel is carried out from micrometer to atomic scale to understand their microstructural evolution.
TL;DR: In this article, a model of dry friction is established based on the method of movable cellular automata (MCA) and the influence of pressure and sliding velocity has been investigated by means of a large number of numerical simulations.
••01 Mar 2007
TL;DR: In this article, a thermal model of railway tread braking is developed for use in routine calculations of wheel and brake block temperatures, where a film with thermal contact resistance is placed at the wheel-rail contact interface.
Abstract: A thermal model of railway tread braking is developed for use in routine calculations of wheel and brake block temperatures. Two-dimensional finite-element models of block(s) and wheel are coupled via a contact interface that controls the heat generation and also the heat partitioning between block and wheel through thermal contact resistances. The surface temperature variations around the wheel circumference as caused by frictional heating and intermediate cooling are accounted for in a mean sense, assuming high-speed sliding conditions. The thermal power generated at the block-wheel interface during braking is determined from train braking data. A model for heat transfer from the rolling wheel into the rail is developed where a film with thermal contact resistance is placed at the wheel-rail contact interface. The present model can be used to efficiently design tread braking systems for both freight and passenger trains. It can handle stop braking, drag braking at constant brake power, and also intermediate periods of cooling. The temperature history during a full train route can be calculated. The inclusion of heat transfer from wheel to rail means that the model is useful for comparing brake rig tests, where normally the chilling influence from the rail is not included, with in-field tests. Two companion papers with experimental results supplement the present numerical modelling. A brief numerical example demonstrates the heat partitioning and the influence of rail chill (about 30 per cent) for two braking configurations.
TL;DR: In this article, a simple formulation of flash temperature theory is given, which reduces the mathematical complexities and instead emphasises the relevant physical considerations, and the use of the theory is illustrated by some new experimental results on the breakdown of Perspex and the wear of steels.
01 Jan 1942
01 Jan 1937
TL;DR: A survey of the history of the flash temperature concept and its application in the design of rubbing components that are prone to scuffing can be found in this paper, along with an outline of the theory that is based on this concept and formulas for calculating flash temperatures.
TL;DR: In this paper, the Laplace transforms and the method of Green's functions were used to analyze the contact temperatures and temperature fields of components in relative sliding motion, and it was shown that each kind of fluctuation causes a rise of the maximum contact temperature.