NUMERICAL MODEL AND EXPERIMENTAL STUDY OF TEMPERATURE FIELDS IN A SINGLE APPLICATION OF RAILWAY TREAD BRAKE

摘要

The purpose of this study was to develop a numerical model to calculate temperature distribution during braking process and compare the results with temperature values obtained by means of an experiment. The experimental part of this study was performed on a dynamometer equipped with a full-scale railway wheel and brake shoe according to specification of a rolling stock operator. Temperature was measured by thermocouples installed below the surface of the wheel and recorded during entire brake application. For the purpose of numerical simulation, a three-dimensional model of a railway wheel and segments of friction material was developed. To increase the accuracy of the calculations, finer finite element mesh was used near the contact area. Initial temperature distribution in the friction pair was defined. The input data for the model were based on the experiment performed on a full-scale dynamometer. Two approaches are presented: one assuming constant value of the coefficient of friction, other considering its dependency on velocity of sliding surfaces and temperature. Temperature evolution throughout the brake application, calculated using the numerical model is compared with the experimental data. The numerical method applied in this study provided results which correspond well to values obtained by means of an experiment. The study presents results of simulation of a single brake application in one of possible tread brake configurations. One set of brake application parameters, such as initial velocity, braked mass and contact pressure was considered. The model created for the purpose of this study may be developed and applied to simulate temperature distribution in friction pairs of similar type.