Numerical Model of the Railway Brake Disk for the Temperature and Axial Thermal Stress Analyses

Abstract

Increases in travel speeds and traffic density in railway sector impose challenges on the modern disk-pad brake systems such as higher temperatures and stresses resulting in cracks/hot spots and a degraded system performance. The prediction of disk thermal behavior under challenging conditions has become an important engineering issue. In this study, a model is developed using the finite difference method with realistic time-dependent boundary conditions and different experimental convection correlations with non-uniform time-step size features. A previous numerical/experimental study on the thermal behavior of railway disk brake is partly adopted and enhanced. The results of the developed model agree well with the results of the previous study. A practical prediction method for thermal stresses in the disk is applied using the axial temperature distributions at several time instants from locations with highest temperature. Apart from that, same configuration of the disk with the pad is modeled in simcenter star-ccm+ which is a well-validated commercial computational fluid dynamics software to compare the results and computation times with that of the developed model. Using this model, an investigation has been conducted on the effect of temperature-dependent material properties on thermal behavior of the disk. The developed numerical model can simulate the conditions experienced by a railway disk in a relatively new standard (EN 14535-3) considering the transient thermal behavior and axial thermal stress distribution with relatively low computational time and reasonable accuracy. Also, in this study, valuable insights are obtained on the effect of variable thermal properties of the disk and convection correlations on the disk thermal behavior.