Optimizing Proportions of Railway Brake Discs by Temperature Transients Evaluation

Abstract

When evaluating the performances of railway brake discs, the ability to accumulate and spread heat to the air plays a major role, since wear of synthetic lining and disc deterioration are strongly dependent on maximum temperatures attained on the surface in contact with the friction pad. The energy developed during brake application gives rise to an increase of disc temperature, which can be correlated to braking power, braking sequences and durations and to disc features. Maximum temperatures are attained on the friction surface of the disc. Determination of the thermal cycle subsequent to brake application can be considered preliminary to the study of lining and disc wear. The present work proposes a simple method using finite difference numerical analysis to evaluate the efficiency of the brake disc in dissipating the heat, both on a constant speed and an up-to-stop brake application. The effect of the various dimensional parameters, such as number of ribs, disc thickness and ribs width, is considered with the aim of achieving a first rough optimization of the required size of disc brake. The results related to a commercial size disc brake are given.