Caractérisation thermomécanique de disques de frein ferroviaires multimatériaux

Thermomechanical characterization of multimaterial railways brake discs

¹ Laboratoire d’Automatique et de Mécanique Industrielles et Humaines, URA CNRS 1775 Université de Valenciennes et du Hainaut-Cambrésis, Valenciennes
² C.I.M.T. GEC Alsthom Transport S.A., Marly

Abstract

A new brake disc design is examined in order to improve high energy railway braking. The solution which consists to use friction materials able to endure hard thermomechanical conditions and to limit heat transfer toward the axle has been studied for multimaterial discs. The brake disc is composed of three distinct components : a stand disc, a thermal barrier flange and a friction flange. The insertion of a thermal barrier flange allows the use of aluminium alloy for the stand disc, reducing significantly the mass of the braking disc.

Continuous braking simulations made on 1/4 reduced scale discs have allowed the study of the influence of thermal barrier position and thickness on disc and pad temperatures as well as on total mass disc. The friction material pair composed of an aluminium titanate pad and a Ni-Cr/Cr₃C₂ cermet coated steel disc is very interesting as for friction coefficient stability and wear resistance. Endurance tests have shown that this system is able to damageless dissipate a 2 MJ energy per reduced disc side, which corresponds to 36 MJ for a disc on the scale 1. The studied friction material pair is also insensitive to humidity, a basic advantage in comparison with the common braking systems.