Analysis of tribological behaviour of pad-disc contact in railway braking - Part 1. Laboratory test development, compromises between actual and simulated tribological triplets

In the field of railway braking, improving the performances of friction brake systems requires better knowledge of the local tribological behaviour of pad-disc contact under braking conditions. After analysing the tribological triplet involved in railway braking, this paper focuses on the development of laboratory tests for studying local physical phenomena caused by friction in braking. The aim is to generate at reduced scale similar contact conditions to those at full-scale. An original braking tribometer is presented whose design is based on similitude rules between reduced-scale and full-scale. As it is difficult to reproduce representative full-scale thermal loading generated by friction at reduced-scale, compromises are needed and the choice of experimental parameters, based on a non-dimensional conversion rule, is discussed. The results obtained at reduced-scale are presented and comparison with results available at full-scale shows that the reduced-scale tests are very representative. (c) 2006 Elsevier B.V. All rights reserved.