Two-/three-dimensional hybrid model of the thermomechanical behaviour of disc brakes

Abstract

Prediction of the surface temperature in friction braking systems is the main problem in the analysis of thermal dissipation and surface degradations such as wear, phase transformation, cracks, etc. The first difficulty of the thermal prediction is presented by the complex interactions between the thermal, mechanical and tribological behaviour. The second problem is due to the multiscale aspect, from the macroscopic response of the disc and brake pads (conduction, distortions, etc.) to local surface effects (surface roughness, wear debris, phase changes, etc.). This paper aims to propose a macrostructural model of the thermomechanical behaviour of the disc brake, taking into account the real three-dimensional geometry of the disc-pad couple. Contact surface variations, distortions and wear are taken into account. Real body geometry and thermoelastoplastic modelling of the disc material are specially introduced. Such a model aims to give predictions of the thermal gradients varying with time and of the thermomechanical response of the components. Predictions of the temperature distributions are compared with experimental measurements obtained by thermographs and thermocouples. Such a model seems to be a suitable base for the study of the thermal dissipation and the thermomechanical behaviour and for the introduction of local friction effects.