Instabilities Induced by Thermal-Mechanical Couplings in Clutch and Brake Discs

The interaction between thermal buckling and thermoelastic instability (TEI) can play an importance role in frictionally-excited hot spot development in automotive disc brakes. In this study the distributions of temperature variations were obtained from the eigenmodes based on the classical TEI analyses. The critical buckling temperatures and the associated deformation modes were subsequently computed using the commercial software ABAQUS. The effects of sliding speed, coefficient of friction and boundary conditions have been investigated for both banding and focal modes. It is concluded that the TEI induced temperature variations can significantly alter the distribution of thermal stresses, and that there could exist a strong coupling between TEI and thermal buckling under some conditions. Although the analyses were performed in the settings of clutch applications, the conclusions are applicable to brake discs as well because of the shared similarities. Adding the complexity in the brake disc geometry such as hat and vent sections is an ongoing research.