Design of High Performance CMC Brake Discs

摘要

Ceramic matrix composite (CMC) materials based on 2D-carbon fibre preforms show high heat-absorption capacities and good tribological as well as thermocechanical properties. 'To take advantage of the full lightweight potential of these new materials in hith performance automotive brake discs, the thermal conductivity transverse to the friction surface has to be high~ in order to reduce the surface temperature. Expermental tests showed that lower surface temperatures prevent over- heating of the brake's periphery and stabilizes tbc friction behaviour. In this study different design approaches with improved transverse heat conductivity have been investigated by finite elenment analysis. C/C-SiC bolts as well as SiC coatings and combinations of them have been inivestigated and compared with an orthotropic brake disc. showing a reduction of temperature ot up to 50 . Original sized brake discs `with C/C-SiC have been manufactured and tested under real conditions which verified the calculations. Using only low-cost CMC materials and avoiding any additional processing steps. the potential of C/C-SiC brake discs are very attractive under tribologtical as well as under economical aspects.