Thermo-mechanical analysis of functionally graded wheel-mounted brake disk

Having higher speed for trains requires improvement in braking performances. The brake system is an important part of locomotive safety system in which the mechanical energy is converted to the thermal energy and distributed through the disks and pads. As a result, the temperature at the disks surfaces increases sharply. This phenomenon is called the thermal shock that causes the negative effects on the brake disk surface such as fast aging, early wear, thermal cracks and the brake fade. Using Functionally graded materials (FGMs) which are more resistant to the thermal shock is a new trend to deal with this issue. In this study, the effects of using FG materials in the wheel-mounted brake disk R920K for the ER24PC locomotive on its thermo-mechanical behavior are investigated. For this purpose, the uncoupled thermo-mechanical analysis is performed for the disk made of FG Al-A359/SiCp, aluminum and ductile cast iron materials. Comparing the results of brake disk made of ductile cast iron with those from experimental data, the accuracy of present FE model is verified. Concerning the stress analysis, it is shown that the safety factor for the disk made of FG material is higher than the other ones. Furthermore, the gradation index of FG material has the most important effect on the thermo-mechanical performance of FG disks.