Thermal-mechanical coupled topology optimization of C/C-SiC brake disks considering temperature-related and KS dual polymerization

Carbon-fiber-reinforced silicon carbide (C/C-SiC) ceramic matrix composites have emerged as a leading candidate for next-generation lightweight high-performance brake disks. However, conventional topology optimization approaches based on stress or compliance constraints fail to capture the temperature-driven degradation mechanism that governs the safety of ceramic composites. To address this gap, this paper proposes a thermal-mechanical coupled topology optimization framework for C/C-SiC brake disks with temperature-dependent material properties. A radially graded reinforcement distribution is introduced to enhance local thermal performance, and an element-level high-temperature resistance margin together with a complementary thermo-mechanical safety index is formulated to simultaneously characterize thermal degradation risk and stress-induced failure. A Kreisselmeier–Steinhauser double aggregation strategy in both space and time is developed to efficiently handle the massive transient element-wise constraints. The framework is implemented within the SIMP scheme with adjoint sensitivity analysis, providing a generalizable design methodology for ceramic composite brake systems. The numerical results show that the optimized topology reduces the peak temperature by 18.6%, decreases the maximum von Mises stress by 23.0% compared with the initial brake disk design. The safety constraint value decreases from 0.092 to −0.014, corresponding to an absolute reduction of 0.106, and the constraint is changed from violation to satisfaction.