Parametric Multiscale Homogenization and Coupled Thermo-Structural Analysis of Hybrid Al–SiC–Gr Brake Discs via Sequential Micromechanical Modeling

This study presents a hierarchical multiscale homogenization framework to evaluate the thermo-mechanical performance of hybrid aluminum matrix composites (HAMCs) reinforced with Silicon Carbide (SiC) particles and Graphite (Gr) for lightweight automotive brake discs. A sequential homogenization strategy was employed in which an Aluminum–5 vol.% Graphite hybrid matrix was first established using the Rule of Mixtures and the Halpin–Tsai model, followed by the incorporation of 5–25 vol.% SiC using the Mori–Tanaka homogenization scheme. Three-dimensional Representative Volume Elements (RVEs) with periodic boundary conditions were generated in ANSYS Material Designer(v2025) to determine the effective mechanical properties, while the effective thermal properties were evaluated using the homogenization formulations described in the methodology. The resulting effective material properties were subsequently used in a macro-scale finite element model of a ventilated brake disc for coupled thermo-structural analysis. The results show that increasing the SiC content significantly enhances the effective elastic stiffness while maintaining a stable thermo-mechanical response with marginal variations in global deformation. Compared with conventional gray cast iron, the proposed hybrid composites reduced the maximum operating temperature from 322.77 °C to approximately 280 °C and decreased the maximum total deformation by approximately 45% under identical loading conditions. The proposed framework establishes a computational link between composite microstructure and component-level performance, providing an efficient numerical methodology for the design and optimization of lightweight automotive brake discs.