Sequential Thermo-Mechanical Finite Element Evaluation of a Ventilated Automotive Brake Disc

Abstract

Automotive brake rotors experience rapid thermal loading during high-energy braking, producing non-uniform temperature fields that can lead to thermal stress, deformation, and reduced structural margin. This study presents a sequential thermo-mechanical finite element methodology for evaluating the response of a ventilated gray-cast-iron brake disc under a representative passenger-car braking event. A three-dimensional rotor model is developed with local mesh refinement in the rubbing track, ventilation openings, fillets, and hub-transition regions. Vehicle kinetic energy is converted into a transient surface heat flux applied over the friction surfaces, while convection and radiation are imposed on exposed rotor surfaces. After completion of the transient thermal solution, the calculated nodal temperature field is transferred to a structural model together with braking torque and hub constraints. Mesh convergence is verified before evaluating peak temperature, von Mises stress, and total deformation. For the representative baseline condition, the medium mesh predicts a peak rotor temperature of approximately 406 °C, a maximum von Mises stress of about 162 MPa, and a maximum deformation of approximately 0.19 mm. The temperature maximum occurs within the friction track, whereas the highest structural stress develops near ventilation and hub-transition regions where thermal expansion is locally constrained. An illustrative comparison with a solid rotor further indicates higher temperature, stress, and deformation when ventilation is removed. The proposed methodology provides a computationally efficient framework for design-stage comparison of brake rotor geometry, thermal loading, and structural response prior to prototype testing.