DOI: 10.18245/ijaet.1924457 ISSN: 2146-9067

Thermo-kinetic wear regime mapping of C/SiC automotive brake discs: a physics-based model for abrasive–oxidative mechanism transition

Emre Burak Ertuş
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Carbon fiber reinforced silicon carbide (C/SiC) ceramic brake discs offer superior wear resistance under normal driving conditions yet suffer accelerated material loss at elevated temperatures due to carbon oxidation. This study presents a thermo-kinetic wear model that couples a lumped-capacitance thermal solver with the Archard equation for mechanical (abrasive) wear and Arrhenius kinetics for oxidative wear, using exclusively published material data for short-fibre liquid-silicon-infiltrated (LSI) C/SiC. The contact pressure is derived from the vehicle deceleration through an exact torque balance, ensuring energy conservation between the vehicle kinetic energy and the frictional heat input. Two representative braking scenarios are simulated; a single emergency stop from 130 km/h with 10 m/s² deceleration and a five-cycle winding road scenario from 130 to 60 km/h with 7 m/s² deceleration and 15 s cooling intervals. The emergency stop produces a peak temperature of 210°C and a modelled abrasive wear depth of approximately 0.022 μm. The cyclic scenario induces progressive thermal ratcheting; the oxidation onset temperature (400°C) is first exceeded during the fourth cycle, and by the fifth cycle the peak temperature reaches 474°C with an oxidative wear fraction of 20%. Steady-state wear regime maps in T–v space at 2 MPa reveal that the abrasive-to-oxidative transition occurs in a narrow temperature band of 520–585°C and is nearly velocity-independent. The cycle by cycle analysis demonstrates that the transition from purely abrasive to mixed-mechanism wear occurs within a single additional braking cycle once the onset threshold is crossed, underscoring the importance of the regime maps as predictive design tools for identifying the critical thermal boundary. Sensitivity analysis confirms that the regime boundary shifts by only ≈44 °C over the 1–3 MPa pressure range and is robust to activation energy variations of ±30 kJ/mol.

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