Thermomechanical and friction properties of brake discs for high-speed light-load vehicles

During the braking process, temperature of brake disc in high-speed light-load vehicles sharply increases, causing the thermal fatigue crack. Therefore, it is necessary to design new brake disc and study its thermomechanical and friction properties. Here, authors designed new brake discs by way of constructing biomimetic nonsmooth structures in contact surface, then conducted simulation and experiment to quantify their effect on thermomechanical and friction properties. Compared with the smooth brake disc and under the initial velocity 120/160/200 km/h, the brake disc with straight grooves reduces the friction temperature that exhibits the reduction rate of 27.16%, 36.25% and 31.20%. Equivalent stress shows the increase rate of 61.64%, 46.92% and 71.58%, but these values are within the material yield strength. Experiment results showed the biomimetic brake discs have slightly smaller friction coefficient (0.32–0.48) but significantly lower friction temperature (41.7°C–77.9°C) than the smooth brake disc (0.56, 96.7°C). The biomimetic brake disc with straight grooves and air inlets exhibit relatively better performance, resulting from the superior capability in dissipating heat. This study demonstrates biomimetic nonsmooth structures can improve brake disc’s thermomechanical properties, which provides an available design approach for brake discs in high-speed light-load vehicles.