Study on bionic design of brake drum surface morphology and its anti-wear mechanism

To explore the anti-wear mechanism of drum brakes and improve their wear resistance, this paper investigates the wear performance of brake drums and friction pads and proposes a biomimetic surface design method for brake drums. Biomimetic brake drum samples with point, striped and grid-shaped surface unit structures are designed, and contact stress and wear mechanical models between the brake drum surface units and friction pads are established. The influence mechanism of different unit shapes on the contact stress and wear of friction pads is analysed theoretically. Semi-metallic, organic non-asbestos (NAO), and ceramic friction pad samples are tested in reciprocating wear tests against the three biomimetic brake drums. The effect of surface unit shapes on the contact stress is simulated using Abaqus software. The study examines the impact of surface unit shape, arrangement, spacing, height, angle and friction pad material on the wear resistance of the biomimetic brake drums. Striped and grid-shaped biomimetic brake drums are produced and tested in thermal fatigue bench tests with semi-metallic friction pads to verify the influence of unit shape parameters on the wear and fatigue performance of the brake drums. The wear test results show that the biomimetic brake drums have significantly better wear resistance than untreated brake drums. The thermal fatigue bench test results show that the grid-shaped biomimetic brake drum’s fatigue life increases by 38%, and self-wear is reduced by 62%. When the vehicle speed is 60 km/h, the braking torque of the striped brake drum increases by 5%, and the braking torque of the grid brake drum increases by 9.5%. Both the braking performance and wear resistance of the brake drum are improved.