Contact stiffness modelling and analysis of brake disc with rough geometrical topography and manufacturing deviation

Contact stiffness plays an important role in braking efficiency, braking squeal, and vibration response of brake system. However, randomness of manufacturing deviations caused in manufacturing process can lead to unsteadiness of the contact stiffness. To investigate the quantitative relationship between manufacturing tolerance and fluctuation of the contact stiffness, a contact stiffness model of brake disc is established through statistical rough contact theory and nonlinear stuck-slipped spring element, and then its effectiveness is validated by experimental data. Based on the model, a comprehensive analysis of various types of manufacturing deviations is conducted. The result shows that both normal and tangential initial contact stiffness are weakened by angular deviation and positively associated with positional deviation. This paper provides a novel way to reveal the inner mechanical relationship between macro-micro topography and initial contact stiffness of brake disc, which is significant for guiding tolerance design and performance optimisation of the brake system.