Dynamic Models and Analysis of Key Factors Influencing Stick–Slip Vibration in Disc Brake Systems
Stick–slip vibration in disc brake systems at low speeds arises from the interaction of multiple factors, posing persistent challenges for high-speed train safety and passenger comfort. This study establishes three- and four-degree-of-freedom (DOF) dynamic models that incorporate wheel–rail adhesion and nonlinear friction, validated through line testing. System stability, stick–slip bifurcation characteristics, and key influencing factors are analyzed via numerical simulation. Results demonstrate that the four-DOF model, by accounting for normal motion, avoids the over-evaluation of system stability inherent in the three-DOF model. In the three-DOF model, tangential stiffness is the primary factor inducing chaotic stick–slip vibration. In the four-DOF model, tangential stiffness predominantly affects vibration amplitude, while normal stiffness governs the onset of chaos. Damping exhibits minimal influence on chaotic stick–slip occurrence. Optimal parameter ranges are identified: brake disc rotational inertia of 5–9 kg·m² and 11–22 kg·m², and friction pad mass of 7–17 kg, which effectively mitigate chaotic stick–slip vibration. These findings provide quantitative guidelines for brake system design, enhancing operational reliability and reducing wear-related failures in high-speed rail applications.