Dynamic modeling and brake stick-slip vibration analysis of a vehicle-track system with disc-pad nonlinear frictions

A longitudinal-vertical coupled dynamics model (LVCDM) of a vehicle-track system (VTS) with disc brake systems is established, incorporating disc-pad nonlinear friction using the Stribeck model, with parameters derived from block-on-disc tribological tests. This model integrates the brake system with the VTS through nonlinear frictions in wheel-rail and disc-pad interface. Dynamic effects between the rotational motion of brake disc and the longitudinal, vertical, and pitch motions of VTS various components are captured. This model, validated through field tests, enables in-depth investigations into brake stick-slip vibrations of VTS. The results indicate that brake stick-slip vibrations intensify its own oscillations, thereby degrading braking performance. Additionally, it induces significant vibrations of bogie frames and wheelsets, adversely affecting vehicle ride comfort and running safety.