A spatial vehicle–track coupled dynamics model and its application in analyzing braking behaviors

The brake system is a critical component of a high-speed train, directly impacting its operational safety. To investigate thoroughly the dynamic responses of a vehicle–track coupled system during braking, a spatial vehicle–track coupled dynamics model (SVTCDM) has been developed that incorporates flexible track and brake systems. In the model, finite element method is employed to construct models of the track, wheelset, and brake components, acquiring mass, stiffness, and damping parameters for these parts. The dynamic responses of these flexible components are calculated using the modal superposition method. Furthermore, the interactions between the brake pad and disc, including normal contact and tangential, are simulated using a contact model and Stribeck model, respectively. The relative motions and dynamic forces perform the coupling effects between the brake systems and the vehicle–track system. The established model, validated by field test data, effectively simulates the dynamic characteristics of the vehicle–track system. Finally, the dynamic behavior of the vehicle–track system during the braking condition has been simulated and discussed. The results show that the vibration of the brake systems is also directly affected by wheel–rail excitation. Additionally, the wheel–rail contact force, torsional vibration of disc and wheelset, and track vibration have been aggravated by the presence of brake force. Therefore, it is imperative to consider the influence of the brake system in analyses of vehicle dynamics, particularly concerning vibration behavior and structural strength during the braking process.