In-service parametric modelling a rail vehicle׳s axle-box hydraulic damper for high-speed transit problems

• We proposed an improved damper model better than which in the European standard.
• We created a full in-service parametric model of a high-speed train axle damper.
• Improper rubber attachment stiffness can greatly degrade damping capability.
• Entrained air ratio effect would be remarkable if it exceeded a medium level.
• The accumulated small clearance should not be omitted in design and engineering.

Due to the high-speed operation of modern rail vehicles and severe in-service environment of their hydraulic dampers, it has become important to establish more practical and accurate damper models and apply those models in high-speed transit problem studies. An improved full parametric model with actual in-service parameters, such as variable viscous damping, comprehensive stiffness and small mounting clearance was established for a rail vehicle׳s axle-box hydraulic damper. A subtle variable oil property model was built and coupled to the modelling process, which included modelling of the dynamic flow losses and the relief-valve system dynamics. The experiments validated the accuracy and robustness of the established full in-service parametric model and simulation which captured the damping characteristics over an extremely wide range of excitation speeds. Further simulations were performed using the model to uncover the effects of key in-service parameter variations on the nominal damping characteristics of the damper. The obtained in-service parametric model coupled all of the main factors that had significant impacts on the damping characteristics, so that the model could be useful in more extensive parameter effects analysis, optimal specification and product design optimisation of hydraulic dampers for track-friendliness, ride comfort and other high-speed transit problems.