Parametric Modeling Of An Axle-box Hydraulic Damper For High-speed Operations

Hydraulic dampers, which are key rail vehicle suspension components, play animportant role in achieving vehicle’s stability and ride comfort. With theirever-increasing operation speeds, modern rail vehicles are very sensitive to dampers’internal or external parameter variations. Therefore, the traditional specification anddesign methods of hydraulic dampers for rail vehicles become limited in adapting tohigh-speed operation situations, so it is crucial and significant in establishingin-service parametric model for hydraulic dampers in this regard.A macro damper model, which is more adaptive to high-speed operations thanthat of the Maxwell model described in the European standard, was suggested for anaxle-box rail vehicle hydraulic damper. A concrete mathematical in-serviceparametric model of the damper was then established based on the concept, in themodeling process, the dynamic oil properties, dynamic fluid losses and valvedynamics are all considered. Simulation was performed using the established model inMATLAB environment, and followed comparison of simulation results and testresults of the axle-box hydraulic damper verified that the developed model is correctand accurate. Extensive parameter sensitivity analysis were performed in predictingthe effects of rubber attachment stiffness, entrained air ratio of the oil and theaccumulated small mounting clearance on the dynamic damping characteristics of theaxle-box hydraulic damper.The suggested macro concept and the established full mathematical in-serviceparametric model for the rail vehicle hydraulic damper could meet the more severerequirements of components for high-speed rail. It could also be the right andeffective theory for damper product design and rail vehicle dynamics analysis.