In-service Parametric Modeling Of A Hydraulic Yaw Damper With Double Relief-valve-systems

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 become more sensitive todampers’ parameter variations. Therefore, it is significant to design better damperproducts in achieving better performance of bogies and vehicles.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 arail vehicle hydraulic yaw damper with double relief-valve-systems. A mathematicalin-service parametric model of the yaw damper was then established based on theconcept, in the modeling process, dynamic fluid losses, the dynamic oil properties,rubber attachment stiffness, oil stiffness and mounting seat stiffness are all considered.Simulation was performed using the established model in Matlab environment, andfollowed comparison of simulation results and test results of the hydraulic yawdamper verified that the developed model is correct and accurate. Extensive parametersensitivity analysis were performed in predicting the effects of rubber attachmentstiffness, entrained air ratio of the oil and the accumulated small mounting clearanceon the dynamic damping characteristics of the yaw damper.The established full mathematical in-service parametric model for the rail vehiclehydraulic yaw damper with double relief-valve-systems 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.