Research On Mechanical Model And Dynamic Behaviour Of Yaw Damper For Railway Vehicles

Yaw damper is one of the key suspension components of locomotive to improve the operation stability.The structural differences of yaw damper lead to inconsistent internal oil flow direction so that the shock absorber shows a great difference of dynamic characteristics in tensile or tensile stroke.Therefore,thoroughly studying of the mechanical model and dynamic characteristics of anti-hunting shock absorbers for different oil flow directions in active service what is of great significance to optimize the suspension parameters and improve the dynamic performance of railway vehicles.In this paper,based on different types of oil flow for yaw dampers used on vehicles in service,the structural characteristics of anti-hunting dampers for different types of oil flow are analyzed.Physical parameter model of the yaw damper is preliminarily established including with oil path,valve system,leakage,oil properties and other factors what are to provide a theoretical basis for the establishment of the yaw damper physical simulation model.An improved algorithm for evaluating the dynamic characteristics of the hydraulic shock absorber is proposed aiming at the limitation of the current algorithm of the dynamic characteristics of the hydraulic shock absorber.Through the comparison of the two dynamic characteristic algorithms,it is proved that the improved algorithm can accurately reproduce the actual difference between the tensile and compressive performance of the yaw damper with different oil flow types and high reliability of the improved algorithm.What the AMESim physical parameter models of yaw damper are established that is based on the anti-snake shock absorber with different types of oil flow.By comparing the static and dynamic dynamometer diagrams of bench test,AMESim simulation model and Maxwell simplified series model,it is proved that the Maxwell simplified series model has higher computational error and the trustworthiness of AMESim simulation model.The rig test results of the anti-hunting damper with different oil flow types and the simulation results of the AMESim model are compared and calculated by using the improved algorithm.Through the comparison between the frequency-change characteristics the dynamic stiffness and the frequency-change characteristics of the dynamic damping,the high accuracy of the AMESim simulation model for yaw damper with different oil flow types is further demonstrated.From the perspective of the instantaneous pressure change of the high-pressure chamber of each stroke,the mechanism of the dynamic and static characteristics of the yaw dampers for different types of oil flow was studied.Because of greatly increased the volume of oil in the high pressure chamber for the compression stroke under small amplitude excitation.The lower instantaneous high pressure results in the compression damping force that is much less than the rebound damping force.Finally,taking the oil-bidirectional flow anti-hunting shock absorber as an example,the effects of damping valves’ structural parameters,oil properties,and rubber ball joint parameters on the performance of the yaw damper are discussed.Co-simulation model of yaw damper and vehicle real-time interaction was established by Simpack/Simulink/AMESim co-simulation technology.The influences of the AMESim shock absorber simulation model and the traditional Maxwell simplified simulation model on the dynamic performance of the vehicle are compared.As a result,some suggestions for how to choose the yaw damper model for the vehicle dynamics simulation are provided.Anti-hunting dampers have the high limitations and errors in the simulation of the vehicle system dynamics when the Maxwell simplified series model is used as the input force element.