Study Of Failure Mechanics Of Hydraulic Dampers For Railway Vehicles

The hydraulic damper is an important part of the bogies for railway vehicles,and plays a very important role in improving the safety and stability of railway vehicles.With the increasing load and speed of railway transportation,studying the failure mechanism of hydraulic dampers is of great significance to improve the service reliability of these key components and ensure the safe operation of vehicles.Taking a series of vertical hydraulic dampers of an electric locomotive as the research object,the fatigue fracture failure of the piston rod assembly in its engineering application is addressed.First,the piston rod assembly was subjected to static stress analysis and weld structure strength check;then the dynamic load simulation of the multi-body system based on the service model of the damper was used to obtain the actual service load spectrum.Using actual service load spectrum as input,transient dynamics analysis and fatigue life analysis of piston rod components were performed.The research shows that under actual service conditions,the maximum dynamic stress of the piston rod assembly of the damper can be increased by 39.31% ～ 41.46%,and the fatigue life mileage can be reduced by 49.4% ～89%.This explains why the product is designed to meet the requirements,but in actual service fatigue fracture failures occur.Aiming at the problem of damping force failure caused by oil leakage of damper,the friction and wear leakage mechanism of damper was studied.Due to different leakage mechanisms,the effects of pressure cylinder barrel wear and piston rod wear on the damper damping performance are also different.Research shows that the damping force of the damper under wear conditions can be reduced by 10.7% ～ 62.3% compared to the normal conditions.When the damper is worn and oil leakage occurs in the actual working process,the damping force of the oil pressure damper will decrease.When the damping force falls below 80% of the rated damping force,the damper damping force fails.In view of this,the damping force evaluation standard of allowable wear of damper is put forward,The failure of damping force caused by oil leakage should be considered in the initial design and maintenance to avoid the occurrence of this working condition.The research methods and results provided theoretical basis and reference for the product design,performance prediction and maintenance of hydraulic dampers for railway vehicles.