Analysis on Carbody Vertical Abnormal Vibration Characteristics and Causes of Light Rail Transit
Carbody vertical abnormal vibration of light rail transit during operation seriously impact the passengers'ride comfort.To address this issue,carbody vertical vibration characteristics of light rail transit is studied through field test,theoretical analysis and simulation reproduction and the causes of abnormal vibration are clarified.The results show that the carbody vertical vibration frequency with 7.5 Hz is the main reason for the deterioration of the light rail transit ride comfort.The trailer of the light rail transit exhibits a vibration mode of floating up and down,while the adjacent vehicles pitch in the opposite direction.The frequency of carbody pitching motion is significantly affected by the longitudinal stiffness of the elastic articulation,while the secondary vertical stiffness of the bogie and the longitudinal deviation from carbody gravity to the bogie have a minor impact.The insufficient stiffness of the elastic articulation is the preliminary cause,with a measured hinge stiffness of 11.87 MN/m,which is far below the design value.A simulation model based on the measured data reproduces the carbody abnormal vibration and confirms that the insufficient longitudinal stiffness of the elastic articulation is the root cause.This relevant research provides technical support for addressing abnormal vibration problems and enhancing the performance of light rail transit.