Random Vibration Analysis of the Underframe Structure on a High-Speed Train

Build a dynamic analysis model about the coupling system of the vehicle and the underframe suspension structure. Different combination methods are employed in order to analyze the random vibration of the interior suspension structures of underframe structure, then 2 kinds of analysis model are built: the first one is the traditional analysis model of which elastic combination is ignored between the interior suspension structures, the combination are considered to be rigid combination; the second one is the model of which elastic combination is considered between interior suspension structures. In this paper the example is a structure of the traction converter under the car-body of high-speed train and the eccentric load of the electric machine installed in the structure of the traction converter is simplified and applied on the rotor spindle of the electric machine. The railway vehicles accurate random vibration analysis method is employed to analyze the random vibration on the 2 kinds of the analysis model. Calculated results indicated that the stress of the traction converter mainly focus on 3 frequency band that are 2 Hz, 6 Hz and 60 Hz, correspond respectively the mainly vibration frequency of the car-body, rigid-body vibration frequency of the traction converter caused by the suspension stiffness between the car-body and underframe and the basic frequency of the eccentric load of the electric machine which is considered as the most significant impact. As the rubber damper is employed at the combination between the suspension steel beam and case in the traction converter the dynamics index of vibration and stress of the first one is superior to the second one which the rigid combination is employed and the impact caused by the eccentric load of the electric machine is obvious attenuated.