Vertical Random Vibration Analysis Of Train-Bridge Coupling System

With the development of modern high speed railroads, the research of train-bridge dynamic interaction has attracted worldwide attention by scholars. The responses of train-bridge coupling system are random obviously, the main factor which causes the random vibration of train-bridge coupling system is track random irregularity, so it is reasonable to use the theory of probability and statistics to solve this problem. However, the complexity and low efficiency of the conventional random vibration methods has considerably restricted the development of the relevant research work. In this paper, based on the theoretical framework of random vibration, the preudo excitation method (PEM for short) is applied in the random vibration analysis of train-bridge coupling time-dependent system, the useful conclusions from the work are benefit for the research of train-bridge coupling random vibration. The main work in this paper can be summarized as follows:1The vehicle is simplified as moving sprung mass model, considering the inertial force of wheelset, the random responses of couping time-dependent system are deduced with PEM. The time-dependent power spectrum and standard deviation of system responses can be got from the preudo responses. The program to calculate the vehicle-bridge random responses under moving sprung mass model is developed on MATLAB platform.2The two-suspensions vehicle model which has10DOFs is adopted to analyze random responses of the coupling system under high speed train. Considering the time-delay excitaions under wheelsets on account of the distance of wheelsets, the vertical track random irregularity excitaions can be supposed as uniformly modulated and multi-point fully coherent random excitaions. The random excitaions can be transformed as a series of certain preudo excitation with PEM. The preudo responses can be calculated by solve dynamic equation of subsystem iteratively with successive integration method, and then the time-dependent power spectrum and standard deviation of random responses can be got from the preudo responses easily. The program to calculate the train-bridge random responses is developed on MATLAB platform. The influence on random vibration of system which arise from the inertial force of wheelset, the derivatives of track irregularity, the modulation of track irregularity, the velocity of train and track irregularity level have been discussed.