Coupling Vibration Analysis And Running Safety Probability Assessment Of High-speed Railway Train-bridge System In Seismic

With the pursuit of efficiency in this era,the speed of high-speed railway trains has been constantly improved.Due to the advantages in crossing the restrictions of complex terrain and closing of running lines,the proportion of bridge in high-speed railway construction is increasing.And simply supported box beam is widely used because of its high rigidity and strong adaptability.However,in China,the seismicity is of high frequency,and many high-speed railway lines pass through the crisscrossed seismic zones.As a result,the probability of trains running on the bridge during the earthquake is very high,and the dynamic interaction between high-speed trains and the bridge is more complex,which is a challenge to the running safety of train.In this paper,based on the theory and research method of train-bridge coupling vibration analysis and bridge dynamic response in seismic analysis,the dynamic simulation model of train-bridge system for seismic response analysis is established by taking the common-span simply supported bridge on high-speed railways in China as the research object.The dynamic time-history analysis method is used to study the coupled vibration response of train-bridge system and its statistical probability characteristics at different train speeds,seismic as well as intensity considering random variability of seismic.The main research points of the paper are as follows.(1)The theory and modeling method of multi-body system dynamics is adopted,the multi-body model of train is established by software SIMPACK and the finite element model of bridge is established by ANSYS in this paper,and the nonlinear factors such as wheel-rail contact relationship are considered.After that,according to the coupled integration method of bridge in the form of elastomer in multi-body system,the coupled vibration model of train-bridge considering track irregularity is simulated.(2)The large-mass method is employed to as seismic excitations input method of train-bridge coupled system in seismic.Four typical seismic waves are selected to calculate the space vibration responses of train and bridge at different seismic intensity and train speeds via IDA mode.And the influence of seismic intensity and running speed on the coupled vibration dynamic index of train and bridge is compared and analyzed.Meanwhile,the running safety and stationarity of train and vibration state of the bridge are assessed depending on the relevant evaluation criteria.(3)Du XL-Chen HQ seismic power spectrum function and the theory of random vibration are adopted in this paper,time-history samples of artificial seismic acceleration are synthesized by trigonometric series method which is taking the spectral intensity factor,the predominant frequency of the site and damping ratio as random parameters.The random seismic response of the train-bridge system is analyzed by Monte-Carlo simulation with the artificial seismic acceleration samples as the excitation input of system.Then,the statistical laws of the seismic responses of the train and bridge are obtained by a Matlab program.Finally,the probability characteristics of the seismic responses of train and bridge at different train speeds and seismic intensity are studied.