Condition Monitoring Method Of High-Speed Railway Bridge Based On Vehicle Bridge Coupling Effect

Bridge frequency and track irregularity on the bridge are directly related to the safety of the bridge structure itself and the train on the bridge,which has become the key content of railway bridge condition monitoring.However,the existing methods almost ignore the vehicle bridge coupling effect and the coupling effect of frequency and track irregularity on the observation response,resulting in large errors in the monitoring results.On the other hand,due to the uncertainty of noise and system parameters,the actual monitoring results inevitably introduce uncertainty.Therefore,this paper studies the condition monitoring method of high-speed railway bridges based on vehicle bridge coupling effect,which can realize the real-time and accurate monitoring of high-speed railway bridges,and quantify the uncertainty of monitoring results.The main research contents of this paper include the following aspects:(1)Based on the principle of stochastic dynamics,the vehicle bridge vertical coupling dynamic model and its stochastic motion equation are established.Taking the four axle vehicle as the vehicle model,the simply supported beam is assumed to be an Euler beam,the vibration mode superposition method is used to model the bridge,and the coupling of vehicle system and bridge system is realized according to the vehicle bridge constraint equation.The vehicle bridge coupling vibration system established is time-varying and random.(2)Considering the influence of observation noise,a monitoring method of bridge state(frequency and track irregularity)is proposed based on recursive Bayesian Kalman filter,which can estimate bridge frequency and track irregularity at the same time,and quantify the uncertainty of estimation.(3)Further considering the uncertainty of system parameters,the random characteristics of parameter uncertainty are simulated by sigma point particles,and a new identification method of bridge state statistical characteristics considering the influence of parameter uncertainty is proposed.(4)Considering the long-term influence of train load information on bridge state,a dynamic weighing algorithm of high-speed bridge based on vehicle bridge coupling effect is further proposed.The algorithm can use the dynamic response of instrumented bridge to monitor the vehicle load information in real time,identify the two mass parameters of railway bridge freight vehicles,body mass and eccentric load distance,and quantify the uncertainty of identification results,so as to provide data support for the long-term evaluation of bridge state.