The Response Of Vehicle Bridge Coupling Vibration System Under The Debris Flow

With the continuous development of high speed railway,the railway has high speed,high frequency and large proportion of bridge.Such characteristics increase the probability that the train is running on the bridge when the disaster happens.Due to the frequent debris flow disaster in Southwest China,the debris flow is often occurred in the course of the train,which not only brings great inconvenience to the railway transportation,but also can cause serious personal injury.It is particularly important to study the vibration response of vehicle-bridge coupling under the impact of debris flow.And it has important guiding significance to the railway line selection and construction work,but also is helpful to improve the safety of vehicle operation.The dynamic response of vehicle-bridge coupling system will increase under the impact load of debris flow.However,how much the influence of debris flow on the vehicle-bridge coupling system is and what kind of factors have a greater impact on the vehicle-bridge coupling system both need to be further studied.At the same time,the influence of the bridge damaged by debris flow on the vehicle bridge coupling system is also worth exploring.Based on the above two points,the research contents of this paper are as follows:(1)Firstly,the process and mechanism of debris flow are introduced.And the related parameters of the debris flow are determined,including the bulk density,velocity,flow rate,attack force and impact height,and so on,to obtain the impact load and the location of the debris flow.(2)In this paper,the dynamic analysis model of vehicle-bridge is established in ANSYS Workbench software.Considering the geometric compatibility and static equilibrium wheel and rail,the friction contact is used to determine the contact relationship between wheel and rail in software.And through the MATLAB programming,the track irregularity spectrum is introduced in the vehicle bridge coupling system.The dynamic response of vehicle-bridge coupling system is solved by using the step-by-step integration method of software transient dynamics module.(3)A simple bridge in the southwest mountain area is taken as the research object.The dynamic response of the vehicle bridge coupling system with or without debris flow impact load is calculated and analyzed,and the different working conditions of the large rock are also taken into account.The results show that the impact force of the large rock is the main factor to determine the value of dynamic response of the vehicle bridge under the debris flow impact effect.And the corresponding suggestions are given to the actual project by comparing with the current codes.(4)In the end,the local area of damaged bridge that hit by the boulder is to deal with reduced stiffness.And the dynamic response of vehicle-bridge coupling system is studied under the case of bridge damaged.The influence of different damage location to the dynamic response of vehicle-bridge coupling system is calculated.It's concluded that when a large stone hit the bridge,the closer to the bottom of the pier of the damage location is,the greater to the dynamic response of the train and bridge is.It is also unfavorable to the safety of the train.