Research On The Dynamic Performance Of The Telescopic Device Of The Open Deck Steel Truss Girder Bridge And Its Impact On The Train Driving On The Freight Line

Open Deck Steel Truss Bridge plays an important role in freight transportation because of its low cost,convenient construction design,and adaptability to large-span bridge stiffness requirements.As the beam end expansion joint and the supporting expansion rail joint applied on the large Open Deck Steel Truss Bridge have achieved domestic autonomy,the performance of the beam end expansion joint in service and its wheel rails’ interaction force on the bridge and vehicle dynamic performance is of great significance to guarantee the safety of line operation.In this paper,the main bridge of Diaokou River Extra Large Bridge with the new beam end telescoping device applied on the newly built Dongying Port Shugang Railway is used as the research object.Using the ANSYS and SIMPACK joint simulation method,the freight train is carried out under the action of various factors The dynamic simulation analysis of the whole process of running on the bridge,the main research contents are as follows:(1)A detailed analysis model including the steel truss main bridge,the concrete approach bridge,the track structure on the open deck bridge and the beam end expansion device was established.Fully considered the nonlinear factors of the track structure on the bridge.Based on the combination of local climatic conditions and the temperature distribution characteristics of the steel truss bridge,the heating and cooling of the steel truss bridge were calculated separately.The telescopic performance of the beam-end telescopic device is clarified,and the irregular curve of the rail track on the bridge caused by the temperature-dependent deformation of the steel truss bridge is extracted,and then it is superimposed with the time-domain sample of the irregular spectrum of the speed-increasing trunk line in China as a dynamic simulation Irregular incentives.(2)The flexible system model of the steel truss bridge with exposed bridge deck track structure is reduced by degrees of substructure analysis to improve the efficiency of simulation analysis.Appropriate main degrees of freedom are selected and the calculation results of the low-order natural modes of the bridge structure in the finite element are compared to verify the accuracy of the degree of freedom reduction.(3)An 8-group multi-body dynamic model including locomotives and freight cars was established,and the nonlinear mechanical characteristics of the force elements between rigid bodies were considered.In the position of the rail telescopic regulator near the beam end,the profile of the rail head is discretized to achieve the purpose of dynamically changing the geometric relationship of the wheel and rail contact in the rail telescopic regulator.The appropriate calculation method of wheel-rail force is considered,and the train and flexible track bridge are assembled to form a dynamic analysis model of the vehicle-bridge system.(4)A variety of analysis conditions were set up to explore the changes in the profile of the rail expansion and contraction regulator,the interaction between the rail expansion and contraction regulator and the flexible foundation of the rail bridge,and the two factors superimposed on the track irregularity on the bridge.Impact.Finally,according to the expansion and contraction of the beam end telescopic device,the spacing of the movable sleeper of the beam joint is adjusted,and the dynamic performance of the beam end telescopic device under the state of extreme tension and compression is compared.The research methods and results in this paper can provide a reference for the design and application of the beam end expansion joint on the steel truss bridge on the open deck of freight lines.