Analysis Of 3-dimensional Dynamic Behavior Of Vehicle And Ballastless Track Coupling System With Finite Elements

With the increase of the passenger line speed and traffic density,the dynamic effect between vehicle and track has become more and more prominent and complex.Thus according to the dynamics theory establishing a coupling system model of vehicle and ballastless track for studying on the structural and mechanical characteristics of ballastless track is of great practical significance.This paper begins with establishing a three-dimensional beam-plate element model of ballastless track,then has done some work on vehicle-track dynamics and analysis of the dynamic characteristics of ballastless track,providing some references for future in-depth studying in this field.According to the structure characteristics of ballastless track,the three-dimensional beam-plate element of ballastless track is proposed and its stiffness,mass and damping matrices are deduced.The beam-plate element of ballastless track is compared with the3-layer beam element in theory: In the 3-layer beam element the track slab and concrete base are simplified to two-dimensional beam elements.Beneath the rail beam there are track and concrete base beams.In the beam-plate element the track slab and concrete base are simplified to three-dimensional curved rectangular plate element.Beneath the rail beam there are two track and two concrete base plates.The vehicle and ballastless track elements(considering 3-layer beam element and beam-plate element)are assembled to the vehicle and ballastless track systems.The dynamic equations of the vehicle and ballastless track systems are solved by the cross iterative algorithm which not only reduces the analysis scale of the problem,but also reduces the difficulty of programming.Based on the beam-plate element on elastic base,the three-dimensional dynamic model of vehicle and ballastless track coupling system is established.Use MATLAB to program the calculating software.The influence of dynamic response of the vehicle and track structure by the track irregularity and vehicle speed,obtaining the following conclusions:(1)The vertical rail deflection curve and wheel-rail force is calculated by the program and compared to the reference and experimental data,getting a good agreement.(2)The dynamic response influence of vehicle and track is analyzed by the track irregularity with CRH3 simulating vehicle and CRTS II slab ballastless track simulating track.Conclusions show as follows: Track irregularity has evident influence on the response of vehicle and track structure,especially for rail displacement and acceleration,wheel acceleration and wheel-rail force.(3)Influence on the dynamic response of vehicle and track by the track irregularity and vehicle speed is as follows: when the speed increases from 200 to 400 km/h,the dynamic responses of track structures have large increases,the responses of vehicle structures have different increases,the wheel-rail contact force between vehicle and track increases from 114.13 to 170.34,an increase of 49.3%.Based on the beam-plate and 3-layer beam elements of ballastless track,the dynamic models of vehicle and ballastless track coupling system are established.Use MATLAB to program the calculating software.Analysis of the parameter of the CRTS? Slab ballastless track has been done.The conclusions are as follows:(1)Comprehensive calculations adequately reflect simplicity and practicality of the cross iteration algorithm on the vehicle-track coupling system dynamic model.(2)Considering different stiffnesses and dampings of the fastening system,CA mortar layer and roadbed,using beam-plate structure model to calculate the response of track the result is in the same trend,proving the correctness of the model and algorithm.By studying the influence of different parameters on the dynamic response of track structure,a reasonable range of values of ballastless track structure parameters is obtained(3)The vehicle and ballastless track coupling system dynamic model and cross iterative algorithm which providing a theoretical reference to studying the dynamic performance of CRTS?Slab track and the designing standard are generally applicable to the analysis of other ballastless track.Finally based on a comprehensive summary of the thesis work,some problems required to be solved is put forward.