Modeling and Simulation of Bridge - Track - Train Systems at High Service Velocities with LS-DYNA

The paper develops a new methodology of FE modeling and simulation of the bridge – track – train systems at high service velocities with the use of selected CAE systems. The methodology is presented on the KNI 140070 viaduct with composite (steel – concrete) superstructure and 14.40 m span length, located on the Central Main Line, Poland. A ballasted track and two types of high speed trains have been modeled physically and numerically. The study includes German ICE-3 (InterCityExpress) train with classic bogies and Korean KTX (Korea Train eXpress close to French TGV) train with classic and Jacobs bogies. A methodology of the FE modeling and simulation of the bridge – track – moving train system is based on the following concept. The physical and numerical modeling of the viaduct – track – train system was performed with Altair HyperMesh® and LS-PrePost® software. The FE model of the bridge superstructure consisted of 4-node shell elements (main beams) and 8-node 48 DOF solid elements (RC platform). In order to simulate the moving train – track interaction, RAIL_TRACK and RAIL_TRAIN modules available in LS-DYNA system were used. Hughes-Liu beam elements were used for rail modeling whereas rail fastenings were simulated using one-dimensional discrete spring and damper elements. Carbodies, bogie frames and wheelsets were considered as rigid bodies and they were modeled using shell and beam elements. Cylindrical and revolute constrained joints and discrete springs and dampers were applied to connect components of the FE model of rail-vehicles. In the longitudinal direction, the FE mesh of the system is based on a 600 mm length module. DYNAMIC_RELAXATION is omitted via applying the static wheel loads increasing in the cosine shape in the 2-sec initial time interval. The quasi steady-state wave in the track is generated after the initial time interval. Dynamic response of the bridge – track – train system is registered in the form of displacement and acceleration time- histories at the design cross-sections as well as displacement and stress contours in reference to main steel beams.