Dynamic interaction of suspension-type monorail vehicle and bridge: Numerical simulation and experiment

To evaluate the dynamic behaviour of suspension-type monorail (STM) system, a coupled dynamic model of the STM vehicle-bridge system has been developed based on multibody dynamics and finite element (FE) theory. In the model, both the spatial vehicle model with 21 degrees of freedom and the 3-dimensional FE model of the bridge structure for a particular STM system are established by using ANSYS parametric design language (APDL). The vehicle subsystem is coupled with the bridge subsystem through the contact relation between the vehicle tire and bridge inner surface. Then, a mixed explicit and implicit integration method is used to solve the coupled dynamic model. Finally, the dynamic responses of the vehicle-bridge system are calculated by adopting the established model, which are compared with the field test data. Results show that the simulation with the proposed dynamic model is in good agreement with the filed test data. Some apparent discrepancies can be distinguished when the bridge is treated as rigid body and flexible body, respectively, showing the importance of considering the flexible bridge and demonstrating several modelling advantages of the proposed coupled dynamic model. Overall, the train has good operation stability, and the lateral stability of car body is worse than its vertical stability because of the special vehicle structure. The first-order natural frequencies of the bridge in the vertical and lateral-torsional directions are about 5.60 Hz and 2.27 Hz, respectively. The bridge lateral acceleration is significantly larger than the vertical accelerations at the bridge middle-span section due to the low lateral stiffness of the bridge. These conclusions could provide a useful guidance for design of the STM system.