With the ongoing development and deployment of medium-low speed maglev vehicles in China, it has become common to increase operational speeds from 100$$ km/h up to 140$$ km/h or even 160$$ km/h, necessitating further studies and simulation models to understand the implications of these changes. This paper analyzes medium-speed maglev vehicle-track-girder coupling dynamic performance at a speed of 160$$ km/h. First, a field dynamics experiment is carried out on the Changsha Maglev Express with a running speed of 80–140$$ km/h. Then we introduce the distributed coupling simulation platform for maglev transportation system (MTS-DCSP) and the vehicle-track-girder coupling model, taking into account the complex vehicle structure, the guideway structure, and the Proportion Integral Differential (PID) levitation control system. Together, this platform and model can conduct a simulation of the complete process at scale and at all degrees of freedom to obtain accurate results. Our analysis of the results gives an accurate portrayal of the coupling dynamics properties and validates the coupling model. The results from the field experiments together with the coupling simulation demonstrate that the medium-speed maglev train can operate safely and stably within the range of 140–160$$ km/h. While at 140$$ km/h, however, the Sperling ride quality index (RQI) is about 2.5, which is within the Excellent grade range, at a speed of 160$$ km/h, the Sperling ride quality index can increase to as high as 2.74, which is a grade of Good. Therefore, it is necessary to optimize the parameters of the secondary suspension system to improve the ride comfort of the maglev vehicle at 160$$ km/h.

To investigate the dynamic effects of bolster-hanger length on the 600 km/h high-speed EMS maglev vehicles, a dynamic model of three-car trainset is established, considering the kinematic relation of the bolster-hanger mechanism and the active levitation/guidance control system. Model validation is carried out by comparing simulated results with test results of Shanghai high-speed maglev vehicles. Then, the proposed model is used to simulate the dynamic response of maglev vehicles with four different hanger lengths of 0.12, 0.18, 0.24, 0.36 m and passing through the straight track, the horizontal curve and the vertical curve. Simulated results indicate that because of the too short hanger maglev vehicles cannot pass through safely the sharp horizontal curve, and deteriorate the lateral dynamic performance of maglev vehicles on the straight track. The too long hanger may increase the lateral displacement of the carbody and lateral forces of rubber stops of maglev vehicles on the large-radius horizontal curve. The hanger length has little influence on the dynamic response of maglev vehicle on the vertical curve. In sum, the medium-long (0.24 m) hanger can provide a stronger curve negotiation capacity and better ride quality of high-speed maglev vehicles.

The traditional electromagnetic force calculation method does not consider the non-linear magnetization characteristics of the ferromagnetic material or the magnetic resistance in full circuit, resulting in large calculation errors when the electromagnet operation state is far from the rated state, and causing the dynamics simulation results to diverge from the actual situation. A more accurate analytical formula for electromagnetic force is derived based on the full circuit magnetic resistance modification and considering the non-linear magnetization characteristics of ferromagnetic materials. Then combined with the finite element simulation analysis, the magnetic resistance modification (MRM) method is proposed for calculating electromagnetic levitation force and guiding force. This MRM method greatly improves the accuracy of electromagnetic force calculations and provides greater accuracy for EMS maglev vehicle dynamics simulations.

The violent coupled vibration between the electromagnetically levitated vehicles and the steel switch girder had happened in several engineering practices, especially under the very low speed conditions. In order to simulate accurately the abnormal vibration and explore its underlying causes, this paper develops a distributed co-simulation framework, including maglev vehicle dynamic modelling by SIMPACK software, switch dynamic modelling by ANSYS software and a co-simulation coupler developed by C++ language to implement co-simulation of maglev vehicles and switch girder system. Dynamic response of maglev vehicles and switch girder system under various conditions of running speed and structural damping ratio are simulated and compared to obtain the mechanism and characteristics of coupled vibration. These results agree well with dynamic phenomena happened in the engineering practices. Further analysis shows that the levitation modules are impacted in turn by the vertical misalignments and rotation angles at both ends of switch girder, so that vibration energy of the switch girder cannot be attenuated rapidly by its relatively small damping and dead weight. The severe coupled vibration can be suppressed effectively by adding the tuned mass dampers, but improving constraints of switch girder and optimizing levitation control parameters should be paid more attention in the future.