To investigate the vibration characteristics of long-span suspension bridges under the impact of high-speed trains, a method for conducting a time–frequency domain analysis of the dynamic response of a coupled system is presented in this study. First, the finite element model of a suspension bridge is established to conduct modal analysis, and simulation results are compared with measured data to validate the correctness of the bridge model. Subsequently, a multi-body dynamics model of a high-speed train is developed. Then, two approaches, the dummy method and flexible-track method, are employed to create the train–bridge coupled system. Finally, the flexible-track method is used to perform time–frequency domain analysis of the system under complex operational conditions. The research revealed that large-span suspension bridges exhibit lower natural frequencies. The vertical bending vibrations of the main beam have the potential to significantly impact train operations. Under the combined impact of cable tension and wheel–rail forces, the vibration patterns of large-span suspension bridges become notably intricate. The number of trains and their loading configurations both exert influence over the dominant frequencies and amplitudes in the PSD of bridges. In the complex traffic of large-span suspension bridges, the rational arrangement of travel lanes can reduce the possibility of resonance in the bridge–train system.

为了研究大跨度悬索桥在高速列车冲击下的振动特性，本研究提出了一种对耦合系统动态响应进行时频域分析的方法。首先建立悬索桥有限元模型进行模态分析，并将仿真结果与实测数据进行比较，验证桥梁模型的正确性。随后，开发了高速列车的多体动力学模型。然后，采用虚拟法和柔性轨道法两种方法来创建车桥耦合系统。最后，采用柔性轨迹方法对复杂运行条件下的系统进行时频域分析。研究表明，大跨度悬索桥的固有频率较低。主梁的垂直弯曲振动有可能对列车运行产生重大影响。在缆索张力和轮轨力的共同影响下，大跨度悬索桥的振动模式变得异常复杂。列车数量及其荷载配置都会对桥梁 PSD 的主频率和振幅产生影响。在大跨度悬索桥交通复杂的情况下，合理布置行驶车道可以减少桥车系统共振的可能性。