Irregularities of rail joints ordinarily induce high-frequency impacts on wheel–rail contact systems, which may further influence vehicle–track interaction. In this study, a three-dimensional locomotive-track coupled dynamics model that uses the wheelset flexibility was developed. The wheelset rigid motion and elastic deformation are calculated based on the multi-body dynamics theory and finite element method, respectively. The effectiveness of this model was validated. The effect of wheelset flexibility on locomotive–track interaction due to rail weld irregularities is analysed by comparing the dynamic responses obtained using the rigid model and the proposed rigid–flexible coupled model. The proposed model is applied to the sensitivity analysis of the wheelset response to the rail weld geometry irregularity. The results show that the dominant frequency of the wheel–rail force or axle–box acceleration is 81 Hz, which is the 1st bending modal frequency of the wheelset. The P2 resonance frequency is easily excited owing to impacts of rail weld irregularities, which may induce the formation of locomotive wheel polygonization. The wheelset acceleration was more sensitive to the wavelength than the depth of the rail weld irregularities. The wavelength characteristics can be significant in vehicle vibration-based condition monitoring of rail weld irregularities.

轨道接头的不规则性通常会对轮轨接触系统产生高频影响，这可能会进一步影响车辆与轨道的相互作用。在这项研究中，开发了一种利用轮对柔性的三维机车-轨道耦合动力学模型。轮对刚体运动和弹性变形分别基于多体动力学理论和有限元法计算。验证了该模型的有效性。通过比较使用刚性模型和所提出的刚柔耦合模型获得的动态响应，分析了轮对柔性对由于钢轨焊缝不规则性而导致的机车轨道相互作用的影响。将所提出的模型应用于轮对响应对钢轨焊缝几何不规则性的敏感性分析。结果表明，轮轨力或轴箱加速度的主频率为 81 Hz，这是轮对的第一弯曲模态频率。由于钢轨焊缝不平整的影响，容易激发P2共振频率，这可能导致机车车轮多边形化的形成。轮对加速度对波长的敏感性高于钢轨焊缝不规则的深度。波长特性在基于车辆振动的钢轨焊缝不规则状态监测中具有重要意义。轮对加速度对波长的敏感性高于钢轨焊缝不规则的深度。波长特性在基于车辆振动的钢轨焊缝不规则状态监测中具有重要意义。轮对加速度对波长的敏感性高于钢轨焊缝不规则的深度。波长特性在基于车辆振动的钢轨焊缝不规则状态监测中具有重要意义。