Shen Longjiang, He Shizhong
CRRC Zhuzhou Locomotive CO., LTD, Zhuzhou, 412001, China.
Sci Rep. 2024 Sep 14;14(1):21484. doi: 10.1038/s41598-024-72146-z.
A wealth of practical cases indicates that the fatigue failure of subway bogies primarily stems from the modal resonance of the structure. If the modal characteristics of the entire vehicle, including equipment and bogies, are mismatched, rail vehicles may experience abnormal vibrations and noise. Therefore, it is imperative to conduct modal analysis and matching design for subway vehicle bogies to ensure smooth operation, reduce structural vibrations and noise, and enhance vehicle safety and ride comfort. Modal identification methods under the ambient l excitations during vehicle operation were employed to identify the modal parameters of the bogie structure before and after wheel reprofiling and under different load conditions. According to the test results, wheel reprofiling has minimal impact on the modal parameters of the structure, but with an increase in load, the modal frequencies of each order generally increase. This is associated with boundary constraint states, such as the increased stiffness of the bogie air spring with an increase in vehicle load. By comparing the test results with simulation analysis results of the bogie structure under free and constrained states, it is evident that simulating realistic boundary constraint conditions is crucial to ensure the accuracy of the finite element model. Based on frequency isolation criteria and vibration isolation theory, a frequency planning basis for the bogie structure was established. The study found that as the vehicle load increases, changes in the boundary conditions of the bogie affecting the elastic modal frequencies of the structure may have a certain impact on matching design, and may even better comply with the requirements of frequency management equations. This provides a new direction for subsequent scholars researching modal matching design.
大量实际案例表明，地铁转向架的疲劳失效主要源于结构的模态共振。如果包括设备和转向架在内的整车模态特性不匹配，轨道车辆可能会出现异常振动和噪声。因此，对地铁车辆转向架进行模态分析和匹配设计势在必行，以确保运行平稳，减少结构振动和噪声，提高车辆安全性和乘坐舒适性。采用车辆运行过程中环境激励下的模态识别方法，识别车轮重新修形前后以及不同载荷工况下转向架结构的模态参数。根据测试结果，车轮重新修形对结构的模态参数影响极小，但随着载荷增加，各阶模态频率总体呈上升趋势。这与边界约束状态有关，比如随着车辆载荷增加，转向架空气弹簧刚度增大。通过将测试结果与转向架结构在自由和约束状态下的仿真分析结果进行比较，显然模拟实际边界约束条件对于确保有限元模型的准确性至关重要。基于频率隔离准则和隔振理论，建立了转向架结构的频率规划依据。研究发现，随着车辆载荷增加，转向架边界条件的变化影响结构的弹性模态频率，可能对匹配设计产生一定影响，甚至可能更好地符合频率管理方程的要求。这为后续学者研究模态匹配设计提供了新方向。
