基于ODS FRF某城际车工作状态下模态贡献分析

摘要

Modal contribution problem of intercity rails under working conditions is studied. First of all, the static exciter experiment is done for the intercity rail, and its modal parameters are identified with LMS.Test.Lab software. Then, the experiment of tracking the intercity rail is done, and the acceleration vibration response of the intercity rail under different speed levels is measured. According to ODS FRF concept, its operational deflection shapes (ODS) are given at the peaks of the ODS FRF envelope curve. Finally, according to the modal superposition principle, it is concluded that the typical ODS of the intercity rail under different speed levels is contributed by body’s up-and-down vibration, body’s nodding and body’s 1st order vertical bending. The results also show that the ODS with the same frequency may be contributed by different intrinsic modals and the frequency of the ODS may have some offset under different speed levels.%为研究某城际车工作状态下模态贡献问题，首先用激振器对该城际车进行了静态台架实验，利用LMS. Test. Lab软件识别其模态参数。然后对该城际列车进行线路实验，测试其不同速度级下的加速度振动响应。根据ODS FRF概念，给出了城际车在ODS FRF包络曲线峰值处的工作变形。最后根据模态叠加原理，得出不同速度级下，该城际车不同频率下工作变形主要由车体沉浮、车体点头及车体1阶垂弯贡献的结论。同时结果显示，不同速度级下，同一频率下工作变形可能由不同固有模态贡献；不同速度级下，同一工作变形频率可能会发生偏移。