70%低地板轻轨列车车内声学计算与分析

Acoustic Calculation and Analysis of the Inner Carbody on 70% Low-floor Vehicle

通过对70%低地板车辆进行动力学建模,仿真得出车辆正常运行时二系结构与车体连接处的力和两处下铰力,以此作为激励对车体结构有限元模型进行频率响应计算。用计算得到的车体位移激励车体声学有限元模型,得到车内声学模态、声场分布和ISO标准场点响应。结果显示,车体在几个特定频率下的声压级超出了车内噪声指标。通过对几个特定频率下的各板件声场贡献量计算,得到车顶正贡献量较大,可提供给厂方进行结构优化。同时,根据结构模态、声学模态计算结果对车体下吊设备频率提出了建议。

By modeling the dynamic structure of 70% low- floor vehicle, the force between the secondary suspension system and the carbody, the joint reaction force of vehicles can be simulated. Then, these forces are used as the incen- tive to calculate the frequency response of the carbody FE model. The response that shows the displacement of vehicle in each frequencyis used to stimulate the carbody＇s acoustic FIE model, thusthe acoustic modal, the sound field distribu- tion as well as the ISO standards field point responses are obtaine. The result of the acoustic calculation of vehicle＇s inner carbody shows that the sound pressure level （SPL） of certain frequencies goes beyond the limit of noise index. Through calculating the contributions of each plate in the specific frequencies, the car roof appears to have the posi- tive contribution to the whole carbody, and provides a ref- erence for the optimization of the panels. Meanwhile, some reasonable proposals for frequencies of hanging equipment in accordance with the results of the structural modal and the acoustic modelare put forward.