基于模态贡献量分析方法的地铁车辆结构降噪优化研究

地铁列车的运行过程中伴随着不同程度的车体板件振动,由此而引起的车体板件辐射噪声是地铁列车车内噪声的重要来源之一。应用模态贡献量分析方法,研究了车体板件的振动对车内场点声压级的影响特性,并通过修改局部板件等效厚度的方式改善车内声场。将地板等效厚度减少2 mm后,场点43 Hz、82 Hz频率处的线性声压级均降低了6 dB以上。通过模态贡献量分析找出对车内噪声贡献较大的模态,并结合其模态振型以及板件节点贡献量分析进行针对性结构优化,这种方法可以起到改善车内场点处声学响应的效果。

Research of Metro Vehicle Structure-borne Reduction Noise Optimization Based on Modal Contribution Analysis

Different degrees of vibration of the body panels occur when the train is operating.The resulting radiated noise is one of the major sources of noise in metro trains.Modal contribution analysis method was applied to study the characteristics of the influence that vehicle body panels vibration has on the interior sound field,which was improved by modifying the equivalent thickness of certain panels.When the thickness of the floor panels was reduced by 2 mm,the linear sound pressure of field points at 43 Hz and 82 Hz was reduced by 6 dB or more.Modal contribution analysis can be used to locate the modal that contributes to the interior noise more.By analyzing the mode shape and panel node contribution of this modal,targeted structure optimization was conducted.This method is proved effective to improve the acoustic response of vehicle interior field points.