车辆驾驶室降噪设计与仿真研究

Simulation Study and Design of Noise Reduction of Vehicle Cab

研究驾驶室内噪声是车辆乘坐舒适性问题,由于车身的振动产生噪声,车辆的舒适性差。为了降低室内噪声通过对驾驶室进行试验模态分析,得出固有频率和基本振型变化,发现频率为120.44Hz时驾驶室内噪声影响最大。对驾驶室壁板采用辛几何解析法和面板声学贡献度分析,得出对顶板驾驶员耳旁声压级影响最大。为解决上述问题,对驾驶室顶板采用加筋板的降噪方法,利用声辐射理论,对改进后的驾驶室降噪效果进行数值仿真,得出改进后驾驶室内的声压降低了10.3dB,有效的抑制了低频噪声,提高了车辆的舒适性。

Cab noise is one of important indexes of vehicle ride comfort. Through experimental modal analysis of cab, the natural frequency and changes of fundamental vibration mode were obtained in the paper, it was found that influence of roof vibration is maximum to cab noise. Symplectic geometry analytic method was adopted to calculate the natural frequency of cab＇s roof, and its value is basically consistent with experimental data. On the basis of this, the contribution degree of panel acoustic was analysed, which further proves that the siding which has outstanding contribution to sound pressure of driver＇s right ear is roof. The noise reduction method of stiffened plate was adopted to cab＇s roof. Based on acoustic radiation theory, the numerical simulation of effect on noise reduction of improved cab was carried out. Sound pressure of the improved cab was reduced byll. 3dB, and low frequency noise was suppressed. The above results fully verify that the noise reduction method is effective.