基于FE-SEA混合法的汽车镁合金前围板隔声量数值计算

Sound insulation numerical calculation of an automobile magnesium alloy dash based on FE-SEA hybrid method

为研究中频域的结构噪声,采用有限元-统计能量分析(FE-SEA)混合法对汽车板件的隔声性能进行了研究,该方法具备适用于低频域的有限元或边界元法和适用于高频域的统计能量分析的优点.结合混合法理论,建立克莱斯勒Viper跑车镁合金压铸前围板的混合模型,验证该方法应用于汽车车身薄壁件中低频隔声量计算的可行性.对混合模型的入射侧施加混响声场(DAF)作为声激励,在透射侧施加半自由声场(SIF)作为功率接收器,由数值计算结果得到前围板中低频率范围内的隔声量曲线,与试验结果对比,表明两者结果基本吻合,从而很好地证明了有限元-统计能量混合法用于解决本模型的中频声学问题的可行性.介绍了区域声学包装法,即在隔声量曲线低谷频率范围(100～500Hz)内,将简易声学包装施加到结构表面振动速度较大处,可以有效地优化前围板的总体隔声性能.

In order to solve the structure-borne noise in middle frequency range, an advanced method named hybrid finite element-statistical energy analysis （FE-SEA） was introduced to calculate the sound insulation performance of automobile components. This method possesses the advantages of finite element method or boundary element method for low frequency range and statistical energy analysis for high frequency range. According to the FE-SEA theory, a hybrid model of the Chrysler Viper magnesium alloy dash was built to validate whether the hybrid method was feasible to calculate the sound transmission loss of automobile body panel in middle frequency range. Diffuse acoustic field （DAF） was applied to the incident side of hybrid model as the acoustic excitation and semi infinite field （SIF） was applied to the transmitted side as the sound power receptor. The result of numerical calculation agreed well with that of experiment, which validated the feasibility of the hybrid FE-SEA method in solving the mid-frequency acoustic problems of the dash panel. Finally, the application of regional sound package method shows the advantage and convenience to optimize the surface vibration around the frequency of sound transmission loss curve trough （100-500 Hz） in order to get a better sound insulation quality.