针对试验中发现的空滤器壳体辐射噪声大问题，综合运用模态计算、进气压力频谱计算、拓扑优化、形貌优化和声学有限元法解决了该问题。首先，通过模态计算，得出了空滤器外壳的各阶振型和模态频率。接着分析了发动机的进气压力波频谱，找出了进气压力较大的频段，由此可知空滤器辐射噪声大是由于第1阶频率较低引起的。然后，通过拓扑优化和形貌优化，找出了筋的最佳布置位置，使空滤器外壳的第1阶频率得到大幅提高。最后，通过辐射噪声的计算，确认了改进后的空滤器外壳的总声功率级降低了13.8 dB，噪声改进效果非常明显。%Modal calculation, frequency spectrum calculation of intake pressure, topology analysis, topography analy-sis and acoustic FEM were employed to solve the serious radiation noise problem of an air cleaner’s shell. Firstly, vibration modes and eigen-frequencies of the air cleaner shell were obtained by modal computation. Secondly, the intake pressure spectrum was analyzed and the frequency zone with large intake pressure was determined. It was found that the large radia-tion noise of the air cleaner was resulted from the low 1st order frequency. Finally, the optimal position of the ribs was dis-covered by topology and topography analysis, so that the 1st order frequency of the air cleaner could be enhanced greatly. The result of the radiation noise computation show that the total sound power level of the air cleaner can be reduced by 13.8 dB after the modification and the improvement effect is very obvious.
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