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从理论和实验上探讨了加工误差对马氏理论关于超微孔微穿孔板(micro-perforated panel,MPP)吸声结构适用性的影响。建立了计及加工误差的MPP理论分析模型,并应用MEMS工艺制作了超微孔MPP,由于工艺本身存在一定的加工误差,造成实际孔径与设计孔径10%~20%的偏差,在阻抗管中测量得到其垂直入射吸声系数。将实验结果和计及加工误差的理论预测值与马氏理论预测值进行对比发现,差别均较小,最大误差仍在6%以内,说明马氏理论在计及加工误差的情况下仍然适用。此外,对马氏理论关于加工误差的适用极限进行了仿真计算,结果表明,适用极限的大小具体依赖于超微孔MPP的孔径大小。
The effect of machining error on the applicability of Markov theory to the microporous structure of micro-perforated panel (MPP) was discussed theoretically and experimentally. The MPP theoretical analysis model considering the machining error was established and the microporous MPP was fabricated by using the MEMS technology. Due to the processing error inherent in the process itself, the deviation of the actual aperture from the designed aperture by 10% to 20% Measured by its vertical incidence of sound absorption coefficient. The experimental results and theoretical predictions of machining errors are compared with those of the Markov theory. The differences are small and the maximum error is still within 6%, which shows that the Markov theory is still applicable when the machining errors are taken into account. In addition, the application of Markov theory to machining error is simulated. The results show that the size of the applicable limit depends on the pore size of microporous MPP.