非织造布的孔洞分形维数对其吸声性能的影响

为明确孔洞特征在非织造布吸声机制中的作用，使用SW260型双传声器驻波管测量了6块非织造布试样背后有空气层时的吸声性能，同时通过计盒维数方法计算出他们的孔洞面积分形维数。结果表明，非织造布样品背后增厚的空气层使得样品在该测试频域的吸声系数进一步增大，同时使得吸声曲线初始段上升的斜率变大，从而吸声峰向低频域移动。此外，非织造布的孔洞具有很强的分形特征，随着孔洞面积分形维数的增大，非织造布的最大吸声系数随之增大，同时其吸声曲线的共振峰向低频区域移动。

Effect of nonwovens pore fractal dimensions on their acoustic absorption behaviors

In order to clarify the effect of pore characteristic on sound absorption behaviors of nonwovens, Sound absorption behaviors of six nonwovens are measured by SW260 double-microphones standing wave tube, and then their pore area fractal dimensions are calculated by box-counting method. The results indicate that increasing air gap improves the absorption coefficient on the tested frequency, and the absorption curve moves towards lower frequency. In addition, the results show that the pore structures of nonwovens have obvious fractal characteristics. The acoustic absorption coefficient grows linearly with increasing area fractal dimension, while the absorption peak moves towards lower frequency.