梯度纤维多孔材料的吸声特性及结构优化

Sound Absorption Characteristics and Structure Optimization of Gradient Fibrous Porous Materials

利用金属纤维为原料,制成内部具有梯度孔结构的金属纤维多孔吸声材料。梯度孔结构可分为孔隙度梯度和丝径梯度,分别研究了这2种梯度结构的吸声特性。结果表明,厚度在6~30 mm范围内时,孔隙度梯度结构按照孔隙度从大到小的顺序排列有利于提高全频的吸声性能;厚度为3 mm时,孔隙度梯度结构的排列顺序对吸声性能的影响规律恰好相反;丝径梯度结构的吸声特点是当厚度为3 mm时,细丝径纤维多孔材料在前,全频吸声性能较好;当厚度≥15mm时,粗丝径纤维多孔材料在前,全频吸声性能好;厚度在3~15 mm之间,2种排列方式的丝径梯度结构的吸声-频率曲线存在一个交点,随着厚度的增加,该交点逐渐向低频方向移动。

Sound absorption materials were prepared using metal fibre as the raw material. The pore of the prepared material possessed gradient arrangement. The gradient pore structure can be carved up two kinds, porosity gradient structure（PGS） and fiber diameter gradient structure（FGS）. The sound absorption characteristics of two kinds of the structures were studied. The results indicate that when the thickness is between 6 mm and 30 mm, the porosity of the PGS arranged from high to low, can enhance the sound absorption performance in the whole frequency range from 50 Hz to 6400 Hz. But this law is just opposite to that of the thinner PGS when thickness is about 3 mm. The characteristic of the FGS is as follows. When the thin fiber is in the front of the structure（the thickness is 3 mm）, the sound absorption performance is very well in whole frequency; when the thick fiber is in the front of the structure（the thickness is ≥15 mm）, the sound absorption performance is very well in whole frequency. When the thickness is in the range from 3 mm to 15 mm, there is an intersection point between the sound absorption-frequency curves of the FGS with two kinds of arranging way. The intersection point moves to lower frequency with the increasing of the thickness,