The Influence of Variable Section of Orifice on Sound Absorption Characteristics of Thick Microperforated Panel
The Influence of Variable Section of Orifice on Sound Absorption Characteristics of Thick Microperforated Panel
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发表时间：
2011
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通讯作者：
He Li-yan
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作者：
He Li-yan
厚微穿孔板中的孔口通常是截面均匀的直孔。虽然厚度的增加延长了MPP的S使用范围，但MPP的声阻抗最终会改变其吸声系数。改善这一劣化的方法之一是在厚壁MPP中采用变截面孔口。本文采用环氧树脂制备了10 mm厚的变截面孔阶梯形模芯MPP，并对其声学性能进行了测试。结果表明，变截面开孔MPP的吸声频带得到了扩展。与传统的直孔和等截面孔MPPS相比，其吸收频率范围从300~700 Hz扩展到310~830 Hz，圆锥孔MPPS的平均吸收系数从0.45增加到0.54。
The orifices in thick microperforated panels(MPPs) are normally straight holes with uniform section. Although the increase in thickness extends the MPP' s application,the eventually change of acoustic impedance of MPP will reduce its absorption coefficient.One way to improve this deterioration is to use variable section for the orifices in the thick MPPs.In this paper,10mm thick MPPs with varying section holes molded by tapering and step-shaped molding cores are prepared by using epoxy resin,and their acoustic characters are measured.Results show that the sound-absorption band of the MPPs with varying-section holes is extended.Compared with conventional MPPs with straight and uniform sectionnal holes,the absorption frequency range extended from 300～700Hz to 310～830Hz,and average absorption coefficient increases from 0.45 to 0.54 for MPPs with conical holes.