振動端蓋下多孔吸音材料聲阻抗

Local Impedance of Sound Absorption Material under Vibrating End Plate

朱智義(Chih-I Chu) ； 林炳宏(Bing-Hung Lin) ； 羅啟宏(Chi-Hung Luo)

《中華民國振動與噪音工程學會論文集》 2008 (2008/05) Pp. 394-396

https://doi.org/10.30028/CSSVANNUAL.200805.0394

摘要

本文探討多孔吸音材料端蓋為可振動下，對吸音材料表面聲阻抗的影響。假設聲波在空氣介質與多孔吸音材料中皆是以平面波傳遞，而計算時所需之泡棉吸音材料特徵阻抗與複變波數則是以雙腔室法量測而得。研究結果顯示當端蓋振動速度為正時（激發源同相）時，阻抗實部與虛部皆增加，但當端蓋振動速度為負時，阻抗實部與虛部皆減少。

關鍵字

聲阻抗 ； 多孔吸音材料 ； 振動

並列摘要

In this paper, the effect of a moving end plate on the local impedance for a porous material is studied. The characteristic impedance and complex wave number for the porous material-a common foam, is first measured using the two-cavity method. Both in air and porous material, the plane wave theory is then applied. Analysis results show that the real as well as imaginary parts of local impedance is increased if the end plate and sound source move in phase, particularly in low frequency region. On the contrary, if the end plate and sound source move out of phase, the local impedance is decreased.

並列關鍵字

local impedance ； porous material ； vibration