Effect of characterization of porous metal fiber media on sound absorption coefficient

Abstract

Porous metal fiber media (PMFM) is a kind of advanced structural and functional material, and it has attracted a wide spread attention owing to excellent sound absorption performance. The sound absorption property of PMFM is mainly influenced by the fiber diameter, the average pore size and thickness of PMFM. In the paper, three stainless steel fibers with the diameters (∅) of 8, 12 and 20 µm were used to make PMFM with the average pore sizes of 10, 20, 30 and 40 µm and the thicknesses of 1, 2 and 3 mm by air-laid and sintering processes. The sound absorption coefficients of PMFM were tested in impedance tube using two-microphone transfer-function method according to ISO 10534-2 and ASTM E1050-98 international standards at room temperature. The results show that when the frequency ranges from 50 Hz to 6,400 Hz in material with the average pore size of 20 µm and the thickness of 3 mm and the fiber diameter of ∅8 µm, the average sound absorption coefficient is the highest.

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“…4 and 5, with increasing thickness, the rate of absorption coefficient grows both at low frequencies and at middle frequencies. A study by Wang et al on the absorption properties of metallic fibers showed that with increasing thickness, the absorption coefficient increased [27], due to the losses caused by frictional losses [6]. Therefore, the sound energy is attenuated.…”