Abstract

There have been some previous studies on the acoustic properties of metal foams, with the main relevant works focused on the aluminum foam, but quite fewer on the metal foams of non-aluminum species. Such research, especially, has not yet been found on the stainless steel foam, of which the pore-structure related parameters and the morphology are quite different from the aluminum foam. The present work provides the investigations on the sound absorption performance of the 304 stainless steel foam and its composite structure. A sort of three-dimensional reticular stainless steel foam was successfully prepared, with the average pore size of about 1.8 mm and the porosity of about 93.7%. The sound absorption performance was investigated at 200–6300 Hz for this foam and at 2500–4000 Hz for its composite structures. The results show the whole absorption performance of the sample can be significantly improved by introducing an air gap, and further improved with introduction of both the gap and a perforated plate. It was found that when the thickness of the gap increased (from 3.5 to 17.5 mm), the resultant change of the resonance frequency of the sample could lead to a decrease of the absorption coefficient at a certain frequency range, and the total absorption efficiency could be significantly increased.

Graphic Abstract

中文翻译：

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网状结构的高多孔性不锈钢泡沫的吸声性能

摘要

以前已经有一些关于金属泡沫的声学特性的研究，主要的相关工作集中在铝泡沫上，而很少涉及非铝类金属泡沫。尤其是尚未对不锈钢泡沫进行这样的研究，其与孔结构相关的参数和形态与铝泡沫完全不同。本工作对304不锈钢泡沫及其复合结构的吸声性能进行了研究。成功地制备了一种三维网状不锈钢泡沫，其平均孔径约为1.8mm，孔隙率约为93.7％。研究了这种泡沫在200–6300 Hz以及复合结构在2500–4000 Hz的吸声性能。结果表明，通过引入空气间隙可以显着改善样品的整体吸收性能，并且通过引入间隙和多孔板可以进一步改善样品的整体吸收性能。结果发现，当间隙的厚度增加（从3.5到17.5 mm）时，样品共振频率的变化会导致在一定频率范围内吸收系数的降低，总吸收效率会降低。显着增加。

图形摘要