Abstract Many different solutions exist to improve the low-frequency sound absorption performance of acoustic resonators, extending or coiling up space into the resonator being some of the most widespread. In this context, modern additive manufacturing processes pose a new scenario in which these devices can be engineered to yield outstanding acoustic properties. In a recent work by the authors, a solution consisting of a perforated panel with oblique perforations was analyzed, results showing an enhanced sound absorption performance when compared to traditional perforated panel absorbers. This technical note aims to show the potential of these panels when used in multi-layer arrangements both to widen their effective sound absorption bandwidth and to improve their low-frequency performance. A simplified approach that relies on the fluid-equivalent theory was used together with the Transfer Matrix Method (TMM) to analyse different configurations, prediction results showing a good agreement when compared to experiments in an impedance tube over additive manufactured samples. Unlike other perforated-based solutions, the proposed system avoids addressing the cavity design while showing improved sound absorption features.

中文翻译：

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带斜穿孔的多层穿孔板吸收器

摘要 存在许多不同的解决方案来提高声学谐振器的低频吸声性能，其中最普遍的是将空间扩展或盘绕到谐振器中。在这种情况下，现代增材制造工艺提出了一种新方案，在该方案中，可以对这些设备进行设计以产生出色的声学特性。在作者最近的一项工作中，分析了一种由带有斜穿孔的穿孔板组成的解决方案，结果表明，与传统的穿孔板吸声器相比，吸声性能有所提高。本技术说明旨在展示这些面板在用于多层布置时的潜力，以扩大其有效吸声带宽并改善其低频性能。依赖于流体当量理论的简化方法与传递矩阵方法 (TMM) 一起使用来分析不同的配置，与阻抗管中的增材制造样品的实验相比，预测结果显示出良好的一致性。与其他基于穿孔的解决方案不同，所提出的系统避免了解决空腔设计问题，同时显示出改进的吸声特性。