In this paper, a micro-perforated panel (MPP) composite structure consisting of an inhomogeneous MPP (IMPP) backed with J-shaped cavities of different depths for low-frequency sound absorption is proposed. The goal is to increase the low-frequency (≤ 500 Hz) sound absorption performance of the IMPP. Sound absorption in a frequency range of 300–480 Hz was achieved with parallel-arranged IMPPs backed by J-shaped cavities, with average absorption of greater than 90%. A parametric analysis was used to optimize the structure's geometric parameters for the specified frequency range. The results show that when the length and volume of the back cavity depths increase, the low-frequency sound absorption peaks shift to a lower frequency. Similarly, the sound absorption curves are enhanced and move towards lower frequencies as the thickness of the IMPP increases. The structure was studied using an electro-acoustic equivalent circuit model (ECM) and finite element method (FEM) simulation. Model prototypes were then made using stereolithography (SLA) and verified by a square-shaped impedance tube-based experimental study to determine the normal absorption coefficient. The results revealed that the three types of curves, namely theoretical, FEM simulation, and experimental, were in good agreement.

在本文中，提出了一种微穿孔板（MPP）复合结构，该结构由不均匀的MPP（IMPP）背衬不同深度的J形空腔组成，用于低频吸声。目标是提高 IMPP 的低频（≤ 500 Hz）吸声性能。300-480 Hz 频率范围内的吸声是通过由 J 形腔支持的平行排列的 IMPP 实现的，平均吸声大于 90%。参数分析用于优化指定频率范围内的结构几何参数。结果表明，随着后腔深度的长度和体积的增加，低频吸声峰向低频移动。相似地，随着 IMPP 厚度的增加，吸声曲线会增强并向低频移动。使用电声等效电路模型 (ECM) 和有限元法 (FEM) 仿真研究了该结构。然后使用立体光刻 (SLA) 制作模型原型，并通过基于方形阻抗管的实验研究进行验证，以确定正常吸收系数。结果表明，三种类型的曲线，即理论曲线、有限元模拟曲线和实验曲线，具有良好的一致性。然后使用立体光刻 (SLA) 制作模型原型，并通过基于方形阻抗管的实验研究进行验证，以确定正常吸收系数。结果表明，三种类型的曲线，即理论曲线、有限元模拟曲线和实验曲线，具有良好的一致性。然后使用立体光刻 (SLA) 制作模型原型，并通过基于方形阻抗管的实验研究进行验证，以确定正常吸收系数。结果表明，三种类型的曲线，即理论曲线、有限元模拟曲线和实验曲线，具有良好的一致性。