In this paper, a thin meta-structure with several detuned multi-order micro-perforated panels with backing cavity (MPPB) for sound absorption is proposed, aiming to obtain broadband underwater sound absorption at low frequency. The MPPBs are designed with the method that inserting several micro-perforated panels into the origin backing cavity. In doing so, more sound absorption peaks can be obtained at higher frequencies, while the total thickness of the structure and the origin sound absorption peak are almost unchanged. The mechanism of multi-order resonance is analyzed in detail based on the electro-acoustic analogy and verified by the finite element simulation (FEA). Furthermore, the specific relationship between sound absorption performances and key parameters of MPPBs are investigated thoroughly. On this basis, by precisely adjusting the parameters of MPPBs and making them in a parallel arrangement, an 11-unit meta-structure with a thickness of only 75 mm is achieved, in which the maximum absorption coefficient of almost 100% and average absorption coefficient of 80% at 1380–3150 Hz.

在本文中，一个薄的元为了获得低频水下宽带吸声，提出了一种具有多个带有背衬腔（MPPB）的失谐多阶微孔板的结构。MPPB的设计方法是将几个微穿孔的面板插入原始背衬腔中。这样做，可以在更高的频率上获得更多的吸声峰，而结构的总厚度和原始吸声峰几乎不变。基于电声模拟，详细分析了多级共振的机理，并通过有限元模拟（FEA）进行了验证。此外，对MPPB的吸声性能与关键参数之间的具体关系进行了深入研究。在此基础上，元厚度的只75毫米-结构实现，其中的几乎100％的最大吸收系数，并在1380-3150赫兹的80％的平均吸收系数。