The scope of this paper is to investigate the sound transmission loss of a typical fuselage panel section, as well as to propose solutions based on the inclusion of a periodic pattern inside its foam core, which aim at passively improving the acoustic performance in a mid-high range of frequencies. In detail, a new fuselage panel configuration is numerically studied, starting from the state of the art regarding the acoustic packages based on porous meta-materials. The main novelties of the present work are represented by the application of a meta-core solution inside an acoustic package of aeronautical interest, as well as a systematic investigation of the effects deriving from its geometrical parameters. In order to reach this goal, a numerical model of a fuselage panel section is studied, and the effect of several periodic patterns are simulated; more specifically, twelve configurations are taken into account, each with different radius of the inclusions and number of unit cells along the thickness. For each of these layouts, the mass increase of the so-called meta-core, compared to that of its classical homogeneous counterpart, is estimated, together with the associated mid-band frequency and amplitude of the sound transmission loss peak, which is caused by the additional acoustic modes excited by the periodic nature of the meta-core itself. Results are presented in terms of tables and graphs, which may constitute a good basis in order to perform preliminary design considerations that could be interesting for further generalizations.

本文的范围是研究典型机身面板部分的声音传输损失，并基于在其泡沫芯内包含周期性模式提出解决方案，旨在被动地提高中间的声学性能。高频率范围。详细地，从基于多孔超材料的声学组件的现有技术开始，对新的机身面板配置进行了数值研究。目前工作的主要新颖之处在于元核心解决方案在航空学声学包内的应用，以及对其几何参数产生的影响的系统研究。为了达到这一目标，研究了机身面板截面的数值模型，并模拟了几种周期模式的效果；更具体地说，考虑了十二种配置，每种配置都具有不同的夹杂物半径和沿厚度方向的晶胞数量。对于这些布局中的每一个，与经典的同质对应物相比，所谓的元核心的质量增加，以及相关的中频带频率和声音传输损耗峰值的幅度被估计，这是引起的通过由元核心本身的周期性特性激发的额外声学模式。结果以表格和图形的形式呈现，这可以构成一个良好的基础，以便进行初步设计考虑，这对于进一步的概括可能很有趣。对于这些布局中的每一个，与经典的同质对应物相比，所谓的元核心的质量增加，以及相关的中频带频率和声音传输损耗峰值的幅度被估计，这是引起的通过由元核心本身的周期性特性激发的额外声学模式。结果以表格和图形的形式呈现，这可以构成一个良好的基础，以便进行初步设计考虑，这对于进一步的概括可能很有趣。对于这些布局中的每一个，与经典的同质对应物相比，所谓的元核心的质量增加，以及相关的中频带频率和声音传输损耗峰值的幅度被估计，这是引起的通过由元核心本身的周期性特性激发的额外声学模式。结果以表格和图形的形式呈现，这可以构成一个良好的基础，以便进行初步设计考虑，这对于进一步的概括可能很有趣。这是由元核心本身的周期性激发的额外声学模式引起的。结果以表格和图形的形式呈现，这可以构成一个良好的基础，以便进行初步设计考虑，这对于进一步的概括可能很有趣。这是由元核心本身的周期性激发的额外声学模式引起的。结果以表格和图形的形式呈现，这可以构成一个良好的基础，以便进行初步设计考虑，这对于进一步的概括可能很有趣。