Abstract—

The concept of phononic crystals is employed to improve vibroacoustic properties of truss core sandwich beams. A typical sandwich beam exhibits a flexural wave bandgap, as well as significant vibration attenuation, from 968 to 2132 Hz without adding any structure. Therefore it has big advantages of easy manufacturing and lightweight over sandwich beams with local resonators, which include complex structures and additional weight. In addition, through developing simplified model, the analytic expressions are obtained to determine bandgap edges. The results show bandgap structure can be engineered by adjusting the geometrical dimensions of the unit cell. The fundamental origin of the bandgap is Bragg scattering of the local flexural wave, which results from metastructure of the sandwich beam. Benefiting from the low stiffness face sheets and mechanism of Bragg scattering, the structure owns a bandgap with low frequency and broad width at the same time. Hence the truss core sandwich structure has great potential in engineering practice to reduce the sound and vibration transmission.

中文翻译：

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桁架芯夹心梁中的宽带和低频带隙

摘要-

声子晶体的概念被用来改善桁架芯夹层梁的振动声学特性。典型的夹层梁在不添加任何结构的情况下，从 968 到 2132 Hz 具有弯曲波带隙以及显着的振动衰减。因此，与具有复杂结构和额外重量的带有局部谐振器的夹层梁相比，它具有易于制造和重量轻的巨大优势。此外，通过建立简化模型，得到解析表达式以确定带隙边缘。结果表明，可以通过调整晶胞的几何尺寸来设计带隙结构。带隙的基本起源是局部弯曲波的布拉格散射，这是由夹心梁的元结构引起的。受益于低刚度面板和布拉格散射机制，该结构同时具有低频和宽宽度的带隙。因此，桁架芯夹层结构在工程实践中具有降低声、振传递的巨大潜力。