分形凹角蜂窝结构声子晶体振动带隙特性

凹角结构具有优良的减振降噪特性,可以有效衰减结构振动响应,蜂窝结构具有优良的力学特性并已经较为普遍地被应用到工程之中,因此凹角蜂窝的复合结构引起了学者们的关注。本文通过对内凹蜂窝结构分形设计,构建了一种新型声子晶体模型。基于有限元方法对分形凹角蜂窝结构进行分析,计算能带结构以及振动传输特性,分析结构的负泊松比特性以及结构分形对振动带隙的影响。通过改变壁厚和内凹角度等参数,以及在分形结构顶点处填充钢材,可以更好地对某些频段振动产生抑制。结果表明:分形结构仍具有负泊松比特性,分形结构在二阶结构产生的带隙更宽,壁厚和凹角角度的增加会导致结构振动带隙向高频区域转移,填充钢材会使带隙变宽。

Vibration Bandgap Characteristics of Phononic Crystals with Fractal Concave Angle Honeycomb Structure

The concave corner structure has excellent vibration and noise reduction characteristics to effectively attenuate the structural vibration response, honeycomb structure with excellent mechanical properties has been more commonly used in engineering, so the composite structure of concave corner honeycomb has attracted the attention of scholars. A novel phononic crystal model was created using the inner concave honeycomb structure's fractal design. Based on the finite element method, the fractal concave angle honeycomb structure was analyzed to calculate the energy band structure and vibration transmission characteristics, as well as to examine the negative Poisson ratio characteristics of the structure and the effect of the structural fractal on the vibration band gap. By varying parameters such as wall thickness and the angle of the inner concavity, filling the steel at the apex of the fractal structure can provide better suppression of certain frequency bands of vibration. The results show that the fractal structure still has negative Poisson ratio characteristics, the fractal structure produces a wider band gap in the second-order structure, the increase in wall thickness and concave angle causes the structural vibration band gap to shift to the high-frequency region, the filled steel causes the band gap to widen.