管道超结构轴向带隙特性分析及实验研究

本文提出一种新型管道超结构元胞构型，其轴向振动带隙包括局域共振型和布拉格(Bragg)散射型两种带隙，该结构在2 500 Hz内共有两阶带隙，且第二阶带隙频率范围较宽。分别应用传递矩阵法和有限元法计算了该结构的能带结构分布及有限周期结构传输特性；搭建了包含4个元胞的管道超结构实验平台进行振动测试，并与计算结果进行对比验证；最后讨论了不同参数对其带隙分布的影响规律。结果表明，所研究管道超结构在2 500 Hz内共有两阶带隙，第一阶带隙主要为局域共振型带隙，凸台和振子的几何尺寸对其影响较大，元胞尺寸对其影响较小。第二阶带隙主要为布拉格散射型带隙，带隙宽度可达923 Hz,该带隙分布随元胞长度、凸台长度和振子厚度改变而改变。合理设计结构各部分几何尺寸，可满足工程中特定频段抑振的需求。

Numerical and Experimental Study on Axial Band Gap Characteristics of Pipeline Metastructure

In this paper, a new type of pipeline metastructure is proposed. Its axial vibration band gaps include both local resonance and Bragg scattering. The structure has two order band gap within 2 500 Hz, and the frequency range of the second order band gap is wide. The energy band structure distribution and finite-period structure transmission characteristics of the structure were calculated by the transfer matrix method and the finite element method respectively. A pipeline metastructure experimental platform with 4 cells was built to test the vibration, and the test data were compared with the calculation results. Finally, the influences of different parameters on the band gap distribution are discussed. The results show that there are two band gaps in the studied pipe metastructure within 2 500 Hz. The first order band gap is mainly local resonant band gap, which is greatly affected by the geometric dimensions of the boss and the vibrator, but less affected by the cell size. The second order band gap is mainly Bragg scattering band gap, and the width of which could reach 923 Hz. The band gap distribution varies with the cell length, boss length and oscillator thickness. The reasonable design of the geometric dimensions of each part of the structure can meet the needs of vibration suppression in specific frequency bands in the project.