可控超结构复合带隙特性研究

Study on the complex band gap characteristic of controllable metastructure

  • 摘要: 可控超结构可根据目标需求调节结构的带隙特性,实现对不同工况下结构减振的可控调节,在航空航天、轨道交通等工程领域具有广泛的应用前景。本文提出一种新型可控超结构构型,可同时产生局域共振和布拉格散射两种带隙,通过施加位移可实现对带隙的有效调控。应用COMSOL软件建立了该结构的有限元模型,研究了4种可控超结构构型的能带分布及其在外加位移激励作用下的带隙特性调控规律,开展了该结构的振动传输特性实验,并与数值结果进行对比验证。研究结果表明,四振子复合带隙可控超结构在0~800 Hz范围内共有3条完全带隙,第一阶带隙范围低至134.48~287.53 Hz,第二阶带隙范围为307.26~447.81 Hz,第三阶带隙范围为662.44~679.43 Hz。对比分析4种元胞构型带隙特性,在一定频率范围内,随着振子数量增加,带隙数量减少,带宽增加,带隙位置逐渐上移;施加结构位移可有效调控结构带隙,随着位移值增加,结构中低频局域共振带隙变化较小,布拉格带隙中心频率逐渐上移,并出现新带隙。本研究表明该结构在带隙范围内具有良好的减振特性。结果表明所设计的复合带隙可控超结构可实现对复合带隙的调控,为超结构减振设计研究提供有益的参考。

     

    Abstract: The controllable metastructure can adjust the band gap characteristic of the structure according to the target requirements, and realize the controllable adjustment of structural vibration reduction under different working conditions. It has a wide application prospect in aerospace, rail transit and other engineering fields. A new controllable metastructure configuration was proposed, which can simultaneously generate two kinds of band gaps, local resonance and Bragg scattering. The band gap can be effectively controlled by applying displacement. The finite element model of the structure was established by COMSOL software. The energy band distribution of four controllable metastructure configurations and the regulation of band gap characteristics under external displacement excitation were studied. The vibration transmission characteristics of the structure were tested and compared with the numerical results. The results show that the four-oscillator composite band gap controllable metastructure has three complete band gaps in the range of 0-800 Hz. The first-order band gap range is as low as 134.48-287.53 Hz, the second-order band gap range is 307.26-447.81 Hz, and the third-order band gap range is 662.44-679.43 Hz. The band gap characteristics of four cell configurations were compared and analyzed. In a certain frequency range, as the number of oscillators increases, the number of band gaps decreases, the bandwidth increases, and the band gap position gradually moves up. The application of structural displacement can effectively control the structural band gap. As the displacement value increases, the low-frequency local resonance band gap in the structure changes little, and the center frequency of the Bragg band gap gradually moves up, and a new band gap appears. This study shows that the structure has good vibration reduction characteristics in the band gap range. The results show that the designed composite band gap controllable metastructure can realize the regulation of the composite band gap, which provides a useful reference for the research of metastructure vibration reduction design.

     

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