珍珠层复合堆叠材料中弹性波传播特性研究

Propagation properties of elastic waves in a stacking composite material like nacre

通过建立珍珠层复合堆叠材料的拉伸剪切链模型和二维有限元模型,利用多重多级子结构方法研究声子晶体材料带隙特性。结果表明,珍珠层材料是一种具有较低及较宽一阶带隙且多个高频平直带的Bragg型声子晶体,这意味着此材料会导致非常宽的频率衰减区出现,并且其结构与带隙产生机理均不同于局域共振型声子晶体,所以不会出现类Fano干涉现象,更利于实现低频减振的目的。传输特性计算验证了多重多级子结构带隙计算结果的正确性和有效性。进一步研究表明带隙特性主要取决于硬材料("Brick")的密度以及软材料("Mortar")的弹性模量,珍珠层材料的一阶带隙受到这两个材料参数的耦合作用,适当匹配两种材料参数值可以获得更大的相对带隙,也可以进行带隙调控,为设计新型减振隔振材料提供指导。

A tension-shear chain model and a 2D finite element model of nacre,a kind of stacking composite material,were built up,and its band gap was computed based on a multi-level substructure scheme.The results showed that the nacre-like material is a kind of Bragg phononic crystal holding a relatively wide first order band gap in a lower frequency domain and several flat bands in a higher frequency domain,so this kind of material can lead to the vibration reduction in a wide frequency range;moreover,this kind of material is more efficient to realize the goal of vibration reduction at low frequencies,because it doesn＆#39;t have Fano-like interference phenomena,they happen in local areas resonant phononic crystals for the mechanism of their band gaps.Furthermore,the transmission characteristics were computed to verify the results of band gap.The further study demonstrated that band gap characteristics are mainly influenced by the density of the hard mineral component （“Brick”） and the elastic modulus of the soft component （“Mortar”）,the first order band gap of nacre-like material subjects to the coupling influence of the two material parameters;an appropriate match of the two material parameters can gain a larger relative band gap,the band gap is adjustable as well.The nacre-like material provided a guide for the design of new vibration reduction materials.