一种新型二维三组元水泥基拟声子晶体复合材料的低频带隙特性与应用

Low frequency bandgap characteristics and application of a novel two-dimensional three-component cement-based phononic-like crystal composite material

为了拓宽混凝土超材料的弹性波带隙宽度和数量,本文基于局域共振理论设计了一种新型二维三组元水泥基拟声子晶体。首先,采用有限元方法计算和研究了该新型二维三组元水泥基拟声子晶体的能带结构、振动模态、位移场和衰减特性。其次,分析了带隙形成机制和影响因素,并根据质量-弹簧系统模型推导了带隙范围的理论估计式。最后,将该水泥基拟声子晶体应用到地铁道床上,分析了水泥基拟声子晶体地铁道床的减振性能。结果表明:该新型二维三组元水泥基拟声子晶体在200 Hz频段内打开了5条低频带隙,在带隙频率范围内,衰减值大多都在10 dB以上,衰减效果较好;带隙的打开与各原胞的振动特征呈现出对应关系,因特定原胞的平移振动触发,由特定原胞与基体的耦合作用的强度所控制;散射体材料的密度、包裹层材料的弹性模量及厚度是影响其带隙的主要因素;由新型二维三组元水泥基拟声子晶体组成的水泥基拟声子晶体地铁道床在1~200 Hz频段内的振动加速度均小于普通混凝土地铁道床,最大插入损失为10.22 dB,插入损失平均值为8.76 dB,具有显著的减振性能。

In order to widen the width and number of elastic bandgap of concrete metamaterials,a novel twodimensional three-component cement-based phononic-like crystal was designed based on local resonance theory.Firstly,the finite element method was used to calculate and study the energy band structure,vibration mode,displacement field and attenuation characteristics of the novel two-dimensional three-component cement-based phononic-like crystal.Secondly,the formation mechanism and influencing factors of the bandgap were analyzed,and the theoretical estimation of the bandgap range was derived according to the mass-spring system model.Finally,the cement-based phononic-like crystal was applied to the subway track bed,and the vibration reduction performance of the cement-based phononic-like crystal subway track bed was analyzed.The results show that the novel two-dimensional three-component cement-based phononic-like crystal opens 5 low-frequency bandgaps in the 200 Hz frequency range,and the attenuation values are mostly above 10 dB within the bandgap frequency range,and the attenuation effect is good.The opening of the bandgap corresponds to the vibration characteristics of each primitive cell,which is triggered by the translational vibration of a specific primitive cell and controlled by the strength of the coupling between the specific primitive cell and the matrix.The density of scatterer material,elastic modulus and thickness of cladding material are the main factors affecting the bandgap.In the 1-200 Hz frequency band,the vibration acceleration of the cement-based phononic-like crystal subway track bed composed of the novel two-dimensional three-component cement-based phononic-like crystal is lower than that of the ordinary concrete subway track bed,and the maximum insertion loss is 10.22 dB and the average insertion loss is 8.76 dB,which has remarkable vibration reduction performance.