Chen Chen, Lei Jincheng, Liu Zishun
International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Materials (Basel). 2022 Feb 8;15(3):1246. doi: 10.3390/ma15031246.
Structural vibration induced by low frequency elastic waves presents a great threat to infrastructure such as buildings, bridges, and nuclear structures. In order to reduce the damage of low frequency structural vibration, researchers proposed the structure of seismic metamaterial, which can be used to block the propagation of low frequency elastic wave by adjusting the frequency range of elastic wave propagation. In this study, based on the concept of phononic crystal, a ternary seismic metamaterial is proposed to attenuate low frequency vibration by generating band gaps. The proposed metamaterial structure is periodically arranged by cube units, which consist of rubber coating, steel scatter, and soft matrix (like soil). The finite element analysis shows that the proposed metamaterial structure has a low frequency band gap with 8.5 Hz bandwidth in the range of 0-20 Hz, which demonstrates that the metamaterial can block the elastic waves propagation in a fairly wide frequency range within 0-20 Hz. The frequency response analysis demonstrates that the proposed metamaterial can effectively attenuate the low frequency vibration. A simplified equivalent mass-spring model is further proposed to analyze the band gap range which agrees well with the finite element results. This model provides a more convenient method to calculate the band gap range. Combining the proposed equivalent mass-spring model with finite element analysis, the effect of material parameters and geometric parameters on the band gap characteristic is investigated. This study can provide new insights for low frequency vibration attenuation.
低频弹性波引起的结构振动对建筑物、桥梁和核结构等基础设施构成了巨大威胁。为了减少低频结构振动的破坏，研究人员提出了地震超材料结构，它可以通过调整弹性波传播的频率范围来阻止低频弹性波的传播。在本研究中，基于声子晶体的概念，提出了一种三元地震超材料，通过产生带隙来衰减低频振动。所提出的超材料结构由立方单元周期性排列而成，这些立方单元由橡胶涂层、钢散射体和软基体（如土壤）组成。有限元分析表明，所提出的超材料结构在0-20Hz范围内有一个带宽为8.5Hz的低频带隙，这表明该超材料可以在0-20Hz的相当宽的频率范围内阻止弹性波的传播。频率响应分析表明，所提出的超材料可以有效地衰减低频振动。进一步提出了一个简化等效质量-弹簧模型来分析带隙范围，该模型与有限元结果吻合良好。该模型为计算带隙范围提供了一种更方便的方法。将所提出的等效质量-弹簧模型与有限元分析相结合，研究了材料参数和几何参数对带隙特性的影响。本研究可为低频振动衰减提供新的见解。
