Metamaterials are artificially structured materials that enable wave attenuation in band gaps. However, opening an ultralow-frequency band gap is still a challenge, since it is hard to realize near-zero stiffness in a traditional way. In this paper, a one-dimensional tunable quasi-zero-stiffness (QZS) metamaterial is engineered for ultralow-frequency (about a few tens Hertz) wave attenuation. Design optimization on the configuration of this new metamaterial is conducted to achieve quasi-zero stiffness. The dispersion relation is derived theoretically based on a lumped diatomic chain model, and then the band structure is revealed. The characteristics of longitudinal wave propagation in the metamaterial are studied by both numerical analyses and FE simulations, which are also validated by experimental tests. The results indicate that the stiffness is deformation-related, and the band gap can be tuned substantially by just changing the pre-compression. Therefore, the quasi-zero stiffness and then the ultralow-frequency band gap can be fulfilled by pre-compressing the metamaterial properly.

超材料是人工结构化的材料，可以使带隙中的波衰减。然而，由于难以以传统方式实现接近零的刚度，因此打开超低频带隙仍然是挑战。在本文中，设计了一种一维可调谐准零刚度（QZS）超材料，用于超低频（约几十赫兹）的波衰减。对该新型超材料的配置进行了设计优化，以实现准零刚度。根据集总双原子链模型从理论上推导色散关系，然后揭示能带结构。通过数值分析和有限元模拟研究了超材料中纵向波传播的特性，并通过实验测试对其进行了验证。结果表明，刚度与变形有关，并且仅通过改变预压缩即可基本上调整带隙。因此，可以通过适当地预压缩超材料来实现准零刚度，然后实现超低频带隙。