Mechanical metamaterials with tunable bandgaps are promising solutions for wave control and vibration mitigation under various frequency scales. For the metamaterials consisting of tensegrities, their bandgaps are currently regulated through the prestresses or loads. In this Letter, we propose a novel and powerful approach to tune the bandgap characteristics of tensegrity metamaterials by introducing structural defects. The metamaterial is constructed using truncated regular octahedral tensegrities (TROTs) and circular plates as elementary cells. An analytical model is established for evaluating the effective stiffness of TROT under uniaxial loads. Using both Bloch theorem-based simulations and frequency response tests, we show that the proposed chain without defects can hold a bandgap. Interestingly, we find that the introduction of structural defects leads to several flat branches within the bandgap, namely defect states. These defect states are localized and determined by the damage degree of cells and total number of damaged cells. The tensegrity metamaterials with designed defect states are expected to hold a variety of applications, for instance, in the fields of exploiting advanced isolators and novel filters.

带隙可调的机械超材料是在各种频率范围内用于波控制和减振的有前途的解决方案。对于由张力组成的超材料，其带隙目前通过预应力或载荷进行调节。在这封信中，我们提出了一种新颖而强大的方法，通过引入结构缺陷来调整张力超材料的带隙特性。使用截断的规则八面体张力（TROT）和圆形板作为基本单元构造超材料。建立了用于评估TROT在单轴载荷下的有效刚度的分析模型。使用基于Bloch定理的仿真和频率响应测试，我们表明所提出的无缺陷链可以保持带隙。有趣的是缺陷状态。这些缺陷状态是局部的，并由细胞的损伤程度和受损细胞的总数决定。具有设计缺陷状态的张力超材料有望在例如先进隔离器和新型过滤器的开发领域中拥有多种应用。