地震能量的传播主要通过弹性波发生。如果输入结构的地震力可以从源头直接减小,然后可以保护结构免受地震波能量的影响。地震超材料,被认为是具有不同于传统材料性质的周期性结构,利用波的传播特性和带隙来耗散地震波的能量。当地震波位于带隙中时,有效地减少了地震波能量的传播,保护结构免受地震扰动造成的破坏。在实际应用中,定位低于10Hz的地震频率是地震超材料的挑战。在常用的方法中,采用高质量的材料来诱导局部共振的效果,这在经济上是不可行的。在这项研究中,提出了一种使用拉胀几何的轻量化设计,以促进抗震超材料的实际可行性。通过将常规地震超材料与拉胀几何形状的超材料进行比较,可以证明这种设计的好处。使用拉胀几何形状定义不同的几何参数,以确定具有最佳带隙性能的结构。进行了有限元模拟,以评估拉胀地震超材料在时域和频域中的减振效果。此外,单元结构的质量和刚度之间的关系是从一维周期结构的解析解得出的,验证了拉胀超材料的模态分析结果。这项研究提供了轻质的地震超材料,体积小,并具有低频带隙的实际应用。
The propagation of earthquake energy occurs primarily through elastic waves. If the seismic force input to a structure can be directly reduced from the source, then the structure can be protected from seismic wave energy. Seismic metamaterials, regarded as periodic structures with properties different from conventional materials, use wave propagation characteristics and bandgaps to dissipate seismic wave energy. When the seismic wave is located in the bandgap, the transmission of seismic wave energy is effectively reduced, which protects the structure from the damage caused by seismic disturbance. In practical application, locating seismic frequencies below ten Hz is a challenge for seismic metamaterials. In the commonly used method, high-mass materials are employed to induce the effect of local resonance, which is not economically feasible. In this study, a lightweight design using
auxetic geometry is proposed to facilitate the practical feasibility of seismic metamaterials. The benefits of this design are proven by comparing conventional seismic metamaterials with metamaterials of
auxetic geometry. Different geometric parameters are defined using
auxetic geometry to determine the structure with the best bandgap performance. Finite element simulations are conducted to evaluate the vibration reduction benefits of
auxetic seismic metamaterials in time and frequency domains. Additionally, the relationship between the mass and stiffness of the unit structure is derived from the analytical solution of one-dimensional periodic structures, and modal analysis results of
auxetic metamaterials are verified. This study provides seismic metamaterials that are lightweight, small in volume, and possess low-frequency bandgaps for practical applications.