A multi-dimensional quasi-zero-stiffness mechanical metamaterial with different directional vibration isolation capabilities

To address the issue that traditional structures might inhibit the propagation of elastic waves only in one direction, a multi-dimensional (MD) quasi-zero-stiffness (QZS) mechanical metamaterial with multi-directional vibration isolation capability is proposed in this paper. The quasi-static mechanical properties and bandgap characteristics of the structure are investigated by a combination of simulation and experiment, revealing the influence of different cell numbers and frame thicknesses on the elastic wave propagation characteristics. Meanwhile, the vibration isolation performance of metamaterials with different material damping is explored by Rayleigh damping. The results demonstrate that the MD-QZS metamaterials proposed in this paper have excellent low-frequency attenuation ability for elastic waves in multi-directions, and the proportion of the bandgap under different loading directions within 0-200 Hz is about 60%-70%, offering an outstanding low-frequency broadband vibration isolation capability. In addition, each bandgap is almost constant with the number of unit cells, but the starting frequency would increase progressively as the frame thickness increasing. Meanwhile, the low-frequency vibration isolation performance of the metamaterial could be further enhanced by selecting the material with suitable damping. The MD-QZS mechanical metamaterials presented in this paper could provide a reference in the field of multi-functional structural design and supply a novel solution to the problem of multi-directional vibration isolation.