Optimization of Band Gap of 1D Elastic Metamaterial Under Impact Load by Regulating Stiffness

Designing materials that mitigate impacts effectively are crucial for protecting people and structures. Here, a single-resonator metamaterial with negative mass characteristics is proposed for impact mitigation, and numerical analysis of wave propagation shows explicitly how the spring stiffness and number of unit cells influence that mitigation. The results show clearly that a metamaterial with differing microstructural stiffness is better at mitigating the effect of a shock wave than one with a unique stiffness. Also, there is a critical number of unit cells beyond which the shock wave is not attenuated further, but the fabrication complexity increases. In the 40 groups of microstructural regions in this example, the attenuation effect no longer increases when there are more than 35 groups. This work offers guidance for microstructure designs in metamaterials and provides new ideas for using metamaterials to mitigate shock waves.