Analysis of the Influence of Initial Stress on the Bandgap Characteristics of Configuration-Controllable Metamaterials

Configuration-controllable metamaterials are a kind of metamaterials whose bandgaps can be effectively adjusted through configuration control, but the configuration changes also produce initial stress. In this paper, the distribution of the initial stress of the configuration-controllable metamaterial under axial displacement and the influence of initial stress on the band gap characteristics of the structure were analyzed using numerical and experimental methods. The results show that initial stress has a significant influence on the bandgap characteristics, and the position and width of the bandgap change with the magnitude of the initial stress. The bandgap distribution of the structure after considering the initial stress is more consistent with the reported experimental results. The influence of initial stress on bandgap cannot be ignored. When the compressive loading displacement is 10 mm, the frequency range of the first bandgap is 262 Hz–310 Hz and that of the second bandgap is 394 Hz–405 Hz. And the frequency range of the first and second bandgaps will be converted into 254 Hz–291 Hz and 391 Hz–400 Hz when considering initial stress. The initial stress generated by compression deformation reduces the frequency of the structural bandgap. The beginning and ending frequencies of the first bandgap will move toward low frequencies, and the first bandgap will close when the compression displacement reaches 30 mm. The initial stress generated by tensile deformation increases the frequency of the structural bandgap. The beginning and ending frequencies of the first bandgap move toward high frequencies, and the bandgap will close when the tensile displacement is 30 mm.