Investigation of novel 3D-printed diatomic and local resonant metamaterials with impact mitigation capacity

Abstract

A novel dual local resonance metamaterial chain, at a low frequency regime (<200 Hz), is designed and fabricated using selective laser sintering technology for characterization of wave attenuation and impact mitigation, consisting of a main structure and cantilever-in-mass resonators as a periodic sub-structure. The dispersion characteristics and mode polarization of metamaterial chains with various resonators are studied using a mass-spring model and finite element modelling simulation. The results clearly demonstrate the bandgap of the dual resonance system is extended by both the local resonance and diatomic resonance mechanisms. A parametric study is established to optimize the bandgap ratio, revealing that the bandgap of the design can be shifted by changing the stiffness ratio between two resonators in the sub-structure. The wave attenuation in the frequency domain obtained from impact modal tests exhibits a good agreement with computational results. In particular, the dynamic load attenuation capacities of the metamaterial chains under different impact durations are studied using impact mitigation tests, which show that the dual resonance design has the best attenuation performance under impact force, where the transmission rate is driven down to 0.2, compared with 0.48 for the design without resonators.