Impact mitigation performance of hybrid metamaterial with a low frequency bandgap

Abstract Elastic metamaterials exhibit a significant potential in wave attenuation and impact mitigation application owing to their unusual dynamic performance. This work is aimed at investigating the properties and impact mitigation performance of a novel hybrid metamaterial (HMM) fabricated using 3D printing based on a selective laser sintering (SLS) technology. This HMM consists of periodic mass inclusions integrated with a conventional reentrant frame, producing a local resonance mechanism and negative Poisson's ratio properties. Dispersion characteristics and vibration modes are numerically demonstrated, and the results indicate three wide bandgaps in low frequency ranges induced by the local resonance mechanism. The wave attenuation capacity of the HMM is explored numerically and experimentally, and it proves that the bandgap of the HMM can be flexibly tailored by adjusting geometrical configuations of HMM. A comprehensive comparison between the wave mitigation capacity of HMM and the base reentrant structure is established computationally under different modulated unit impact pulses. When the bandgap overlap ratio is 42.5%, HMM can reduce the transmitted peak force by a factor of 2.17 and the root mean square (RMS) value of the reaction force by a factor of 1.59, highlighting the role of bandgap overlap ratio in enhancing the impact mitigation performance of HMM. Furthermore, an impact test indicates that the HMM shows an approximately 22.6% better mitigation performance under the same impact energy than that of a conventional reentrant structure. These results confirm the potential application of the proposed hybrid metamaterial in impact mitigation and noise control.