<p>Elastic metamaterials are architected structures that have constitutive properties not commonly found in nature. By tailoring such properties, elastic metamaterials have the ability of mitigating elastic waves generated by, for instance, impact waves. The first models of elastic metamaterials for impact wave attenuation were based on the concept of negative effective mass density. Such unique property was obtained by mass-spring dissipative systems containing one or more internal resonators. The stop band frequency obtained in such systems depends on the number of resonators involved in the design. Several researches have reported high performance of mass-spring dissipative systems for attenuation of impact waves. However, their fabrication is still a complex issue, because of the internal geometry and the use of different materials. Furthermore, the band gap produced by the mass-spring system corresponds to a narrow range of frequencies, which requires adding more internal resonators to increase the bandwidth limitation.</p><p>This work proposes an elastic metamaterial for absorbing energy from impact waves. The mechanism behind such design is equivalent to a mass-spring dissipative system. However, instead of using multiple materials representing each component, we design a structure made of a single material. Such structure is composed by internal structures whose geometric parameters are chosen to perform the same functionality of the mass-spring system. The stop band average frequency is defined by geometric parameters, which allows tailoring the metamaterial for different applications. Finite Element Analysis is performed to obtain the band structure and the transmissibility of the elastic metamaterial as a function of the geometric parameters. A series of numerical simulations is conducted to evaluate the impact wave mitigation behavior. The proposed metamaterial is verified by comparing its outcomes with those obtained by the equivalent mass-spring system. The findings of this work contribute to increasing the performance of protective structures in reducing the effect of impact waves.</p>

Single Phased Elastic Metamaterials for Wave Filtering

Paper Proceedings: https://asmedigitalcollection.asme.org/SMASIS/SMASIS2021/volume/85499

ASME 2021 Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS2021)

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