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Sandwich-Structured Woodpile Metamaterials for Impact Mitigation

The objective of this study was to investigate 3D woodpile metamaterials for mitigating impact-induced vibrations by leveraging their local resonant and nonlinear contact characteristics. For experimental demonstrations, we designed, fabricated and tested prototypes of sandwich-structured woodpile metamaterials consisting of two plates, slender cylindrical rods and fasteners. We experimentally and numerically obtained impact responses of sandwich-structured woodpile metamaterials under various geometries and boundary conditions. We found that sandwich-structured woodpile metamaterials could efficiently manipulate and attenuate the impact vibrations due to their local bending motions and nonlinear contact between members. In addition, sandwich-structured woodpile metamaterials could have high damping as well as high stiffness by controlling the rod spacing. The findings from this study suggest sandwich-structured woodpile metamaterials can be used as structural components for impact-induced vibration mitigation.