Dynamic Responses and Energy Absorption of Mechanical Metamaterials Composed of Buckling Beams

Purpose: The rich dynamic responses and complex dissipation behaviors of metamaterials with different loading speeds and specific stiffness are investigated. To our knowledge, this work studies systematically for the first time the mutual interaction among these mechanical parameters. Methods: The metamaterials composed of PCBs (prefabricated curved beams) are modeled as a corresponding NDT (nonlinear damping tandem) model, where the PCB is depicted as a nonlinear spring, the structural mass is simplified as lumped mass, and the energy dissipation is described by equivalent viscous damping. Results: The external low-frequency/speed energy can be transformed into high-frequency vibrations via the fully elastic buckling of unstable elements and dissipated, distinguishing it from plastic dissipation. The dissipation process appears to be instantaneous under quasi-static conditions as well as dynamic loadings, which is in sharp contrast to the viscoelastic effect. Conclusion: The dynamic responses and dissipation behaviors depend crucially on the mutual interactions of loading speed and specific stiffness under dynamic loadings.