Energy Absorption of Hourglass Shaped Lattice Metastructures

Background: The architected mechanical metastructures have garnered significant research attention for various engineering applications due to their remarkable mechanical properties and unique deformation behavior. The lattice-based micro-structured materials have shown enhanced mechanical properties and the ability to control wave propagation, making them ideal for multifunctional applications. Objective: We report the family of lattice-based hourglass metastructures within the optimal design scope and its geometrical parameter selection. The lattice-based energy absorption performance and their damping characteristics have been classified based on different constitutive lattices. Methods: Herein, the uniaxial compressive response and lattice-based energy absorption capacity of a novel hybrid configuration, hourglass-shaped, consists of auxetic and honeycomb-based lattice, are systematically investigated through theoretical, finite element simulation and experimental methods. The proposed hourglass-shaped unit cell is a combination of two oppositely oriented coaxial domes that give more flexibility to control dynamic response and enhance lattice functionality passively. An additive manufacturing route has fabricated a series of hourglass-shaped lattice metastructures with nylon-based material. Results: It was found from the experimental data that the Ideal energy absorption efficiency parameter (E _i) is highest for the case of the auxetic-based hourglass with the increment of 22% and 35% than the solid shell and honeycomb lattice-based metastructure, respectively. The specific energy absorption parameters data have also been evaluated and compared with the numerical computational results. Conclusion: The combination of numerical simulation, additive layer manufacturing (3D printing), and experimental testing are implemented to quantitatively determine the lattice-based energy absorption properties and justify their evaluation. This study suggests the utilization of novel hourglass lattice-based metastructure for multifunctional engineering applications.