Mechanical design and energy absorption performances of rational gradient lattice metamaterials

In this study, geometrically gradient lattice structures with controllable deformation features and adjustable mechanical properties were proposed, and comparisons between experiments and simulations were performed for demonstrating their promising mechanical application potentials. Firstly, three types of unit cells with same relative density were obtained by scaling at different times, and assembled layer by layer for generating final graded architected metamaterials. Afterwards, quasi-static compression experiments and finite element simulations were performed for studying the deformation mechanisms and mechanical responses of as-fabricated graded lattice metamaterials. Effect of gradient design schemes, neighboring graded metamaterials interfaces and spatial gradient directions were compared and analyzed based on test and simulation results, where the energy absorption capabilities were evaluated with energy absorption efficiency and specific energy absorption (SEA), etc. The results showed that the deformation mechanisms of gradient lattice were beneficial for elevating energy absorption efficiency and manipulating the stress incremental process step by step. The design schemes of solid continuous plate interfaces were effective for enhancing the load-bearing capacity and improving the energy absorption performances.