Superior compressive behaviour of alveolar biomimetic interlaced hollow lattice metastructures

Advancements in additive manufacturing have significantly enhanced the designability of lattice structures for superior compression resistance. Inspired by the sac-like morphology of alveolar tissues, an alveolar biomimetic interlaced hollow lattice metastructure with superimposed double pipes is proposed. This metastructure features customisable geometric parameters, offering strong designability, unique compression deformation behaviour, and distinct mechanical responses. Specimens with different geometric dimensions are fabricated from Inconel 718 by selective laser melting. Detailed surface morphology evaluations using scanning electron microscopy and X-ray scanning reveal high-fidelity manufacturing outcomes. A novel refined finite element model, based on X-ray data, accurately predicts the mechanical behaviour of millimeter-scale lattice structures, validated through rigorous experiments. Compressive performance of the metastructures under different size parameters is investigated using both experimental testing and finite element simulations, revealing that the 45° metastructure exhibits the highest energy absorption efficiency of 90%. The enhancement of self-supporting effect is significant, especially the 30° double-cell structure energy absorption capacity is increased by 51% compared to single-cell case. Additionally, gradient metastructures are designed and tested, demonstrating effective suppression of shear band formation and increasing energy absorption capacity up to 26%. The proposed hollow lattice metastructure holds great potential for load bearing and energy absorption applications.