Inverse-designed 3D sequential metamaterials achieving extreme stiffness

Mechanical metamaterials signify a groundbreaking leap in material science and engineering. The intricate and experience-dependent design process poses a challenge in uncovering architectural material sequences with exceptional mechanical properties. This study introduces inverse-designed 3D sequential metamaterials with outstanding mechanical attributes, achieved through a novel computational framework. The explored sequences based on Schoen's I-graph–wrapped package (IWP) and Schwarz Primitive (Schwarz P) surpass the Hashin-Shtrikman upper bound of Young's modulus at relative densities of 0.24 and 0.43, outperforming previous records. Optimized Body-Centered-Cubic (BCC) truss-based sets outperform traditional ones by 72.7%. This innovative approach can be extended for metamaterial customization, involving the optimization of multi-directional Young's modulus, total stiffness, and the addition of isotropy constraints. The paper explores the characteristics and implications of this innovation, emphasizing the impact of geometric and topological variations on mechanical performance. These metamaterial sequences offer unparalleled adaptability, and hold significant potential in structural engineering and adaptive mechanical systems, opening avenues for technological advancements. • 3D Sequential Metamaterials with extreme stiffness . Materials, based on IWP and Schwarz P sequences, surpass the Hashin–Shtrikman upper bound of Young's modulus at relative densities of 0.24 and 0.43, setting new records. Optimized BCC truss-based sets outperform traditional ones by 72.7%. • Metamaterial customization . The innovative approach can be extended to customize different stiffness properties of metamaterials sequences, including maximization of bulk modulus, shear modulus, total stiffness, etc. • Topological analysis . During the evolution of features within microstructure sequences characterized, the identification of these topological features provides valuable insights for designing metamaterials with more superior stiffness performance.