Genetic optimization of partitioned architected lattices for broadband sound absorption

This study presents a computationally efficient optimization framework for designing architected lattice structures with broadband sound absorption. An equivalent material model was developed to replace the detailed lattice geometry with a homogeneous layer characterized by frequency-dependent complex impedance and propagation constant. This approach reduces the computational cost of acoustic simulations by more than three orders of magnitude compared with direct finite element modeling, enabling large-scale genetic-algorithm-based exploration of plate placement configurations. The optimized structures exhibit substantially enhanced broadband absorption relative to conventional octet lattices. The equivalent material method accurately reproduced the acoustic responses of both baseline and optimized geometries, showing strong agreement with full resolution simulations. To validate the numerical predictions, three optimized specimens were fabricated using a Stereolithography Apparatus (SLA) process. Impedance tube measurements confirmed the broadband absorption performance and demonstrated that the proposed designs remain effective even in the presence of geometric imperfections introduced during manufacturing. Overall, the results establish the proposed framework as a powerful and manufacturable strategy for engineering high-performance acoustic metamaterials.