Broadband sound-absorbing and mechanically robust plate lattices with manufacturing-driven architecture

Modern engineering demands structural materials that not only withstand mechanical loads but also address additional functional requirements, such as noise control, driving the need for innovative multifunctional designs. Plate lattices, known for their mechanical robustness, provide a promising foundation for achieving multifunctionality. In a twist, the inherent manufacturing need for perforations in plate lattices, which are closed-cell structures, presents a previously untapped opportunity to achieve substantial gains in acoustic performance. These perforations effectively transform plate lattices into multi-layered Helmholtz resonators. Using high-fidelity acoustical impedance solutions that we have developed, we then present an optimised plate lattice configuration that achieves local absorption coefficients of 1 and an average coefficient of 0.73 across a broad frequency range from 1000 to 6400 Hz. The structure also maintains good elastic isotropy while demonstrating excellent large deformation recovery, retaining 78% of ultimate stress and 90% of sound absorption after cycle testing at 20% strain. Further, it has shown the potential of impact mitigation with an inertial effect attenuation rate of 423.33 s-1 under a drop hammer impact carrying 62 J of energy and 2.82 m/s of contact velocity. Overall, our study highlights a pathway for achieving multifunctional performance through manufacturing-informed design and genetic-algorithm-based parametric optimisation.