All-in-One: An Interwoven Dual-Phase Strategy for Acousto-Mechanical Multifunctionality in Microlattice Metamaterials

Multifunctional materials that integrate noise absorption, high stiffness, and isotropic elasticity are increasingly sought after for all-in-one applications. However, conventional microlattice metamaterials—whether truss, shell, or plate—often excel in only one property and struggle to embrace all due to structural constraints. Herein, this work presents a new additive concept—via interweaving different lattice architectures to simultaneously enhance both sound absorption and elastic properties in microlattices. The interwoven design strategy starts by analyzing a particular structure, introducing a reinforcing structure to partition air domains, compensate for local stiffness deficiencies, and improve structural integrity. As a proof of concept, the focus is on using an octet truss as the original phase and a customized truss as the reinforcing phase. The methodology enables highly customizable geometric configurations, harnessing machine learning and multi-objective optimization to achieve superior multifunctional performance. Experimental results show that these optimized microlattices overcome traditional physical limitations, simultaneously achieve broadband sound absorption, high stiffness, and elastic isotropy. The broadband absorption results from a finely tuned over-damped resonant response, while the remarkable elastic performance is attributed to efficient load transfer and complementary configurations. This work unveils a groundbreaking design paradigm for innovative multifunctional materials.