Hybrid lattice metamaterials integrating noise mitigation and energy absorption

Noise and impact protection are essential for safeguarding human health and ensuring the safe operation of advanced equipment. However, the low-frequency and broadband nature of noise in real-world application environments, combined with the requirement to maintain mechanical performance under stringent lightweight constraints, presents significant challenges for the design of such structures. To address this issue, an acoustic–mechanical multifunctional hybrid lattice metamaterial (HLM) is proposed by combining spherical shell lattices with truss lattices. Integrating theoretical derivation, finite element simulation and experimental validation, this study clarifies the resonant sound absorption mechanism and acoustic-mechanical functional decoupling characteristics of the proposed HLM. By optimizing the configuration of the internal truss lattice, the specific energy absorption of the structure is improved by approximately 113 %, reaching about 6.1 J/g. Meanwhile, the parallel-arrayed configuration enables the HLM to deliver an average sound absorption coefficient of ∼0.95 over the frequency range of 500–1300 Hz. Furthermore, it can be integrated with porous materials, allowing the effective absorption bandwidth to be further extended into an ultra-broad frequency range. This work establishes a novel framework for the compact integration of acoustic and mechanical functionalities, thereby expanding the potential applications of metamaterials in practical fields such as aerospace, construction, and defense.