Computational study of sound absorption in TPMS lattice materials using a thermoviscous model

Additive manufacturing has enabled the development of metamaterials with superior acoustic performance; however, the complex interplay between additively manufactured metamaterials and thermoviscous effects for enhanced sound absorption remains insufficiently understood, hindering the design of advanced metamaterials for noise reduction. In this study, the sound absorption properties of triply periodic minimal surface (TPMS) lattices are investigated numerically, using a thermoviscous acoustics model, and validated experimentally using a two-microphone impedance tube technique in accordance with ISO 10534–2. Eight sheet TPMS lattices (Neovius, FRD, FKS, Diamond, IWP, Gyroid, Primitive, and a hybrid of Primitive and Neovius (P + N)) are systematically examined with respect to topology, cell size (3 mm, 5 mm, and 7.5 mm), porosity (90 %, 80 %, and 70 %), and thickness (10 mm, 15 mm, and 20 mm). The numerical results indicate that TPMS effectively absorbs sound in the upper midrange of the audio frequency spectrum (2 kHz–5 kHz), a range critical for human hearing. The findings reveal that viscous dissipation is the predominant mechanism; reducing cell size, increasing thickness, and lowering porosity all enhance viscous dissipation, thereby increasing the sound absorption coefficient (SAC). Among the eight TPMS metamaterials studied, the previously unexplored hybrid P + N lattice, which integrates absorption-enhancing neck and cavity features from Primitive and Neovius topologies, exhibits the highest SAC in the 1 kHz–6 kHz range and delivers superior acoustic performance. This work identifies key geometric factors governing the sound absorption performance of TPMS lattices and quantifies them through pore area analysis, supporting the development of multifunctional sustainable infrastructures and advancing the material-by-design paradigm for future noise reduction applications. • Sound absorption of TPMSand hybrid lattice metamaterials is studied via experiments and simulations. • A novel Primitive + Neovius (P + N) hybrid lattice is introduced and shows strong broadband sound absorption. • Viscous dissipation is identified as the dominant sound absorption mechanism in TPMS lattices. • P + N hybrid lattice achieves peak absorption in the 1–6 kHz range, key for human hearing. • Pore area–based analysis helps rapidly screen TPMS topologies for acoustic absorption applications.