Labyrinthine Acoustic Metamaterials for grazing Sound Waves
Giuseppe PETRONE, Alessandro CASABURO, Giuseppe CATAPANE
Abstract. This study presents a novel acoustic liner configuration developed using additive manufacturing, which enables precise geometric control. The proposed design modifies traditional honeycomb sandwich structures with microperforated plates (MPPs) by integrating a labyrinth channel inside the honeycomb core. MPPs provide both structural integrity and acoustic functionality by serving as inlets to the labyrinth, inducing thermal and viscous dissipation. A numerical model was developed in COMSOL Multiphysics using the Pressure Acoustics module, with MPPs modeled through dedicated boundary conditions and thermo-viscous effects applied to cavity walls. The predicted Transmission Loss results were validated experimentally using an impedance tube with grazing incidence. Numerical and experimental data showed good agreement, confirming the reliability of the model and demonstrating that the proposed liner achieves Noise Transmission Loss (NSTL) values exceeding 50 dB at the first resonance frequency. These promising results highlight the potential of this configuration for future aero-acoustic applications.
Keywords
Acoustic Metamaterial, Labyrinth, Transmission Loss, Grazing Waves
Published online 7/20/2026, 5 pages
Copyright © 2026 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: Giuseppe PETRONE, Alessandro CASABURO, Giuseppe CATAPANE, Labyrinthine Acoustic Metamaterials for grazing Sound Waves, Materials Research Proceedings, Vol. 69, pp 293-297, 2026
DOI: https://doi.org/10.21741/9781644904251-52
The article was published as article 52 of the book CEAS – AIDAA Conference 2025
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
References
[1] DL. Sutliff, DM Nark, MG Jones, Multi-degree-of-freedom liner development: Concept to flight test, International Journal of Aeroacoustics, 20, 5-7 (2021), 792-825. https://doi:10.1177/1475472X211023860
[2] M.B. Galles, M.G. Jones and D.M. Nark, An Initial Assessment of Variable Depth Liner Optimization for Ducted Proprotor Applications, AIAA 2022-2821. 28th AIAA/CEAS Aeroacoustics 2022 Conference (2022), https://doi.org/10.2514/6.2022-2821.
[3] M.C. Brown and M.G. Jones, Evaluation of Variable Facesheet Liner Configurations for Broadband Noise Reduction, AIAA 2020-2616, AIAA AVIATION 2020 FORUM, (2020), https://doi.org/10.2514/6.2020-2616
[4] S. Palani, P. Murray, A. McAlpine, K. Knepper and C. Richter, Experimental and numerical assessment of novel acoustic liners for aero-engine applications, In 28th AIAA/CEAS Aeroacoustics 2022 Conference. American Institute of Aeronautics and Astronautics (2022), https://doi.org/10.2514/6.2022-2900
[5] S. Palani, P. Murray, A. McAlpine, D. Sasaki and C. Richter, Slanted septum and multiple folded cavity liners for broadband sound absorption, International Journal of Aeroacoustics, 20, 5-7 (2021), pp. 633–661, https://doi.org/10.1177/1475472X211023835
[6] G. Catapane, G. Petrone, O. Robin, K. Verdiere, Coiled quarter wavelength resonators for low-frequency sound absorption under plane wave and diffuse acoustic field excitations, Applied Acoustics, 209 (2023), 109402, https://doi.org/10.1016/j.apacoust.2023.109402
