Research data for "Thin Acoustic-Composite Structures With Metamaterial Inclusions for Enhanced Low- Frequency Sound Absorption"

This dataset contains research data used to prepare the publication:M.A. Niedzielczyk, T.G. Zieliński, "Thin Acoustic-Composite Structures With Metamaterial Inclusions for Enhanced Low-Frequency Sound Absorption", ASME Journal of Vibration and Acoustics 148(4) (2026), 041008. DOI: 10.1115/1.4070949This research was supported by the National Science Centre (NCN), Poland, under grant agreement 2021/41/B/ST8/04492.All data are provided in columns in ASCII (.txt) files.The "CAL-Absorption.txt" file contains sound absorption values ​​calculated for an 18-mm thick acoustic composite and its components. All sound absorption layer configurations have the same thickness of 18 mm. The file contains five columns of data with labels. The labels indicate what follows:"Freq" - the frequency;"2xFelt9" - the sound absorption for a dual-felt panel, i.e. 9mm+9mm=18mm thick;"Felt9Gap9" - the sound absorption for a 9-mm felt panel backed by a 9-mm air gap;"Lab18" - the sound absorption for a 18-mm thick labyrinthine acoustic metamaterial;"Comp18" - the sound absorption for the 18-mm thick composite made of a 9-mm porous felt matrix (backed by a 9-mm air gap) with a 18-mm thick labyritnine inclusion.These results were obtained using original codes developed in the MATLAB environment.The "DNS-Lab+Felt+Air.txt" file contains the results of a computationally demanding Direct Numerical Simulation (DNS) performed for an 18-mm thick acoustic composite made of a 9-mm porous felt matrix (backed by a 9-mm air gap) with an 18-mm thick labyrinthine metamaterial inclusion backed by a rigid wall. The computational frequency is given in the first column, and the corresponding sound absorption coefficient values ​​calculated for the composite are given in the second column.These results were obtained by the Finite Element Method using COMSOL Multiphysics software.The "EXP-Components+Composite.txt" file contains the sound absorption measurement results for the investigated composite (porous felt matrix + 3D printed inclusion) and all its components. The first column lists measurement frequencies while the sound absorption values are given in the following columns.All measurement results were obtained using a Bruel&Kjaer impedance tube measurement kit.