Dionysios T. G. Katerelos

The evolution of musical instrument manufacturing has prompted a quest for innovative materials beyond traditional wood. This review explores the utilization of composite materials, 3D-printed materials, and metamaterials as favorable alternatives. The investigation is driven by challenges such as the scarcity of high-quality tonewoods, variations in wood properties, and environmental concerns. Carbon fiber, graphite fiber, ceramic polymers, and nanocomposites present promising alternatives, offering advantages in durability, weight reduction, and customizable acoustics. The integration of 3D printing technology introduces a cutting-edge dimension, enabling intricate, precisely engineered components, optimizing instrument structure, and allowing unprecedented customization. Additionally, this article explores metamaterials, leveraging unique mechanical properties from structural design rather than constituent materials. Metamaterials offer unprecedented capabilities for tailoring instrument vibrational characteristics by providing unparalleled control over sound production. The review provides a thorough analysis, including manufacturing methods for composite materials, metamaterials, and 3D printing in musical instruments. Comprehensive examinations of vibrational and acoustical analyses related to composite materials, 3D-printed materials, and metamaterials, for the evaluation of musical instruments, are presented. This overview, supported by experimental and numerical simulation methods, offers valuable insights for the future development of musical instruments.

In this work, a phononic metamaterial that could be a reliable solution for several sound attenuation applications is examined numerically and experimentally. The proposed structure consists of a spherical shell connected with cylindrical conduits in a simple cubic arrangement. Numerical calculations, using the finite element method, and experimental measurements of the sound transmission loss were performed, providing significant evidence of the applicability of the proposed metamaterial in sound attenuation applications. For the validation of the complete acoustic bandgaps by the structure, the research was expanded to the examination of all high symmetry spatial directions. The results for all the examined spatial directions provided wide acoustic bandgaps, thus validating the evidence of complete acoustic bandgaps by the structure over a wide frequency range of the audio spectrum. Furthermore, the contribution of each part of the structure was separately analyzed, providing the physical insight for a deeper understanding of the response of the structure and the principal mechanism of the bandgap formation. The findings of this research prove that the proposed metamaterial could be a functionable unit for efficient sound attenuation applications.