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Description
Additive manufacturing technologies enable the development of innovative and high-performance acoustic materials, allowing the design of complex structures. These fabrication techniques support a high degree of geometric customization that challenges the acoustic standardized characterization methods and their feasible application in the design process. One aspect that has been unexplored is the characterization of hybrid acoustic materials (HAMs) that integrate sound absorption and diffusion within a single element. This contribution focuses on the sound scattering performances of 3D printed HAMs, designed and developed by BioG3D (Greece), and explores the challenges of their characterization in a small-scaled reverberation room (Politecnico di Torino, Italy). The effects of ten 3D quarter-circle Truchet tiles combined in two different configurations have been fabricated using a large format industrial LCD 3D printer and daylight resin. The experimental investigations aimed at providing insights on the sensitivity of the measurement procedure of the random-incidence scattering coefficient, as defined in ISO 17497-1:2004, applied to the two different configurations. The results showed that the two tested scattering surfaces do not show significant differences despite the variation of the two configurations, which allows for a higher flexibility in the space design and application. It is highlighted that the characterization method is particularly demanding, as it relies on two custom 3D printed scaled samples which requires higher accuracy and precision in the printing process, consequently increasing fabrication costs.