Sound absorption properties of spinodoid structures with spatially varying properties

Creating lightweight structures with tailored noise reduction at low-frequencies remains a major engineering challenge. Open-celled porous structures with low relative densities offer a possible solution to this problem. Spinodoids—structures with microstructural architectures based on spinodal decomposition—have been recently shown to provide robust and tunable mechanical properties. Here, we study the sound absorption properties of spinodoids with spatially varying properties such as relative density, spinodoid type, and wavenumbers. We generate the sample geometries using MATLAB and print them using low-cost additive manufacturing methods. The printed samples were then tested using a normal impedance tube setup to characterize their absorption coefficients. Our results show that spatially gradient spinodoids provide an attractive solution for designing multifunctional structures with application-specific acoustic properties.