Triply periodic minimal surface based lattices for acoustic performance

Environmental noise pollution is exacerbated by accelerated urbanization and different sources generate a unique sound spectrum. To address the aforementioned issue, triply periodic minimal surface acoustic absorbers were additively manufactured with three geometrical parameters (porosity, sample thickness, and wall thickness) patterns to absorb sound across a wide range of frequencies. TPMS absorbers made from Abs resin were manufactured using VAT polymerization additive manufacturing (SLA) technology. The acoustic properties of these absorbers were evaluated using the impedance tube technique across a frequency range of 100-6400 Hz and discussed. The four TPMS absorbers exhibit slight variations in density as a result of their distinct unit cell sizes, which are necessary to uphold constant porosity levels. This study found multiple parameters, especially the nature of the surfaces, porosity ranges, sample thicknesses, and wall thickness of the tested sound-absorbing TPMS 3D printed structure, significantly impacted the sound absorption performance. At the ideal process parameters of 80% lattice porosity, 60 mm sample thickness, and 0.8 mm wall thickness, the gyroid lattice obtained a peak sound absorption coefficient of 0.945, a noise reduction coefficient of 0.50, and an average sound absorption of 0.575. The suggested 3D-printed TPMS acoustic absorbers, inspired by nature, can be placed on construction walls or transportation applications, depending on the desired acoustic absorption range.