Enhancing sound absorption through geometric symmetry alterations in additively manufactured triply periodic minimal surface structures

Cellular structures are essential for sound attenuation in various industrial and commercial applications. The stochastic nature of traditional foams makes it challenging to tailor their properties for specific applications. Additively manufactured Triply Periodic Minimal Surface (TPMS) structures have emerged as a promising alternative for sound absorption applications. These structures offer customizable sound absorption capabilities due to their unique geometric properties and porosity. While traditional methods such as altering porosity and introducing gradients have been used to modify their acoustic properties, they often lead to increased weight and fabrication difficulties. We propose leveraging their mathematical formulation to alter the inherent symmetry of TPMS structures as a novel approach to manipulate their acoustic properties. This allows property enhancement and customization without the weight penalties or fabrication complications associated with traditional methods. In this study, the samples are fabricated using the stereolithography additive manufacturing method and are tested for their sound absorption properties using the two-microphone normal incidence method. Current results demonstrate that specific alterations in geometric symmetry can significantly improve sound absorption properties, making it possible to tailor absorption characteristics in designing acoustic liners for specific applications.