Acoustic absorptions of multifunctional polymeric cellular structures based on triply periodic minimal surfaces fabricated by stereolithography

Polymeric cellular structures based on triply periodic minimal surfaces (TPMS) have been widely studied for applications in multiple disciplines due to their multifunctionality. However, there is limited acoustic application by TPMS-based structures as their acoustic properties remain largely unknown. In this paper, TPMS-based structures are fabricated by additive manufacturing and investigated as a novel solution to sound absorption in the upper midrange frequency. Structures based on three typical surface types (Primitive, Gyroid and Diamond) with three geometry-related parameters (volume fraction, unit cell size and height) are manufactured by stereolithography and tested by two-microphone impedance method in the frequency range of 2000-6000 Hz. The results show that the structures based on Diamond surfaces exhibit excellent absorption abilities among the three types in a wide bandwidth. High absorption coefficients can be achieved by a large volume fraction or a small unit cell size while the effective frequency ranges can be adjusted by the height. This study extends the multifunctionality of TPMS-based cellular structures to include acoustic absorption and will facilitate the development of guidelines on designing the optimal acoustic absorbers by cellular structures in future.