Experimental and numerical studies on the acoustic performance of simple cubic structure lattices fabricated by digital light processing

Sound absorption is one of the important properties of porous materials such as foams and lattices. Many mathematical models in the literature are capable of modeling the acoustic properties of lattices. However, appropriate models need to be chosen for specific lattice structures on a case-by-case basis and require significant experience in acoustic modeling. This work aims to provide simplified insights into different mathematical models for the simple cubic lattice. The strut lengths and radii of the unit cells were varied, and the sound absorption properties were measured using an impedance tube. The sound absorption coefficients of the lattices generally increased and exhibited more resonant-like behavior as the strut radius increased. The Delany-Bazley (DB) model and the multi-layered micropore-cavity (MMC) model were used to simulate the acoustic properties of the lattices. The correction factors in the MMC were calculated based on empirical relations fitted using experimental data of the design geometry parameters. Results show that the DB model was able to model the sound absorption coefficients for lattice samples with porosities as low as 0.7, while the MMC with resonator theory is a more appropriate acoustics approach for lattices with porosities lower than 0.7. This work will be highly useful for materials researchers who are studying the acoustic properties of novel porous materials, as well as manufacturers of acoustic materials interested in the additive manufacturing of lattice structures for sound absorption and insulation applications.