Dynamic Schwarz Meta-Foams: Customizable Solutions for Environmental Noise Reduction.

In an era marked by increasing environmental challenges affecting human well-being, traditional acoustic materials struggle to effectively handle the diverse and multi-frequency nature of harmful environmental noises. This has spurred a demand for innovative acoustic metamaterial solutions by utilizing sustainable design strategies. This research introduces tunable Schwarz metamaterial capable of transforming into a soft meta-foam to solve the complex problems of varying environmental noises. This study primarily focuses on adjusting single to multiple sound-blocking bandgaps mechanism using a multi-layered approach, incorporating the Schwarz P-type triply periodic minimal surface (TPMS) and its elective soft foam counterpart, known as tunable Schwarz meta-foams (TSMF-x). The tunable design parameters of the unit cell, multi-layered TPMS, and soft programmable TSMF-lichen version are comprehensively explored including a fire-safety test. The results demonstrate these enhanced flame retardant meta-foam families have the potential to be used for mid-to-high-frequency environmental noises in industrial equipment and smart homes for sustainable architecture and environmental health applications.