The application of acoustic and elastic metamaterials into the building envelope

This research addresses two significant environmental impacts of urbanization and mechanization: noise pollution and ventilation. Noise pollution is increasingly recognized as a pervasive physical and mental health concern, linked to a growing array of medical conditions. Meanwhile, ventilation problems in many homes lead to excessive dampness, contributing to respiratory health issues. Current construction technology does not provide affordable solutions to these challenges, and the industry continues to rely on homogeneous materials. Cost-effective lightweight construction methods often fail to adequately reduce noise transmission between dwellings, while mechanical ventilation systems are costly, and passive trickle vents typically provide insufficient airflow. This study explores using metastructures and metasurfaces to improve sound insulation, with a focus on scalable, practical implementation. Consisting of metamaterial systems, they incorporate elements designed to reflect, absorb, and guide acoustic waves. The paper presents applications of locally resonant metamaterials, phononic crystals, subwavelength coiled acoustic resonators, and passive noise-cancellation waveguides utilizing Fano-resonance. Our findings demonstrate the effectiveness of these systems, with both experimental and simulation results showing a strong correlation. Diffuse-field testing indicates significant sound attenuation within the targeted frequency bands. We assess the advantages of each approach and identify the most effective methods.