Foldable acoustic metamaterial for underwater broadband low-frequency noise mitigation

Monopile offshore wind foundations are typically installed using hydraulic impact hammers, generating intense underwater noise that can propagate over 50 km from the installation site. This noise poses significant risks to marine life, potentially causing auditory injury and behavioral disturbances. Existing noise mitigation strategies, such as bubble screens, are hindered by high costs, energy demands, and limited scalability, while resonance-based metamaterials are constrained by narrow operational bandwidths. Developing broadband, efficient underwater noise mitigation solutions that are cost-effective, scalable, and easy to manufacture remains a critical challenge. In this talk, we present a novel acoustic metamaterial design that delivers ultra-broadband noise mitigation at low frequencies with a compact, deep subwavelength structure. The design is modular and fully foldable, enabling mass production and simplifying transportation for large-scale offshore applications.