CAREER: Low-Frequency Acoustic Damping Metamaterials Based on Trapped Bubbles

The control and attenuation of low-frequency sound waves remain a longstanding challenge in many engineering fields. Because low-frequency acoustic waves have large wavelengths, conventional materials often require thick and heavy structures to achieve meaningful sound reduction. Developing lightweight and effective approaches for controlling low-frequency sound therefore remains an important scientific and technological challenge. This project explores a new class of acoustic materials that use microscopic bubbles trapped within carefully designed structures. When exposed to sound waves, these bubbles resonate and dissipate acoustic energy, enabling efficient attenuation of low-frequency sound without relying on large mass or thickness. The research will advance fundamental understanding of acoustic wave–bubble interactions and establish design principles for bubble-based acoustic metamaterials. The resulting knowledge may enable new strategies for controlling sound in engineered environments, directly contributing to the national interest by reducing noise pollution and advancing underwater acoustic technologies. The project also integrates research with education by involving undergraduate and graduate students in interdisciplinary training at the intersection of acoustics, materials, and microengineering. Outreach activities will introduce K–12 students and educators to wave physics and emerging materials technologies, helping expand the workforce in science and engineering. This CAREER project investigates the physics and engineering of acoustic metamaterials formed by structurally trapped bubbles embedded in designed microcavity structures. Bubble-based acoustic metamaterials represent a new class of lightweight fluidic metamaterials that exploit strong bubble resonance and energy dissipation. The research aims to establish a physics-based framework for understanding and designing bubble-based acoustic damping systems. The project will develop theoretical and computational models to describe bubble resonance, nonlinear oscillations, bubble–bubble coupling, and multiple scattering in periodic bubble arrays. Experimental studies will fabricate engineered microstructures that trap and stabilize gas bubbles with controlled geometry and spacing, enabling systematic investigation of how cavity design governs acoustic resonance and attenuation. Measurements of bubble dynamics and acoustic transmission will validate theoretical predictions and establish design principles for bubble-based acoustic metamaterials. The research will also investigate environmental robustness and stability under varying temperature, pressure, and fluid conditions and explore scalable fabrication strategies. The resulting framework will enable new approaches for designing lightweight metamaterials capable of efficient low-frequency acoustic damping. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2540390 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Yang Lin | Institution: University of Rhode Island, KINGSTON, RI | Award Amount: $560,672 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2540390 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2540390.html