A 3D-printed plastic ring showing the helical structure of an acoustic metamaterial.

Silencer Might Benefit Built Environment

  March 15, 2019

By Naomi Millán

Boston University researchers have developed a material that can block 94 percent of sound while still allowing airflow. The material has a ringlike internal structure that sends the sound back to the source and can be tuned to match different sound sources, according the university.

Most acoustics-management products in buildings rely on blocking or absorbing sound waves and are generally solid-panel structures. Conversely, the Boston University researchers developed a helical structure that interferes with the transmission of the sound wave and acts as a silencer that can be specifically mathematically designed to match a problematic source of noise.

Possible future applications for the technology could be to make fans and HVAC systems essentially silent while still allowing air circulation, researchers say. The open and lightweight nature of the researcher's sound-cancelling structure means it could be scaled up to build other structures, such as walls. While the 3D printed test structure was designed as a ring, the exterior shape could be any shape, such as a hexagon or square.

Other potential applications for the technology include making medical equipment, such as MRIs, quieter, or blocking the noise from delivery drones. The findings were published in Physical Review B.

Naomi Millán is senior editor of Building Operating Management.


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