Scientists Create Material That Blocks Sound, but Not Air or Light
|futurism.com 14 Mar 2019 at 12:30|
By combining math with 3D printing, researchers from Boston University have created a new material that seemingly defies logic: light and air have no trouble passing through it â€” but sound cannot.
â€śThe idea is that we can now mathematically design an object that can block the sounds of anything,â€ť researcher Xin Zhang said in a press release Â â€” meaning the future could be far quieter than the present.
In a paper published in the journalÂ Physical Review BÂ , the researchers describe the work that went into creating what they callÂ their â€ś acoustic metamaterial .â€ť
They started by calculating the dimensions and specification a material would need to have to be able to reflect incoming sound waves back to their source without blocking air or light.Â Then they 3D printed the material into a donut shape and attached it to one end of aÂ PVC pipe, the other end of which they attached to a loudspeaker.
When they blasted a high-pitched note from the loudspeaker, they found that the shape blocked 94 percent of the sound coming through the pipe.
â€śThe moment we first placed and removed the silencerâ€¦was literally night and day,â€ť researcher Jacob Nikolajczyk said in the press release. â€śWe had been seeing these sorts of results in our computer modeling for months â€” but it is one thing to see modeled sound pressure levels on a computer, and another to hear its impact yourself.â€ť
The researchers envision many applications for theirÂ acoustic metamaterial, which they claim isnâ€™t limited to the donut shape demonstrated by their research.
â€śOur structure is super lightweight, open, and beautiful,â€ť Zhang and her fellow researcher Reza Ghaffarivardavagh said in theÂ press release . â€śEach piece could be used as a tile or brick to scale up and build a sound-canceling, permeable wall.â€ť
They also note the potential to use the material to dampen the sound of drones,Â HVAC systems, or evenÂ MRI machinesÂ â€” seemingly anything that makes noise could make less noise with the addition of this new material.