Title: Revolutionary Sound-Suppressing Silk Fabric: A Thin Sheet of Material for Quiet Spaces
Researchers from the Massachusetts Institute of Technology (MIT) and other institutions have developed a groundbreaking sound-suppressing silk fabric that can create quiet spaces in various environments. This innovative material, which is merely thicker than a human hair, contains specialized fibers that vibrate when a voltage is applied. The researchers leveraged these vibrations to suppress sound in two distinct ways.
The first method involves the vibrating fabric generating sound waves that interfere with unwanted noise, effectively canceling it out, similar to noise-canceling headphones. The second approach, which is more surprising, entails holding the fabric still to suppress vibrations vital to sound transmission. This technique prevents noise from being transmitted through the fabric, quieting the volume beyond. Moreover, the second approach allows for noise reduction in larger spaces like rooms or cars.
Using common materials like silk, canvas, and muslin, the researchers created noise-suppressing fabrics that can be readily implemented in real-world spaces. Possible applications include using such fabric for dividers in open workspaces or thin fabric walls that prevent sound from passing through.
Grace Yang SM ’21, PhD ’24, the study’s lead author, explains, “Noise is much easier to create than quiet. We dedicate a lot of space to thick walls to keep noise out. Grace’s work provides a new mechanism for creating quiet spaces with a thin sheet of fabric.” Yoel Fink, a professor in the departments of Materials Science and Engineering and Electrical Engineering and Computer Science, adds, “If we can control those vibrations and stop them from happening, we can stop the noise that is generated, as well.”
In addition to its noise-canceling properties, the sound-suppressing silk fabric can also emit sound waves, acting as a fabric loudspeaker. This capability allows the material to cancel out unwanted soundwaves directly. Researchers demonstrated this by playing Bach’s “Air” using a 130-micrometer sheet of silk mounted on a circular frame.
The researchers further expanded on this idea, leveraging fabric vibrations to suppress sound in larger areas. This technique enables sound suppression in spaces such as bedrooms, effectively reducing noise from neighbors or other sources.
In direct suppression mode, the fabric can significantly reduce the volume of sounds up to 65 decibels (about as loud as enthusiastic human conversation). In vibration-mediated suppression mode, the fabric can reduce sound transmission up to 75 percent.
Moving forward, the researchers aim to explore the use of their fabric to block sound of multiple frequencies. This would likely require complex signal processing and additional electronics. The researchers also plan to further study the architecture of the fabric to optimize performance by adjusting factors like the number of piezoelectric fibers, the direction in which they are sewn, or the applied voltages.
This work is funded, in part, by the National Science Foundation (NSF), the Army Research Office (ARO), the Defense Threat Reduction Agency (DTRA), and the Wisconsin Alumni Research Foundation.
In conclusion, the revolutionary sound-suppressing silk fabric presents a significant leap in creating quiet spaces in various environments. Its ability to suppress sound in multiple ways, act as a fabric loudspeaker, and be tailored for optimal performance opens up exciting opportunities for implementing this innovative material in various applications.
