2024-05-07 マサチューセッツ工科大学(MIT)
1. 音波キャンセル: 布が生成する音波で不要な音を打ち消します。
2. 振動抑制: 布を固定し、音の伝達に重要な振動を抑えることで、音の伝播を防ぎます。
この布は、シルクやキャンバス、モスリンなどの一般的な素材で作られ、オフィスの仕切りや薄い壁として使える可能性があります。研究者は今後、複数の周波数の音を抑制するための改良を進めたいと考えています。
＜関連情報＞
- https://news.mit.edu/2024/sound-suppressing-silk-can-create-quiet-spaces-0507
- https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202313328
シルクとコットンの単層織物による音響放射と能動的消音 Single Layer Silk and Cotton Woven Fabrics for Acoustic Emission and Active Sound Suppression
Grace H. Yang, Jinuan Lin, Henry Cheung, Guanchun Rui, Yongyi Zhao, Latika Balachander, Taigyu Joo, Hyunhee Lee, Zachary P. Smith, Lei Zhu, Chu Ma, Yoel Fink
Advanced Materials Published: 01 April 2024
DOI:https://doi.org/10.1002/adma.202313328
Abstract
Whether intentionally generating acoustic waves or attempting to mitigate unwanted noise, sound control is an area of challenge and opportunity. This study investigates traditional fabrics as emitters and suppressors of sound. When attached to a single strand of a piezoelectric fiber actuator, a silk fabric emits up to 70 dB of sound. Despite the complex fabric structure, vibrometer measurements reveal behavior reminiscent of a classical thin plate. Fabric pore size relative to the viscous boundary layer thickness is found—through comparative fabric analysis—to influence acoustic-emission efficiency. Sound suppression is demonstrated using two distinct mechanisms. In the first, direct acoustic interference is shown to reduce sound by up to 37 dB. The second relies on pacifying the fabric vibrations by the piezoelectric fiber, reducing the amplitude of vibration waves by 95% and attenuating the transmitted sound by up to 75%. Interestingly, this vibration-mediated suppression in principle reduces sound in an unlimited volume. It also allows the acoustic reflectivity of the fabric to be dynamically controlled, increasing by up to 68%. The sound emission and suppression efficiency of a 130 µm silk fabric presents opportunities for sound control in a variety of applications ranging from apparel to transportation to architecture.
