Nanowerk April 23, 2024
A team of researchers in the US (MIT, University of Wisconsin–Madison, Case Western University) investigated traditional fabrics as emitters and suppressors of sound. They found that when attached to a single strand of a piezoelectric fiber actuator, silk fabric emits up to 70 dB of sound. Despite the complex fabric structure, vibrometer measurements revealed behavior reminiscent of a classical thin plate. Fabric pore size relative to the viscous boundary layer thickness was found to influence acoustic-emission efficiency. They demonstrated sound suppression using two distinct mechanisms – direct acoustic interference where sound reduced by up to 37 dB, and pacifying the fabric vibrations by the piezoelectric fiber, which reduced the amplitude of vibration waves by 95% and attenuated the transmitted sound by up to 75%. Vibration-mediated suppression in principle reduced sound in an unlimited volume, and allowed the acoustic reflectivity of the fabric to be dynamically controlled, increasing by up to 68%. According to the researchers 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… read more. Open Access TECHNICAL ARTICLEÂ
Schematic of the preform being drawn into fiber… Credit: Advanced Materials, 01 April 2024