MIT News  May 7, 2024
A team of researchers in the US (MIT, University of Wisconsin, Case Western Reserve University, Rhode Island School of Design) investigated traditional fabrics as emitters and suppressors of sound. When attached to a single strand of a piezoelectric fiber actuator, a silk fabric emitted 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 two sound suppression using two distinct mechanisms. In the first, direct acoustic interference was shown to reduce sound by up to 37 dB. The second method relied 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%. It allowed 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… read more. Open Access TECHNICAL ARTICLE
a) Schematic of the preform being drawn into fiber… Credit: Advanced Materials, 01 April 2024