MIT News November 20, 2024 Challenges in miniaturizing and characterizing acoustic metamaterials in high-frequency (megahertz) regimes have hindered progress toward experimentally implementing ultrasonic-wave control. A team of researchers in the US (MIT, Kansas City National Security Campus) presented an inertia design framework based on positioning microspheres to tune responses of 3D microscale metamaterials. They demonstrated tunable quasi-static stiffness by up to 75% and dynamic longitudinal-wave velocities by up to 25% while maintaining identical material density. The researchers explored the tunable static and elastodynamic property relation. According to the researchers their design framework expands the quasi-static and dynamic metamaterial property space […]
Tag Archives: Sound propagation
This sound-suppressing silk can create quiet spaces
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 […]