In rods and beams, piezoelectric patches with external circuits have been extensively
studied to dampen structural vibrations at the sound source. This work uses a large flat-layer …

An online tunable acoustic metamaterial with the optional aperture and adjustable cavity is
proposed to satisfy noise reduction requirements for various frequency ranges. Its sound …

Frequency limit and applicable frequency range of planar piezoelectric metamaterials
connected to external circuits have not been well defined in estimating the sound …

In this paper, a sub-wavelength sector acoustic metamaterial (SAM) cell was presented for
duct noise attenuation. A numerical model considering thermal-viscous loss was established …

To prevent noise pollution, a hexagonal acoustic metamaterial cell combining multiple
parallel Helmholtz resonators with optional apertures is proposed. There were 6 trapezoidal …

Aiming at noise isolation in low frequency range, this paper presents a novel kind of
membrane sound insulator featuring a bistable actuation, by combining magnets and …

Purpose This study aims to propose a novel acoustic metamaterial waveguide with active
switchable channels by changing the magnetic field strength. Design/methodology …