Study on Acoustic Metasurface for Phase Shift Control

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details

Abstract

Metamaterials are artificial materials consisting of some special microstructures. Wave propagation in the metamaterial has some special properties which can not be observed in the natural media. Some metamaterials with microstructure arranged only on the surfaces still make incident waves perform special behavior, which is called the metasurface. Currently, metasurface was mainly studied to control the reflection, transmission, and absorption of sound, so it is also called acoustic metasurface. The microstructures of metasurfaces are usually resonators which absorb sound wave effectively while air resonate inside it. In this case, resonators can also be regarded as structures that can control the phase shift of reflected waves, so that the reflected and incident waves have a destructive interference. Controlling phase shift of sound by metasurfaces is a potential topic. Schroeder diffuser used on walls in concert halls is an example of controlling the phase shift of reflected sound. By using surface irregularities of wall, the inconsistent phase shift of reflected sound reduce the reflected sound and echo in confined spaces. Therefore, this project intends to study the microstructure that can control the phase shift of sound on the surfaces of bodies. By arranging the microstructures properly, an acoustic metasurface can be designed to control sound scattering or focusing. The work included numerical simulation, design and fabrication of specimens, and experimental measurements. The phase shift of reflected wave caused by microstructures such as open cavities and tubes will be studied firstly. Then the arrangement of different-phase-delay microstructures will be analyzed to form an acoustic metasurface, and the control of sound reflection or transmission will be processed. Then specimens of metasurface plates will be fabricated. The phase delay of different microstructures and sound pressure field will be measured. The study is expected to be valuable in the fields of building acoustics and noise control.

Project IDs

Project ID:PB10907-4407
External Project ID:MOST109-2221-E182-018
StatusFinished
Effective start/end date01/08/2031/07/21

Keywords

  • metamaterial
  • acoustic metasurface
  • phase control
  • Schroeder diffuser

Fingerprint

Explore the research topics touched on by this project. These labels are generated based on the underlying awards/grants. Together they form a unique fingerprint.