Elastoacoustic wave propagation in a biphasic mechanical metamateriala)

Area of Science:

• Materials Science
• Acoustics
• Solid Mechanics

Background:

• Humans are sensitive to airborne sound and mechanical vibrations below 20 kHz.
• Developing effective vibration reduction and sound insulation filters is crucial for human comfort and safety.

Purpose of the Study:

• To present a high-contrast biphasic mechanical metamaterial for multifunctional vibration and sound insulation.
• To demonstrate the modification of metamaterial properties for broad acoustic and elastic wave bandgaps.
• To develop and test a mechanical metafilter for practical engineering applications.

Main Methods:

• A hybrid analytical-computational technique was used to solve the eigenproblem for wave propagation.
• Waveform classification was based on polarization factors quantifying energy distribution in solid and fluid phases.
• A computational framework was employed to simulate the forced response and transmission coefficients of the metafilter.

Main Results:

• The proposed metamaterial exhibits complete and large bandgaps for acoustic and elastic waves.
• The metafilter design effectively modifies the frequency dispersion spectrum.
• Quantitative results show remarkable reduction in transmitted sound and vibration signals within the human sensitivity range.

Conclusions:

• The developed mechanical metamaterial and metafilter offer a viable technical solution for passive control of broadband sound and vibration.
• The metafilter demonstrates significant performance in reducing transmitted responses in critical frequency bands.
• This research contributes to the advancement of metamaterials for noise and vibration mitigation.