Deep-Subwavelength Composite Metamaterial Unit for Concurrent Ventilation and Broadband Acoustic Insulation

Area of Science:

• Acoustic Engineering
• Materials Science
• Metamaterials

Background:

• Achieving simultaneous ventilation and broadband sound insulation is a critical challenge in noise control.
• Existing solutions like porous absorbers and membrane metamaterials have limitations in ventilation or bandwidth.
• Conventional methods often involve trade-offs between airflow and sound insulation performance.

Purpose of the Study:

• To develop a novel ventilated composite metamaterial unit (VCMU) for integrated ventilation and sound insulation.
• To investigate the acoustic performance and ventilation efficiency of the proposed VCMU.
• To explore the potential applications of the VCMU in noise-sensitive environments.

Main Methods:

• Design and fabrication of a VCMU integrating labyrinth channels and Helmholtz resonators.
• Utilized coupled transfer matrix modeling and finite-element simulations to analyze acoustic performance.
• Experimental validation using impedance tube testing to confirm simulation results.

Main Results:

• The VCMU demonstrated exceptional ventilation efficiency via a central flow channel.
• Achieved broadband sound transmission loss (STL) from 860-1634 Hz, with a mean of 18.4 dB and six distinct STL peaks.
• The VCMU maintained a sub-wavelength thickness (λ/31 at 860 Hz).

Conclusions:

• The developed VCMU effectively addresses the challenge of balancing ventilation and broadband sound insulation.
• Fano-Helmholtz resonance mechanisms are key to the broadband noise reduction capabilities.
• The VCMU offers a scalable and customizable solution for integrated ventilation and noise reduction in various applications.