Structural Optimization and Performance Analysis of Acoustic Metamaterials with Parallel Unequal Cavities

Area of Science:

• Acoustics
• Materials Science
• Mechanical Engineering

Background:

• Industrial noise poses risks to worker health and productivity.
• Effective low-frequency sound absorption is crucial for manufacturing environments.
• Existing solutions often lack efficiency or are too thick for practical application.

Purpose of the Study:

• To design and optimize an acoustic metamaterial for broadband sound absorption in the low-frequency range.
• To achieve high sound absorption with a limited total thickness.
• To ensure the material's suitability for mass production and industrial application.

Main Methods:

• Development of a theoretical model for a hexagonal acoustic metamaterial with parallel, unequal cavities.
• Optimization of aperture lengths using the particle swarm optimization algorithm.
• Acoustic finite element simulation for initial parameter determination.
• Analysis of manufacturing error impacts.

Main Results:

• Achieved an average absorption coefficient of 0.87 (384-667 Hz) for a 50 mm thick metamaterial.
• Demonstrated an average absorption coefficient of 0.83 (265-525 Hz) for a 70 mm thick metamaterial.
• Obtained an average absorption coefficient of 0.82 (156-250 Hz) for a 100 mm thick metamaterial.

Conclusions:

• The proposed acoustic metamaterial exhibits excellent low-frequency sound absorption performance.
• Experimental results validate the theoretical model and optimization algorithm's effectiveness.
• The metamaterial is extensible, suitable for mass production, and applicable for industrial noise control.