Digitally Controlled Piezoelectric Metamaterial for Low-Frequency and High-Efficiency Sound Absorption

Area of Science:

• Acoustics
• Materials Science
• Control Systems Engineering

Background:

• Low-frequency sound absorption remains a significant challenge in various engineering applications.
• Traditional passive acoustic materials often struggle with efficiency and bulkiness at lower frequencies.
• Metamaterials offer unique acoustic properties but often lack dynamic tunability.

Purpose of the Study:

• To propose and validate a novel membrane-type metamaterial with digitally controlled piezoelectric actuation for enhanced low-frequency sound absorption.
• To investigate two active control strategies (Resistance Enhancement and Resonance Enhancement) for optimizing sound absorption.
• To develop a coupled model for characterizing the system's performance and validate it experimentally.

Main Methods:

• Integration of an aluminum membrane with programmable piezoelectric patches (PZTs) and a sealed air cavity.
• Implementation of real-time digital feedback control to dynamically adjust circuit impedance.
• Development of a coupled piezoelectric-structural-acoustic model for system analysis.
• Validation using finite element simulations and impedance tube experiments.

Main Results:

• Demonstration of nearly complete sound absorption around the resonant frequency.
• Broadening of the absorption bandwidth through multi-resonance superposition.
• Confirmation that active control strategies modulate acoustic impedance for efficient electromechanical energy conversion.
• Validation of the coupled model through numerical and experimental data.

Conclusions:

• The proposed membrane metamaterial with active piezoelectric control offers a novel approach to low-frequency noise mitigation.
• The digital control strategies effectively optimize electromechanical energy conversion for high-efficiency sound absorption.
• This work presents a viable methodology for active noise control and acoustic energy management.