Switchable Bidirectional Sound Absorption Via Exceptional Point Modulation in Acoustic Metastructures with...

Area of Science:

• Acoustics
• Materials Science
• Physics

Background:

• Acoustic metamaterials enable advanced sound wave manipulation.
• Sound-absorbing metamaterials offer subwavelength control and high-efficiency absorption.
• Existing designs often lack bidirectional absorption, limiting applications.

Purpose of the Study:

• To present a switchable bidirectional acoustic metastructure.
• To achieve broadband and frequency-selective absorption in both directions.
• To develop a generalized theoretical framework for EP-based switching strategies.

Main Methods:

• Integrating interleaved resonator coupling with exceptional point (EP) modulation.
• Coordinating resonant interactions via impedance matching and controlled energy dissipation.
• Validating performance through theoretical, numerical, and experimental analyses.

Main Results:

• Demonstrated broadband absorption (478–670 Hz) and discrete peaks (260, 542 Hz) under opposite incidences.
• Achieved deep-subwavelength scale absorption with robust bidirectional performance.
• Developed a generalized framework for translating acoustic parameters into impedance forms for EP-based switching.

Conclusions:

• The proposed metastructure offers practical, high-performance bidirectional acoustic wave control.
• The developed theoretical framework enables functional extension from unidirectional to bidirectional absorption.
• This work presents a novel physics-driven pathway for advanced acoustic manipulation.