Acoustic performance optimization of natural-fiber micro-perforated panels backed by an optimized...

Area of Science:

• Materials Science
• Acoustics Engineering
• Environmental Science

Background:

• Noise pollution is a significant public health and urban sustainability issue.
• Developing effective and eco-friendly acoustic solutions is crucial.
• Traditional noise control materials often lack sustainability and high performance.

Purpose of the Study:

• To develop a high-performance hybrid sound absorber using renewable natural fibers.
• To optimize the material composition and geometry for superior broadband sound absorption.
• To create a sustainable and scalable noise-control solution.

Main Methods:

• Fabrication of a micro-perforated panel (MPP) from alkali-treated flax and rice husks.
• Development of an optimized polyurethane-fibrogranule (PU-FG) composite backing with renewable fillers.
• Systematic optimization using response surface methodology (RSM) with central composite design (CCD).
• Characterization of acoustic performance (SAA, NRC) and morphological analysis (SEM).

Main Results:

• An optimized hybrid absorber achieved a sound absorption average (SAA) of 0.82 and a noise reduction coefficient (NRC) of 0.85.
• Effective broadband absorption from 100-2500 Hz was achieved through combined Helmholtz resonance and visco-thermal losses.
• The system features a 1.61% porosity MPP, 28.5 mm front air gap, 40 mm PU-FG backing, and 30 mm rear air gap.
• Morphological analysis revealed hierarchical pore structures that enhance tortuosity and adhesion.

Conclusions:

• The developed hybrid absorber demonstrates high-performance, lightweight, and efficient broadband sound absorption.
• The use of renewable natural fibers (flax, rice husks) enhances the sustainability of the noise-control material.
• This offers a practical and scalable pathway for sustainable noise control in architectural, transportation, and urban settings.