An efficient approach for broadband sound absorption using periodic multi-layer solid inclusions in acoustic coatings

Area of Science:

• Materials Science
• Acoustics
• Naval Engineering

Background:

• Anechoic coatings are crucial for the acoustic stealth of underwater equipment.
• Broadband sound absorption is a key challenge in designing effective acoustic coatings.

Purpose of the Study:

• To propose and investigate multi-layer acoustic coatings with periodic solid inclusions for broadband sound absorption.
• To develop an analytical model for predicting the acoustic properties of such coatings.
• To optimize coating structures for enhanced sound absorption performance.

Main Methods:

• Derivation of an analytical model to calculate effective material and geometric parameters of inclusion layers.
• Application of the transfer matrix method to determine acoustic absorption properties.
• Utilizing a genetic algorithm for optimizing multi-layer coating structures.
• Comparison of the analytical model with the finite element method for validation.

Main Results:

• The analytical model was validated as a viable and efficient alternative to the finite element method.
• Investigation into the effect of geometrical parameters on acoustic performance with single-layer steel inclusions.
• A two-layer optimized structure achieved broadband sound absorption from 1780 Hz to 8890 Hz (over two octaves) with subwavelength thickness.
• Analysis of the influence of different scatterer materials on sound absorption.

Conclusions:

• The developed analytical model provides an efficient method for designing and analyzing acoustic coatings.
• Optimized multi-layer structures with periodic solid inclusions offer significant broadband sound absorption capabilities.
• This research offers theoretical guidance for the practical design of advanced acoustic stealth solutions for underwater equipment.