Extremely effective broadband low-frequency sound absorption with inhomogeneous micro-perforated panel (iMPP) backed with spider-web designed cavities

Abstract

Low-frequency wideband noise reduction has posed a significant problem to the scientific and technical communities in recent years. A single layer of a parallel-arranged inhomogeneous micro-perforated panel (iMPP) coupled with spider-web designed cavities is offered as a composite acoustic structure in this paper. Three different spider-web shapes have been designed and studied, i.e. circular, octagonal, and square. By controlling the different inhomogeneous patterns, perforation ratio, the thickness of iMPP, and back cavity depths, a broader multipeak low-frequency sound-absorbing performance equivalent to different resonant frequencies can be achieved. To anticipate the sound absorption coefficient of the new design, both theoretical analysis and finite-element method (FEM) simulation are executed. The predicted and FEM simulation sound absorption results of the new composite structure are verified in the experimental investigation using a square-designed sound impedance tube. By a subwavelength thickness of just 100 mm, a highly effective low-frequency broadband sound-absorbing composite structure is successfully attained by integrating many inhomogeneous MPP unit cells supported with spider-web-designed cavities. The average sound absorption coefficient is over 90% ( α = 0.94) within the bandgap of 230 Hz to 470 Hz. Compared to traditional sound-absorbing materials, the composite structure comprises inhomogeneous MPP coupled with spider-web-designed cavities, which may provide good absorption performance while maintaining a modest and robust construction for active low-frequency noise suppression.

3D Printed Nature Pattern Metastructure for The Sound Absorption Coefficient

“…Miniaci et al [7] discovered that metastructures inspired by spiderweb patterns effectively establish band gaps for low frequencies. Furthermore, Rafique et al [8] explored the potential of spiderweb-like structures as rear cavities for micro-perforated non-homogeneous panels, assessing their sound-absorbing efficiency. The increasingly prevalent adoption of 3D printing across industries has presented significant avenues for producing and advancing sound-absorbing materials, particularly acoustic metastructures.…”

Sound absorption performance of natural areca plant husk fibers: Experimental and theoretical study

“…They found that random fiber reinforcement composites showed the maximum SAC due to the untreated fiber reinforcement in the composites. Rafique et al 24 discussed the SA properties of microperforated samples with spider web-shaped cavities using the impedance tube technique. Gokulkumar et al 25 analyzed the SA properties of tea and pineapple leaf fibers composites.…”