Broadband lightweight metal-mesh-integrated acoustic metaliner

Abstract

Engine nacelle acoustic liners are key components in modern aircraft engine noise control. The high-bypass-ratio turbofan engines possessing outstanding performance impose stringent constraints on the noise reduction design, thereby presenting multifaceted challenges for acoustic liners in terms of sound absorption performance, installation space, and mechanical properties. Consequently, the development of novel acoustic liners with lightweight, broadband sound absorption characteristics and excellent mechanical performance has become a critical research priority. In this study, we present a novel double-layer honeycomb metaliner featuring embedded apertures and surface metal mesh to address these challenges. The embedded aperture configurations with varying lengths enable flexible acoustic impedance manipulation. The comprehensive effects of resistive modulation by the metal mesh and coupling among the sound absorption units suppress the impedance oscillation and further enhance the low-frequency broadband sound absorption efficiency. The experimental and simulation results demonstrate that the proposed liner, with a thickness of 39 mm, achieves an average sound absorption coefficient of 0.912 within the frequency range of 1000 to 5000 Hz. Furthermore, mechanical tests reveal that the honeycomb structure exhibits a superior load-bearing capacity and weight efficiency compared to traditional square structures. This study offers a promising solution for the next generation of aircraft engine noise control, with potential applications in aerospace and other industries that require efficient sound attenuation in complex environments.