| description abstract | Abstract. Acoustic metamaterials, specifically engineered for high-temperature applications, play a pivotal role in mitigating noise under extreme conditions, particularly for low-frequency noise control. Traditional porous materials often face challenges such as material degradation and diminished absorption efficiency at elevated temperatures. Additionally, the inherent irregularity of their microporous structures complicates the precise control and optimization of their sound absorption performance. In this study, we employed additive manufacturing techniques to fabricate geometrically precise microlattice materials with tunable sound absorption capabilities. By integrating these microlattice structures with a backed air cavity, we enhanced low-frequency sound absorption through multiple energy dissipation mechanisms, including thermal-viscous dissipation and resonance mechanisms. The temperature-dependent sound absorption characteristics of this composite absorber were systematically investigated through theory, simulation, and experiment. The underlying sound absorption mechanisms and temperature effects were elucidated based on simulated acoustic contours. Furthermore, the influence of geometric parameters on sound absorption performance was explored, leading to the identification of an optimal configuration. This composite absorber not only exhibits low-frequency and broadband sound absorption but also offers better tunability for targeted applications compared to traditional porous materials. This work is expected to contribute to the development of acoustic metamaterials for noise control and reduction in high-temperature applications. | |
