Manually Tunable Ventilated Metamaterial Absorbers

TL;DR

This paper introduces a manually tunable ventilated acoustic metamaterial absorber that allows post-fabrication adjustment of operating frequencies while maintaining high absorption and ventilation, addressing a key limitation in current metamaterials.

Contribution

It presents a novel ventilated sound absorber with manual tuning capability using an intricate slider, enabling adjustable frequency response post-fabrication.

Findings

Experimental demonstration of tunable absorption performance

Effective model based on coupled lossy oscillators explains the mechanism

Potential applications in complex pipe systems requiring frequency adjustment

Abstract

For most acoustic metamaterials, once they have been fabricated, their operating frequencies and functions cannot be adjusted, which is an intrinsic barrier for development of realistic applications. The study to overcome this limit has become a significant issue in acoustic metamaterial engineering. Although with the advance of metamaterials in the past two decades, a series of methods such as electric or magnetic control have been proposed, most of them can only work in the condition of no fluid passage. Some metamaterials with large transmission losses have been proposed, but the sounds are essentially reflected rather than absorbed. Here, to overcome this intrinsic difficulty, we propose a ventilated sound absorber that can be manually tuned in a large range after being manufactured. During the tuning which is achieved through an intricately designed slider, high-performance absorption and ventilation are both ensured. The tunable ventilated sound absorber is demonstrated experimentally and the effective model of coupled lossy oscillators can be employed to understand its mechanism. The manually tunable ventilated metamaterial has the potential application values in various complicated pipe systems that require frequency adjustment and it also establishes the foundation for future development of active tunable ventilated acoustic metamaterials.