Wang Han, Ma Pengwei, Fan Xueling
Xi'an Key Laboratory of Extreme Environment and Protection Technology, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Materials (Basel). 2024 Dec 6;17(23):5992. doi: 10.3390/ma17235992.
Tunable perfect acoustic absorption at subwavelength thickness has been a prominent topic in scientific research and engineering applications. Although metamaterials such as labyrinthine metasurfaces and coiling-up-space metamaterials can achieve subwavelength low-frequency acoustic absorption, efficiently realizing tunable absorption under uniform and limited size conditions remains challenging. In this paper, we introduce a folded slit to enhance the micro-slit acoustic absorber, effectively improving its low-frequency acoustic absorption performance and successfully achieving a perfect acoustic absorption coefficient of 0.99 at a thickness of only 3.1 cm. By adjusting just two parameters of the folded area, we can efficiently achieve a tunable resonant frequency ranging from 525 to 673 Hz and a tunable acoustic absorption bandwidth of 56.5% to 60.2%, simultaneously maintaining uniform external dimensions. Additionally, the folded-slit absorber demonstrates a broader acoustic absorption bandwidth at lower frequencies, enhancing broadband absorption capabilities in the low-frequency domain. These results hold significant potential for the design of highly efficient, thin and tunable acoustic absorbers.
亚波长厚度下的可调谐完美吸声一直是科学研究和工程应用中的一个突出课题。尽管诸如迷宫式超表面和卷曲空间超材料等超材料可以实现亚波长低频吸声，但在均匀且尺寸有限的条件下有效实现可调谐吸收仍然具有挑战性。在本文中，我们引入了一种折叠狭缝来增强微狭缝吸声器，有效提高其低频吸声性能，并在仅3.1厘米的厚度下成功实现了0.99的完美吸声系数。通过仅调整折叠区域的两个参数，我们可以有效地实现525至673赫兹的可调谐共振频率和56.5%至60.2%的可调谐吸声带宽，同时保持外部尺寸均匀。此外，折叠狭缝吸声器在较低频率下表现出更宽的吸声带宽，增强了低频域的宽带吸收能力。这些结果对于高效、薄型和可调谐吸声器的设计具有重要潜力。
