Traditional acoustic liners used in nacelles and fan ducts include a perforated face sheet bonded to a honeycomb core. A tunable acoustic liner with a piezoelectric substrate is developed to overcome the shortages of current liner such as unchangeable structure and uncontrollable bandwidth. After the piezoelectric panel deformed under the driving voltage, the resonant chamber changed, and the resonant frequency shifts. The finite element method is used to calculate the acoustic system’s resonant frequency and sound pressure distribution. The transmission loss measurement was carried out in an impedance tube to demonstrate the broadband noise control effect of the liner. The experiment result indicates that the TL peak frequency keeps linear with the driving voltage, and the sensitivity is measured to be 0.1 Hz/V. A DC amplified circuit using photo resistor is designed based on constructing the function of driving voltage and noise frequency. Benefit from the adaptive algorithm, when the noise frequency offsets from 756 to 788 Hz, the driving voltage can be automatically regulated from 110 to 420 V, and the liner always keeps resonating. Meanwhile, the sound level was reduced. The adaptive noise control is realized for broadband noise reduction.

机舱和风扇管道中使用的传统隔音衬垫包括粘合到蜂窝芯上的穿孔面板。开发具有压电衬底的可调谐声学衬里，以克服当前衬里的不足，例如结构不变和带宽无法控制。压电板在驱动电压作用下变形后，谐振腔发生变化，谐振频率发生偏移。有限元法用于计算声学系统的共振频率和声压分布。在阻抗管中进行传输损耗测量，以证明衬管的宽带噪声控制效果。实验结果表明，TL峰值频率与驱动电压保持线性关系，测得的灵敏度为0.1 Hz / V。在构造驱动电压和噪声频率功能的基础上，设计了一种采用光敏电阻的直流放大电路。得益于自适应算法，当噪声频率从756 Hz偏移到788 Hz时，驱动电压可以自动从110 V调整到420 V，并且衬管始终保持谐振。同时，声音水平降低了。实现自适应噪声控制以降低宽带噪声。