可调频Helmholtz共振器声学性能

Acoustic Performance of Tunable Helmholtz Resonator

传统的Helmholtz共振器属于被动消声结构,只要结构确定,其消声频率就被确定,然而,实际噪声环境中,频率经常发生改变。针对这种情况,设计出一种可调频Helmholtz共振器。利用压电陶瓷替代Helmholtz共振器的刚性背板,通过调节施加在压电陶瓷上的电压,改变其腔体体积,使得消声频率偏移。结果表明,压电陶瓷在施加400V电压后,可以产生0.515mm的位移;Helmholtz共振器在不同电压下,共振频率偏移了80Hz;设计的自适应控制程序可适应频率多变的噪声环境。

Traditional Helmholtz resonators belonged to passive silencer structures,and its acoustic performances were determined as long as its structures were determined.However,frequency often changed in actual noise environment.In response to this situation,a tunable frequency Helmholtz resonator was proposed.Piezoelectric ceramics which was instead of rigid backplane of the Helmholtz resonator changed the volume of chamber by adjusting the voltage applied to the piezoelectric ceramics,thereby distorted the silencer frequency.Experiments show that the piezoelectric ceramic in the applications of 400 V voltage may produce 0.515 mm displacement.Resonant frequency of the Helmholtz resonator is shifted by 80 Hz at different voltages,and a control program is designed to meet the frequency changing noise environments.