低频声有源吸收理论研究

THEORETICAL STUDY ON ACTIVE ABSORPTION OF LOW-FREQUENCY SOUND

为了吸收低频入射声 ,作者提出了一种有源吸声结构 ,本文从理论上研究了该结构的吸声性能。文章首先建立理论模型 ,然后通过近场方法和求解弹性板 -声腔耦合系统结构响应推导了有源控制前后反射声功率的计算公式 ,然后按声反射功率最小化准则求得最佳有源吸声效果。最后通过一系列算例证明了该吸声结构吸收低频声波的有效性 。

In the paper,active absorption of low frequency incident sound is theoretically investigated.The theoretical model of the proposed active surface is firstly established,and then by solving response of the cavity_structure coupled system,an analytical expression for calculation of reflected acoustic power is derived based on the nearfield approach,and the optimum sound reduction in the reflected sound power before and after control are obtained using the active minimization strategy. It is shown from a series of numerical examples that the proposed active surface is suitable for absorption of low frequency incident sound in threedimensional space. Finally the dependence of sound absorption on the location of the secondary force source is investigated theoretically.