基于声辐射模态的有源结构声传入及其辐射控制

从辐射模态的概念和角度研究利用结构误差传感方法对弹性封闭空间结构声辐射进行传感和有源控制。首先分析了辐射模态的数学和物理意义并揭示了辐射模态与声腔模态之间的内在耦合关系。通过声辐射模态建立了弹性封闭空间结构声辐射传感和有源控制模型,并提出了通过传感器阵列测量结构表面有限点的振速分布和设计特定的辐射模态空间滤波器来获得控制所需的误差信号。在此基础上对封闭空间结构声辐射有源控制和误差传感策略进行了深入的理论和数值仿真分析,重点讨论了传感器的数量和布放对辐射模态传感及其有源控制效果的影响。结果表明:辐射模态与声腔模态的耦合具有严格的选择性,各阶辐射模态的形状和与相耦合的主导声模态在耦合面上的形状非常相似;利用结构传感技术传感封闭空间的辐射模态时测点不足或空间采样不足将可能产生较严重的模态泄漏问题,使得不希望的结构模态泄露进所测的辐射模态当中来。在低频范围内,一般只需传感并最小化前三阶有效辐射模态声势能,在更低频和空间声模态频率附近,只需最小化前一阶最有效辐射模态声势能,便能和总声势能最小化策略控制效果基本一样。

Active control of sound transmission and radiation into an enclosure based on acoustic radiation modes

The problem of sensing and active control of sound radiation into an enclosure was studied from the point of view of the acoustic radiation mode using the structural error sensing.First,the physical characteristics of the radiation modes and the inherent relationships between the acoustic modes and the radiation modes were analyzed in detail.A model for the active control of sound radiation from the vibrating structure into an enclosure was presented based on the radiation modes sensing,and a method for obtaining the error signal using the sensor array and designed radiation modes filter was proposed.The numerical simulations and analyses with the proposed strategy were conducted.The influence of the number and location on the error sensing and active control was discussed.The simulation results demonstrate that the coupling between radiation modes and cavity modes is strictly selective;the radiation mode shape is very similar with the projection on the coupling surface of coupled main cavity mode.In general the potential energy of the first three radiation modes needs to be sensed and minimized at the low frequency range to attain the similar control effect to the potential energy minimization(PEM),however at the lower frequencies or near the natural frequencies of the cavity, only the first most efficient radiation mode needs to be minimized to attain the similar effect to the PEM.