双层板腔结构声传输及其有源控制研究

利用子系统模态综合方法,结合阻抗-导纳矩阵法,建立了双层板腔结构向自由空间声传输及其在入射板PZT控制、辐射板PZT控制,和腔中次级声源作动等多种控制策略下,系统物理模型的统一的分析模型,导出了系统模态响应及最优次级源强度的统一的阻抗-导纳矩阵表达式。该模型表达式各部分物理意义清晰、明确,便于进行系统耦合理论、有源控制及其机理的分析和数值研究。然后,在此基础上对双层板腔结构声传输有源控制进行了全面深入的数值计算和分析研究,重点探讨了控制方法策略及系统参数对有源控制效果的影响及其对应的控制机理。结果表明:入射板PZT作动辐射声功率最小控制策略是通过入射板、声腔和辐射板三个子系统的模态抑制或重组达到消声的目的,涉及多种复杂控制机理,对入射板、辐射板和声腔模态均有效,但对入射板模态更有效;在低频段声腔(0,0,0)模态在系统耦合响应中起主导作用,因此利用腔中次级声源作动能获得较理想的控制效果,是一种较好的控制策略;由于声腔模态与结构模态间复杂的耦合关系,使得某些频率处腔中声势能一定程度上的降低并不一定导致系统声传输损失的增加,因此,腔中声势能最小控制策略不一定能够获得理想的声传输控制效果。 

An analytical investigation of active control of sound transmission through double panel-cavity system

Combing the subsystem modal coupling theory and the impedance-mobility approach,a general analytical models is developed for the analysis and active control of structural acoustic transmission through the double panel-cavity structure into the free field,in which control methods including incident panel piezoelectric (PZT) actuator,acoustic actuator in cavity,radiating panel PZT actuator are considered.The matrix formulae for calculating the modal response of the coupled structural acoustic system and optimal secondary source strengths are obtained.On the basis,active control of sound transmission through the double panel-cavity system is studied analytically and numerically in detail.Simulations and analyses are conducted to compare the control effects between different control strategies and examine the dominant control mechanisms involved in each control case,and the effect of system parameters on control effect is also examined.The results demonstrate that the incident panel actuator can obtain sound attenuation by modal suppression or rearrangement of three subsystems so complex control mechanisms are involved and it is effective for incident panel modes,cavity modes and radiating panel modes.Using the secondary acoustic source in the cavity is a better control strategy compared to the other control strategies due to the dominance of the acoustic mode (0,0,0) in the modal couplings and energy transmission in the low frequency range.