可调动力吸振器降噪设计方法研究

Reduction of sound radiation from plate using vibration absorbers

可调动力吸振器的出现拓展了动力吸振器的应用范围,然而将其应用于降噪声学设计,目前研究得并不充分,这主要是由于声学实验和声学数值仿真的代价与难度所致。本文采用声学边界元法与结构动力优化方法,研究了四边简支板在不同设计准则下采用可调动力吸振器进行降噪声学设计的效果,为可调谐动力吸振器的降噪应用提供指导。数值计算结果表明,将调谐、解调作为声学设计策略各有优缺点。调谐策略的优点是能将动力吸振器作用区域附近的振动降为最低,但并不能保证噪声指标减少最多。解调策略的优点是能将全局声学指标降到最低,但在实际应用中噪声信号的采集和反馈控制代价过高。本文建议采用振动水平极小化策略来代替解调和调谐策略进行声学优化设计。数值计算结果与文献实验结果的对比验证了本文策略的有效性。同时本文研究了动力吸振器参数对主振系统整体和局部模态的影响。

Vibration absorbers have been widely used to minimize the vibration of structures, while studies on the reduction of noise are not fully operated because of the costs and difficulties in acoustic numerical simulation and experiment. The presented paper verified the effectiveness of noise reduction using the adaptive tuned vibration absorbers （ATVA） for simply supported plate by means of acoustic boundary element method and structural dynamic optimal method. Numerical results show that using the tune method for acoustic design can deeply reduce the locally vibration, but it can not guarantee the most global reduction of noise;while using detune method can minimize the global sound pressure level with the expense of signal collection and feedback control. Finally a new acoustic design method concerning the global least square vibration is proposed, and numerical results show the validity of the method. In addition, the paper shows the effects on the global and local modes of vibrating system because of changes with vibration absorber＇s parameters.