基于有限点振速信息的复合层合板声功率优化

Acoustic Power Optimization of Laminate Composited Plate Based on Limited Vibration Velocity Distributions

在低频时,控制第一阶声辐射模态幅值可有效控制辐射总声功率。为了降低层合板结构辐射声功率,提出了一种基于声辐射模态的有限点速度信息获得层合板结构声辐射模态幅值。通过在层合板表面上测量少数点振动速度信息,求解声辐射模态展开构成的欠定方程组,得到前几阶声辐射模态幅值近似值。以第一阶声辐射模态幅值与近似值之差绝对值作为目标函数,利用遗传算法,得到最优有限个测量点位置。以8层层合板为例,通过4个最优速度信息计算得到第一阶声辐射模态幅值与理论值基本一致,同时对优化前后声功率衰减量进行对比,结果表明,通过利用有限点振速信息可有效控制层合板结构辐射总声功率。

Controlling the first order acoustic radiation modes of a plate has been previously shown to reduce efficiently its total sound radiation at low frequency. In order to control acoustic radiation power of the laminate composited plate, in this paper, a limited vibration velocity distributions measurement strategy based on acoustic radiation modes to measure the first order acoustic radiation modes was proposed. By measuring the vibrating velocity distributions at a few points of vibrating plate surface and solving the underdetermined equations of the radiation mode expansion, the approximate values of amplitudes of the first four order radiation modes can be obtained. Taking the difference between the first order acoustic radiation mode amplitude and the corresponding approximation as the objective function, the optimal the velocity measurement locations were obtained using genetic algorithm. With a shown example of the eight-layer laminate composited plate, the first order acoustic radiation mode amplitude and the corresponding approximation were almost same through the four optimal velocity measurement locations. And the acoustic radiation power before and after optimization were discussed. The analysis and comparison of the numerical data show that it is feasible to reduce efficiently its total sound radiation at low frequency using limited vibration velocity distributions.