矩形薄板全频段隔声特性分析

Characteristics Analysis of Rectangular Sheet’s Transmission Loss in Full Frequency Band Based on FEM

建筑声学中质量作用定律等理论不满足于轻质薄板隔声量的计算,解析法只能粗略描绘隔声特性曲线,不能满足于实际工程需要。利用有限元软件ACTRAN建立薄板隔声量计算模型,得到不同材料属性、几何参数及边界条件下矩形薄板在全频段的隔声量,分析薄板的材料属性、几何参数及边界条件对隔声量的影响规律。研究结果表明:(1)与解析法结果对比,有限元法计算的隔声量曲线很好的符合解析法所体现的规律性并弥补了解析法的一些不足;(2)对于薄板,阻尼控制区与质量控制区没有明显界限,其模态共振的影响延伸到整个质量控制区;(3)薄板振动模态与隔声量曲线中"低谷"一一对应;(4)在薄板的高阶模态区,其最大振动位移在板面上朝某一方向移动,有波的趋势。

Since the theory of mass action law in architectural acoustics can not meet the need of transmission loss （TL） calculation for light sheets, the analytical method can only roughly describe the characteristic of the TL and can not satisfy the requirement of actual engineering projects. In this paper, a model for computation of a sheet＇ s transmission loss was developed by means of the finite element software ACTRAN. The TL curves of a rectangular sheet in full frequency band were plotted for different material parameters, different geometrical parameters, and different boundary conditions. It was found that the TL curves obtained by FEM can match with the common laws obtained by analytical method well, and make up for some defects of the analytical method. The TL curves of a simply supported sheet show that there is no obvious interface between the damping control zone and the mass control zone, and the influence of the modal resonance on TL can be extended to the whole quality control zone. The valleys of the curves of the vibration modes and the TL correspond to each other. In the area of high order vibration modes, the positions of maximum displacement moves in a same direction of the sheet and the tendency of vibration wave can be found.