双层结构薄板箱体减振降噪技术

Vibration and Noise Reduction for Double-Layer Thin-Wall Box

通过阻尼比的理论计算和实验测试,对黏性流体减振降噪机理进行了研究.针对等效薄板箱体,设计了不同油量单层结构、不同间距无孔隔板双层结构和不同穿孔隔板双层结构下的模态实验,得到了相应的阻尼特性.并通过基于平均阻尼比的阻尼综合特性计算,对比分析了不同工况的整体变化趋势.研究结果表明,箱体流体量的增加、无孔隔板和穿孔隔板的引入在不同程度上提高了系统的阻尼比,降低了系统的声辐射功率;相比无孔隔板双层结构,穿孔隔板的系统阻尼并没有明显提高,但有较好的高频阻尼特性.

Utilizing theoretical calculation and measurement of damping ratio, the mechanism in reducing vibration of viscous liquid is investigated. Aiming at the equivalent thin-wall box, the modal experiments, of which include single-layer box with various oil volume, double-layer box with various diaphragm plate distance and with various hole-number, are designed. The corresponding damping ratios are gained. Through the combined characteristic calculation based on the mean damping ratio, the whole change trends of various working conditions are studied. The results indicate that the increase of box liquid volume and the introduction of diaphragm plates can enhance the damping ratio of the system and reduce the power of acoustic radiation of the system. Especially, compared with diaphragm plates without holes, diaphragm plates with holes do not further increase the damping ratio of system, but have better damping characteristics in the high frequency band.