附加自由阻尼板阻尼材料降噪拓扑优化

Topology optimization for noise reduction of structures with free damping

对附加自由阻尼的板件结构,考虑粘贴阻尼材料前后,中性面位置的变化,利用Matlab编程建立自由阻尼板有限元模型,并利用Rayleigh积分法推导了薄板结构的辐射声压表达式;以辐射声场内某点的声压最小为目标,阻尼材料的体积为约束条件,建立拓扑优化模型。以悬臂板结构为例,编写了拓扑优化程序,利用渐进结构优化算法,获得了阻尼材料的最优布局,并与以模态损耗因子最大为目标的拓扑优化结果进行了对比。结果表明:在主要关注目标是结构的声学性能时,直接以声压为目标的优化方法比以模态损耗因子最大为目标的优化方法更有针对性,效果更好。利用实验对仿真结果进行了实验验证。

Based on field measured data of near-ground at the heights of 10m, 20m and 30m affected by typhoon HAIKUI in Shanghai Pudong District, the variations of gust factor, turbulence intensity, the peak factor and turbulence integral scale were collected and analyzed. The results showed that all gust factors decreased with the increase of height and wind speed; all turbulence intensities at different heights decreased with wind speed; the peak factor increased substantially with the mean wind speed but the change wasn’t obvious and its discreteness was larger, and the observed height had smaller effect on the change of peak factor with time intervals; all turbulence integral scales had increasing trend and its discreteness also slightly increased with the mean wind speed, and longitudinal and lateral turbulence integral scales at different heights increased with time interval.