加筋圆柱壳声辐射特性研究及声学优化设计

Research of Sound Radiation Characteristics of a Stiffened Cylindrical Shell and Its Acoustic Optimal Design

为研究全频段加筋圆柱壳声辐射特性,基于VA-ONE建立FE-BEM混合法、FE-SEA混合法及SEA法低中高全频段的计算模型,并进行加筋圆柱壳辐射声功率的计算,从结构固有模态角度研究了各阶模态的声辐射效率。结果表明,加筋能够减小圆柱壳结构的总体辐射声功率,尤其可以减小低频段的辐射声功率;在中低频区,各阶模态的模态辐射效率具有较大差异,在中高频区,则相差不大。进一步研究了激励位置、壳厚、材质及辐射介质对加筋圆柱壳声辐射特性的影响。为减小加筋圆柱壳对外场点的辐射声功率,基于NCT模块及Design Optimization模块进行声学优化设计,结果表明,将GA算法与SQP算法或MMA算法组合使用不仅可以减少运算时间,而且可以获得较好的优化方案。

In order to study the full-band acoustic radiation characteristics of stiffened cylindrical shells,the low frequency computation model based on FE-BEM method,the mid frequency computation model based on FE-SEA method and the high frequency computation model based on SEA method are established in VA-ONE.The sound radiation power of the stiffened cylindrical shell is computed and analyzed with these models.From the point of view of the inherent modals of the structure,the acoustic radiation efficiency of each modal is studied.The results show that the reinforcement can reduce the total sound radiated power of the cylindrical shell structure especially in the low frequency band.In the medium and low frequency region,the modal radiation efficiencies of different vibration modes are quite different.In the medium and high frequency region,their difference is not obvious.Furthermore,the influence of the excitation position,shell thickness,material property and radiation medium on the acoustic radiation characteristics of the stiffened cylindrical shell is studied.In order to reduce the sound radiation power of the stiffened cylindrical shell to the external field,the acoustic optimal design is carried out based on the NCT module and Design Optimization module.The results show that the combination of GA algorithm with SQP algorithm or MMAalgorithm can reduce the computation time and yield a better optimization scheme.